init

.idea/.name

@@ -0,0 +1 @@
+UsbKeyboard

.idea/UsbKeyboard.iml

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.idea/misc.xml

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.idea/modules.xml

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.idea/vcs.xml

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ArduinoNotes.txt

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+Notes On Integrating AVRUSB with Arduino
+========================================
+
+* Note the license(s) under which AVRUSB is distributed.
+
+* See also: http://code.rancidbacon.com/ProjectLogArduinoUSB
+
+* Note: The pins we use on the PCB (not protoboard) hardware shield are:
+
+     INT0 == PD2 == IC Pin 4 == Arduino Digital Pin 2 == D+
+
+     ---- == PD4 == -------- == Arduino Digital Pin 4 == D-
+
+     ---- == PD5 == -------- == Arduino Digital Pin 5 == pull-up
+
+  (DONE: Change to not use PD3 so INT1 is left free?)
+
+* In order to compile a valid 'usbconfig.h' file must exit. The content of this
+  file will vary depending on whether the device is a generic USB device,
+  generic HID device or specific class of HID device for example.
+
+  The file 'usbconfig-prototype.h' can be used as a starting point, however
+  it might be easier to use the 'usbconfig.h' from one of the example projects.
+
+  TODO: Specify the settings that need to be changed to match the shield
+        design we use.
+
+* (NOTE: Initial 'usbconfig.h' used will be based on the file from
+ 'HIDKeys.2007-03-29'.) (Note: Have now upgraded to V-USB 2009-08-22.)
+
+* Versions of the Arduino IDE prior to 0018 won't compile our library
+  so it needs to be pre-compiled with:
+
+    avr-g++  -Wall -Os -I. -DF_CPU=16000000 -mmcu=atmega168  -c usbdrvasm.S  -c usbdrv.c

Changelog.txt

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+This file documents changes in the firmware-only USB driver for atmel's AVR
+microcontrollers. New entries are always appended to the end of the file.
+Scroll down to the bottom to see the most recent changes.
+
+2005-04-01:
+  - Implemented endpoint 1 as interrupt-in endpoint.
+  - Moved all configuration options to usbconfig.h which is not part of the
+    driver.
+  - Changed interface for usbVendorSetup().
+  - Fixed compatibility with ATMega8 device.
+  - Various minor optimizations.
+
+2005-04-11:
+  - Changed interface to application: Use usbFunctionSetup(), usbFunctionRead()
+    and usbFunctionWrite() now. Added configuration options to choose which
+    of these functions to compile in.
+  - Assembler module delivers receive data non-inverted now.
+  - Made register and bit names compatible with more AVR devices.
+
+2005-05-03:
+  - Allow address of usbRxBuf on any memory page as long as the buffer does
+    not cross 256 byte page boundaries.
+  - Better device compatibility: works with Mega88 now.
+  - Code optimization in debugging module.
+  - Documentation updates.
+
+2006-01-02:
+  - Added (free) default Vendor- and Product-IDs bought from voti.nl.
+  - Added USBID-License.txt file which defines the rules for using the free
+    shared VID/PID pair.
+  - Added Readme.txt to the usbdrv directory which clarifies administrative
+    issues.
+
+2006-01-25:
+  - Added "configured state" to become more standards compliant.
+  - Added "HALT" state for interrupt endpoint.
+  - Driver passes the "USB Command Verifier" test from usb.org now.
+  - Made "serial number" a configuration option.
+  - Minor optimizations, we now recommend compiler option "-Os" for best
+    results.
+  - Added a version number to usbdrv.h
+
+2006-02-03:
+  - New configuration variable USB_BUFFER_SECTION for the memory section where
+    the USB rx buffer will go. This defaults to ".bss" if not defined. Since
+    this buffer MUST NOT cross 256 byte pages (not even touch a page at the
+    end), the user may want to pass a linker option similar to
+    "-Wl,--section-start=.mybuffer=0x800060".
+  - Provide structure for usbRequest_t.
+  - New defines for USB constants.
+  - Prepared for HID implementations.
+  - Increased data size limit for interrupt transfers to 8 bytes.
+  - New macro usbInterruptIsReady() to query interrupt buffer state.
+
+2006-02-18:
+  - Ensure that the data token which is sent as an ack to an OUT transfer is
+    always zero sized. This fixes a bug where the host reports an error after
+    sending an out transfer to the device, although all data arrived at the
+    device.
+  - Updated docs in usbdrv.h to reflect changed API in usbFunctionWrite().
+
+* Release 2006-02-20
+
+  - Give a compiler warning when compiling with debugging turned on.
+  - Added Oleg Semyonov's changes for IAR-cc compatibility.
+  - Added new (optional) functions usbDeviceConnect() and usbDeviceDisconnect()
+    (also thanks to Oleg!).
+  - Rearranged tests in usbPoll() to save a couple of instructions in the most
+    likely case that no actions are pending.
+  - We need a delay between the SET ADDRESS request until the new address
+    becomes active. This delay was handled in usbPoll() until now. Since the
+    spec says that the delay must not exceed 2ms, previous versions required
+    aggressive polling during the enumeration phase. We have now moved the
+    handling of the delay into the interrupt routine.
+  - We must not reply with NAK to a SETUP transaction. We can only achieve this
+    by making sure that the rx buffer is empty when SETUP tokens are expected.
+    We therefore don't pass zero sized data packets from the status phase of
+    a transfer to usbPoll(). This change MAY cause troubles if you rely on
+    receiving a less than 8 bytes long packet in usbFunctionWrite() to
+    identify the end of a transfer. usbFunctionWrite() will NEVER be called
+    with a zero length.
+
+* Release 2006-03-14
+
+  - Improved IAR C support: tiny memory model, more devices
+  - Added template usbconfig.h file under the name usbconfig-prototype.h
+
+* Release 2006-03-26
+
+  - Added provision for one more interrupt-in endpoint (endpoint 3).
+  - Added provision for one interrupt-out endpoint (endpoint 1).
+  - Added flowcontrol macros for USB.
+  - Added provision for custom configuration descriptor.
+  - Allow ANY two port bits for D+ and D-.
+  - Merged (optional) receive endpoint number into global usbRxToken variable.
+  - Use USB_CFG_IOPORTNAME instead of USB_CFG_IOPORT. We now construct the
+    variable name from the single port letter instead of computing the address
+    of related ports from the output-port address.
+
+* Release 2006-06-26
+
+  - Updated documentation in usbdrv.h and usbconfig-prototype.h to reflect the
+    new features.
+  - Removed "#warning" directives because IAR does not understand them. Use
+    unused static variables instead to generate a warning.
+  - Do not include <avr/io.h> when compiling with IAR.
+  - Introduced USB_CFG_DESCR_PROPS_* in usbconfig.h to configure how each
+    USB descriptor should be handled. It is now possible to provide descriptor
+    data in Flash, RAM or dynamically at runtime.
+  - STALL is now a status in usbTxLen* instead of a message. We can now conform
+    to the spec and leave the stall status pending until it is cleared.
+  - Made usbTxPacketCnt1 and usbTxPacketCnt3 public. This allows the
+    application code to reset data toggling on interrupt pipes.
+
+* Release 2006-07-18
+
+  - Added an #if !defined __ASSEMBLER__ to the warning in usbdrv.h. This fixes
+    an assembler error.
+  - usbDeviceDisconnect() takes pull-up resistor to high impedance now.
+
+* Release 2007-02-01
+
+  - Merged in some code size improvements from usbtiny (thanks to Dick
+    Streefland for these optimizations!)
+  - Special alignment requirement for usbRxBuf not required any more. Thanks
+    again to Dick Streefland for this hint!
+  - Reverted to "#warning" instead of unused static variables -- new versions
+    of IAR CC should handle this directive.
+  - Changed Open Source license to GNU GPL v2 in order to make linking against
+    other free libraries easier. We no longer require publication of the
+    circuit diagrams, but we STRONGLY encourage it. If you improve the driver
+    itself, PLEASE grant us a royalty free license to your changes for our
+    commercial license.
+
+* Release 2007-03-29
+
+  - New configuration option "USB_PUBLIC" in usbconfig.h.
+  - Set USB version number to 1.10 instead of 1.01.
+  - Code used USB_CFG_DESCR_PROPS_STRING_DEVICE and
+    USB_CFG_DESCR_PROPS_STRING_PRODUCT inconsistently. Changed all occurrences
+    to USB_CFG_DESCR_PROPS_STRING_PRODUCT.
+  - New assembler module for 16.5 MHz RC oscillator clock with PLL in receiver
+    code.
+  - New assembler module for 16 MHz crystal.
+  - usbdrvasm.S contains common code only, clock-specific parts have been moved
+    to usbdrvasm12.S, usbdrvasm16.S and usbdrvasm165.S respectively.
+
+* Release 2007-06-25
+
+  - 16 MHz module: Do SE0 check in stuffed bits as well.
+
+* Release 2007-07-07
+
+  - Define hi8(x) for IAR compiler to limit result to 8 bits. This is necessary
+    for negative values.
+  - Added 15 MHz module contributed by V. Bosch.
+  - Interrupt vector name can now be configured. This is useful if somebody
+    wants to use a different hardware interrupt than INT0.
+
+* Release 2007-08-07
+
+  - Moved handleIn3 routine in usbdrvasm16.S so that relative jump range is
+    not exceeded.
+  - More config options: USB_RX_USER_HOOK(), USB_INITIAL_DATATOKEN,
+    USB_COUNT_SOF
+  - USB_INTR_PENDING can now be a memory address, not just I/O
+
+* Release 2007-09-19
+
+  - Split out common parts of assembler modules into separate include file
+  - Made endpoint numbers configurable so that given interface definitions
+    can be matched. See USB_CFG_EP3_NUMBER in usbconfig-prototype.h.
+  - Store endpoint number for interrupt/bulk-out so that usbFunctionWriteOut()
+    can handle any number of endpoints.
+  - Define usbDeviceConnect() and usbDeviceDisconnect() even if no
+    USB_CFG_PULLUP_IOPORTNAME is defined. Directly set D+ and D- to 0 in this
+    case.
+
+* Release 2007-12-01
+
+  - Optimize usbDeviceConnect() and usbDeviceDisconnect() for less code size
+    when USB_CFG_PULLUP_IOPORTNAME is not defined.
+
+* Release 2007-12-13
+
+  - Renamed all include-only assembler modules from *.S to *.inc so that
+    people don't add them to their project sources.
+  - Distribute leap bits in tx loop more evenly for 16 MHz module.
+  - Use "macro" and "endm" instead of ".macro" and ".endm" for IAR
+  - Avoid compiler warnings for constant expr range by casting some values in
+    USB descriptors.
+
+* Release 2008-01-21
+
+  - Fixed bug in 15 and 16 MHz module where the new address set with
+    SET_ADDRESS was already accepted at the next NAK or ACK we send, not at
+    the next data packet we send. This caused problems when the host polled
+    too fast. Thanks to Alexander Neumann for his help and patience debugging
+    this issue!
+
+* Release 2008-02-05
+
+  - Fixed bug in 16.5 MHz module where a register was used in the interrupt
+    handler before it was pushed. This bug was introduced with version
+    2007-09-19 when common parts were moved to a separate file.
+  - Optimized CRC routine (thanks to Reimar Doeffinger).
+
+* Release 2008-02-16
+
+  - Removed outdated IAR compatibility stuff (code sections).
+  - Added hook macros for USB_RESET_HOOK() and USB_SET_ADDRESS_HOOK().
+  - Added optional routine usbMeasureFrameLength() for calibration of the
+    internal RC oscillator.
+
+* Release 2008-02-28
+
+  - USB_INITIAL_DATATOKEN defaults to USBPID_DATA1 now, which means that we
+    start with sending USBPID_DATA0.
+  - Changed defaults in usbconfig-prototype.h
+  - Added free USB VID/PID pair for MIDI class devices
+  - Restructured AVR-USB as separate package, not part of PowerSwitch any more.
+
+* Release 2008-04-18
+
+  - Restructured usbdrv.c so that it is easier to read and understand.
+  - Better code optimization with gcc 4.
+  - If a second interrupt in endpoint is enabled, also add it to config
+    descriptor.
+  - Added config option for long transfers (above 254 bytes), see
+    USB_CFG_LONG_TRANSFERS in usbconfig.h.
+  - Added 20 MHz module contributed by Jeroen Benschop.
+
+* Release 2008-05-13
+
+  - Fixed bug in libs-host/hiddata.c function usbhidGetReport(): length
+    was not incremented, pointer to length was incremented instead.
+  - Added code to command line tool(s) which claims an interface. This code
+    is disabled by default, but may be necessary on newer Linux kernels.
+  - Added usbconfig.h option "USB_CFG_CHECK_DATA_TOGGLING".
+  - New header "usbportability.h" prepares ports to other development
+    environments.
+  - Long transfers (above 254 bytes) did not work when usbFunctionRead() was
+    used to supply the data. Fixed this bug. [Thanks to Alexander Neumann!]
+  - In hiddata.c (example code for sending/receiving data over HID), use
+    USB_RECIP_DEVICE instead of USB_RECIP_INTERFACE for control transfers so
+    that we need not claim the interface.
+  - in usbPoll() loop 20 times polling for RESET state instead of 10 times.
+    This accounts for the higher clock rates we now support.
+  - Added a module for 12.8 MHz RC oscillator with PLL in receiver loop.
+  - Added hook to SOF code so that oscillator can be tuned to USB frame clock.
+  - Added timeout to waitForJ loop. Helps preventing unexpected hangs.
+  - Added example code for oscillator tuning to libs-device (thanks to
+    Henrik Haftmann for the idea to this routine).
+  - Implemented option USB_CFG_SUPPRESS_INTR_CODE.
+
+* Release 2008-10-22
+
+  - Fixed libs-device/osctune.h: OSCCAL is memory address on ATMega88 and
+    similar, not offset of 0x20 needs to be added.
+  - Allow distribution under GPLv3 for those who have to link against other
+    code distributed under GPLv3.
+
+* Release 2008-11-26
+
+  - Removed libusb-win32 dependency for hid-data example in Makefile.windows.
+    It was never required and confused many people.
+  - Added extern uchar usbRxToken to usbdrv.h.
+  - Integrated a module with CRC checks at 18 MHz by Lukas Schrittwieser.
+
+* Release 2009-03-23
+
+  - Hid-mouse example used settings from hid-data example, fixed that.
+  - Renamed project to V-USB due to a trademark issue with Atmel(r).
+  - Changed CommercialLicense.txt and USBID-License.txt to make the
+    background of USB ID registration clearer.
+
+* Release 2009-04-15
+
+  - Changed CommercialLicense.txt to reflect the new range of PIDs from
+    Jason Kotzin.
+  - Removed USBID-License.txt in favor of USB-IDs-for-free.txt and
+    USB-ID-FAQ.txt
+  - Fixed a bug in the 12.8 MHz module: End Of Packet decection was made in
+    the center between bit 0 and 1 of each byte. This is where the data lines
+    are expected to change and the sampled data may therefore be nonsense.
+    We therefore check EOP ONLY if bits 0 AND 1 have both been read as 0 on D-.
+  - Fixed a bitstuffing problem in the 16 MHz module: If bit 6 was stuffed,
+    the unstuffing code in the receiver routine was 1 cycle too long. If
+    multiple bytes had the unstuffing in bit 6, the error summed up until the
+    receiver was out of sync.
+  - Included option for faster CRC routine.
+    Thanks to Slawomir Fras (BoskiDialer) for this code!
+  - Updated bits in Configuration Descriptor's bmAttributes according to
+    USB 1.1 (in particular bit 7, it is a must-be-set bit now).
+
+* Release 2009-08-22

CommercialLicense.txt

@@ -0,0 +1,166 @@
+V-USB Driver Software License Agreement
+Version 2009-08-03
+
+THIS LICENSE AGREEMENT GRANTS YOU CERTAIN RIGHTS IN A SOFTWARE. YOU CAN
+ENTER INTO THIS AGREEMENT AND ACQUIRE THE RIGHTS OUTLINED BELOW BY PAYING
+THE AMOUNT ACCORDING TO SECTION 4 ("PAYMENT") TO OBJECTIVE DEVELOPMENT.
+
+
+1 DEFINITIONS
+
+1.1 "OBJECTIVE DEVELOPMENT" shall mean OBJECTIVE DEVELOPMENT Software GmbH,
+Grosse Schiffgasse 1A/7, 1020 Wien, AUSTRIA.
+
+1.2 "You" shall mean the Licensee.
+
+1.3 "V-USB" shall mean all files included in the package distributed under
+the name "vusb" by OBJECTIVE DEVELOPMENT (http://www.obdev.at/vusb/)
+unless otherwise noted. This includes the firmware-only USB device
+implementation for Atmel AVR microcontrollers, some simple device examples
+and host side software examples and libraries.
+
+
+2 LICENSE GRANTS
+
+2.1 Source Code. OBJECTIVE DEVELOPMENT shall furnish you with the source
+code of V-USB.
+
+2.2 Distribution and Use. OBJECTIVE DEVELOPMENT grants you the
+non-exclusive right to use, copy and distribute V-USB with your hardware
+product(s), restricted by the limitations in section 3 below.
+
+2.3 Modifications. OBJECTIVE DEVELOPMENT grants you the right to modify
+the source code and your copy of V-USB according to your needs.
+
+2.4 USB IDs. OBJECTIVE DEVELOPMENT furnishes you with one or two USB
+Product ID(s), sent to you in e-mail. These Product IDs are reserved
+exclusively for you. OBJECTIVE DEVELOPMENT has obtained USB Product ID
+ranges under the Vendor ID 5824 from Wouter van Ooijen (Van Ooijen
+Technische Informatica, www.voti.nl) and under the Vendor ID 8352 from
+Jason Kotzin (Clay Logic, www.claylogic.com). Both owners of the Vendor IDs
+have obtained these IDs from the USB Implementers Forum, Inc.
+(www.usb.org). OBJECTIVE DEVELOPMENT disclaims all liability which might
+arise from the assignment of USB IDs.
+
+2.5 USB Certification. Although not part of this agreement, we want to make
+it clear that you cannot become USB certified when you use V-USB or a USB
+Product ID assigned by OBJECTIVE DEVELOPMENT. AVR microcontrollers don't
+meet the electrical specifications required by the USB specification and
+the USB Implementers Forum certifies only members who bought a Vendor ID of
+their own.
+
+
+3 LICENSE RESTRICTIONS
+
+3.1 Number of Units. Only one of the following three definitions is
+applicable. Which one is determined by the amount you pay to OBJECTIVE
+DEVELOPMENT, see section 4 ("Payment") below.
+
+Hobby License: You may use V-USB according to section 2 above in no more
+than 5 hardware units. These units must not be sold for profit.
+
+Entry Level License: You may use V-USB according to section 2 above in no
+more than 150 hardware units.
+
+Professional License: You may use V-USB according to section 2 above in
+any number of hardware units, except for large scale production ("unlimited
+fair use"). Quantities below 10,000 units are not considered large scale
+production. If your reach quantities which are obviously large scale
+production, you must pay a license fee of 0.10 EUR per unit for all units
+above 10,000.
+
+3.2 Rental. You may not rent, lease, or lend V-USB or otherwise encumber
+any copy of V-USB, or any of the rights granted herein.
+
+3.3 Transfer. You may not transfer your rights under this Agreement to
+another party without OBJECTIVE DEVELOPMENT's prior written consent. If
+such consent is obtained, you may permanently transfer this License to
+another party. The recipient of such transfer must agree to all terms and
+conditions of this Agreement.
+
+3.4 Reservation of Rights. OBJECTIVE DEVELOPMENT retains all rights not
+expressly granted.
+
+3.5 Non-Exclusive Rights. Your license rights under this Agreement are
+non-exclusive.
+
+3.6 Third Party Rights. This Agreement cannot grant you rights controlled
+by third parties. In particular, you are not allowed to use the USB logo or
+other trademarks owned by the USB Implementers Forum, Inc. without their
+consent. Since such consent depends on USB certification, it should be
+noted that V-USB will not pass certification because it does not
+implement checksum verification and the microcontroller ports do not meet
+the electrical specifications.
+
+
+4 PAYMENT
+
+The payment amount depends on the variation of this agreement (according to
+section 3.1) into which you want to enter. Concrete prices are listed on
+OBJECTIVE DEVELOPMENT's web site, usually at
+http://www.obdev.at/vusb/license.html. You agree to pay the amount listed
+there to OBJECTIVE DEVELOPMENT or OBJECTIVE DEVELOPMENT's payment processor
+or reseller.
+
+
+5 COPYRIGHT AND OWNERSHIP
+
+V-USB is protected by copyright laws and international copyright
+treaties, as well as other intellectual property laws and treaties. V-USB
+is licensed, not sold.
+
+
+6 TERM AND TERMINATION
+
+6.1 Term. This Agreement shall continue indefinitely. However, OBJECTIVE
+DEVELOPMENT may terminate this Agreement and revoke the granted license and
+USB-IDs if you fail to comply with any of its terms and conditions.
+
+6.2 Survival of Terms. All provisions regarding secrecy, confidentiality
+and limitation of liability shall survive termination of this agreement.
+
+
+7 DISCLAIMER OF WARRANTY AND LIABILITY
+
+LIMITED WARRANTY. V-USB IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+KIND. TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, OBJECTIVE
+DEVELOPMENT AND ITS SUPPLIERS HEREBY DISCLAIM ALL WARRANTIES, EITHER
+EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND
+NON-INFRINGEMENT, WITH REGARD TO V-USB, AND THE PROVISION OF OR FAILURE
+TO PROVIDE SUPPORT SERVICES. THIS LIMITED WARRANTY GIVES YOU SPECIFIC LEGAL
+RIGHTS. YOU MAY HAVE OTHERS, WHICH VARY FROM STATE/JURISDICTION TO
+STATE/JURISDICTION.
+
+LIMITATION OF LIABILITY. TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW,
+IN NO EVENT SHALL OBJECTIVE DEVELOPMENT OR ITS SUPPLIERS BE LIABLE FOR ANY
+SPECIAL, INCIDENTAL, INDIRECT, OR CONSEQUENTIAL DAMAGES WHATSOEVER
+(INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS PROFITS,
+BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, OR ANY OTHER PECUNIARY
+LOSS) ARISING OUT OF THE USE OF OR INABILITY TO USE V-USB OR THE
+PROVISION OF OR FAILURE TO PROVIDE SUPPORT SERVICES, EVEN IF OBJECTIVE
+DEVELOPMENT HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. IN ANY
+CASE, OBJECTIVE DEVELOPMENT'S ENTIRE LIABILITY UNDER ANY PROVISION OF THIS
+AGREEMENT SHALL BE LIMITED TO THE AMOUNT ACTUALLY PAID BY YOU FOR V-USB.
+
+
+8 MISCELLANEOUS TERMS
+
+8.1 Marketing. OBJECTIVE DEVELOPMENT has the right to mention for marketing
+purposes that you entered into this agreement.
+
+8.2 Entire Agreement. This document represents the entire agreement between
+OBJECTIVE DEVELOPMENT and you. It may only be modified in writing signed by
+an authorized representative of both, OBJECTIVE DEVELOPMENT and you.
+
+8.3 Severability. In case a provision of these terms and conditions should
+be or become partly or entirely invalid, ineffective, or not executable,
+the validity of all other provisions shall not be affected.
+
+8.4 Applicable Law. This agreement is governed by the laws of the Republic
+of Austria.
+
+8.5 Responsible Courts. The responsible courts in Vienna/Austria will have
+exclusive jurisdiction regarding all disputes in connection with this
+agreement.
+

License.txt

@@ -0,0 +1,361 @@
+OBJECTIVE DEVELOPMENT GmbH's V-USB driver software is distributed under the
+terms and conditions of the GNU GPL version 2 or the GNU GPL version 3. It is
+your choice whether you apply the terms of version 2 or version 3. The full
+text of GPLv2 is included below. In addition to the requirements in the GPL,
+we STRONGLY ENCOURAGE you to do the following:
+
+(1) Publish your entire project on a web site and drop us a note with the URL.
+Use the form at http://www.obdev.at/vusb/feedback.html for your submission.
+
+(2) Adhere to minimum publication standards. Please include AT LEAST:
+    - a circuit diagram in PDF, PNG or GIF format
+    - full source code for the host software
+    - a Readme.txt file in ASCII format which describes the purpose of the
+      project and what can be found in which directories and which files
+    - a reference to http://www.obdev.at/vusb/
+
+(3) If you improve the driver firmware itself, please give us a free license
+to your modifications for our commercial license offerings.
+
+
+
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.
+                       59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Library General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+  To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have.  You must make sure that they, too, receive or can get the
+source code.  And you must show them these terms so they know their
+rights.
+
+  We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+  Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software.  If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+  Finally, any free program is threatened constantly by software
+patents.  We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary.  To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                    GNU GENERAL PUBLIC LICENSE
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+  0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License.  The "Program", below,
+refers to any such program or work, and a "work based on the Program"
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language.  (Hereinafter, translation is included without limitation in
+the term "modification".)  Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope.  The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+  1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+  2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+    a) You must cause the modified files to carry prominent notices
+    stating that you changed the files and the date of any change.
+
+    b) You must cause any work that you distribute or publish, that in
+    whole or in part contains or is derived from the Program or any
+    part thereof, to be licensed as a whole at no charge to all third
+    parties under the terms of this License.
+
+    c) If the modified program normally reads commands interactively
+    when run, you must cause it, when started running for such
+    interactive use in the most ordinary way, to print or display an
+    announcement including an appropriate copyright notice and a
+    notice that there is no warranty (or else, saying that you provide
+    a warranty) and that users may redistribute the program under
+    these conditions, and telling the user how to view a copy of this
+    License.  (Exception: if the Program itself is interactive but
+    does not normally print such an announcement, your work based on
+    the Program is not required to print an announcement.)
+
+These requirements apply to the modified work as a whole.  If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works.  But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+  3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+    a) Accompany it with the complete corresponding machine-readable
+    source code, which must be distributed under the terms of Sections
+    1 and 2 above on a medium customarily used for software interchange; or,
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+    years, to give any third party, for a charge no more than your
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+
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+    to distribute corresponding source code.  (This alternative is
+    allowed only for noncommercial distribution and only if you
+    received the program in object code or executable form with such
+    an offer, in accord with Subsection b above.)
+
+The source code for a work means the preferred form of the work for
+making modifications to it.  For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
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+anything that is normally distributed (in either source or binary
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+If distribution of executable or object code is made by offering
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+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+  4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License.  Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+  5. You are not required to accept this License, since you have not
+signed it.  However, nothing else grants you permission to modify or
+distribute the Program or its derivative works.  These actions are
+prohibited by law if you do not accept this License.  Therefore, by
+modifying or distributing the Program (or any work based on the
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+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+  6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
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+You are not responsible for enforcing compliance by third parties to
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+
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+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
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+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all.  For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
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+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
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+integrity of the free software distribution system, which is
+implemented by public license practices.  Many people have made
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+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+  8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded.  In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+  9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number.  If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation.  If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+  10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
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+of promoting the sharing and reuse of software generally.
+
+                            NO WARRANTY
+
+  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
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+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
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+
+  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
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+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+    Gnomovision version 69, Copyright (C) year name of author
+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Library General
+Public License instead of this License.

Readme.txt

@@ -0,0 +1,158 @@
+This is the Readme file to Objective Development's firmware-only USB driver
+for Atmel AVR microcontrollers. For more information please visit
+http://www.obdev.at/vusb/
+
+This directory contains the USB firmware only. Copy it as-is to your own
+project and add all .c and .S files to your project (these files are marked
+with an asterisk in the list below). Then copy usbconfig-prototype.h as
+usbconfig.h to your project and edit it according to your configuration.
+
+
+TECHNICAL DOCUMENTATION
+=======================
+The technical documentation (API) for the firmware driver is contained in the
+file "usbdrv.h". Please read all of it carefully! Configuration options are
+documented in "usbconfig-prototype.h".
+
+The driver consists of the following files:
+  Readme.txt ............. The file you are currently reading.
+  Changelog.txt .......... Release notes for all versions of the driver.
+  usbdrv.h ............... Driver interface definitions and technical docs.
+* usbdrv.c ............... High level language part of the driver. Link this
+                           module to your code!
+* usbdrvasm.S ............ Assembler part of the driver. This module is mostly
+                           a stub and includes one of the usbdrvasm*.S files
+                           depending on processor clock. Link this module to
+                           your code!
+  usbdrvasm*.inc ......... Assembler routines for particular clock frequencies.
+                           Included by usbdrvasm.S, don't link it directly!
+  asmcommon.inc .......... Common assembler routines. Included by
+                           usbdrvasm*.inc, don't link it directly!
+  usbconfig-prototype.h .. Prototype for your own usbdrv.h file.
+* oddebug.c .............. Debug functions. Only used when DEBUG_LEVEL is
+                           defined to a value greater than 0. Link this module
+                           to your code!
+  oddebug.h .............. Interface definitions of the debug module.
+  usbportability.h ....... Header with compiler-dependent stuff.
+  usbdrvasm.asm .......... Compatibility stub for IAR-C-compiler. Use this
+                           module instead of usbdrvasm.S when you assembler
+                           with IAR's tools.
+  License.txt ............ Open Source license for this driver.
+  CommercialLicense.txt .. Optional commercial license for this driver.
+  USB-ID-FAQ.txt ......... General infos about USB Product- and Vendor-IDs.
+  USB-IDs-for-free.txt ... List and terms of use for free shared PIDs.
+
+(*) ... These files should be linked to your project.
+
+
+CPU CORE CLOCK FREQUENCY
+========================
+We supply assembler modules for clock frequencies of 12 MHz, 12.8 MHz, 15 MHz,
+16 MHz, 16.5 MHz 18 MHz and 20 MHz. Other clock rates are not supported. The
+actual clock rate must be configured in usbdrv.h unless you use the default
+12 MHz.
+
+12 MHz Clock
+This is the traditional clock rate of V-USB because it's the lowest clock
+rate where the timing constraints of the USB spec can be met.
+
+15 MHz Clock
+Similar to 12 MHz, but some NOPs inserted. On the other hand, the higher clock
+rate allows for some loops which make the resulting code size somewhat smaller
+than the 12 MHz version.
+
+16 MHz Clock
+This clock rate has been added for users of the Arduino board and other
+ready-made boards which come with a fixed 16 MHz crystal. It's also an option
+if you need the slightly higher clock rate for performance reasons. Since
+16 MHz is not divisible by the USB low speed bit clock of 1.5 MHz, the code
+is somewhat tricky and has to insert a leap cycle every third byte.
+
+12.8 MHz and 16.5 MHz Clock
+The assembler modules for these clock rates differ from the other modules
+because they have been built for an RC oscillator with only 1% precision. The
+receiver code inserts leap cycles to compensate for clock deviations. 1% is
+also the precision which can be achieved by calibrating the internal RC
+oscillator of the AVR. Please note that only AVRs with internal 64 MHz PLL
+oscillator can reach 16.5 MHz with the RC oscillator. This includes the very
+popular ATTiny25, ATTiny45, ATTiny85 series as well as the ATTiny26. Almost
+all AVRs can reach 12.8 MHz, although this is outside the specified range.
+
+See the EasyLogger example at http://www.obdev.at/vusb/easylogger.html for
+code which calibrates the RC oscillator based on the USB frame clock.
+
+18 MHz Clock
+This module is closer to the USB specification because it performs an on the
+fly CRC check for incoming packets. Packets with invalid checksum are
+discarded as required by the spec. If you also implement checks for data
+PID toggling on application level (see option USB_CFG_CHECK_DATA_TOGGLING
+in usbconfig.h for more info), this ensures data integrity. Due to the CRC
+tables and alignment requirements, this code is bigger than modules for other
+clock rates. To activate this module, you must define USB_CFG_CHECK_CRC to 1
+and USB_CFG_CLOCK_KHZ to 18000 in usbconfig.h.
+
+20 MHz Clock
+This module is for people who won't do it with less than the maximum. Since
+20 MHz is not divisible by the USB low speed bit clock of 1.5 MHz, the code
+uses similar tricks as the 16 MHz module to insert leap cycles.
+
+
+USB IDENTIFIERS
+===============
+Every USB device needs a vendor- and a product-identifier (VID and PID). VIDs
+are obtained from usb.org for a price of 1,500 USD. Once you have a VID, you
+can assign PIDs at will.
+
+Since an entry level cost of 1,500 USD is too high for most small companies
+and hobbyists, we provide some VID/PID pairs for free. See the file
+USB-IDs-for-free.txt for details.
+
+Objective Development also has some license offerings which include product
+IDs. See http://www.obdev.at/vusb/ for details.
+
+
+DEVELOPMENT SYSTEM
+==================
+This driver has been developed and optimized for the GNU compiler version 3
+(gcc 3). It does work well with gcc 4, but with bigger code size. We recommend
+that you use the GNU compiler suite because it is freely available. V-USB
+has also been ported to the IAR compiler and assembler. It has been tested
+with IAR 4.10B/W32 and 4.12A/W32 on an ATmega8 with the "small" and "tiny"
+memory model. Not every release is tested with IAR CC and the driver may
+therefore fail to compile with IAR. Please note that gcc is more efficient for
+usbdrv.c because this module has been deliberately optimized for gcc.
+
+
+USING V-USB FOR FREE
+====================
+The AVR firmware driver is published under the GNU General Public License
+Version 2 (GPL2) and the GNU General Public License Version 3 (GPL3). It is
+your choice whether you apply the terms of version 2 or version 3.
+
+If you decide for the free GPL2 or GPL3, we STRONGLY ENCOURAGE you to do the
+following things IN ADDITION to the obligations from the GPL:
+
+(1) Publish your entire project on a web site and drop us a note with the URL.
+Use the form at http://www.obdev.at/vusb/feedback.html for your submission.
+If you don't have a web site, you can publish the project in obdev's
+documentation wiki at
+http://www.obdev.at/goto.php?t=vusb-wiki&p=hosted-projects.
+
+(2) Adhere to minimum publication standards. Please include AT LEAST:
+    - a circuit diagram in PDF, PNG or GIF format
+    - full source code for the host software
+    - a Readme.txt file in ASCII format which describes the purpose of the
+      project and what can be found in which directories and which files
+    - a reference to http://www.obdev.at/vusb/
+
+(3) If you improve the driver firmware itself, please give us a free license
+to your modifications for our commercial license offerings.
+
+
+COMMERCIAL LICENSES FOR V-USB
+=============================
+If you don't want to publish your source code under the terms of the GPL,
+you can simply pay money for V-USB. As an additional benefit you get
+USB PIDs for free, reserved exclusively to you. See the file
+"CommercialLicense.txt" for details.
+

USB-ID-FAQ.txt

@@ -0,0 +1,149 @@
+Version 2009-08-22
+
+==========================
+WHY DO WE NEED THESE IDs?
+==========================
+
+USB is more than a low level protocol for data transport. It also defines a
+common set of requests which must be understood by all devices. And as part
+of these common requests, the specification defines data structures, the
+USB Descriptors, which are used to describe the properties of the device.
+
+From the perspective of an operating system, it is therefore possible to find
+out basic properties of a device (such as e.g. the manufacturer and the name
+of the device) without a device-specific driver. This is essential because
+the operating system can choose a driver to load based on this information
+(Plug-And-Play).
+
+Among the most important properties in the Device Descriptor are the USB
+Vendor- and Product-ID. Both are 16 bit integers. The most simple form of
+driver matching is based on these IDs. The driver announces the Vendor- and
+Product-IDs of the devices it can handle and the operating system loads the
+appropriate driver when the device is connected.
+
+It is obvious that this technique only works if the pair Vendor- plus
+Product-ID is unique: Only devices which require the same driver can have the
+same pair of IDs.
+
+
+=====================================================
+HOW DOES THE USB STANDARD ENSURE THAT IDs ARE UNIQUE?
+=====================================================
+
+Since it is so important that USB IDs are unique, the USB Implementers Forum,
+Inc. (usb.org) needs a way to enforce this legally. It is not forbidden by
+law to build a device and assign it any random numbers as IDs. Usb.org
+therefore needs an agreement to regulate the use of USB IDs. The agreement
+binds only parties who agreed to it, of course. Everybody else is free to use
+any numbers for their IDs.
+
+So how can usb.org ensure that every manufacturer of USB devices enters into
+an agreement with them? They do it via trademark licensing. Usb.org has
+registered the trademark "USB", all associated logos and related terms. If
+you want to put an USB logo on your product or claim that it is USB
+compliant, you must license these trademarks from usb.org. And this is where
+you enter into an agreement. See the "USB-IF Trademark License Agreement and
+Usage Guidelines for the USB-IF Logo" at
+http://www.usb.org/developers/logo_license/.
+
+Licensing the USB trademarks requires that you buy a USB Vendor-ID from
+usb.org (one-time fee of ca. 2,000 USD), that you become a member of usb.org
+(yearly fee of ca. 4,000 USD) and that you meet all the technical
+specifications from the USB spec.
+
+This means that most hobbyists and small companies will never be able to
+become USB compliant, just because membership is so expensive. And you can't
+be compliant with a driver based on V-USB anyway, because the AVR's port pins
+don't meet the electrical specifications for USB. So, in principle, all
+hobbyists and small companies are free to choose any random numbers for their
+IDs. They have nothing to lose...
+
+There is one exception worth noting, though: If you use a sub-component which
+implements USB, the vendor of the sub-components may guarantee USB
+compliance. This might apply to some or all of FTDI's solutions.
+
+
+=======================================================================
+WHY SHOULD YOU OBTAIN USB IDs EVEN IF YOU DON'T LICENSE USB TRADEMARKS?
+=======================================================================
+
+You have learned in the previous section that you are free to choose any
+numbers for your IDs anyway. So why not do exactly this? There is still the
+technical issue. If you choose IDs which are already in use by somebody else,
+operating systems will load the wrong drivers and your device won't work.
+Even if you choose IDs which are not currently in use, they may be in use in
+the next version of the operating system or even after an automatic update.
+
+So what you need is a pair of Vendor- and Product-IDs for which you have the
+guarantee that no USB compliant product uses them. This implies that no
+operating system will ever ship with drivers responsible for these IDs.
+
+
+==============================================
+HOW DOES OBJECTIVE DEVELOPMENT HANDLE USB IDs?
+==============================================
+
+Objective Development gives away pairs of USB-IDs with their V-USB licenses.
+In order to ensure that these IDs are unique, Objective Development has an
+agreement with the company/person who has bought the USB Vendor-ID from
+usb.org. This agreement ensures that a range of USB Product-IDs is reserved
+for assignment by Objective Development and that the owner of the Vendor-ID
+won't give it to anybody else.
+
+This means that you have to trust three parties to ensure uniqueness of
+your IDs:
+
+  - Objective Development, that they don't give the same PID to more than
+    one person.
+  - The owner of the Vendor-ID that they don't assign PIDs from the range
+    assigned to Objective Development to anybody else.
+  - Usb.org that they don't assign the same Vendor-ID a second time.
+
+
+==================================
+WHO IS THE OWNER OF THE VENDOR-ID?
+==================================
+
+Objective Development has obtained ranges of USB Product-IDs under two
+Vendor-IDs: Under Vendor-ID 5824 from Wouter van Ooijen (Van Ooijen
+Technische Informatica, www.voti.nl) and under Vendor-ID 8352 from Jason
+Kotzin (Clay Logic, www.claylogic.com). Both VID owners have received their
+Vendor-ID directly from usb.org.
+
+
+=========================================================================
+CAN I USE USB-IDs FROM OBJECTIVE DEVELOPMENT WITH OTHER DRIVERS/HARDWARE?
+=========================================================================
+
+The short answer is: Yes. All you get is a guarantee that the IDs are never
+assigned to anybody else. What more do you need?
+
+
+============================
+WHAT ABOUT SHARED ID PAIRS?
+============================
+
+Objective Development has reserved some PID/VID pairs for shared use. You
+have no guarantee of uniqueness for them, except that no USB compliant device
+uses them. In order to avoid technical problems, we must ensure that all
+devices with the same pair of IDs use the same driver on kernel level. For
+details, see the file USB-IDs-for-free.txt.
+
+
+======================================================
+I HAVE HEARD THAT SUB-LICENSING OF USB-IDs IS ILLEGAL?
+======================================================
+
+A 16 bit integer number cannot be protected by copyright laws. It is not
+sufficiently complex. And since none of the parties involved entered into the
+USB-IF Trademark License Agreement, we are not bound by this agreement. So
+there is no reason why it should be illegal to sub-license USB-IDs.
+
+
+=============================================
+WHO IS LIABLE IF THERE ARE INCOMPATIBILITIES?
+=============================================
+
+Objective Development disclaims all liabilities which might arise from the
+assignment of IDs. If you guarantee product features to your customers
+without proper disclaimer, YOU are liable for that.

USB-IDs-for-free.txt

@@ -0,0 +1,148 @@
+Version 2009-08-22
+
+===========================
+FREE USB-IDs FOR SHARED USE
+===========================
+
+Objective Development has reserved a set of USB Product-IDs for use according
+to the guidelines outlined below. For more information about the concept of
+USB IDs please see the file USB-ID-FAQ.txt. Objective Development guarantees
+that the IDs listed below are not used by any USB compliant devices.
+
+
+====================
+MECHANISM OF SHARING
+====================
+
+From a technical point of view, two different devices can share the same USB
+Vendor- and Product-ID if they require the same driver on operating system
+level. We make use of this fact by assigning separate IDs for various device
+classes. On application layer, devices must be distinguished by their textual
+name or serial number. We offer separate sets of IDs for discrimination by
+textual name and for serial number.
+
+Examples for shared use of USB IDs are included with V-USB in the "examples"
+subdirectory.
+
+
+======================================
+IDs FOR DISCRIMINATION BY TEXTUAL NAME
+======================================
+
+If you use one of the IDs listed below, your device and host-side software
+must conform to these rules:
+
+(1) The USB device MUST provide a textual representation of the manufacturer
+and product identification. The manufacturer identification MUST be available
+at least in USB language 0x0409 (English/US).
+
+(2) The textual manufacturer identification MUST contain either an Internet
+domain name (e.g. "mycompany.com") registered and owned by you, or an e-mail
+address under your control (e.g. "myname@gmx.net"). You can embed the domain
+name or e-mail address in any string you like, e.g.  "Objective Development
+http://www.obdev.at/vusb/".
+
+(3) You are responsible for retaining ownership of the domain or e-mail
+address for as long as any of your products are in use.
+
+(4) You may choose any string for the textual product identification, as long
+as this string is unique within the scope of your textual manufacturer
+identification.
+
+(5) Application side device look-up MUST be based on the textual manufacturer
+and product identification in addition to VID/PID matching. The driver
+matching MUST be a comparison of the entire strings, NOT a sub-string match.
+
+(6) For devices which implement a particular USB device class (e.g. HID), the
+operating system's default class driver MUST be used. If an operating system
+driver for Vendor Class devices is needed, this driver must be libusb or
+libusb-win32 (see http://libusb.org/ and
+http://libusb-win32.sourceforge.net/).
+
+Table if IDs for discrimination by textual name:
+
+PID dec (hex) | VID dec (hex) | Description of use
+==============+===============+============================================
+1500 (0x05dc) | 5824 (0x16c0) | For Vendor Class devices with libusb
+--------------+---------------+--------------------------------------------
+1503 (0x05df) | 5824 (0x16c0) | For generic HID class devices (which are
+              |               | NOT mice, keyboards or joysticks)
+--------------+---------------+--------------------------------------------
+1505 (0x05e1) | 5824 (0x16c0) | For CDC-ACM class devices (modems)
+--------------+---------------+--------------------------------------------
+1508 (0x05e4) | 5824 (0x16c0) | For MIDI class devices
+--------------+---------------+--------------------------------------------
+
+Note that Windows caches the textual product- and vendor-description for
+mice, keyboards and joysticks. Name-bsed discrimination is therefore not
+recommended for these device classes.
+
+
+=======================================
+IDs FOR DISCRIMINATION BY SERIAL NUMBER
+=======================================
+
+If you use one of the IDs listed below, your device and host-side software
+must conform to these rules:
+
+(1) The USB device MUST provide a textual representation of the serial
+number. The serial number string MUST be available at least in USB language
+0x0409 (English/US).
+
+(2) The serial number MUST start with either an Internet domain name (e.g.
+"mycompany.com") registered and owned by you, or an e-mail address under your
+control (e.g. "myname@gmx.net"), both terminated with a colon (":") character.
+You MAY append any string you like for further discrimination of your devices.
+
+(3) You are responsible for retaining ownership of the domain or e-mail
+address for as long as any of your products are in use.
+
+(5) Application side device look-up MUST be based on the serial number string
+in addition to VID/PID matching. The matching must start at the first
+character of the serial number string and include the colon character
+terminating your domain or e-mail address. It MAY stop anywhere after that.
+
+(6) For devices which implement a particular USB device class (e.g. HID), the
+operating system's default class driver MUST be used. If an operating system
+driver for Vendor Class devices is needed, this driver must be libusb or
+libusb-win32 (see http://libusb.org/ and
+http://libusb-win32.sourceforge.net/).
+
+Table if IDs for discrimination by serial number string:
+
+PID dec (hex)  | VID dec (hex) | Description of use
+===============+===============+===========================================
+10200 (0x27d8) | 5824 (0x16c0) | For Vendor Class devices with libusb
+---------------+---------------+-------------------------------------------
+10201 (0x27d9) | 5824 (0x16c0) | For generic HID class devices (which are
+               |               | NOT mice, keyboards or joysticks)
+---------------+---------------+-------------------------------------------
+10202 (0x27da) | 5824 (0x16c0) | For USB Mice
+---------------+---------------+-------------------------------------------
+10203 (0x27db) | 5824 (0x16c0) | For USB Keyboards
+---------------+---------------+-------------------------------------------
+10204 (0x27db) | 5824 (0x16c0) | For USB Joysticks
+---------------+---------------+-------------------------------------------
+10205 (0x27dc) | 5824 (0x16c0) | For CDC-ACM class devices (modems)
+---------------+---------------+-------------------------------------------
+10206 (0x27dd) | 5824 (0x16c0) | For MIDI class devices
+---------------+---------------+-------------------------------------------
+
+
+=================
+ORIGIN OF USB-IDs
+=================
+
+OBJECTIVE DEVELOPMENT Software GmbH has obtained all VID/PID pairs listed
+here from Wouter van Ooijen (see www.voti.nl) for exclusive disposition.
+Wouter van Ooijen has obtained the VID from the USB Implementers Forum, Inc.
+(see www.usb.org). The VID is registered for the company name "Van Ooijen
+Technische Informatica".
+
+
+==========
+DISCLAIMER
+==========
+
+OBJECTIVE DEVELOPMENT Software GmbH disclaims all liability for any
+problems which are caused by the shared use of these VID/PID pairs.

USBID-License.txt

@@ -0,0 +1,154 @@
+Royalty-Free Non-Exclusive Use of USB Product-IDs
+=================================================
+
+Version 2009-04-13
+
+Strictly speaking, this is not a license. You can't give a license to use
+a simple number (such as e.g. 1500) for any purpose. This is a set of rules
+which should make it possible to build USB devices without the requirement
+for individual USB IDs. If you break one of the rules, you will run into
+technical problems sooner or later, but you don't risk legal trouble.
+
+
+OBJECTIVE DEVELOPMENT Software GmbH hereby grants you the non-exclusive
+right to use four USB.org vendor-ID (VID) / product-ID (PID) pairs with
+products based on Objective Development's firmware-only USB driver for
+Atmel AVR microcontrollers:
+
+ * VID = 5824 (=0x16c0) / PID = 1500 (=0x5dc) for devices implementing no
+   USB device class (vendor-class devices with USB class = 0xff). Devices
+   using this pair will be referred to as "VENDOR CLASS" devices.
+
+ * VID = 5824 (=0x16c0) / PID = 1503 (=0x5df) for HID class devices
+   (excluding mice and keyboards). Devices using this pair will be referred
+   to as "HID CLASS" devices.
+
+ * VID = 5824 (=0x16c0) / PID = 1505 (=0x5e1) for CDC class modem devices
+   Devices using this pair will be referred to as "CDC-ACM CLASS" devices.
+
+ * VID = 5824 (=0x16c0) / PID = 1508 (=0x5e4) for MIDI class devices
+   Devices using this pair will be referred to as "MIDI CLASS" devices.
+
+Since the granted right is non-exclusive, the same VID/PID pairs may be
+used by many companies and individuals for different products. To avoid
+conflicts, your device and host driver software MUST adhere to the rules
+outlined below.
+
+OBJECTIVE DEVELOPMENT Software GmbH has obtained these VID/PID pairs from
+Wouter van Ooijen (see www.voti.nl) for exclusive disposition. Wouter van
+Ooijen has obtained the VID from the USB Implementers Forum, Inc.
+(see www.usb.org). The VID is registered for the company name
+"Van Ooijen Technische Informatica".
+
+
+RULES AND RESTRICTIONS
+======================
+
+(1) The USB device MUST provide a textual representation of the
+manufacturer and product identification. The manufacturer identification
+MUST be available at least in USB language 0x0409 (English/US).
+
+(2) The textual manufacturer identification MUST contain either an Internet
+domain name (e.g. "mycompany.com") registered and owned by you, or an
+e-mail address under your control (e.g. "myname@gmx.net"). You can embed
+the domain name or e-mail address in any string you like, e.g.  "Objective
+Development http://www.obdev.at/vusb/".
+
+(3) You are responsible for retaining ownership of the domain or e-mail
+address for as long as any of your products are in use.
+
+(4) You may choose any string for the textual product identification, as
+long as this string is unique within the scope of your textual manufacturer
+identification.
+
+(5) Matching of device-specific drivers MUST be based on the textual
+manufacturer and product identification in addition to the usual VID/PID
+matching. This means that operating system features which are based on
+VID/PID matching only (e.g. Windows kernel level drivers, automatic actions
+when the device is plugged in etc) MUST NOT be used. The driver matching
+MUST be a comparison of the entire strings, NOT a sub-string match. For
+CDC-ACM CLASS and MIDI CLASS devices, a generic class driver should be used
+and the matching is based on the USB device class.
+
+(6) The extent to which VID/PID matching is allowed for non device-specific
+drivers or features depends on the operating system and particular VID/PID
+pair used:
+
+ * Mac OS X, Linux, FreeBSD and other Unixes: No VID/PID matching is
+   required and hence no VID/PID-only matching is allowed at all.
+
+ * Windows: The operating system performs VID/PID matching for the kernel
+   level driver. You are REQUIRED to use libusb-win32 (see
+   http://libusb-win32.sourceforge.net/) as the kernel level driver for
+   VENDOR CLASS devices. HID CLASS devices all use the generic HID class
+   driver shipped with Windows, except mice and keyboards. You therefore
+   MUST NOT use any of the shared VID/PID pairs for mice or keyboards.
+   CDC-ACM CLASS devices require a ".inf" file which matches on the VID/PID
+   pair. This ".inf" file MUST load the "usbser" driver to configure the
+   device as modem (COM-port).
+
+(7) OBJECTIVE DEVELOPMENT Software GmbH disclaims all liability for any
+problems which are caused by the shared use of these VID/PID pairs. You
+have been warned that the sharing of VID/PID pairs may cause problems. If
+you want to avoid them, get your own VID/PID pair for exclusive use.
+
+
+HOW TO IMPLEMENT THESE RULES
+============================
+
+The following rules are for VENDOR CLASS and HID CLASS devices. CDC-ACM
+CLASS and MIDI CLASS devices use the operating system's class driver and
+don't need a custom driver.
+
+The host driver MUST iterate over all devices with the given VID/PID
+numbers in their device descriptors and query the string representation for
+the manufacturer name in USB language 0x0409 (English/US). It MUST compare
+the ENTIRE string with your textual manufacturer identification chosen in
+(2) above. A substring search for your domain or e-mail address is NOT
+acceptable. The driver MUST NOT touch the device (other than querying the
+descriptors) unless the strings match.
+
+For all USB devices with matching VID/PID and textual manufacturer
+identification, the host driver must query the textual product
+identification and string-compare it with the name of the product it can
+control. It may only initialize the device if the product matches exactly.
+
+Objective Development provides examples for these matching rules with the
+"PowerSwitch" project (using libusb) and with the "Automator" project
+(using Windows calls on Windows and libusb on Unix).
+
+
+Technical Notes:
+================
+
+Sharing the same VID/PID pair among devices is possible as long as ALL
+drivers which match the VID/PID also perform matching on the textual
+identification strings. This is easy on all operating systems except
+Windows, since Windows establishes a static connection between the VID/PID
+pair and a kernel level driver. All devices with the same VID/PID pair must
+therefore use THE SAME kernel level driver.
+
+We therefore demand that you use libusb-win32 for VENDOR CLASS devices.
+This is a generic kernel level driver which allows all types of USB access
+for user space applications. This is only a partial solution of the
+problem, though, because different device drivers may come with different
+versions of libusb-win32 and they may not work with the libusb version of
+the respective other driver. You are therefore encouraged to test your
+driver against a broad range of libusb-win32 versions. Do not use new
+features in new versions, or check for their existence before you use them.
+When a new libusb-win32 becomes available, make sure that your driver is
+compatible with it.
+
+For HID CLASS devices it is necessary that all those devices bind to the
+same kernel driver: Microsoft's generic USB HID driver. This is true for
+all HID devices except those with a specialized driver. Currently, the only
+HIDs with specialized drivers are mice and keyboards. You therefore MUST
+NOT use a shared VID/PID with mouse and keyboard devices.
+
+Sharing the same VID/PID among different products is unusual and probably
+violates the USB specification. If you do it, you do it at your own risk.
+
+To avoid possible incompatibilities, we highly recommend that you get your
+own VID/PID pair if you intend to sell your product. Objective
+Development's commercial licenses for V-USB include a PID for
+unrestricted exclusive use.

UsbKeyboard.h

@@ -0,0 +1,264 @@
+/*
+ * Based on Obdev's AVRUSB code and under the same license.
+ *
+ * TODO: Make a proper file header. :-)
+ */
+#ifndef __UsbKeyboard_h__
+#define __UsbKeyboard_h__
+
+#include <avr/pgmspace.h>
+#include <avr/interrupt.h>
+#include <string.h>
+
+#include "usbdrv.h"
+
+// TODO: Work around Arduino 12 issues better.
+//#include <WConstants.h>
+//#undef int()
+
+typedef uint8_t byte;
+
+
+#define BUFFER_SIZE 4 // Minimum of 2: 1 for modifiers + 1 for keystroke 
+
+
+static uchar    idleRate;           // in 4 ms units 
+
+
+/* We use a simplifed keyboard report descriptor which does not support the
+ * boot protocol. We don't allow setting status LEDs and but we do allow
+ * simultaneous key presses. 
+ * The report descriptor has been created with usb.org's "HID Descriptor Tool"
+ * which can be downloaded from http://www.usb.org/developers/hidpage/.
+ * Redundant entries (such as LOGICAL_MINIMUM and USAGE_PAGE) have been omitted
+ * for the second INPUT item.
+ */
+PROGMEM char usbHidReportDescriptor[35] = { /* USB report descriptor */
+  0x05, 0x01,                    // USAGE_PAGE (Generic Desktop) 
+  0x09, 0x06,                    // USAGE (Keyboard) 
+  0xa1, 0x01,                    // COLLECTION (Application) 
+  0x05, 0x07,                    //   USAGE_PAGE (Keyboard) 
+  0x19, 0xe0,                    //   USAGE_MINIMUM (Keyboard LeftControl) 
+  0x29, 0xe7,                    //   USAGE_MAXIMUM (Keyboard Right GUI) 
+  0x15, 0x00,                    //   LOGICAL_MINIMUM (0) 
+  0x25, 0x01,                    //   LOGICAL_MAXIMUM (1) 
+  0x75, 0x01,                    //   REPORT_SIZE (1) 
+  0x95, 0x08,                    //   REPORT_COUNT (8) 
+  0x81, 0x02,                    //   INPUT (Data,Var,Abs) 
+  0x95, BUFFER_SIZE-1,           //   REPORT_COUNT (simultaneous keystrokes) 
+  0x75, 0x08,                    //   REPORT_SIZE (8) 
+  0x25, 0x65,                    //   LOGICAL_MAXIMUM (101) 
+  0x19, 0x00,                    //   USAGE_MINIMUM (Reserved (no event indicated)) 
+  0x29, 0x65,                    //   USAGE_MAXIMUM (Keyboard Application) 
+  0x81, 0x00,                    //   INPUT (Data,Ary,Abs) 
+  0xc0                           // END_COLLECTION 
+};
+
+
+
+/* Keyboard usage values, see usb.org's HID-usage-tables document, chapter
+ * 10 Keyboard/Keypad Page for more codes.
+ */
+#define MOD_CONTROL_LEFT    (1<<0)
+#define MOD_SHIFT_LEFT      (1<<1)
+#define MOD_ALT_LEFT        (1<<2)
+#define MOD_GUI_LEFT        (1<<3)
+#define MOD_CONTROL_RIGHT   (1<<4)
+#define MOD_SHIFT_RIGHT     (1<<5)
+#define MOD_ALT_RIGHT       (1<<6)
+#define MOD_GUI_RIGHT       (1<<7)
+
+#define KEY_A       4
+#define KEY_B       5
+#define KEY_C       6
+#define KEY_D       7
+#define KEY_E       8
+#define KEY_F       9
+#define KEY_G       10
+#define KEY_H       11
+#define KEY_I       12
+#define KEY_J       13
+#define KEY_K       14
+#define KEY_L       15
+#define KEY_M       16
+#define KEY_N       17
+#define KEY_O       18
+#define KEY_P       19
+#define KEY_Q       20
+#define KEY_R       21
+#define KEY_S       22
+#define KEY_T       23
+#define KEY_U       24
+#define KEY_V       25
+#define KEY_W       26
+#define KEY_X       27
+#define KEY_Y       28
+#define KEY_Z       29
+#define KEY_1       30
+#define KEY_2       31
+#define KEY_3       32
+#define KEY_4       33
+#define KEY_5       34
+#define KEY_6       35
+#define KEY_7       36
+#define KEY_8       37
+#define KEY_9       38
+#define KEY_0       39
+
+#define KEY_ENTER   40
+#define KEY_ESCAPE  41
+#define KEY_BSPACE  42
+#define KEY_TAB     43
+#define KEY_SPACE   44
+
+
+#define KEY_HYPHEN    45
+#define KEY_EQUAL     46
+#define KEY_LBRACKET  47
+#define KEY_RBRACKET  48
+#define KEY_BSLASH    49
+#define KEY_HASHTAG   50
+#define KEY_SEMICOLON 51
+#define KEY_QUOTE    52
+#define KEY_TILDE     53
+#define KEY_COMMA     54
+#define KEY_DOT       55
+#define KEY_SLASH     56
+#define KEY_CAPSLOCK  57
+
+#define KEY_F1      58
+#define KEY_F2      59
+#define KEY_F3      60
+#define KEY_F4      61
+#define KEY_F5      62
+#define KEY_F6      63
+#define KEY_F7      64
+#define KEY_F8      65
+#define KEY_F9      66
+#define KEY_F10     67
+#define KEY_F11     68
+#define KEY_F12     69
+
+#define KEY_PRINTSCREEN 70
+#define KEY_SCROLLLOCK  71
+#define KEY_PAUSE       72
+#define KEY_INSERT      73
+#define KEY_HOME        74
+#define KEY_PAGEUP      75
+#define KEY_DELETE      76
+#define KEY_END         77
+#define KEY_PAGEDOWN    78
+
+#define KEY_ARROW_RIGHT 79
+#define KEY_ARROW_LEFT  80
+#define KEY_ARROW_DOWN  81
+#define KEY_ARROW_UP    82
+
+
+#define KEY_NUMLOCK     83
+#define KEYP_SLASH      84
+#define KEYP_STAR       85
+#define KEYP_MINUS      86
+#define KEYP_PLUS       87
+#define KEYP_ENTER      88
+
+class UsbKeyboardDevice {
+ public:
+  UsbKeyboardDevice () {
+    PORTD = 0; // TODO: Only for USB pins?
+    DDRD |= ~USBMASK;
+
+    cli();
+    usbDeviceDisconnect();
+    usbDeviceConnect();
+
+
+    usbInit();
+      
+    sei();
+
+    // TODO: Remove the next two lines once we fix
+    //       missing first keystroke bug properly.
+    memset(reportBuffer, 0, sizeof(reportBuffer));      
+    usbSetInterrupt(reportBuffer, sizeof(reportBuffer));
+  }
+    
+  void update() {
+    usbPoll();
+  }
+    
+  void sendKeyStroke(byte keyStroke) {
+    sendKeyStroke(keyStroke, 0);
+  }
+
+  void sendKeyStroke(byte keyStroke, byte modifiers) {
+      
+    while (!usbInterruptIsReady()) {
+      // Note: We wait until we can send keystroke
+      //       so we know the previous keystroke was
+      //       sent.
+    }
+      
+    memset(reportBuffer, 0, sizeof(reportBuffer));
+
+    reportBuffer[0] = modifiers;
+    reportBuffer[1] = keyStroke;
+        
+    usbSetInterrupt(reportBuffer, sizeof(reportBuffer));
+
+    while (!usbInterruptIsReady()) {
+      // Note: We wait until we can send keystroke
+      //       so we know the previous keystroke was
+      //       sent.
+    }
+      
+    // This stops endlessly repeating keystrokes:
+    memset(reportBuffer, 0, sizeof(reportBuffer));      
+    usbSetInterrupt(reportBuffer, sizeof(reportBuffer));
+
+  }
+    
+  //private: TODO: Make friend?
+  uchar    reportBuffer[4];    // buffer for HID reports [ 1 modifier byte + (len-1) key strokes]
+
+};
+
+UsbKeyboardDevice UsbKeyboard = UsbKeyboardDevice();
+
+#ifdef __cplusplus
+extern "C"{
+#endif 
+  // USB_PUBLIC uchar usbFunctionSetup
+uchar usbFunctionSetup(uchar data[8]) 
+  {
+    usbRequest_t    *rq = (usbRequest_t *)((void *)data);
+
+    usbMsgPtr = UsbKeyboard.reportBuffer; //
+    if((rq->bmRequestType & USBRQ_TYPE_MASK) == USBRQ_TYPE_CLASS){
+      /* class request type */
+
+      if(rq->bRequest == USBRQ_HID_GET_REPORT){
+	/* wValue: ReportType (highbyte), ReportID (lowbyte) */
+
+	/* we only have one report type, so don't look at wValue */
+        // TODO: Ensure it's okay not to return anything here?    
+	return 0;
+
+      }else if(rq->bRequest == USBRQ_HID_GET_IDLE){
+	//            usbMsgPtr = &idleRate;
+	//            return 1;
+	return 0;
+      }else if(rq->bRequest == USBRQ_HID_SET_IDLE){
+	idleRate = rq->wValue.bytes[1];
+      }
+    }else{
+      /* no vendor specific requests implemented */
+    }
+    return 0;
+  }
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+
+#endif // __UsbKeyboard_h__

asmcommon.inc

@@ -0,0 +1,188 @@
+/* Name: asmcommon.inc
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2007-11-05
+ * Tabsize: 4
+ * Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * Revision: $Id$
+ */
+
+/* Do not link this file! Link usbdrvasm.S instead, which includes the
+ * appropriate implementation!
+ */
+
+/*
+General Description:
+This file contains assembler code which is shared among the USB driver
+implementations for different CPU cocks. Since the code must be inserted
+in the middle of the module, it's split out into this file and #included.
+
+Jump destinations called from outside:
+    sofError: Called when no start sequence was found.
+    se0: Called when a package has been successfully received.
+    overflow: Called when receive buffer overflows.
+    doReturn: Called after sending data.
+
+Outside jump destinations used by this module:
+    waitForJ: Called to receive an already arriving packet.
+    sendAckAndReti:
+    sendNakAndReti:
+    sendCntAndReti:
+    usbSendAndReti:
+
+The following macros must be defined before this file is included:
+    .macro POP_STANDARD
+    .endm
+    .macro POP_RETI
+    .endm
+*/
+
+#define token   x1
+
+overflow:
+    ldi     x2, 1<<USB_INTR_PENDING_BIT
+    USB_STORE_PENDING(x2)       ; clear any pending interrupts
+ignorePacket:
+    clr     token
+    rjmp    storeTokenAndReturn
+
+;----------------------------------------------------------------------------
+; Processing of received packet (numbers in brackets are cycles after center of SE0)
+;----------------------------------------------------------------------------
+;This is the only non-error exit point for the software receiver loop
+;we don't check any CRCs here because there is no time left.
+se0:
+    subi    cnt, USB_BUFSIZE    ;[5]
+    neg     cnt                 ;[6]
+    sub     YL, cnt             ;[7]
+    sbci    YH, 0               ;[8]
+    ldi     x2, 1<<USB_INTR_PENDING_BIT ;[9]
+    USB_STORE_PENDING(x2)       ;[10] clear pending intr and check flag later. SE0 should be over.
+    ld      token, y            ;[11]
+    cpi     token, USBPID_DATA0 ;[13]
+    breq    handleData          ;[14]
+    cpi     token, USBPID_DATA1 ;[15]
+    breq    handleData          ;[16]
+    lds     shift, usbDeviceAddr;[17]
+    ldd     x2, y+1             ;[19] ADDR and 1 bit endpoint number
+    lsl     x2                  ;[21] shift out 1 bit endpoint number
+    cpse    x2, shift           ;[22]
+    rjmp    ignorePacket        ;[23]
+/* only compute endpoint number in x3 if required later */
+#if USB_CFG_HAVE_INTRIN_ENDPOINT || USB_CFG_IMPLEMENT_FN_WRITEOUT
+    ldd     x3, y+2             ;[24] endpoint number + crc
+    rol     x3                  ;[26] shift in LSB of endpoint
+#endif
+    cpi     token, USBPID_IN    ;[27]
+    breq    handleIn            ;[28]
+    cpi     token, USBPID_SETUP ;[29]
+    breq    handleSetupOrOut    ;[30]
+    cpi     token, USBPID_OUT   ;[31]
+    brne    ignorePacket        ;[32] must be ack, nak or whatever
+;   rjmp    handleSetupOrOut    ; fallthrough
+
+;Setup and Out are followed by a data packet two bit times (16 cycles) after
+;the end of SE0. The sync code allows up to 40 cycles delay from the start of
+;the sync pattern until the first bit is sampled. That's a total of 56 cycles.
+handleSetupOrOut:               ;[32]
+#if USB_CFG_IMPLEMENT_FN_WRITEOUT   /* if we have data for endpoint != 0, set usbCurrentTok to address */
+    andi    x3, 0xf             ;[32]
+    breq    storeTokenAndReturn ;[33]
+    mov     token, x3           ;[34] indicate that this is endpoint x OUT
+#endif
+storeTokenAndReturn:
+    sts     usbCurrentTok, token;[35]
+doReturn:
+    POP_STANDARD                ;[37] 12...16 cycles
+    USB_LOAD_PENDING(YL)        ;[49]
+    sbrc    YL, USB_INTR_PENDING_BIT;[50] check whether data is already arriving
+    rjmp    waitForJ            ;[51] save the pops and pushes -- a new interrupt is already pending
+sofError:
+    POP_RETI                    ;macro call
+    reti
+
+handleData:
+#if USB_CFG_CHECK_CRC
+    CRC_CLEANUP_AND_CHECK       ; jumps to ignorePacket if CRC error
+#endif
+    lds     shift, usbCurrentTok;[18]
+    tst     shift               ;[20]
+    breq    doReturn            ;[21]
+    lds     x2, usbRxLen        ;[22]
+    tst     x2                  ;[24]
+    brne    sendNakAndReti      ;[25]
+; 2006-03-11: The following two lines fix a problem where the device was not
+; recognized if usbPoll() was called less frequently than once every 4 ms.
+    cpi     cnt, 4              ;[26] zero sized data packets are status phase only -- ignore and ack
+    brmi    sendAckAndReti      ;[27] keep rx buffer clean -- we must not NAK next SETUP
+#if USB_CFG_CHECK_DATA_TOGGLING
+    sts     usbCurrentDataToken, token  ; store for checking by C code
+#endif
+    sts     usbRxLen, cnt       ;[28] store received data, swap buffers
+    sts     usbRxToken, shift   ;[30]
+    lds     x2, usbInputBufOffset;[32] swap buffers
+    ldi     cnt, USB_BUFSIZE    ;[34]
+    sub     cnt, x2             ;[35]
+    sts     usbInputBufOffset, cnt;[36] buffers now swapped
+    rjmp    sendAckAndReti      ;[38] 40 + 17 = 57 until SOP
+
+handleIn:
+;We don't send any data as long as the C code has not processed the current
+;input data and potentially updated the output data. That's more efficient
+;in terms of code size than clearing the tx buffers when a packet is received.
+    lds     x1, usbRxLen        ;[30]
+    cpi     x1, 1               ;[32] negative values are flow control, 0 means "buffer free"
+    brge    sendNakAndReti      ;[33] unprocessed input packet?
+    ldi     x1, USBPID_NAK      ;[34] prepare value for usbTxLen
+#if USB_CFG_HAVE_INTRIN_ENDPOINT
+    andi    x3, 0xf             ;[35] x3 contains endpoint
+#if USB_CFG_SUPPRESS_INTR_CODE
+    brne    sendNakAndReti      ;[36]
+#else
+    brne    handleIn1           ;[36]
+#endif
+#endif
+    lds     cnt, usbTxLen       ;[37]
+    sbrc    cnt, 4              ;[39] all handshake tokens have bit 4 set
+    rjmp    sendCntAndReti      ;[40] 42 + 16 = 58 until SOP
+    sts     usbTxLen, x1        ;[41] x1 == USBPID_NAK from above
+    ldi     YL, lo8(usbTxBuf)   ;[43]
+    ldi     YH, hi8(usbTxBuf)   ;[44]
+    rjmp    usbSendAndReti      ;[45] 57 + 12 = 59 until SOP
+
+; Comment about when to set usbTxLen to USBPID_NAK:
+; We should set it back when we receive the ACK from the host. This would
+; be simple to implement: One static variable which stores whether the last
+; tx was for endpoint 0 or 1 and a compare in the receiver to distinguish the
+; ACK. However, we set it back immediately when we send the package,
+; assuming that no error occurs and the host sends an ACK. We save one byte
+; RAM this way and avoid potential problems with endless retries. The rest of
+; the driver assumes error-free transfers anyway.
+
+#if !USB_CFG_SUPPRESS_INTR_CODE && USB_CFG_HAVE_INTRIN_ENDPOINT /* placed here due to relative jump range */
+handleIn1:                      ;[38]
+#if USB_CFG_HAVE_INTRIN_ENDPOINT3
+; 2006-06-10 as suggested by O.Tamura: support second INTR IN / BULK IN endpoint
+    cpi     x3, USB_CFG_EP3_NUMBER;[38]
+    breq    handleIn3           ;[39]
+#endif
+    lds     cnt, usbTxLen1      ;[40]
+    sbrc    cnt, 4              ;[42] all handshake tokens have bit 4 set
+    rjmp    sendCntAndReti      ;[43] 47 + 16 = 63 until SOP
+    sts     usbTxLen1, x1       ;[44] x1 == USBPID_NAK from above
+    ldi     YL, lo8(usbTxBuf1)  ;[46]
+    ldi     YH, hi8(usbTxBuf1)  ;[47]
+    rjmp    usbSendAndReti      ;[48] 50 + 12 = 62 until SOP
+
+#if USB_CFG_HAVE_INTRIN_ENDPOINT3
+handleIn3:
+    lds     cnt, usbTxLen3      ;[41]
+    sbrc    cnt, 4              ;[43]
+    rjmp    sendCntAndReti      ;[44] 49 + 16 = 65 until SOP
+    sts     usbTxLen3, x1       ;[45] x1 == USBPID_NAK from above
+    ldi     YL, lo8(usbTxBuf3)  ;[47]
+    ldi     YH, hi8(usbTxBuf3)  ;[48]
+    rjmp    usbSendAndReti      ;[49] 51 + 12 = 63 until SOP
+#endif
+#endif

examples/UsbKeyboardDemo1/UsbKeyboardDemo1.pde

@@ -0,0 +1,63 @@
+#include "UsbKeyboard.h"
+
+#define BUTTON_PIN 12
+
+// If the timer isr is corrected
+// to not take so long change this to 0.
+#define BYPASS_TIMER_ISR 1
+
+void setup() {
+  pinMode(BUTTON_PIN, INPUT);
+  digitalWrite(BUTTON_PIN, HIGH);
+  
+#if BYPASS_TIMER_ISR
+  // disable timer 0 overflow interrupt (used for millis)
+  TIMSK0&=!(1<<TOIE0); // ++
+#endif
+}
+
+#if BYPASS_TIMER_ISR
+void delayMs(unsigned int ms) {
+   /*
+  */ 
+  for (int i = 0; i < ms; i++) {
+    delayMicroseconds(1000);
+  }
+}
+#endif
+
+void loop() {
+  
+  UsbKeyboard.update();
+
+  digitalWrite(13, !digitalRead(13));
+
+  if (digitalRead(BUTTON_PIN) == 0) {
+    
+    //UsbKeyboard.sendKeyStroke(KEY_B, MOD_GUI_LEFT);
+    
+    UsbKeyboard.sendKeyStroke(KEY_H);
+    UsbKeyboard.sendKeyStroke(KEY_E);
+    UsbKeyboard.sendKeyStroke(KEY_L);
+    UsbKeyboard.sendKeyStroke(KEY_L);
+    UsbKeyboard.sendKeyStroke(KEY_O);
+
+    UsbKeyboard.sendKeyStroke(KEY_SPACE);
+
+    UsbKeyboard.sendKeyStroke(KEY_W);
+    UsbKeyboard.sendKeyStroke(KEY_O);
+    UsbKeyboard.sendKeyStroke(KEY_R);
+    UsbKeyboard.sendKeyStroke(KEY_L);
+    UsbKeyboard.sendKeyStroke(KEY_D);
+    //UsbKeyboard.sendKeyStroke(KEY_B, MOD_GUI_LEFT);
+
+    UsbKeyboard.sendKeyStroke(KEY_ENTER);
+#if BYPASS_TIMER_ISR  // check if timer isr fixed.
+    delayMs(20);
+#else
+    delay(20);
+#endif
+    
+   }
+
+}

oddebug.c

@@ -0,0 +1,50 @@
+/* Name: oddebug.c
+ * Project: AVR library
+ * Author: Christian Starkjohann
+ * Creation Date: 2005-01-16
+ * Tabsize: 4
+ * Copyright: (c) 2005 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * This Revision: $Id: oddebug.c 692 2008-11-07 15:07:40Z cs $
+ */
+
+#include "oddebug.h"
+
+#if DEBUG_LEVEL > 0
+
+#warning "Never compile production devices with debugging enabled"
+
+static void uartPutc(char c)
+{
+    while(!(ODDBG_USR & (1 << ODDBG_UDRE)));    /* wait for data register empty */
+    ODDBG_UDR = c;
+}
+
+static uchar    hexAscii(uchar h)
+{
+    h &= 0xf;
+    if(h >= 10)
+        h += 'a' - (uchar)10 - '0';
+    h += '0';
+    return h;
+}
+
+static void printHex(uchar c)
+{
+    uartPutc(hexAscii(c >> 4));
+    uartPutc(hexAscii(c));
+}
+
+void    odDebug(uchar prefix, uchar *data, uchar len)
+{
+    printHex(prefix);
+    uartPutc(':');
+    while(len--){
+        uartPutc(' ');
+        printHex(*data++);
+    }
+    uartPutc('\r');
+    uartPutc('\n');
+}
+
+#endif

oddebug.h

@@ -0,0 +1,123 @@
+/* Name: oddebug.h
+ * Project: AVR library
+ * Author: Christian Starkjohann
+ * Creation Date: 2005-01-16
+ * Tabsize: 4
+ * Copyright: (c) 2005 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * This Revision: $Id: oddebug.h 692 2008-11-07 15:07:40Z cs $
+ */
+
+#ifndef __oddebug_h_included__
+#define __oddebug_h_included__
+
+/*
+General Description:
+This module implements a function for debug logs on the serial line of the
+AVR microcontroller. Debugging can be configured with the define
+'DEBUG_LEVEL'. If this macro is not defined or defined to 0, all debugging
+calls are no-ops. If it is 1, DBG1 logs will appear, but not DBG2. If it is
+2, DBG1 and DBG2 logs will be printed.
+
+A debug log consists of a label ('prefix') to indicate which debug log created
+the output and a memory block to dump in hex ('data' and 'len').
+*/
+
+
+#ifndef F_CPU
+#   define  F_CPU   12000000    /* 12 MHz */
+#endif
+
+/* make sure we have the UART defines: */
+#include "usbportability.h"
+
+#ifndef uchar
+#   define  uchar   unsigned char
+#endif
+
+#if DEBUG_LEVEL > 0 && !(defined TXEN || defined TXEN0) /* no UART in device */
+#   warning "Debugging disabled because device has no UART"
+#   undef   DEBUG_LEVEL
+#endif
+
+#ifndef DEBUG_LEVEL
+#   define  DEBUG_LEVEL 0
+#endif
+
+/* ------------------------------------------------------------------------- */
+
+#if DEBUG_LEVEL > 0
+#   define  DBG1(prefix, data, len) odDebug(prefix, data, len)
+#else
+#   define  DBG1(prefix, data, len)
+#endif
+
+#if DEBUG_LEVEL > 1
+#   define  DBG2(prefix, data, len) odDebug(prefix, data, len)
+#else
+#   define  DBG2(prefix, data, len)
+#endif
+
+/* ------------------------------------------------------------------------- */
+
+#if DEBUG_LEVEL > 0
+extern void odDebug(uchar prefix, uchar *data, uchar len);
+
+/* Try to find our control registers; ATMEL likes to rename these */
+
+#if defined UBRR
+#   define  ODDBG_UBRR  UBRR
+#elif defined UBRRL
+#   define  ODDBG_UBRR  UBRRL
+#elif defined UBRR0
+#   define  ODDBG_UBRR  UBRR0
+#elif defined UBRR0L
+#   define  ODDBG_UBRR  UBRR0L
+#endif
+
+#if defined UCR
+#   define  ODDBG_UCR   UCR
+#elif defined UCSRB
+#   define  ODDBG_UCR   UCSRB
+#elif defined UCSR0B
+#   define  ODDBG_UCR   UCSR0B
+#endif
+
+#if defined TXEN
+#   define  ODDBG_TXEN  TXEN
+#else
+#   define  ODDBG_TXEN  TXEN0
+#endif
+
+#if defined USR
+#   define  ODDBG_USR   USR
+#elif defined UCSRA
+#   define  ODDBG_USR   UCSRA
+#elif defined UCSR0A
+#   define  ODDBG_USR   UCSR0A
+#endif
+
+#if defined UDRE
+#   define  ODDBG_UDRE  UDRE
+#else
+#   define  ODDBG_UDRE  UDRE0
+#endif
+
+#if defined UDR
+#   define  ODDBG_UDR   UDR
+#elif defined UDR0
+#   define  ODDBG_UDR   UDR0
+#endif
+
+static inline void  odDebugInit(void)
+{
+    ODDBG_UCR |= (1<<ODDBG_TXEN);
+    ODDBG_UBRR = F_CPU / (19200 * 16L) - 1;
+}
+#else
+#   define odDebugInit()
+#endif
+
+/* ------------------------------------------------------------------------- */
+
+#endif /* __oddebug_h_included__ */

usbconfig-prototype.h

@@ -0,0 +1,369 @@
+/* Name: usbconfig.h
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2005-04-01
+ * Tabsize: 4
+ * Copyright: (c) 2005 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * This Revision: $Id: usbconfig-prototype.h 767 2009-08-22 11:39:22Z cs $
+ */
+
+#ifndef __usbconfig_h_included__
+#define __usbconfig_h_included__
+
+/*
+General Description:
+This file is an example configuration (with inline documentation) for the USB
+driver. It configures V-USB for USB D+ connected to Port D bit 2 (which is
+also hardware interrupt 0 on many devices) and USB D- to Port D bit 4. You may
+wire the lines to any other port, as long as D+ is also wired to INT0 (or any
+other hardware interrupt, as long as it is the highest level interrupt, see
+section at the end of this file).
++ To create your own usbconfig.h file, copy this file to your project's
++ firmware source directory) and rename it to "usbconfig.h".
++ Then edit it accordingly.
+*/
+
+/* ---------------------------- Hardware Config ---------------------------- */
+
+#define USB_CFG_IOPORTNAME      D
+/* This is the port where the USB bus is connected. When you configure it to
+ * "B", the registers PORTB, PINB and DDRB will be used.
+ */
+#define USB_CFG_DMINUS_BIT      4
+/* This is the bit number in USB_CFG_IOPORT where the USB D- line is connected.
+ * This may be any bit in the port.
+ */
+#define USB_CFG_DPLUS_BIT       2
+/* This is the bit number in USB_CFG_IOPORT where the USB D+ line is connected.
+ * This may be any bit in the port. Please note that D+ must also be connected
+ * to interrupt pin INT0! [You can also use other interrupts, see section
+ * "Optional MCU Description" below, or you can connect D- to the interrupt, as
+ * it is required if you use the USB_COUNT_SOF feature. If you use D- for the
+ * interrupt, the USB interrupt will also be triggered at Start-Of-Frame
+ * markers every millisecond.]
+ */
+#define USB_CFG_CLOCK_KHZ       (F_CPU/1000)
+/* Clock rate of the AVR in kHz. Legal values are 12000, 12800, 15000, 16000,
+ * 16500 and 20000. The 12.8 MHz and 16.5 MHz versions of the code require no
+ * crystal, they tolerate +/- 1% deviation from the nominal frequency. All
+ * other rates require a precision of 2000 ppm and thus a crystal!
+ * Default if not specified: 12 MHz
+ */
+#define USB_CFG_CHECK_CRC       0
+/* Define this to 1 if you want that the driver checks integrity of incoming
+ * data packets (CRC checks). CRC checks cost quite a bit of code size and are
+ * currently only available for 18 MHz crystal clock. You must choose
+ * USB_CFG_CLOCK_KHZ = 18000 if you enable this option.
+ */
+
+/* ----------------------- Optional Hardware Config ------------------------ */
+
+/* #define USB_CFG_PULLUP_IOPORTNAME   D */
+/* If you connect the 1.5k pullup resistor from D- to a port pin instead of
+ * V+, you can connect and disconnect the device from firmware by calling
+ * the macros usbDeviceConnect() and usbDeviceDisconnect() (see usbdrv.h).
+ * This constant defines the port on which the pullup resistor is connected.
+ */
+/* #define USB_CFG_PULLUP_BIT          4 */
+/* This constant defines the bit number in USB_CFG_PULLUP_IOPORT (defined
+ * above) where the 1.5k pullup resistor is connected. See description
+ * above for details.
+ */
+
+/* --------------------------- Functional Range ---------------------------- */
+
+#define USB_CFG_HAVE_INTRIN_ENDPOINT    0
+/* Define this to 1 if you want to compile a version with two endpoints: The
+ * default control endpoint 0 and an interrupt-in endpoint (any other endpoint
+ * number).
+ */
+#define USB_CFG_HAVE_INTRIN_ENDPOINT3   0
+/* Define this to 1 if you want to compile a version with three endpoints: The
+ * default control endpoint 0, an interrupt-in endpoint 3 (or the number
+ * configured below) and a catch-all default interrupt-in endpoint as above.
+ * You must also define USB_CFG_HAVE_INTRIN_ENDPOINT to 1 for this feature.
+ */
+#define USB_CFG_EP3_NUMBER              3
+/* If the so-called endpoint 3 is used, it can now be configured to any other
+ * endpoint number (except 0) with this macro. Default if undefined is 3.
+ */
+/* #define USB_INITIAL_DATATOKEN           USBPID_DATA1 */
+/* The above macro defines the startup condition for data toggling on the
+ * interrupt/bulk endpoints 1 and 3. Defaults to USBPID_DATA1.
+ * Since the token is toggled BEFORE sending any data, the first packet is
+ * sent with the oposite value of this configuration!
+ */
+#define USB_CFG_IMPLEMENT_HALT          0
+/* Define this to 1 if you also want to implement the ENDPOINT_HALT feature
+ * for endpoint 1 (interrupt endpoint). Although you may not need this feature,
+ * it is required by the standard. We have made it a config option because it
+ * bloats the code considerably.
+ */
+#define USB_CFG_SUPPRESS_INTR_CODE      0
+/* Define this to 1 if you want to declare interrupt-in endpoints, but don't
+ * want to send any data over them. If this macro is defined to 1, functions
+ * usbSetInterrupt() and usbSetInterrupt3() are omitted. This is useful if
+ * you need the interrupt-in endpoints in order to comply to an interface
+ * (e.g. HID), but never want to send any data. This option saves a couple
+ * of bytes in flash memory and the transmit buffers in RAM.
+ */
+#define USB_CFG_INTR_POLL_INTERVAL      10
+/* If you compile a version with endpoint 1 (interrupt-in), this is the poll
+ * interval. The value is in milliseconds and must not be less than 10 ms for
+ * low speed devices.
+ */
+#define USB_CFG_IS_SELF_POWERED         0
+/* Define this to 1 if the device has its own power supply. Set it to 0 if the
+ * device is powered from the USB bus.
+ */
+#define USB_CFG_MAX_BUS_POWER           100
+/* Set this variable to the maximum USB bus power consumption of your device.
+ * The value is in milliamperes. [It will be divided by two since USB
+ * communicates power requirements in units of 2 mA.]
+ */
+#define USB_CFG_IMPLEMENT_FN_WRITE      0
+/* Set this to 1 if you want usbFunctionWrite() to be called for control-out
+ * transfers. Set it to 0 if you don't need it and want to save a couple of
+ * bytes.
+ */
+#define USB_CFG_IMPLEMENT_FN_READ       0
+/* Set this to 1 if you need to send control replies which are generated
+ * "on the fly" when usbFunctionRead() is called. If you only want to send
+ * data from a static buffer, set it to 0 and return the data from
+ * usbFunctionSetup(). This saves a couple of bytes.
+ */
+#define USB_CFG_IMPLEMENT_FN_WRITEOUT   0
+/* Define this to 1 if you want to use interrupt-out (or bulk out) endpoints.
+ * You must implement the function usbFunctionWriteOut() which receives all
+ * interrupt/bulk data sent to any endpoint other than 0. The endpoint number
+ * can be found in 'usbRxToken'.
+ */
+#define USB_CFG_HAVE_FLOWCONTROL        0
+/* Define this to 1 if you want flowcontrol over USB data. See the definition
+ * of the macros usbDisableAllRequests() and usbEnableAllRequests() in
+ * usbdrv.h.
+ */
+#define USB_CFG_LONG_TRANSFERS          0
+/* Define this to 1 if you want to send/receive blocks of more than 254 bytes
+ * in a single control-in or control-out transfer. Note that the capability
+ * for long transfers increases the driver size.
+ */
+/* #define USB_RX_USER_HOOK(data, len)     if(usbRxToken == (uchar)USBPID_SETUP) blinkLED(); */
+/* This macro is a hook if you want to do unconventional things. If it is
+ * defined, it's inserted at the beginning of received message processing.
+ * If you eat the received message and don't want default processing to
+ * proceed, do a return after doing your things. One possible application
+ * (besides debugging) is to flash a status LED on each packet.
+ */
+/* #define USB_RESET_HOOK(resetStarts)     if(!resetStarts){hadUsbReset();} */
+/* This macro is a hook if you need to know when an USB RESET occurs. It has
+ * one parameter which distinguishes between the start of RESET state and its
+ * end.
+ */
+/* #define USB_SET_ADDRESS_HOOK()              hadAddressAssigned(); */
+/* This macro (if defined) is executed when a USB SET_ADDRESS request was
+ * received.
+ */
+#define USB_COUNT_SOF                   0
+/* define this macro to 1 if you need the global variable "usbSofCount" which
+ * counts SOF packets. This feature requires that the hardware interrupt is
+ * connected to D- instead of D+.
+ */
+/* #ifdef __ASSEMBLER__
+ * macro myAssemblerMacro
+ *     in      YL, TCNT0
+ *     sts     timer0Snapshot, YL
+ *     endm
+ * #endif
+ * #define USB_SOF_HOOK                    myAssemblerMacro
+ * This macro (if defined) is executed in the assembler module when a
+ * Start Of Frame condition is detected. It is recommended to define it to
+ * the name of an assembler macro which is defined here as well so that more
+ * than one assembler instruction can be used. The macro may use the register
+ * YL and modify SREG. If it lasts longer than a couple of cycles, USB messages
+ * immediately after an SOF pulse may be lost and must be retried by the host.
+ * What can you do with this hook? Since the SOF signal occurs exactly every
+ * 1 ms (unless the host is in sleep mode), you can use it to tune OSCCAL in
+ * designs running on the internal RC oscillator.
+ * Please note that Start Of Frame detection works only if D- is wired to the
+ * interrupt, not D+. THIS IS DIFFERENT THAN MOST EXAMPLES!
+ */
+#define USB_CFG_CHECK_DATA_TOGGLING     0
+/* define this macro to 1 if you want to filter out duplicate data packets
+ * sent by the host. Duplicates occur only as a consequence of communication
+ * errors, when the host does not receive an ACK. Please note that you need to
+ * implement the filtering yourself in usbFunctionWriteOut() and
+ * usbFunctionWrite(). Use the global usbCurrentDataToken and a static variable
+ * for each control- and out-endpoint to check for duplicate packets.
+ */
+#define USB_CFG_HAVE_MEASURE_FRAME_LENGTH   0
+/* define this macro to 1 if you want the function usbMeasureFrameLength()
+ * compiled in. This function can be used to calibrate the AVR's RC oscillator.
+ */
+#define USB_USE_FAST_CRC                0
+/* The assembler module has two implementations for the CRC algorithm. One is
+ * faster, the other is smaller. This CRC routine is only used for transmitted
+ * messages where timing is not critical. The faster routine needs 31 cycles
+ * per byte while the smaller one needs 61 to 69 cycles. The faster routine
+ * may be worth the 32 bytes bigger code size if you transmit lots of data and
+ * run the AVR close to its limit.
+ */
+
+/* -------------------------- Device Description --------------------------- */
+
+#define  USB_CFG_VENDOR_ID       0xc0, 0x16 /* = 0x16c0 = 5824 = voti.nl */
+/* USB vendor ID for the device, low byte first. If you have registered your
+ * own Vendor ID, define it here. Otherwise you may use one of obdev's free
+ * shared VID/PID pairs. Be sure to read USB-IDs-for-free.txt for rules!
+ * *** IMPORTANT NOTE ***
+ * This template uses obdev's shared VID/PID pair for Vendor Class devices
+ * with libusb: 0x16c0/0x5dc.  Use this VID/PID pair ONLY if you understand
+ * the implications!
+ */
+#define  USB_CFG_DEVICE_ID       0xdc, 0x05 /* = 0x05dc = 1500 */
+/* This is the ID of the product, low byte first. It is interpreted in the
+ * scope of the vendor ID. If you have registered your own VID with usb.org
+ * or if you have licensed a PID from somebody else, define it here. Otherwise
+ * you may use one of obdev's free shared VID/PID pairs. See the file
+ * USB-IDs-for-free.txt for details!
+ * *** IMPORTANT NOTE ***
+ * This template uses obdev's shared VID/PID pair for Vendor Class devices
+ * with libusb: 0x16c0/0x5dc.  Use this VID/PID pair ONLY if you understand
+ * the implications!
+ */
+#define USB_CFG_DEVICE_VERSION  0x00, 0x01
+/* Version number of the device: Minor number first, then major number.
+ */
+#define USB_CFG_VENDOR_NAME     'o', 'b', 'd', 'e', 'v', '.', 'a', 't'
+#define USB_CFG_VENDOR_NAME_LEN 8
+/* These two values define the vendor name returned by the USB device. The name
+ * must be given as a list of characters under single quotes. The characters
+ * are interpreted as Unicode (UTF-16) entities.
+ * If you don't want a vendor name string, undefine these macros.
+ * ALWAYS define a vendor name containing your Internet domain name if you use
+ * obdev's free shared VID/PID pair. See the file USB-IDs-for-free.txt for
+ * details.
+ */
+#define USB_CFG_DEVICE_NAME     'T', 'e', 'm', 'p', 'l', 'a', 't', 'e'
+#define USB_CFG_DEVICE_NAME_LEN 8
+/* Same as above for the device name. If you don't want a device name, undefine
+ * the macros. See the file USB-IDs-for-free.txt before you assign a name if
+ * you use a shared VID/PID.
+ */
+/*#define USB_CFG_SERIAL_NUMBER   'N', 'o', 'n', 'e' */
+/*#define USB_CFG_SERIAL_NUMBER_LEN   0 */
+/* Same as above for the serial number. If you don't want a serial number,
+ * undefine the macros.
+ * It may be useful to provide the serial number through other means than at
+ * compile time. See the section about descriptor properties below for how
+ * to fine tune control over USB descriptors such as the string descriptor
+ * for the serial number.
+ */
+#define USB_CFG_DEVICE_CLASS        0xff    /* set to 0 if deferred to interface */
+#define USB_CFG_DEVICE_SUBCLASS     0
+/* See USB specification if you want to conform to an existing device class.
+ * Class 0xff is "vendor specific".
+ */
+#define USB_CFG_INTERFACE_CLASS     0   /* define class here if not at device level */
+#define USB_CFG_INTERFACE_SUBCLASS  0
+#define USB_CFG_INTERFACE_PROTOCOL  0
+/* See USB specification if you want to conform to an existing device class or
+ * protocol. The following classes must be set at interface level:
+ * HID class is 3, no subclass and protocol required (but may be useful!)
+ * CDC class is 2, use subclass 2 and protocol 1 for ACM
+ */
+/* #define USB_CFG_HID_REPORT_DESCRIPTOR_LENGTH    42 */
+/* Define this to the length of the HID report descriptor, if you implement
+ * an HID device. Otherwise don't define it or define it to 0.
+ * If you use this define, you must add a PROGMEM character array named
+ * "usbHidReportDescriptor" to your code which contains the report descriptor.
+ * Don't forget to keep the array and this define in sync!
+ */
+
+/* #define USB_PUBLIC static */
+/* Use the define above if you #include usbdrv.c instead of linking against it.
+ * This technique saves a couple of bytes in flash memory.
+ */
+
+/* ------------------- Fine Control over USB Descriptors ------------------- */
+/* If you don't want to use the driver's default USB descriptors, you can
+ * provide our own. These can be provided as (1) fixed length static data in
+ * flash memory, (2) fixed length static data in RAM or (3) dynamically at
+ * runtime in the function usbFunctionDescriptor(). See usbdrv.h for more
+ * information about this function.
+ * Descriptor handling is configured through the descriptor's properties. If
+ * no properties are defined or if they are 0, the default descriptor is used.
+ * Possible properties are:
+ *   + USB_PROP_IS_DYNAMIC: The data for the descriptor should be fetched
+ *     at runtime via usbFunctionDescriptor(). If the usbMsgPtr mechanism is
+ *     used, the data is in FLASH by default. Add property USB_PROP_IS_RAM if
+ *     you want RAM pointers.
+ *   + USB_PROP_IS_RAM: The data returned by usbFunctionDescriptor() or found
+ *     in static memory is in RAM, not in flash memory.
+ *   + USB_PROP_LENGTH(len): If the data is in static memory (RAM or flash),
+ *     the driver must know the descriptor's length. The descriptor itself is
+ *     found at the address of a well known identifier (see below).
+ * List of static descriptor names (must be declared PROGMEM if in flash):
+ *   char usbDescriptorDevice[];
+ *   char usbDescriptorConfiguration[];
+ *   char usbDescriptorHidReport[];
+ *   char usbDescriptorString0[];
+ *   int usbDescriptorStringVendor[];
+ *   int usbDescriptorStringDevice[];
+ *   int usbDescriptorStringSerialNumber[];
+ * Other descriptors can't be provided statically, they must be provided
+ * dynamically at runtime.
+ *
+ * Descriptor properties are or-ed or added together, e.g.:
+ * #define USB_CFG_DESCR_PROPS_DEVICE   (USB_PROP_IS_RAM | USB_PROP_LENGTH(18))
+ *
+ * The following descriptors are defined:
+ *   USB_CFG_DESCR_PROPS_DEVICE
+ *   USB_CFG_DESCR_PROPS_CONFIGURATION
+ *   USB_CFG_DESCR_PROPS_STRINGS
+ *   USB_CFG_DESCR_PROPS_STRING_0
+ *   USB_CFG_DESCR_PROPS_STRING_VENDOR
+ *   USB_CFG_DESCR_PROPS_STRING_PRODUCT
+ *   USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER
+ *   USB_CFG_DESCR_PROPS_HID
+ *   USB_CFG_DESCR_PROPS_HID_REPORT
+ *   USB_CFG_DESCR_PROPS_UNKNOWN (for all descriptors not handled by the driver)
+ *
+ * Note about string descriptors: String descriptors are not just strings, they
+ * are Unicode strings prefixed with a 2 byte header. Example:
+ * int  serialNumberDescriptor[] = {
+ *     USB_STRING_DESCRIPTOR_HEADER(6),
+ *     'S', 'e', 'r', 'i', 'a', 'l'
+ * };
+ */
+
+#define USB_CFG_DESCR_PROPS_DEVICE                  0
+#define USB_CFG_DESCR_PROPS_CONFIGURATION           0
+#define USB_CFG_DESCR_PROPS_STRINGS                 0
+#define USB_CFG_DESCR_PROPS_STRING_0                0
+#define USB_CFG_DESCR_PROPS_STRING_VENDOR           0
+#define USB_CFG_DESCR_PROPS_STRING_PRODUCT          0
+#define USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER    0
+#define USB_CFG_DESCR_PROPS_HID                     0
+#define USB_CFG_DESCR_PROPS_HID_REPORT              0
+#define USB_CFG_DESCR_PROPS_UNKNOWN                 0
+
+/* ----------------------- Optional MCU Description ------------------------ */
+
+/* The following configurations have working defaults in usbdrv.h. You
+ * usually don't need to set them explicitly. Only if you want to run
+ * the driver on a device which is not yet supported or with a compiler
+ * which is not fully supported (such as IAR C) or if you use a differnt
+ * interrupt than INT0, you may have to define some of these.
+ */
+/* #define USB_INTR_CFG            MCUCR */
+/* #define USB_INTR_CFG_SET        ((1 << ISC00) | (1 << ISC01)) */
+/* #define USB_INTR_CFG_CLR        0 */
+/* #define USB_INTR_ENABLE         GIMSK */
+/* #define USB_INTR_ENABLE_BIT     INT0 */
+/* #define USB_INTR_PENDING        GIFR */
+/* #define USB_INTR_PENDING_BIT    INTF0 */
+/* #define USB_INTR_VECTOR         SIG_INTERRUPT0 */
+
+#endif /* __usbconfig_h_included__ */

usbconfig.h

@@ -0,0 +1,371 @@
+/* Name: usbconfig.h
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2005-04-01
+ * Tabsize: 4
+ * Copyright: (c) 2005 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * This Revision: $Id: usbconfig-prototype.h 767 2009-08-22 11:39:22Z cs $
+ */
+
+#ifndef __usbconfig_h_included__
+#define __usbconfig_h_included__
+
+/*
+General Description:
+This file is an example configuration (with inline documentation) for the USB
+driver. It configures V-USB for USB D+ connected to Port D bit 2 (which is
+also hardware interrupt 0 on many devices) and USB D- to Port D bit 4. You may
+wire the lines to any other port, as long as D+ is also wired to INT0 (or any
+other hardware interrupt, as long as it is the highest level interrupt, see
+section at the end of this file).
++ To create your own usbconfig.h file, copy this file to your project's
++ firmware source directory) and rename it to "usbconfig.h".
++ Then edit it accordingly.
+*/
+
+/* ---------------------------- Hardware Config ---------------------------- */
+
+#define USB_CFG_IOPORTNAME      D
+/* This is the port where the USB bus is connected. When you configure it to
+ * "B", the registers PORTB, PINB and DDRB will be used.
+ */
+#define USB_CFG_DMINUS_BIT      4
+/* This is the bit number in USB_CFG_IOPORT where the USB D- line is connected.
+ * This may be any bit in the port.
+ */
+#define USB_CFG_DPLUS_BIT       2
+/* This is the bit number in USB_CFG_IOPORT where the USB D+ line is connected.
+ * This may be any bit in the port. Please note that D+ must also be connected
+ * to interrupt pin INT0! [You can also use other interrupts, see section
+ * "Optional MCU Description" below, or you can connect D- to the interrupt, as
+ * it is required if you use the USB_COUNT_SOF feature. If you use D- for the
+ * interrupt, the USB interrupt will also be triggered at Start-Of-Frame
+ * markers every millisecond.]
+ */
+#define USB_CFG_CLOCK_KHZ       (F_CPU/1000)
+/* Clock rate of the AVR in kHz. Legal values are 12000, 12800, 15000, 16000,
+ * 16500 and 20000. The 12.8 MHz and 16.5 MHz versions of the code require no
+ * crystal, they tolerate +/- 1% deviation from the nominal frequency. All
+ * other rates require a precision of 2000 ppm and thus a crystal!
+ * Default if not specified: 12 MHz
+ */
+#define USB_CFG_CHECK_CRC       0
+/* Define this to 1 if you want that the driver checks integrity of incoming
+ * data packets (CRC checks). CRC checks cost quite a bit of code size and are
+ * currently only available for 18 MHz crystal clock. You must choose
+ * USB_CFG_CLOCK_KHZ = 18000 if you enable this option.
+ */
+
+/* ----------------------- Optional Hardware Config ------------------------ */
+
+#define USB_CFG_PULLUP_IOPORTNAME   D
+/* If you connect the 1.5k pullup resistor from D- to a port pin instead of
+ * V+, you can connect and disconnect the device from firmware by calling
+ * the macros usbDeviceConnect() and usbDeviceDisconnect() (see usbdrv.h).
+ * This constant defines the port on which the pullup resistor is connected.
+ */
+#define USB_CFG_PULLUP_BIT          5
+/* This constant defines the bit number in USB_CFG_PULLUP_IOPORT (defined
+ * above) where the 1.5k pullup resistor is connected. See description
+ * above for details.
+ */
+
+/* --------------------------- Functional Range ---------------------------- */
+
+#define USB_CFG_HAVE_INTRIN_ENDPOINT    1
+/* Define this to 1 if you want to compile a version with two endpoints: The
+ * default control endpoint 0 and an interrupt-in endpoint (any other endpoint
+ * number).
+ */
+#define USB_CFG_HAVE_INTRIN_ENDPOINT3   0
+/* Define this to 1 if you want to compile a version with three endpoints: The
+ * default control endpoint 0, an interrupt-in endpoint 3 (or the number
+ * configured below) and a catch-all default interrupt-in endpoint as above.
+ * You must also define USB_CFG_HAVE_INTRIN_ENDPOINT to 1 for this feature.
+ */
+#define USB_CFG_EP3_NUMBER              3
+/* If the so-called endpoint 3 is used, it can now be configured to any other
+ * endpoint number (except 0) with this macro. Default if undefined is 3.
+ */
+/* #define USB_INITIAL_DATATOKEN           USBPID_DATA1 */
+/* The above macro defines the startup condition for data toggling on the
+ * interrupt/bulk endpoints 1 and 3. Defaults to USBPID_DATA1.
+ * Since the token is toggled BEFORE sending any data, the first packet is
+ * sent with the oposite value of this configuration!
+ */
+#define USB_CFG_IMPLEMENT_HALT          0
+/* Define this to 1 if you also want to implement the ENDPOINT_HALT feature
+ * for endpoint 1 (interrupt endpoint). Although you may not need this feature,
+ * it is required by the standard. We have made it a config option because it
+ * bloats the code considerably.
+ */
+#define USB_CFG_SUPPRESS_INTR_CODE      0
+/* Define this to 1 if you want to declare interrupt-in endpoints, but don't
+ * want to send any data over them. If this macro is defined to 1, functions
+ * usbSetInterrupt() and usbSetInterrupt3() are omitted. This is useful if
+ * you need the interrupt-in endpoints in order to comply to an interface
+ * (e.g. HID), but never want to send any data. This option saves a couple
+ * of bytes in flash memory and the transmit buffers in RAM.
+ */
+#define USB_CFG_INTR_POLL_INTERVAL      10
+/* If you compile a version with endpoint 1 (interrupt-in), this is the poll
+ * interval. The value is in milliseconds and must not be less than 10 ms for
+ * low speed devices.
+ */
+#define USB_CFG_IS_SELF_POWERED         0
+/* Define this to 1 if the device has its own power supply. Set it to 0 if the
+ * device is powered from the USB bus.
+ */
+#define USB_CFG_MAX_BUS_POWER           100
+/* Set this variable to the maximum USB bus power consumption of your device.
+ * The value is in milliamperes. [It will be divided by two since USB
+ * communicates power requirements in units of 2 mA.]
+ */
+#define USB_CFG_IMPLEMENT_FN_WRITE      0
+/* Set this to 1 if you want usbFunctionWrite() to be called for control-out
+ * transfers. Set it to 0 if you don't need it and want to save a couple of
+ * bytes.
+ */
+#define USB_CFG_IMPLEMENT_FN_READ       0
+/* Set this to 1 if you need to send control replies which are generated
+ * "on the fly" when usbFunctionRead() is called. If you only want to send
+ * data from a static buffer, set it to 0 and return the data from
+ * usbFunctionSetup(). This saves a couple of bytes.
+ */
+#define USB_CFG_IMPLEMENT_FN_WRITEOUT   0
+/* Define this to 1 if you want to use interrupt-out (or bulk out) endpoints.
+ * You must implement the function usbFunctionWriteOut() which receives all
+ * interrupt/bulk data sent to any endpoint other than 0. The endpoint number
+ * can be found in 'usbRxToken'.
+ */
+#define USB_CFG_HAVE_FLOWCONTROL        0
+/* Define this to 1 if you want flowcontrol over USB data. See the definition
+ * of the macros usbDisableAllRequests() and usbEnableAllRequests() in
+ * usbdrv.h.
+ */
+#define USB_CFG_LONG_TRANSFERS          0
+/* Define this to 1 if you want to send/receive blocks of more than 254 bytes
+ * in a single control-in or control-out transfer. Note that the capability
+ * for long transfers increases the driver size.
+ */
+/* #define USB_RX_USER_HOOK(data, len)     if(usbRxToken == (uchar)USBPID_SETUP) blinkLED(); */
+/* This macro is a hook if you want to do unconventional things. If it is
+ * defined, it's inserted at the beginning of received message processing.
+ * If you eat the received message and don't want default processing to
+ * proceed, do a return after doing your things. One possible application
+ * (besides debugging) is to flash a status LED on each packet.
+ */
+/* #define USB_RESET_HOOK(resetStarts)     if(!resetStarts){hadUsbReset();} */
+/* This macro is a hook if you need to know when an USB RESET occurs. It has
+ * one parameter which distinguishes between the start of RESET state and its
+ * end.
+ */
+/* #define USB_SET_ADDRESS_HOOK()              hadAddressAssigned(); */
+/* This macro (if defined) is executed when a USB SET_ADDRESS request was
+ * received.
+ */
+#define USB_COUNT_SOF                   0
+/* define this macro to 1 if you need the global variable "usbSofCount" which
+ * counts SOF packets. This feature requires that the hardware interrupt is
+ * connected to D- instead of D+.
+ */
+/* #ifdef __ASSEMBLER__
+ * macro myAssemblerMacro
+ *     in      YL, TCNT0
+ *     sts     timer0Snapshot, YL
+ *     endm
+ * #endif
+ * #define USB_SOF_HOOK                    myAssemblerMacro
+ * This macro (if defined) is executed in the assembler module when a
+ * Start Of Frame condition is detected. It is recommended to define it to
+ * the name of an assembler macro which is defined here as well so that more
+ * than one assembler instruction can be used. The macro may use the register
+ * YL and modify SREG. If it lasts longer than a couple of cycles, USB messages
+ * immediately after an SOF pulse may be lost and must be retried by the host.
+ * What can you do with this hook? Since the SOF signal occurs exactly every
+ * 1 ms (unless the host is in sleep mode), you can use it to tune OSCCAL in
+ * designs running on the internal RC oscillator.
+ * Please note that Start Of Frame detection works only if D- is wired to the
+ * interrupt, not D+. THIS IS DIFFERENT THAN MOST EXAMPLES!
+ */
+#define USB_CFG_CHECK_DATA_TOGGLING     0
+/* define this macro to 1 if you want to filter out duplicate data packets
+ * sent by the host. Duplicates occur only as a consequence of communication
+ * errors, when the host does not receive an ACK. Please note that you need to
+ * implement the filtering yourself in usbFunctionWriteOut() and
+ * usbFunctionWrite(). Use the global usbCurrentDataToken and a static variable
+ * for each control- and out-endpoint to check for duplicate packets.
+ */
+#define USB_CFG_HAVE_MEASURE_FRAME_LENGTH   0
+/* define this macro to 1 if you want the function usbMeasureFrameLength()
+ * compiled in. This function can be used to calibrate the AVR's RC oscillator.
+ */
+#define USB_USE_FAST_CRC                0
+/* The assembler module has two implementations for the CRC algorithm. One is
+ * faster, the other is smaller. This CRC routine is only used for transmitted
+ * messages where timing is not critical. The faster routine needs 31 cycles
+ * per byte while the smaller one needs 61 to 69 cycles. The faster routine
+ * may be worth the 32 bytes bigger code size if you transmit lots of data and
+ * run the AVR close to its limit.
+ */
+
+/* -------------------------- Device Description --------------------------- */
+
+#define  USB_CFG_VENDOR_ID       0x42, 0x42
+/* USB vendor ID for the device, low byte first. If you have registered your
+ * own Vendor ID, define it here. Otherwise you may use one of obdev's free
+ * shared VID/PID pairs. Be sure to read USB-IDs-for-free.txt for rules!
+ * *** IMPORTANT NOTE ***
+ * This template uses obdev's shared VID/PID pair for Vendor Class devices
+ * with libusb: 0x16c0/0x5dc.  Use this VID/PID pair ONLY if you understand
+ * the implications!
+ */
+#define  USB_CFG_DEVICE_ID       0x31, 0xe1
+/* This is the ID of the product, low byte first. It is interpreted in the
+ * scope of the vendor ID. If you have registered your own VID with usb.org
+ * or if you have licensed a PID from somebody else, define it here. Otherwise
+ * you may use one of obdev's free shared VID/PID pairs. See the file
+ * USB-IDs-for-free.txt for details!
+ * *** IMPORTANT NOTE ***
+ * This template uses obdev's shared VID/PID pair for Vendor Class devices
+ * with libusb: 0x16c0/0x5dc.  Use this VID/PID pair ONLY if you understand
+ * the implications!
+ */
+#define USB_CFG_DEVICE_VERSION  0x00, 0x01
+/* Version number of the device: Minor number first, then major number.
+ */
+#define USB_CFG_VENDOR_NAME     'r','t','h','o','n','i','.','c','o','m'
+#define USB_CFG_VENDOR_NAME_LEN 10
+/* These two values define the vendor name returned by the USB device. The name
+ * must be given as a list of characters under single quotes. The characters
+ * are interpreted as Unicode (UTF-16) entities.
+ * If you don't want a vendor name string, undefine these macros.
+ * ALWAYS define a vendor name containing your Internet domain name if you use
+ * obdev's free shared VID/PID pair. See the file USB-IDs-for-free.txt for
+ * details.
+ */
+#define USB_CFG_DEVICE_NAME     'R','o','b','l','o','w','c','h','o','n'
+#define USB_CFG_DEVICE_NAME_LEN 10
+/* Same as above for the device name. If you don't want a device name, undefine
+ * the macros. See the file USB-IDs-for-free.txt before you assign a name if
+ * you use a shared VID/PID.
+ */
+/*#define USB_CFG_SERIAL_NUMBER   'N', 'o', 'n', 'e' */
+/*#define USB_CFG_SERIAL_NUMBER_LEN   0 */
+/* Same as above for the serial number. If you don't want a serial number,
+ * undefine the macros.
+ * It may be useful to provide the serial number through other means than at
+ * compile time. See the section about descriptor properties below for how
+ * to fine tune control over USB descriptors such as the string descriptor
+ * for the serial number.
+ */
+#define USB_CFG_DEVICE_CLASS        0    /* set to 0 if deferred to interface */
+#define USB_CFG_DEVICE_SUBCLASS     0
+/* See USB specification if you want to conform to an existing device class.
+ * Class 0xff is "vendor specific".
+ */
+#define USB_CFG_INTERFACE_CLASS     0x03  /* HID */ /* define class here if not at device level */
+#define USB_CFG_INTERFACE_SUBCLASS  0
+#define USB_CFG_INTERFACE_PROTOCOL  0
+/* See USB specification if you want to conform to an existing device class or
+ * protocol. The following classes must be set at interface level:
+ * HID class is 3, no subclass and protocol required (but may be useful!)
+ * CDC class is 2, use subclass 2 and protocol 1 for ACM
+ */
+#define USB_CFG_HID_REPORT_DESCRIPTOR_LENGTH    35
+/* Define this to the length of the HID report descriptor, if you implement
+ * an HID device. Otherwise don't define it or define it to 0.
+ * If you use this define, you must add a PROGMEM character array named
+ * "usbHidReportDescriptor" to your code which contains the report descriptor.
+ * Don't forget to keep the array and this define in sync!
+ */
+
+/* #define USB_PUBLIC static */
+/* Use the define above if you #include usbdrv.c instead of linking against it.
+ * This technique saves a couple of bytes in flash memory.
+ */
+
+/* ------------------- Fine Control over USB Descriptors ------------------- */
+/* If you don't want to use the driver's default USB descriptors, you can
+ * provide our own. These can be provided as (1) fixed length static data in
+ * flash memory, (2) fixed length static data in RAM or (3) dynamically at
+ * runtime in the function usbFunctionDescriptor(). See usbdrv.h for more
+ * information about this function.
+ * Descriptor handling is configured through the descriptor's properties. If
+ * no properties are defined or if they are 0, the default descriptor is used.
+ * Possible properties are:
+ *   + USB_PROP_IS_DYNAMIC: The data for the descriptor should be fetched
+ *     at runtime via usbFunctionDescriptor(). If the usbMsgPtr mechanism is
+ *     used, the data is in FLASH by default. Add property USB_PROP_IS_RAM if
+ *     you want RAM pointers.
+ *   + USB_PROP_IS_RAM: The data returned by usbFunctionDescriptor() or found
+ *     in static memory is in RAM, not in flash memory.
+ *   + USB_PROP_LENGTH(len): If the data is in static memory (RAM or flash),
+ *     the driver must know the descriptor's length. The descriptor itself is
+ *     found at the address of a well known identifier (see below).
+ * List of static descriptor names (must be declared PROGMEM if in flash):
+ *   char usbDescriptorDevice[];
+ *   char usbDescriptorConfiguration[];
+ *   char usbDescriptorHidReport[];
+ *   char usbDescriptorString0[];
+ *   int usbDescriptorStringVendor[];
+ *   int usbDescriptorStringDevice[];
+ *   int usbDescriptorStringSerialNumber[];
+ * Other descriptors can't be provided statically, they must be provided
+ * dynamically at runtime.
+ *
+ * Descriptor properties are or-ed or added together, e.g.:
+ * #define USB_CFG_DESCR_PROPS_DEVICE   (USB_PROP_IS_RAM | USB_PROP_LENGTH(18))
+ *
+ * The following descriptors are defined:
+ *   USB_CFG_DESCR_PROPS_DEVICE
+ *   USB_CFG_DESCR_PROPS_CONFIGURATION
+ *   USB_CFG_DESCR_PROPS_STRINGS
+ *   USB_CFG_DESCR_PROPS_STRING_0
+ *   USB_CFG_DESCR_PROPS_STRING_VENDOR
+ *   USB_CFG_DESCR_PROPS_STRING_PRODUCT
+ *   USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER
+ *   USB_CFG_DESCR_PROPS_HID
+ *   USB_CFG_DESCR_PROPS_HID_REPORT
+ *   USB_CFG_DESCR_PROPS_UNKNOWN (for all descriptors not handled by the driver)
+ *
+ * Note about string descriptors: String descriptors are not just strings, they
+ * are Unicode strings prefixed with a 2 byte header. Example:
+ * int  serialNumberDescriptor[] = {
+ *     USB_STRING_DESCRIPTOR_HEADER(6),
+ *     'S', 'e', 'r', 'i', 'a', 'l'
+ * };
+ */
+
+#define USB_CFG_DESCR_PROPS_DEVICE                  0
+#define USB_CFG_DESCR_PROPS_CONFIGURATION           0
+#define USB_CFG_DESCR_PROPS_STRINGS                 0
+#define USB_CFG_DESCR_PROPS_STRING_0                0
+#define USB_CFG_DESCR_PROPS_STRING_VENDOR           0
+#define USB_CFG_DESCR_PROPS_STRING_PRODUCT          0
+#define USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER    0
+#define USB_CFG_DESCR_PROPS_HID                     0
+#define USB_CFG_DESCR_PROPS_HID_REPORT              0
+#define USB_CFG_DESCR_PROPS_UNKNOWN                 0
+
+/* ----------------------- Optional MCU Description ------------------------ */
+
+/* The following configurations have working defaults in usbdrv.h. You
+ * usually don't need to set them explicitly. Only if you want to run
+ * the driver on a device which is not yet supported or with a compiler
+ * which is not fully supported (such as IAR C) or if you use a differnt
+ * interrupt than INT0, you may have to define some of these.
+ */
+/* #define USB_INTR_CFG            MCUCR */
+/* #define USB_INTR_CFG_SET        ((1 << ISC00) | (1 << ISC01)) */
+/* #define USB_INTR_CFG_CLR        0 */
+/* #define USB_INTR_ENABLE         GIMSK */
+/* #define USB_INTR_ENABLE_BIT     INT0 */
+/* #define USB_INTR_PENDING        GIFR */
+/* #define USB_INTR_PENDING_BIT    INTF0 */
+/* #define USB_INTR_VECTOR         SIG_INTERRUPT0 */
+
+#define USB_INTR_VECTOR INT0_vect
+
+#endif /* __usbconfig_h_included__ */

usbdrv.c

@@ -0,0 +1,625 @@
+/* Name: usbdrv.c
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2004-12-29
+ * Tabsize: 4
+ * Copyright: (c) 2005 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * This Revision: $Id: usbdrv.c 763 2009-08-22 10:27:24Z cs $
+ */
+
+#include "usbportability.h"
+#include "usbdrv.h"
+#include "oddebug.h"
+
+/*
+General Description:
+This module implements the C-part of the USB driver. See usbdrv.h for a
+documentation of the entire driver.
+*/
+
+/* ------------------------------------------------------------------------- */
+
+/* raw USB registers / interface to assembler code: */
+uchar usbRxBuf[2*USB_BUFSIZE];  /* raw RX buffer: PID, 8 bytes data, 2 bytes CRC */
+uchar       usbInputBufOffset;  /* offset in usbRxBuf used for low level receiving */
+uchar       usbDeviceAddr;      /* assigned during enumeration, defaults to 0 */
+uchar       usbNewDeviceAddr;   /* device ID which should be set after status phase */
+uchar       usbConfiguration;   /* currently selected configuration. Administered by driver, but not used */
+volatile schar usbRxLen;        /* = 0; number of bytes in usbRxBuf; 0 means free, -1 for flow control */
+uchar       usbCurrentTok;      /* last token received or endpoint number for last OUT token if != 0 */
+uchar       usbRxToken;         /* token for data we received; or endpont number for last OUT */
+volatile uchar usbTxLen = USBPID_NAK;   /* number of bytes to transmit with next IN token or handshake token */
+uchar       usbTxBuf[USB_BUFSIZE];/* data to transmit with next IN, free if usbTxLen contains handshake token */
+#if USB_COUNT_SOF
+volatile uchar  usbSofCount;    /* incremented by assembler module every SOF */
+#endif
+#if USB_CFG_HAVE_INTRIN_ENDPOINT && !USB_CFG_SUPPRESS_INTR_CODE
+usbTxStatus_t  usbTxStatus1;
+#   if USB_CFG_HAVE_INTRIN_ENDPOINT3
+usbTxStatus_t  usbTxStatus3;
+#   endif
+#endif
+#if USB_CFG_CHECK_DATA_TOGGLING
+uchar       usbCurrentDataToken;/* when we check data toggling to ignore duplicate packets */
+#endif
+
+/* USB status registers / not shared with asm code */
+uchar               *usbMsgPtr;     /* data to transmit next -- ROM or RAM address */
+static usbMsgLen_t  usbMsgLen = USB_NO_MSG; /* remaining number of bytes */
+static uchar        usbMsgFlags;    /* flag values see below */
+
+#define USB_FLG_MSGPTR_IS_ROM   (1<<6)
+#define USB_FLG_USE_USER_RW     (1<<7)
+
+/*
+optimizing hints:
+- do not post/pre inc/dec integer values in operations
+- assign value of USB_READ_FLASH() to register variables and don't use side effects in arg
+- use narrow scope for variables which should be in X/Y/Z register
+- assign char sized expressions to variables to force 8 bit arithmetics
+*/
+
+/* -------------------------- String Descriptors --------------------------- */
+
+#if USB_CFG_DESCR_PROPS_STRINGS == 0
+
+#if USB_CFG_DESCR_PROPS_STRING_0 == 0
+#undef USB_CFG_DESCR_PROPS_STRING_0
+#define USB_CFG_DESCR_PROPS_STRING_0    sizeof(usbDescriptorString0)
+PROGMEM char usbDescriptorString0[] = { /* language descriptor */
+    4,          /* sizeof(usbDescriptorString0): length of descriptor in bytes */
+    3,          /* descriptor type */
+    0x09, 0x04, /* language index (0x0409 = US-English) */
+};
+#endif
+
+#if USB_CFG_DESCR_PROPS_STRING_VENDOR == 0 && USB_CFG_VENDOR_NAME_LEN
+#undef USB_CFG_DESCR_PROPS_STRING_VENDOR
+#define USB_CFG_DESCR_PROPS_STRING_VENDOR   sizeof(usbDescriptorStringVendor)
+PROGMEM int  usbDescriptorStringVendor[] = {
+    USB_STRING_DESCRIPTOR_HEADER(USB_CFG_VENDOR_NAME_LEN),
+    USB_CFG_VENDOR_NAME
+};
+#endif
+
+#if USB_CFG_DESCR_PROPS_STRING_PRODUCT == 0 && USB_CFG_DEVICE_NAME_LEN
+#undef USB_CFG_DESCR_PROPS_STRING_PRODUCT
+#define USB_CFG_DESCR_PROPS_STRING_PRODUCT   sizeof(usbDescriptorStringDevice)
+PROGMEM int  usbDescriptorStringDevice[] = {
+    USB_STRING_DESCRIPTOR_HEADER(USB_CFG_DEVICE_NAME_LEN),
+    USB_CFG_DEVICE_NAME
+};
+#endif
+
+#if USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER == 0 && USB_CFG_SERIAL_NUMBER_LEN
+#undef USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER
+#define USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER    sizeof(usbDescriptorStringSerialNumber)
+PROGMEM int usbDescriptorStringSerialNumber[] = {
+    USB_STRING_DESCRIPTOR_HEADER(USB_CFG_SERIAL_NUMBER_LEN),
+    USB_CFG_SERIAL_NUMBER
+};
+#endif
+
+#endif  /* USB_CFG_DESCR_PROPS_STRINGS == 0 */
+
+/* --------------------------- Device Descriptor --------------------------- */
+
+#if USB_CFG_DESCR_PROPS_DEVICE == 0
+#undef USB_CFG_DESCR_PROPS_DEVICE
+#define USB_CFG_DESCR_PROPS_DEVICE  sizeof(usbDescriptorDevice)
+PROGMEM char usbDescriptorDevice[] = {    /* USB device descriptor */
+    18,         /* sizeof(usbDescriptorDevice): length of descriptor in bytes */
+    USBDESCR_DEVICE,        /* descriptor type */
+    0x10, 0x01,             /* USB version supported */
+    USB_CFG_DEVICE_CLASS,
+    USB_CFG_DEVICE_SUBCLASS,
+    0,                      /* protocol */
+    8,                      /* max packet size */
+    /* the following two casts affect the first byte of the constant only, but
+     * that's sufficient to avoid a warning with the default values.
+     */
+    (char)USB_CFG_VENDOR_ID,/* 2 bytes */
+    (char)USB_CFG_DEVICE_ID,/* 2 bytes */
+    USB_CFG_DEVICE_VERSION, /* 2 bytes */
+    USB_CFG_DESCR_PROPS_STRING_VENDOR != 0 ? 1 : 0,         /* manufacturer string index */
+    USB_CFG_DESCR_PROPS_STRING_PRODUCT != 0 ? 2 : 0,        /* product string index */
+    USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER != 0 ? 3 : 0,  /* serial number string index */
+    1,          /* number of configurations */
+};
+#endif
+
+/* ----------------------- Configuration Descriptor ------------------------ */
+
+#if USB_CFG_DESCR_PROPS_HID_REPORT != 0 && USB_CFG_DESCR_PROPS_HID == 0
+#undef USB_CFG_DESCR_PROPS_HID
+#define USB_CFG_DESCR_PROPS_HID     9   /* length of HID descriptor in config descriptor below */
+#endif
+
+#if USB_CFG_DESCR_PROPS_CONFIGURATION == 0
+#undef USB_CFG_DESCR_PROPS_CONFIGURATION
+#define USB_CFG_DESCR_PROPS_CONFIGURATION   sizeof(usbDescriptorConfiguration)
+PROGMEM char usbDescriptorConfiguration[] = {    /* USB configuration descriptor */
+    9,          /* sizeof(usbDescriptorConfiguration): length of descriptor in bytes */
+    USBDESCR_CONFIG,    /* descriptor type */
+    18 + 7 * USB_CFG_HAVE_INTRIN_ENDPOINT + 7 * USB_CFG_HAVE_INTRIN_ENDPOINT3 +
+                (USB_CFG_DESCR_PROPS_HID & 0xff), 0,
+                /* total length of data returned (including inlined descriptors) */
+    1,          /* number of interfaces in this configuration */
+    1,          /* index of this configuration */
+    0,          /* configuration name string index */
+#if USB_CFG_IS_SELF_POWERED
+    (1 << 7) | USBATTR_SELFPOWER,       /* attributes */
+#else
+    (1 << 7),                           /* attributes */
+#endif
+    USB_CFG_MAX_BUS_POWER/2,            /* max USB current in 2mA units */
+/* interface descriptor follows inline: */
+    9,          /* sizeof(usbDescrInterface): length of descriptor in bytes */
+    USBDESCR_INTERFACE, /* descriptor type */
+    0,          /* index of this interface */
+    0,          /* alternate setting for this interface */
+    USB_CFG_HAVE_INTRIN_ENDPOINT + USB_CFG_HAVE_INTRIN_ENDPOINT3, /* endpoints excl 0: number of endpoint descriptors to follow */
+    USB_CFG_INTERFACE_CLASS,
+    USB_CFG_INTERFACE_SUBCLASS,
+    USB_CFG_INTERFACE_PROTOCOL,
+    0,          /* string index for interface */
+#if (USB_CFG_DESCR_PROPS_HID & 0xff)    /* HID descriptor */
+    9,          /* sizeof(usbDescrHID): length of descriptor in bytes */
+    USBDESCR_HID,   /* descriptor type: HID */
+    0x01, 0x01, /* BCD representation of HID version */
+    0x00,       /* target country code */
+    0x01,       /* number of HID Report (or other HID class) Descriptor infos to follow */
+    0x22,       /* descriptor type: report */
+    USB_CFG_HID_REPORT_DESCRIPTOR_LENGTH, 0,  /* total length of report descriptor */
+#endif
+#if USB_CFG_HAVE_INTRIN_ENDPOINT    /* endpoint descriptor for endpoint 1 */
+    7,          /* sizeof(usbDescrEndpoint) */
+    USBDESCR_ENDPOINT,  /* descriptor type = endpoint */
+    (char)0x81, /* IN endpoint number 1 */
+    0x03,       /* attrib: Interrupt endpoint */
+    8, 0,       /* maximum packet size */
+    USB_CFG_INTR_POLL_INTERVAL, /* in ms */
+#endif
+#if USB_CFG_HAVE_INTRIN_ENDPOINT3   /* endpoint descriptor for endpoint 3 */
+    7,          /* sizeof(usbDescrEndpoint) */
+    USBDESCR_ENDPOINT,  /* descriptor type = endpoint */
+    (char)0x83, /* IN endpoint number 1 */
+    0x03,       /* attrib: Interrupt endpoint */
+    8, 0,       /* maximum packet size */
+    USB_CFG_INTR_POLL_INTERVAL, /* in ms */
+#endif
+};
+#endif
+
+/* ------------------------------------------------------------------------- */
+
+static inline void  usbResetDataToggling(void)
+{
+#if USB_CFG_HAVE_INTRIN_ENDPOINT && !USB_CFG_SUPPRESS_INTR_CODE
+    USB_SET_DATATOKEN1(USB_INITIAL_DATATOKEN);  /* reset data toggling for interrupt endpoint */
+#   if USB_CFG_HAVE_INTRIN_ENDPOINT3
+    USB_SET_DATATOKEN3(USB_INITIAL_DATATOKEN);  /* reset data toggling for interrupt endpoint */
+#   endif
+#endif
+}
+
+static inline void  usbResetStall(void)
+{
+#if USB_CFG_IMPLEMENT_HALT && USB_CFG_HAVE_INTRIN_ENDPOINT
+        usbTxLen1 = USBPID_NAK;
+#if USB_CFG_HAVE_INTRIN_ENDPOINT3
+        usbTxLen3 = USBPID_NAK;
+#endif
+#endif
+}
+
+/* ------------------------------------------------------------------------- */
+
+#if !USB_CFG_SUPPRESS_INTR_CODE
+#if USB_CFG_HAVE_INTRIN_ENDPOINT
+static void usbGenericSetInterrupt(uchar *data, uchar len, usbTxStatus_t *txStatus)
+{
+uchar   *p;
+char    i;
+
+#if USB_CFG_IMPLEMENT_HALT
+    if(usbTxLen1 == USBPID_STALL)
+        return;
+#endif
+    if(txStatus->len & 0x10){   /* packet buffer was empty */
+        txStatus->buffer[0] ^= USBPID_DATA0 ^ USBPID_DATA1; /* toggle token */
+    }else{
+        txStatus->len = USBPID_NAK; /* avoid sending outdated (overwritten) interrupt data */
+    }
+    p = txStatus->buffer + 1;
+    i = len;
+    do{                         /* if len == 0, we still copy 1 byte, but that's no problem */
+        *p++ = *data++;
+    }while(--i > 0);            /* loop control at the end is 2 bytes shorter than at beginning */
+    usbCrc16Append(&txStatus->buffer[1], len);
+    txStatus->len = len + 4;    /* len must be given including sync byte */
+    DBG2(0x21 + (((int)txStatus >> 3) & 3), txStatus->buffer, len + 3);
+}
+
+USB_PUBLIC void usbSetInterrupt(uchar *data, uchar len)
+{
+    usbGenericSetInterrupt(data, len, &usbTxStatus1);
+}
+#endif
+
+#if USB_CFG_HAVE_INTRIN_ENDPOINT3
+USB_PUBLIC void usbSetInterrupt3(uchar *data, uchar len)
+{
+    usbGenericSetInterrupt(data, len, &usbTxStatus3);
+}
+#endif
+#endif /* USB_CFG_SUPPRESS_INTR_CODE */
+
+/* ------------------ utilities for code following below ------------------- */
+
+/* Use defines for the switch statement so that we can choose between an
+ * if()else if() and a switch/case based implementation. switch() is more
+ * efficient for a LARGE set of sequential choices, if() is better in all other
+ * cases.
+ */
+#if USB_CFG_USE_SWITCH_STATEMENT
+#   define SWITCH_START(cmd)       switch(cmd){{
+#   define SWITCH_CASE(value)      }break; case (value):{
+#   define SWITCH_CASE2(v1,v2)     }break; case (v1): case(v2):{
+#   define SWITCH_CASE3(v1,v2,v3)  }break; case (v1): case(v2): case(v3):{
+#   define SWITCH_DEFAULT          }break; default:{
+#   define SWITCH_END              }}
+#else
+#   define SWITCH_START(cmd)       {uchar _cmd = cmd; if(0){
+#   define SWITCH_CASE(value)      }else if(_cmd == (value)){
+#   define SWITCH_CASE2(v1,v2)     }else if(_cmd == (v1) || _cmd == (v2)){
+#   define SWITCH_CASE3(v1,v2,v3)  }else if(_cmd == (v1) || _cmd == (v2) || (_cmd == v3)){
+#   define SWITCH_DEFAULT          }else{
+#   define SWITCH_END              }}
+#endif
+
+#ifndef USB_RX_USER_HOOK
+#define USB_RX_USER_HOOK(data, len)
+#endif
+#ifndef USB_SET_ADDRESS_HOOK
+#define USB_SET_ADDRESS_HOOK()
+#endif
+
+/* ------------------------------------------------------------------------- */
+
+/* We use if() instead of #if in the macro below because #if can't be used
+ * in macros and the compiler optimizes constant conditions anyway.
+ * This may cause problems with undefined symbols if compiled without
+ * optimizing!
+ */
+#define GET_DESCRIPTOR(cfgProp, staticName)         \
+    if(cfgProp){                                    \
+        if((cfgProp) & USB_PROP_IS_RAM)             \
+            flags = 0;                              \
+        if((cfgProp) & USB_PROP_IS_DYNAMIC){        \
+            len = usbFunctionDescriptor(rq);        \
+        }else{                                      \
+            len = USB_PROP_LENGTH(cfgProp);         \
+            usbMsgPtr = (uchar *)(staticName);      \
+        }                                           \
+    }
+
+/* usbDriverDescriptor() is similar to usbFunctionDescriptor(), but used
+ * internally for all types of descriptors.
+ */
+static inline usbMsgLen_t usbDriverDescriptor(usbRequest_t *rq)
+{
+usbMsgLen_t len = 0;
+uchar       flags = USB_FLG_MSGPTR_IS_ROM;
+
+    SWITCH_START(rq->wValue.bytes[1])
+    SWITCH_CASE(USBDESCR_DEVICE)    /* 1 */
+        GET_DESCRIPTOR(USB_CFG_DESCR_PROPS_DEVICE, usbDescriptorDevice)
+    SWITCH_CASE(USBDESCR_CONFIG)    /* 2 */
+        GET_DESCRIPTOR(USB_CFG_DESCR_PROPS_CONFIGURATION, usbDescriptorConfiguration)
+    SWITCH_CASE(USBDESCR_STRING)    /* 3 */
+#if USB_CFG_DESCR_PROPS_STRINGS & USB_PROP_IS_DYNAMIC
+        if(USB_CFG_DESCR_PROPS_STRINGS & USB_PROP_IS_RAM)
+            flags = 0;
+        len = usbFunctionDescriptor(rq);
+#else   /* USB_CFG_DESCR_PROPS_STRINGS & USB_PROP_IS_DYNAMIC */
+        SWITCH_START(rq->wValue.bytes[0])
+        SWITCH_CASE(0)
+            GET_DESCRIPTOR(USB_CFG_DESCR_PROPS_STRING_0, usbDescriptorString0)
+        SWITCH_CASE(1)
+            GET_DESCRIPTOR(USB_CFG_DESCR_PROPS_STRING_VENDOR, usbDescriptorStringVendor)
+        SWITCH_CASE(2)
+            GET_DESCRIPTOR(USB_CFG_DESCR_PROPS_STRING_PRODUCT, usbDescriptorStringDevice)
+        SWITCH_CASE(3)
+            GET_DESCRIPTOR(USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER, usbDescriptorStringSerialNumber)
+        SWITCH_DEFAULT
+            if(USB_CFG_DESCR_PROPS_UNKNOWN & USB_PROP_IS_DYNAMIC){
+                len = usbFunctionDescriptor(rq);
+            }
+        SWITCH_END
+#endif  /* USB_CFG_DESCR_PROPS_STRINGS & USB_PROP_IS_DYNAMIC */
+#if USB_CFG_DESCR_PROPS_HID_REPORT  /* only support HID descriptors if enabled */
+    SWITCH_CASE(USBDESCR_HID)       /* 0x21 */
+        GET_DESCRIPTOR(USB_CFG_DESCR_PROPS_HID, usbDescriptorConfiguration + 18)
+    SWITCH_CASE(USBDESCR_HID_REPORT)/* 0x22 */
+        GET_DESCRIPTOR(USB_CFG_DESCR_PROPS_HID_REPORT, usbDescriptorHidReport)
+#endif
+    SWITCH_DEFAULT
+        if(USB_CFG_DESCR_PROPS_UNKNOWN & USB_PROP_IS_DYNAMIC){
+            len = usbFunctionDescriptor(rq);
+        }
+    SWITCH_END
+    usbMsgFlags = flags;
+    return len;
+}
+
+/* ------------------------------------------------------------------------- */
+
+/* usbDriverSetup() is similar to usbFunctionSetup(), but it's used for
+ * standard requests instead of class and custom requests.
+ */
+static inline usbMsgLen_t usbDriverSetup(usbRequest_t *rq)
+{
+uchar   len  = 0, *dataPtr = usbTxBuf + 9;  /* there are 2 bytes free space at the end of the buffer */
+uchar   value = rq->wValue.bytes[0];
+#if USB_CFG_IMPLEMENT_HALT
+uchar   index = rq->wIndex.bytes[0];
+#endif
+
+    dataPtr[0] = 0; /* default reply common to USBRQ_GET_STATUS and USBRQ_GET_INTERFACE */
+    SWITCH_START(rq->bRequest)
+    SWITCH_CASE(USBRQ_GET_STATUS)           /* 0 */
+        uchar recipient = rq->bmRequestType & USBRQ_RCPT_MASK;  /* assign arith ops to variables to enforce byte size */
+        if(USB_CFG_IS_SELF_POWERED && recipient == USBRQ_RCPT_DEVICE)
+            dataPtr[0] =  USB_CFG_IS_SELF_POWERED;
+#if USB_CFG_IMPLEMENT_HALT
+        if(recipient == USBRQ_RCPT_ENDPOINT && index == 0x81)   /* request status for endpoint 1 */
+            dataPtr[0] = usbTxLen1 == USBPID_STALL;
+#endif
+        dataPtr[1] = 0;
+        len = 2;
+#if USB_CFG_IMPLEMENT_HALT
+    SWITCH_CASE2(USBRQ_CLEAR_FEATURE, USBRQ_SET_FEATURE)    /* 1, 3 */
+        if(value == 0 && index == 0x81){    /* feature 0 == HALT for endpoint == 1 */
+            usbTxLen1 = rq->bRequest == USBRQ_CLEAR_FEATURE ? USBPID_NAK : USBPID_STALL;
+            usbResetDataToggling();
+        }
+#endif
+    SWITCH_CASE(USBRQ_SET_ADDRESS)          /* 5 */
+        usbNewDeviceAddr = value;
+        USB_SET_ADDRESS_HOOK();
+    SWITCH_CASE(USBRQ_GET_DESCRIPTOR)       /* 6 */
+        len = usbDriverDescriptor(rq);
+        goto skipMsgPtrAssignment;
+    SWITCH_CASE(USBRQ_GET_CONFIGURATION)    /* 8 */
+        dataPtr = &usbConfiguration;  /* send current configuration value */
+        len = 1;
+    SWITCH_CASE(USBRQ_SET_CONFIGURATION)    /* 9 */
+        usbConfiguration = value;
+        usbResetStall();
+    SWITCH_CASE(USBRQ_GET_INTERFACE)        /* 10 */
+        len = 1;
+#if USB_CFG_HAVE_INTRIN_ENDPOINT && !USB_CFG_SUPPRESS_INTR_CODE
+    SWITCH_CASE(USBRQ_SET_INTERFACE)        /* 11 */
+        usbResetDataToggling();
+        usbResetStall();
+#endif
+    SWITCH_DEFAULT                          /* 7=SET_DESCRIPTOR, 12=SYNC_FRAME */
+        /* Should we add an optional hook here? */
+    SWITCH_END
+    usbMsgPtr = dataPtr;
+skipMsgPtrAssignment:
+    return len;
+}
+
+/* ------------------------------------------------------------------------- */
+
+/* usbProcessRx() is called for every message received by the interrupt
+ * routine. It distinguishes between SETUP and DATA packets and processes
+ * them accordingly.
+ */
+static inline void usbProcessRx(uchar *data, uchar len)
+{
+  usbRequest_t    *rq = (usbRequest_t *)((void *)data);
+
+/* usbRxToken can be:
+ * 0x2d 00101101 (USBPID_SETUP for setup data)
+ * 0xe1 11100001 (USBPID_OUT: data phase of setup transfer)
+ * 0...0x0f for OUT on endpoint X
+ */
+    DBG2(0x10 + (usbRxToken & 0xf), data, len + 2); /* SETUP=1d, SETUP-DATA=11, OUTx=1x */
+    USB_RX_USER_HOOK(data, len)
+#if USB_CFG_IMPLEMENT_FN_WRITEOUT
+    if(usbRxToken < 0x10){  /* OUT to endpoint != 0: endpoint number in usbRxToken */
+        usbFunctionWriteOut(data, len);
+        return;
+    }
+#endif
+    if(usbRxToken == (uchar)USBPID_SETUP){
+        if(len != 8)    /* Setup size must be always 8 bytes. Ignore otherwise. */
+            return;
+        usbMsgLen_t replyLen;
+        usbTxBuf[0] = USBPID_DATA0;         /* initialize data toggling */
+        usbTxLen = USBPID_NAK;              /* abort pending transmit */
+        usbMsgFlags = 0;
+        uchar type = rq->bmRequestType & USBRQ_TYPE_MASK;
+        if(type != USBRQ_TYPE_STANDARD){    /* standard requests are handled by driver */
+            replyLen = usbFunctionSetup(data);
+        }else{
+            replyLen = usbDriverSetup(rq);
+        }
+#if USB_CFG_IMPLEMENT_FN_READ || USB_CFG_IMPLEMENT_FN_WRITE
+        if(replyLen == USB_NO_MSG){         /* use user-supplied read/write function */
+            /* do some conditioning on replyLen, but on IN transfers only */
+            if((rq->bmRequestType & USBRQ_DIR_MASK) != USBRQ_DIR_HOST_TO_DEVICE){
+                if(sizeof(replyLen) < sizeof(rq->wLength.word)){ /* help compiler with optimizing */
+                    replyLen = rq->wLength.bytes[0];
+                }else{
+                    replyLen = rq->wLength.word;
+                }
+            }
+            usbMsgFlags = USB_FLG_USE_USER_RW;
+        }else   /* The 'else' prevents that we limit a replyLen of USB_NO_MSG to the maximum transfer len. */
+#endif
+        if(sizeof(replyLen) < sizeof(rq->wLength.word)){ /* help compiler with optimizing */
+            if(!rq->wLength.bytes[1] && replyLen > rq->wLength.bytes[0])    /* limit length to max */
+                replyLen = rq->wLength.bytes[0];
+        }else{
+            if(replyLen > rq->wLength.word)     /* limit length to max */
+                replyLen = rq->wLength.word;
+        }
+        usbMsgLen = replyLen;
+    }else{  /* usbRxToken must be USBPID_OUT, which means data phase of setup (control-out) */
+#if USB_CFG_IMPLEMENT_FN_WRITE
+        if(usbMsgFlags & USB_FLG_USE_USER_RW){
+            uchar rval = usbFunctionWrite(data, len);
+            if(rval == 0xff){   /* an error occurred */
+                usbTxLen = USBPID_STALL;
+            }else if(rval != 0){    /* This was the final package */
+                usbMsgLen = 0;  /* answer with a zero-sized data packet */
+            }
+        }
+#endif
+    }
+}
+
+/* ------------------------------------------------------------------------- */
+
+/* This function is similar to usbFunctionRead(), but it's also called for
+ * data handled automatically by the driver (e.g. descriptor reads).
+ */
+static uchar usbDeviceRead(uchar *data, uchar len)
+{
+    if(len > 0){    /* don't bother app with 0 sized reads */
+#if USB_CFG_IMPLEMENT_FN_READ
+        if(usbMsgFlags & USB_FLG_USE_USER_RW){
+            len = usbFunctionRead(data, len);
+        }else
+#endif
+        {
+            uchar i = len, *r = usbMsgPtr;
+            if(usbMsgFlags & USB_FLG_MSGPTR_IS_ROM){    /* ROM data */
+                do{
+                    uchar c = USB_READ_FLASH(r);    /* assign to char size variable to enforce byte ops */
+                    *data++ = c;
+                    r++;
+                }while(--i);
+            }else{  /* RAM data */
+                do{
+                    *data++ = *r++;
+                }while(--i);
+            }
+            usbMsgPtr = r;
+        }
+    }
+    return len;
+}
+
+/* ------------------------------------------------------------------------- */
+
+/* usbBuildTxBlock() is called when we have data to transmit and the
+ * interrupt routine's transmit buffer is empty.
+ */
+static inline void usbBuildTxBlock(void)
+{
+usbMsgLen_t wantLen;
+uchar       len;
+
+    wantLen = usbMsgLen;
+    if(wantLen > 8)
+        wantLen = 8;
+    usbMsgLen -= wantLen;
+    usbTxBuf[0] ^= USBPID_DATA0 ^ USBPID_DATA1; /* DATA toggling */
+    len = usbDeviceRead(usbTxBuf + 1, wantLen);
+    if(len <= 8){           /* valid data packet */
+        usbCrc16Append(&usbTxBuf[1], len);
+        len += 4;           /* length including sync byte */
+        if(len < 12)        /* a partial package identifies end of message */
+            usbMsgLen = USB_NO_MSG;
+    }else{
+        len = USBPID_STALL;   /* stall the endpoint */
+        usbMsgLen = USB_NO_MSG;
+    }
+    usbTxLen = len;
+    DBG2(0x20, usbTxBuf, len-1);
+}
+
+/* ------------------------------------------------------------------------- */
+
+static inline void usbHandleResetHook(uchar notResetState)
+{
+#ifdef USB_RESET_HOOK
+static uchar    wasReset;
+uchar           isReset = !notResetState;
+
+    if(wasReset != isReset){
+        USB_RESET_HOOK(isReset);
+        wasReset = isReset;
+    }
+#endif
+}
+
+/* ------------------------------------------------------------------------- */
+
+USB_PUBLIC void usbPoll(void)
+{
+schar   len;
+uchar   i;
+
+    len = usbRxLen - 3;
+    if(len >= 0){
+/* We could check CRC16 here -- but ACK has already been sent anyway. If you
+ * need data integrity checks with this driver, check the CRC in your app
+ * code and report errors back to the host. Since the ACK was already sent,
+ * retries must be handled on application level.
+ * unsigned crc = usbCrc16(buffer + 1, usbRxLen - 3);
+ */
+        usbProcessRx(usbRxBuf + USB_BUFSIZE + 1 - usbInputBufOffset, len);
+#if USB_CFG_HAVE_FLOWCONTROL
+        if(usbRxLen > 0)    /* only mark as available if not inactivated */
+            usbRxLen = 0;
+#else
+        usbRxLen = 0;       /* mark rx buffer as available */
+#endif
+    }
+    if(usbTxLen & 0x10){    /* transmit system idle */
+        if(usbMsgLen != USB_NO_MSG){    /* transmit data pending? */
+            usbBuildTxBlock();
+        }
+    }
+    for(i = 20; i > 0; i--){
+        uchar usbLineStatus = USBIN & USBMASK;
+        if(usbLineStatus != 0)  /* SE0 has ended */
+            goto isNotReset;
+    }
+    /* RESET condition, called multiple times during reset */
+    usbNewDeviceAddr = 0;
+    usbDeviceAddr = 0;
+    usbResetStall();
+    DBG1(0xff, 0, 0);
+isNotReset:
+    usbHandleResetHook(i);
+}
+
+/* ------------------------------------------------------------------------- */
+
+USB_PUBLIC void usbInit(void)
+{
+#if USB_INTR_CFG_SET != 0
+    USB_INTR_CFG |= USB_INTR_CFG_SET;
+#endif
+#if USB_INTR_CFG_CLR != 0
+    USB_INTR_CFG &= ~(USB_INTR_CFG_CLR);
+#endif
+    USB_INTR_ENABLE |= (1 << USB_INTR_ENABLE_BIT);
+    usbResetDataToggling();
+#if USB_CFG_HAVE_INTRIN_ENDPOINT && !USB_CFG_SUPPRESS_INTR_CODE
+    usbTxLen1 = USBPID_NAK;
+#if USB_CFG_HAVE_INTRIN_ENDPOINT3
+    usbTxLen3 = USBPID_NAK;
+#endif
+#endif
+}
+
+/* ------------------------------------------------------------------------- */

usbdrv.h

@@ -0,0 +1,759 @@
+/* Name: usbdrv.h
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2004-12-29
+ * Tabsize: 4
+ * Copyright: (c) 2005 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * This Revision: $Id: usbdrv.h 769 2009-08-22 11:49:05Z cs $
+ */
+
+#ifndef __usbdrv_h_included__
+#define __usbdrv_h_included__
+#include "usbconfig.h"
+#include "usbportability.h"
+
+/*
+Hardware Prerequisites:
+=======================
+USB lines D+ and D- MUST be wired to the same I/O port. We recommend that D+
+triggers the interrupt (best achieved by using INT0 for D+), but it is also
+possible to trigger the interrupt from D-. If D- is used, interrupts are also
+triggered by SOF packets. D- requires a pull-up of 1.5k to +3.5V (and the
+device must be powered at 3.5V) to identify as low-speed USB device. A
+pull-down or pull-up of 1M SHOULD be connected from D+ to +3.5V to prevent
+interference when no USB master is connected. If you use Zener diodes to limit
+the voltage on D+ and D-, you MUST use a pull-down resistor, not a pull-up.
+We use D+ as interrupt source and not D- because it does not trigger on
+keep-alive and RESET states. If you want to count keep-alive events with
+USB_COUNT_SOF, you MUST use D- as an interrupt source.
+
+As a compile time option, the 1.5k pull-up resistor on D- can be made
+switchable to allow the device to disconnect at will. See the definition of
+usbDeviceConnect() and usbDeviceDisconnect() further down in this file.
+
+Please adapt the values in usbconfig.h according to your hardware!
+
+The device MUST be clocked at exactly 12 MHz, 15 MHz, 16 MHz or 20 MHz
+or at 12.8 MHz resp. 16.5 MHz +/- 1%. See usbconfig-prototype.h for details.
+
+
+Limitations:
+============
+Robustness with respect to communication errors:
+The driver assumes error-free communication. It DOES check for errors in
+the PID, but does NOT check bit stuffing errors, SE0 in middle of a byte,
+token CRC (5 bit) and data CRC (16 bit). CRC checks can not be performed due
+to timing constraints: We must start sending a reply within 7 bit times.
+Bit stuffing and misplaced SE0 would have to be checked in real-time, but CPU
+performance does not permit that. The driver does not check Data0/Data1
+toggling, but application software can implement the check.
+
+Input characteristics:
+Since no differential receiver circuit is used, electrical interference
+robustness may suffer. The driver samples only one of the data lines with
+an ordinary I/O pin's input characteristics. However, since this is only a
+low speed USB implementation and the specification allows for 8 times the
+bit rate over the same hardware, we should be on the safe side. Even the spec
+requires detection of asymmetric states at high bit rate for SE0 detection.
+
+Number of endpoints:
+The driver supports the following endpoints:
+
+- Endpoint 0, the default control endpoint.
+- Any number of interrupt- or bulk-out endpoints. The data is sent to
+  usbFunctionWriteOut() and USB_CFG_IMPLEMENT_FN_WRITEOUT must be defined
+  to 1 to activate this feature. The endpoint number can be found in the
+  global variable 'usbRxToken'.
+- One default interrupt- or bulk-in endpoint. This endpoint is used for
+  interrupt- or bulk-in transfers which are not handled by any other endpoint.
+  You must define USB_CFG_HAVE_INTRIN_ENDPOINT in order to activate this
+  feature and call usbSetInterrupt() to send interrupt/bulk data.
+- One additional interrupt- or bulk-in endpoint. This was endpoint 3 in
+  previous versions of this driver but can now be configured to any endpoint
+  number. You must define USB_CFG_HAVE_INTRIN_ENDPOINT3 in order to activate
+  this feature and call usbSetInterrupt3() to send interrupt/bulk data. The
+  endpoint number can be set with USB_CFG_EP3_NUMBER.
+
+Please note that the USB standard forbids bulk endpoints for low speed devices!
+Most operating systems allow them anyway, but the AVR will spend 90% of the CPU
+time in the USB interrupt polling for bulk data.
+
+Maximum data payload:
+Data payload of control in and out transfers may be up to 254 bytes. In order
+to accept payload data of out transfers, you need to implement
+'usbFunctionWrite()'.
+
+USB Suspend Mode supply current:
+The USB standard limits power consumption to 500uA when the bus is in suspend
+mode. This is not a problem for self-powered devices since they don't need
+bus power anyway. Bus-powered devices can achieve this only by putting the
+CPU in sleep mode. The driver does not implement suspend handling by itself.
+However, the application may implement activity monitoring and wakeup from
+sleep. The host sends regular SE0 states on the bus to keep it active. These
+SE0 states can be detected by using D- as the interrupt source. Define
+USB_COUNT_SOF to 1 and use the global variable usbSofCount to check for bus
+activity.
+
+Operation without an USB master:
+The driver behaves neutral without connection to an USB master if D- reads
+as 1. To avoid spurious interrupts, we recommend a high impedance (e.g. 1M)
+pull-down or pull-up resistor on D+ (interrupt). If Zener diodes are used,
+use a pull-down. If D- becomes statically 0, the driver may block in the
+interrupt routine.
+
+Interrupt latency:
+The application must ensure that the USB interrupt is not disabled for more
+than 25 cycles (this is for 12 MHz, faster clocks allow longer latency).
+This implies that all interrupt routines must either be declared as "INTERRUPT"
+instead of "SIGNAL" (see "avr/signal.h") or that they are written in assembler
+with "sei" as the first instruction.
+
+Maximum interrupt duration / CPU cycle consumption:
+The driver handles all USB communication during the interrupt service
+routine. The routine will not return before an entire USB message is received
+and the reply is sent. This may be up to ca. 1200 cycles @ 12 MHz (= 100us) if
+the host conforms to the standard. The driver will consume CPU cycles for all
+USB messages, even if they address another (low-speed) device on the same bus.
+
+*/
+
+/* ------------------------------------------------------------------------- */
+/* --------------------------- Module Interface ---------------------------- */
+/* ------------------------------------------------------------------------- */
+
+#define USBDRV_VERSION  20090822
+/* This define uniquely identifies a driver version. It is a decimal number
+ * constructed from the driver's release date in the form YYYYMMDD. If the
+ * driver's behavior or interface changes, you can use this constant to
+ * distinguish versions. If it is not defined, the driver's release date is
+ * older than 2006-01-25.
+ */
+
+
+#ifndef USB_PUBLIC
+#define USB_PUBLIC
+#endif
+/* USB_PUBLIC is used as declaration attribute for all functions exported by
+ * the USB driver. The default is no attribute (see above). You may define it
+ * to static either in usbconfig.h or from the command line if you include
+ * usbdrv.c instead of linking against it. Including the C module of the driver
+ * directly in your code saves a couple of bytes in flash memory.
+ */
+
+#ifndef __ASSEMBLER__
+#ifndef uchar
+#define uchar   unsigned char
+#endif
+#ifndef schar
+#define schar   signed char
+#endif
+/* shortcuts for well defined 8 bit integer types */
+
+#if USB_CFG_LONG_TRANSFERS  /* if more than 254 bytes transfer size required */
+#   define usbMsgLen_t unsigned
+#else
+#   define usbMsgLen_t uchar
+#endif
+/* usbMsgLen_t is the data type used for transfer lengths. By default, it is
+ * defined to uchar, allowing a maximum of 254 bytes (255 is reserved for
+ * USB_NO_MSG below). If the usbconfig.h defines USB_CFG_LONG_TRANSFERS to 1,
+ * a 16 bit data type is used, allowing up to 16384 bytes (the rest is used
+ * for flags in the descriptor configuration).
+ */
+#define USB_NO_MSG  ((usbMsgLen_t)-1)   /* constant meaning "no message" */
+
+struct usbRequest;  /* forward declaration */
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+USB_PUBLIC void usbInit(void);
+/* This function must be called before interrupts are enabled and the main
+ * loop is entered. We exepct that the PORT and DDR bits for D+ and D- have
+ * not been changed from their default status (which is 0). If you have changed
+ * them, set both back to 0 (configure them as input with no internal pull-up).
+ */
+USB_PUBLIC void usbPoll(void);
+/* This function must be called at regular intervals from the main loop.
+ * Maximum delay between calls is somewhat less than 50ms (USB timeout for
+ * accepting a Setup message). Otherwise the device will not be recognized.
+ * Please note that debug outputs through the UART take ~ 0.5ms per byte
+ * at 19200 bps.
+ */
+#ifdef __cplusplus
+} // extern "C"
+#endif
+extern uchar *usbMsgPtr;
+/* This variable may be used to pass transmit data to the driver from the
+ * implementation of usbFunctionWrite(). It is also used internally by the
+ * driver for standard control requests.
+ */
+#ifdef __cplusplus
+extern "C"{
+#endif
+USB_PUBLIC usbMsgLen_t usbFunctionSetup(uchar data[8]);
+#ifdef __cplusplus
+} // extern "C"
+#endif
+/* This function is called when the driver receives a SETUP transaction from
+ * the host which is not answered by the driver itself (in practice: class and
+ * vendor requests). All control transfers start with a SETUP transaction where
+ * the host communicates the parameters of the following (optional) data
+ * transfer. The SETUP data is available in the 'data' parameter which can
+ * (and should) be casted to 'usbRequest_t *' for a more user-friendly access
+ * to parameters.
+ *
+ * If the SETUP indicates a control-in transfer, you should provide the
+ * requested data to the driver. There are two ways to transfer this data:
+ * (1) Set the global pointer 'usbMsgPtr' to the base of the static RAM data
+ * block and return the length of the data in 'usbFunctionSetup()'. The driver
+ * will handle the rest. Or (2) return USB_NO_MSG in 'usbFunctionSetup()'. The
+ * driver will then call 'usbFunctionRead()' when data is needed. See the
+ * documentation for usbFunctionRead() for details.
+ *
+ * If the SETUP indicates a control-out transfer, the only way to receive the
+ * data from the host is through the 'usbFunctionWrite()' call. If you
+ * implement this function, you must return USB_NO_MSG in 'usbFunctionSetup()'
+ * to indicate that 'usbFunctionWrite()' should be used. See the documentation
+ * of this function for more information. If you just want to ignore the data
+ * sent by the host, return 0 in 'usbFunctionSetup()'.
+ *
+ * Note that calls to the functions usbFunctionRead() and usbFunctionWrite()
+ * are only done if enabled by the configuration in usbconfig.h.
+ */
+USB_PUBLIC usbMsgLen_t usbFunctionDescriptor(struct usbRequest *rq);
+/* You need to implement this function ONLY if you provide USB descriptors at
+ * runtime (which is an expert feature). It is very similar to
+ * usbFunctionSetup() above, but it is called only to request USB descriptor
+ * data. See the documentation of usbFunctionSetup() above for more info.
+ */
+#if USB_CFG_HAVE_INTRIN_ENDPOINT
+#ifdef __cplusplus
+extern "C"{
+#endif
+USB_PUBLIC void usbSetInterrupt(uchar *data, uchar len);
+#ifdef __cplusplus
+} // extern "C"
+#endif
+/* This function sets the message which will be sent during the next interrupt
+ * IN transfer. The message is copied to an internal buffer and must not exceed
+ * a length of 8 bytes. The message may be 0 bytes long just to indicate the
+ * interrupt status to the host.
+ * If you need to transfer more bytes, use a control read after the interrupt.
+ */
+#define usbInterruptIsReady()   (usbTxLen1 & 0x10)
+/* This macro indicates whether the last interrupt message has already been
+ * sent. If you set a new interrupt message before the old was sent, the
+ * message already buffered will be lost.
+ */
+#if USB_CFG_HAVE_INTRIN_ENDPOINT3
+USB_PUBLIC void usbSetInterrupt3(uchar *data, uchar len);
+#define usbInterruptIsReady3()   (usbTxLen3 & 0x10)
+/* Same as above for endpoint 3 */
+#endif
+#endif /* USB_CFG_HAVE_INTRIN_ENDPOINT */
+#if USB_CFG_HID_REPORT_DESCRIPTOR_LENGTH    /* simplified interface for backward compatibility */
+#define usbHidReportDescriptor  usbDescriptorHidReport
+/* should be declared as: PROGMEM char usbHidReportDescriptor[]; */
+/* If you implement an HID device, you need to provide a report descriptor.
+ * The HID report descriptor syntax is a bit complex. If you understand how
+ * report descriptors are constructed, we recommend that you use the HID
+ * Descriptor Tool from usb.org, see http://www.usb.org/developers/hidpage/.
+ * Otherwise you should probably start with a working example.
+ */
+#endif  /* USB_CFG_HID_REPORT_DESCRIPTOR_LENGTH */
+#if USB_CFG_IMPLEMENT_FN_WRITE
+USB_PUBLIC uchar usbFunctionWrite(uchar *data, uchar len);
+/* This function is called by the driver to provide a control transfer's
+ * payload data (control-out). It is called in chunks of up to 8 bytes. The
+ * total count provided in the current control transfer can be obtained from
+ * the 'length' property in the setup data. If an error occurred during
+ * processing, return 0xff (== -1). The driver will answer the entire transfer
+ * with a STALL token in this case. If you have received the entire payload
+ * successfully, return 1. If you expect more data, return 0. If you don't
+ * know whether the host will send more data (you should know, the total is
+ * provided in the usbFunctionSetup() call!), return 1.
+ * NOTE: If you return 0xff for STALL, 'usbFunctionWrite()' may still be called
+ * for the remaining data. You must continue to return 0xff for STALL in these
+ * calls.
+ * In order to get usbFunctionWrite() called, define USB_CFG_IMPLEMENT_FN_WRITE
+ * to 1 in usbconfig.h and return 0xff in usbFunctionSetup()..
+ */
+#endif /* USB_CFG_IMPLEMENT_FN_WRITE */
+#if USB_CFG_IMPLEMENT_FN_READ
+USB_PUBLIC uchar usbFunctionRead(uchar *data, uchar len);
+/* This function is called by the driver to ask the application for a control
+ * transfer's payload data (control-in). It is called in chunks of up to 8
+ * bytes each. You should copy the data to the location given by 'data' and
+ * return the actual number of bytes copied. If you return less than requested,
+ * the control-in transfer is terminated. If you return 0xff, the driver aborts
+ * the transfer with a STALL token.
+ * In order to get usbFunctionRead() called, define USB_CFG_IMPLEMENT_FN_READ
+ * to 1 in usbconfig.h and return 0xff in usbFunctionSetup()..
+ */
+#endif /* USB_CFG_IMPLEMENT_FN_READ */
+
+extern uchar usbRxToken;    /* may be used in usbFunctionWriteOut() below */
+#if USB_CFG_IMPLEMENT_FN_WRITEOUT
+USB_PUBLIC void usbFunctionWriteOut(uchar *data, uchar len);
+/* This function is called by the driver when data is received on an interrupt-
+ * or bulk-out endpoint. The endpoint number can be found in the global
+ * variable usbRxToken. You must define USB_CFG_IMPLEMENT_FN_WRITEOUT to 1 in
+ * usbconfig.h to get this function called.
+ */
+#endif /* USB_CFG_IMPLEMENT_FN_WRITEOUT */
+#ifdef USB_CFG_PULLUP_IOPORTNAME
+#define usbDeviceConnect()      ((USB_PULLUP_DDR |= (1<<USB_CFG_PULLUP_BIT)), \
+                                  (USB_PULLUP_OUT |= (1<<USB_CFG_PULLUP_BIT)))
+#define usbDeviceDisconnect()   ((USB_PULLUP_DDR &= ~(1<<USB_CFG_PULLUP_BIT)), \
+                                  (USB_PULLUP_OUT &= ~(1<<USB_CFG_PULLUP_BIT)))
+#else /* USB_CFG_PULLUP_IOPORTNAME */
+#define usbDeviceConnect()      (USBDDR &= ~(1<<USBMINUS))
+#define usbDeviceDisconnect()   (USBDDR |= (1<<USBMINUS))
+#endif /* USB_CFG_PULLUP_IOPORTNAME */
+/* The macros usbDeviceConnect() and usbDeviceDisconnect() (intended to look
+ * like a function) connect resp. disconnect the device from the host's USB.
+ * If the constants USB_CFG_PULLUP_IOPORT and USB_CFG_PULLUP_BIT are defined
+ * in usbconfig.h, a disconnect consists of removing the pull-up resisitor
+ * from D-, otherwise the disconnect is done by brute-force pulling D- to GND.
+ * This does not conform to the spec, but it works.
+ * Please note that the USB interrupt must be disabled while the device is
+ * in disconnected state, or the interrupt handler will hang! You can either
+ * turn off the USB interrupt selectively with
+ *     USB_INTR_ENABLE &= ~(1 << USB_INTR_ENABLE_BIT)
+ * or use cli() to disable interrupts globally.
+ */
+extern unsigned usbCrc16(unsigned data, uchar len);
+#define usbCrc16(data, len) usbCrc16((unsigned)(data), len)
+/* This function calculates the binary complement of the data CRC used in
+ * USB data packets. The value is used to build raw transmit packets.
+ * You may want to use this function for data checksums or to verify received
+ * data. We enforce 16 bit calling conventions for compatibility with IAR's
+ * tiny memory model.
+ */
+#ifdef __cplusplus
+extern "C"{
+#endif
+extern unsigned usbCrc16Append(unsigned data, uchar len);
+#ifdef __cplusplus
+} // extern "C"
+#endif
+#define usbCrc16Append(data, len)    usbCrc16Append((unsigned)(data), len)
+/* This function is equivalent to usbCrc16() above, except that it appends
+ * the 2 bytes CRC (lowbyte first) in the 'data' buffer after reading 'len'
+ * bytes.
+ */
+#if USB_CFG_HAVE_MEASURE_FRAME_LENGTH
+extern unsigned usbMeasureFrameLength(void);
+/* This function MUST be called IMMEDIATELY AFTER USB reset and measures 1/7 of
+ * the number of CPU cycles during one USB frame minus one low speed bit
+ * length. In other words: return value = 1499 * (F_CPU / 10.5 MHz)
+ * Since this is a busy wait, you MUST disable all interrupts with cli() before
+ * calling this function.
+ * This can be used to calibrate the AVR's RC oscillator.
+ */
+#endif
+extern uchar    usbConfiguration;
+/* This value contains the current configuration set by the host. The driver
+ * allows setting and querying of this variable with the USB SET_CONFIGURATION
+ * and GET_CONFIGURATION requests, but does not use it otherwise.
+ * You may want to reflect the "configured" status with a LED on the device or
+ * switch on high power parts of the circuit only if the device is configured.
+ */
+#if USB_COUNT_SOF
+extern volatile uchar   usbSofCount;
+/* This variable is incremented on every SOF packet. It is only available if
+ * the macro USB_COUNT_SOF is defined to a value != 0.
+ */
+#endif
+#if USB_CFG_CHECK_DATA_TOGGLING
+extern uchar    usbCurrentDataToken;
+/* This variable can be checked in usbFunctionWrite() and usbFunctionWriteOut()
+ * to ignore duplicate packets.
+ */
+#endif
+
+#define USB_STRING_DESCRIPTOR_HEADER(stringLength) ((2*(stringLength)+2) | (3<<8))
+/* This macro builds a descriptor header for a string descriptor given the
+ * string's length. See usbdrv.c for an example how to use it.
+ */
+#if USB_CFG_HAVE_FLOWCONTROL
+extern volatile schar   usbRxLen;
+#define usbDisableAllRequests()     usbRxLen = -1
+/* Must be called from usbFunctionWrite(). This macro disables all data input
+ * from the USB interface. Requests from the host are answered with a NAK
+ * while they are disabled.
+ */
+#define usbEnableAllRequests()      usbRxLen = 0
+/* May only be called if requests are disabled. This macro enables input from
+ * the USB interface after it has been disabled with usbDisableAllRequests().
+ */
+#define usbAllRequestsAreDisabled() (usbRxLen < 0)
+/* Use this macro to find out whether requests are disabled. It may be needed
+ * to ensure that usbEnableAllRequests() is never called when requests are
+ * enabled.
+ */
+#endif
+
+#define USB_SET_DATATOKEN1(token)   usbTxBuf1[0] = token
+#define USB_SET_DATATOKEN3(token)   usbTxBuf3[0] = token
+/* These two macros can be used by application software to reset data toggling
+ * for interrupt-in endpoints 1 and 3. Since the token is toggled BEFORE
+ * sending data, you must set the opposite value of the token which should come
+ * first.
+ */
+
+#endif  /* __ASSEMBLER__ */
+
+
+/* ------------------------------------------------------------------------- */
+/* ----------------- Definitions for Descriptor Properties ----------------- */
+/* ------------------------------------------------------------------------- */
+/* This is advanced stuff. See usbconfig-prototype.h for more information
+ * about the various methods to define USB descriptors. If you do nothing,
+ * the default descriptors will be used.
+ */
+#define USB_PROP_IS_DYNAMIC     (1 << 14)
+/* If this property is set for a descriptor, usbFunctionDescriptor() will be
+ * used to obtain the particular descriptor. Data directly returned via
+ * usbMsgPtr are FLASH data by default, combine (OR) with USB_PROP_IS_RAM to
+ * return RAM data.
+ */
+#define USB_PROP_IS_RAM         (1 << 15)
+/* If this property is set for a descriptor, the data is read from RAM
+ * memory instead of Flash. The property is used for all methods to provide
+ * external descriptors.
+ */
+#define USB_PROP_LENGTH(len)    ((len) & 0x3fff)
+/* If a static external descriptor is used, this is the total length of the
+ * descriptor in bytes.
+ */
+
+/* all descriptors which may have properties: */
+#ifndef USB_CFG_DESCR_PROPS_DEVICE
+#define USB_CFG_DESCR_PROPS_DEVICE                  0
+#endif
+#ifndef USB_CFG_DESCR_PROPS_CONFIGURATION
+#define USB_CFG_DESCR_PROPS_CONFIGURATION           0
+#endif
+#ifndef USB_CFG_DESCR_PROPS_STRINGS
+#define USB_CFG_DESCR_PROPS_STRINGS                 0
+#endif
+#ifndef USB_CFG_DESCR_PROPS_STRING_0
+#define USB_CFG_DESCR_PROPS_STRING_0                0
+#endif
+#ifndef USB_CFG_DESCR_PROPS_STRING_VENDOR
+#define USB_CFG_DESCR_PROPS_STRING_VENDOR           0
+#endif
+#ifndef USB_CFG_DESCR_PROPS_STRING_PRODUCT
+#define USB_CFG_DESCR_PROPS_STRING_PRODUCT          0
+#endif
+#ifndef USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER
+#define USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER    0
+#endif
+#ifndef USB_CFG_DESCR_PROPS_HID
+#define USB_CFG_DESCR_PROPS_HID                     0
+#endif
+#if !(USB_CFG_DESCR_PROPS_HID_REPORT)
+#   undef USB_CFG_DESCR_PROPS_HID_REPORT
+#   if USB_CFG_HID_REPORT_DESCRIPTOR_LENGTH /* do some backward compatibility tricks */
+#       define USB_CFG_DESCR_PROPS_HID_REPORT       USB_CFG_HID_REPORT_DESCRIPTOR_LENGTH
+#   else
+#       define USB_CFG_DESCR_PROPS_HID_REPORT       0
+#   endif
+#endif
+#ifndef USB_CFG_DESCR_PROPS_UNKNOWN
+#define USB_CFG_DESCR_PROPS_UNKNOWN                 0
+#endif
+
+/* ------------------ forward declaration of descriptors ------------------- */
+/* If you use external static descriptors, they must be stored in global
+ * arrays as declared below:
+ */
+#ifndef __ASSEMBLER__
+extern
+#if !(USB_CFG_DESCR_PROPS_DEVICE & USB_PROP_IS_RAM)
+PROGMEM
+#endif
+char usbDescriptorDevice[];
+
+extern
+#if !(USB_CFG_DESCR_PROPS_CONFIGURATION & USB_PROP_IS_RAM)
+PROGMEM
+#endif
+char usbDescriptorConfiguration[];
+
+extern
+#if !(USB_CFG_DESCR_PROPS_HID_REPORT & USB_PROP_IS_RAM)
+PROGMEM
+#endif
+char usbDescriptorHidReport[];
+
+extern
+#if !(USB_CFG_DESCR_PROPS_STRING_0 & USB_PROP_IS_RAM)
+PROGMEM
+#endif
+char usbDescriptorString0[];
+
+extern
+#if !(USB_CFG_DESCR_PROPS_STRING_VENDOR & USB_PROP_IS_RAM)
+PROGMEM
+#endif
+int usbDescriptorStringVendor[];
+
+extern
+#if !(USB_CFG_DESCR_PROPS_STRING_PRODUCT & USB_PROP_IS_RAM)
+PROGMEM
+#endif
+int usbDescriptorStringDevice[];
+
+extern
+#if !(USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER & USB_PROP_IS_RAM)
+PROGMEM
+#endif
+int usbDescriptorStringSerialNumber[];
+
+#endif /* __ASSEMBLER__ */
+
+/* ------------------------------------------------------------------------- */
+/* ------------------------ General Purpose Macros ------------------------- */
+/* ------------------------------------------------------------------------- */
+
+#define USB_CONCAT(a, b)            a ## b
+#define USB_CONCAT_EXPANDED(a, b)   USB_CONCAT(a, b)
+
+#define USB_OUTPORT(name)           USB_CONCAT(PORT, name)
+#define USB_INPORT(name)            USB_CONCAT(PIN, name)
+#define USB_DDRPORT(name)           USB_CONCAT(DDR, name)
+/* The double-define trick above lets us concatenate strings which are
+ * defined by macros.
+ */
+
+/* ------------------------------------------------------------------------- */
+/* ------------------------- Constant definitions -------------------------- */
+/* ------------------------------------------------------------------------- */
+
+#if !defined __ASSEMBLER__ && (!defined USB_CFG_VENDOR_ID || !defined USB_CFG_DEVICE_ID)
+#warning "You should define USB_CFG_VENDOR_ID and USB_CFG_DEVICE_ID in usbconfig.h"
+/* If the user has not defined IDs, we default to obdev's free IDs.
+ * See USB-IDs-for-free.txt for details.
+ */
+#endif
+
+/* make sure we have a VID and PID defined, byte order is lowbyte, highbyte */
+#ifndef USB_CFG_VENDOR_ID
+#   define  USB_CFG_VENDOR_ID   0xc0, 0x16  /* = 0x16c0 = 5824 = voti.nl */
+#endif
+
+#ifndef USB_CFG_DEVICE_ID
+#   if USB_CFG_HID_REPORT_DESCRIPTOR_LENGTH
+#       define USB_CFG_DEVICE_ID    0xdf, 0x05  /* = 0x5df = 1503, shared PID for HIDs */
+#   elif USB_CFG_INTERFACE_CLASS == 2
+#       define USB_CFG_DEVICE_ID    0xe1, 0x05  /* = 0x5e1 = 1505, shared PID for CDC Modems */
+#   else
+#       define USB_CFG_DEVICE_ID    0xdc, 0x05  /* = 0x5dc = 1500, obdev's free PID */
+#   endif
+#endif
+
+/* Derive Output, Input and DataDirection ports from port names */
+#ifndef USB_CFG_IOPORTNAME
+#error "You must define USB_CFG_IOPORTNAME in usbconfig.h, see usbconfig-prototype.h"
+#endif
+
+#define USBOUT          USB_OUTPORT(USB_CFG_IOPORTNAME)
+#define USB_PULLUP_OUT  USB_OUTPORT(USB_CFG_PULLUP_IOPORTNAME)
+#define USBIN           USB_INPORT(USB_CFG_IOPORTNAME)
+#define USBDDR          USB_DDRPORT(USB_CFG_IOPORTNAME)
+#define USB_PULLUP_DDR  USB_DDRPORT(USB_CFG_PULLUP_IOPORTNAME)
+
+#define USBMINUS    USB_CFG_DMINUS_BIT
+#define USBPLUS     USB_CFG_DPLUS_BIT
+#define USBIDLE     (1<<USB_CFG_DMINUS_BIT) /* value representing J state */
+#define USBMASK     ((1<<USB_CFG_DPLUS_BIT) | (1<<USB_CFG_DMINUS_BIT))  /* mask for USB I/O bits */
+
+/* defines for backward compatibility with older driver versions: */
+#define USB_CFG_IOPORT          USB_OUTPORT(USB_CFG_IOPORTNAME)
+#ifdef USB_CFG_PULLUP_IOPORTNAME
+#define USB_CFG_PULLUP_IOPORT   USB_OUTPORT(USB_CFG_PULLUP_IOPORTNAME)
+#endif
+
+#ifndef USB_CFG_EP3_NUMBER  /* if not defined in usbconfig.h */
+#define USB_CFG_EP3_NUMBER  3
+#endif
+
+#ifndef USB_CFG_HAVE_INTRIN_ENDPOINT3
+#define USB_CFG_HAVE_INTRIN_ENDPOINT3   0
+#endif
+
+#define USB_BUFSIZE     11  /* PID, 8 bytes data, 2 bytes CRC */
+
+/* ----- Try to find registers and bits responsible for ext interrupt 0 ----- */
+
+#ifndef USB_INTR_CFG    /* allow user to override our default */
+#   if defined  EICRA
+#       define USB_INTR_CFG EICRA
+#   else
+#       define USB_INTR_CFG MCUCR
+#   endif
+#endif
+#ifndef USB_INTR_CFG_SET    /* allow user to override our default */
+#   if defined(USB_COUNT_SOF) || defined(USB_SOF_HOOK)
+#       define USB_INTR_CFG_SET (1 << ISC01)                    /* cfg for falling edge */
+        /* If any SOF logic is used, the interrupt must be wired to D- where
+         * we better trigger on falling edge
+         */
+#   else
+#       define USB_INTR_CFG_SET ((1 << ISC00) | (1 << ISC01))   /* cfg for rising edge */
+#   endif
+#endif
+#ifndef USB_INTR_CFG_CLR    /* allow user to override our default */
+#   define USB_INTR_CFG_CLR 0    /* no bits to clear */
+#endif
+
+#ifndef USB_INTR_ENABLE     /* allow user to override our default */
+#   if defined GIMSK
+#       define USB_INTR_ENABLE  GIMSK
+#   elif defined EIMSK
+#       define USB_INTR_ENABLE  EIMSK
+#   else
+#       define USB_INTR_ENABLE  GICR
+#   endif
+#endif
+#ifndef USB_INTR_ENABLE_BIT /* allow user to override our default */
+#   define USB_INTR_ENABLE_BIT  INT0
+#endif
+
+#ifndef USB_INTR_PENDING    /* allow user to override our default */
+#   if defined  EIFR
+#       define USB_INTR_PENDING EIFR
+#   else
+#       define USB_INTR_PENDING GIFR
+#   endif
+#endif
+#ifndef USB_INTR_PENDING_BIT    /* allow user to override our default */
+#   define USB_INTR_PENDING_BIT INTF0
+#endif
+
+/*
+The defines above don't work for the following chips
+at90c8534: no ISC0?, no PORTB, can't find a data sheet
+at86rf401: no PORTB, no MCUCR etc, low clock rate
+atmega103: no ISC0? (maybe omission in header, can't find data sheet)
+atmega603: not defined in avr-libc
+at43usb320, at43usb355, at76c711: have USB anyway
+at94k: is different...
+
+at90s1200, attiny11, attiny12, attiny15, attiny28: these have no RAM
+*/
+
+/* ------------------------------------------------------------------------- */
+/* ----------------- USB Specification Constants and Types ----------------- */
+/* ------------------------------------------------------------------------- */
+
+/* USB Token values */
+#define USBPID_SETUP    0x2d
+#define USBPID_OUT      0xe1
+#define USBPID_IN       0x69
+#define USBPID_DATA0    0xc3
+#define USBPID_DATA1    0x4b
+
+#define USBPID_ACK      0xd2
+#define USBPID_NAK      0x5a
+#define USBPID_STALL    0x1e
+
+#ifndef USB_INITIAL_DATATOKEN
+#define USB_INITIAL_DATATOKEN   USBPID_DATA1
+#endif
+
+#ifndef __ASSEMBLER__
+
+typedef struct usbTxStatus{
+    volatile uchar   len;
+    uchar   buffer[USB_BUFSIZE];
+}usbTxStatus_t;
+
+extern usbTxStatus_t   usbTxStatus1, usbTxStatus3;
+#define usbTxLen1   usbTxStatus1.len
+#define usbTxBuf1   usbTxStatus1.buffer
+#define usbTxLen3   usbTxStatus3.len
+#define usbTxBuf3   usbTxStatus3.buffer
+
+
+typedef union usbWord{
+    unsigned    word;
+    uchar       bytes[2];
+}usbWord_t;
+
+typedef struct usbRequest{
+    uchar       bmRequestType;
+    uchar       bRequest;
+    usbWord_t   wValue;
+    usbWord_t   wIndex;
+    usbWord_t   wLength;
+}usbRequest_t;
+/* This structure matches the 8 byte setup request */
+#endif
+
+/* bmRequestType field in USB setup:
+ * d t t r r r r r, where
+ * d ..... direction: 0=host->device, 1=device->host
+ * t ..... type: 0=standard, 1=class, 2=vendor, 3=reserved
+ * r ..... recipient: 0=device, 1=interface, 2=endpoint, 3=other
+ */
+
+/* USB setup recipient values */
+#define USBRQ_RCPT_MASK         0x1f
+#define USBRQ_RCPT_DEVICE       0
+#define USBRQ_RCPT_INTERFACE    1
+#define USBRQ_RCPT_ENDPOINT     2
+
+/* USB request type values */
+#define USBRQ_TYPE_MASK         0x60
+#define USBRQ_TYPE_STANDARD     (0<<5)
+#define USBRQ_TYPE_CLASS        (1<<5)
+#define USBRQ_TYPE_VENDOR       (2<<5)
+
+/* USB direction values: */
+#define USBRQ_DIR_MASK              0x80
+#define USBRQ_DIR_HOST_TO_DEVICE    (0<<7)
+#define USBRQ_DIR_DEVICE_TO_HOST    (1<<7)
+
+/* USB Standard Requests */
+#define USBRQ_GET_STATUS        0
+#define USBRQ_CLEAR_FEATURE     1
+#define USBRQ_SET_FEATURE       3
+#define USBRQ_SET_ADDRESS       5
+#define USBRQ_GET_DESCRIPTOR    6
+#define USBRQ_SET_DESCRIPTOR    7
+#define USBRQ_GET_CONFIGURATION 8
+#define USBRQ_SET_CONFIGURATION 9
+#define USBRQ_GET_INTERFACE     10
+#define USBRQ_SET_INTERFACE     11
+#define USBRQ_SYNCH_FRAME       12
+
+/* USB descriptor constants */
+#define USBDESCR_DEVICE         1
+#define USBDESCR_CONFIG         2
+#define USBDESCR_STRING         3
+#define USBDESCR_INTERFACE      4
+#define USBDESCR_ENDPOINT       5
+#define USBDESCR_HID            0x21
+#define USBDESCR_HID_REPORT     0x22
+#define USBDESCR_HID_PHYS       0x23
+
+//#define USBATTR_BUSPOWER        0x80  // USB 1.1 does not define this value any more
+#define USBATTR_SELFPOWER       0x40
+#define USBATTR_REMOTEWAKE      0x20
+
+/* USB HID Requests */
+#define USBRQ_HID_GET_REPORT    0x01
+#define USBRQ_HID_GET_IDLE      0x02
+#define USBRQ_HID_GET_PROTOCOL  0x03
+#define USBRQ_HID_SET_REPORT    0x09
+#define USBRQ_HID_SET_IDLE      0x0a
+#define USBRQ_HID_SET_PROTOCOL  0x0b
+
+/* ------------------------------------------------------------------------- */
+
+#endif /* __usbdrv_h_included__ */

usbdrvasm.S

@@ -0,0 +1,385 @@
+/* Name: usbdrvasm.S
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2007-06-13
+ * Tabsize: 4
+ * Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * Revision: $Id: usbdrvasm.S 761 2009-08-12 16:30:23Z cs $
+ */
+
+/*
+General Description:
+This module is the assembler part of the USB driver. This file contains
+general code (preprocessor acrobatics and CRC computation) and then includes
+the file appropriate for the given clock rate.
+*/
+
+#define __SFR_OFFSET 0      /* used by avr-libc's register definitions */
+#include "usbportability.h"
+#include "usbdrv.h"         /* for common defs */
+
+/* register names */
+#define x1      r16
+#define x2      r17
+#define shift   r18
+#define cnt     r19
+#define x3      r20
+#define x4      r21
+#define x5		r22
+#define bitcnt  x5
+#define phase   x4
+#define leap    x4
+
+/* Some assembler dependent definitions and declarations: */
+
+#ifdef __IAR_SYSTEMS_ASM__
+    extern  usbRxBuf, usbDeviceAddr, usbNewDeviceAddr, usbInputBufOffset
+    extern  usbCurrentTok, usbRxLen, usbRxToken, usbTxLen
+    extern  usbTxBuf, usbTxStatus1, usbTxStatus3
+#   if USB_COUNT_SOF
+        extern usbSofCount
+#   endif
+    public  usbCrc16
+    public  usbCrc16Append
+
+    COMMON  INTVEC
+#   ifndef USB_INTR_VECTOR
+        ORG     INT0_vect
+#   else /* USB_INTR_VECTOR */
+        ORG     USB_INTR_VECTOR
+#       undef   USB_INTR_VECTOR
+#   endif /* USB_INTR_VECTOR */
+#   define  USB_INTR_VECTOR usbInterruptHandler
+    rjmp    USB_INTR_VECTOR
+    RSEG    CODE
+
+#else /* __IAR_SYSTEMS_ASM__ */
+
+#   ifndef USB_INTR_VECTOR /* default to hardware interrupt INT0 */
+#       define USB_INTR_VECTOR  SIG_INTERRUPT0
+#   endif
+    .text
+    .global USB_INTR_VECTOR
+    .type   USB_INTR_VECTOR, @function
+    .global usbCrc16
+    .global usbCrc16Append
+#endif /* __IAR_SYSTEMS_ASM__ */
+
+
+#if USB_INTR_PENDING < 0x40 /* This is an I/O address, use in and out */
+#   define  USB_LOAD_PENDING(reg)   in reg, USB_INTR_PENDING
+#   define  USB_STORE_PENDING(reg)  out USB_INTR_PENDING, reg
+#else   /* It's a memory address, use lds and sts */
+#   define  USB_LOAD_PENDING(reg)   lds reg, USB_INTR_PENDING
+#   define  USB_STORE_PENDING(reg)  sts USB_INTR_PENDING, reg
+#endif
+
+#define usbTxLen1   usbTxStatus1
+#define usbTxBuf1   (usbTxStatus1 + 1)
+#define usbTxLen3   usbTxStatus3
+#define usbTxBuf3   (usbTxStatus3 + 1)
+
+
+;----------------------------------------------------------------------------
+; Utility functions
+;----------------------------------------------------------------------------
+
+#ifdef __IAR_SYSTEMS_ASM__
+/* Register assignments for usbCrc16 on IAR cc */
+/* Calling conventions on IAR:
+ * First parameter passed in r16/r17, second in r18/r19 and so on.
+ * Callee must preserve r4-r15, r24-r29 (r28/r29 is frame pointer)
+ * Result is passed in r16/r17
+ * In case of the "tiny" memory model, pointers are only 8 bit with no
+ * padding. We therefore pass argument 1 as "16 bit unsigned".
+ */
+RTMODEL "__rt_version", "3"
+/* The line above will generate an error if cc calling conventions change.
+ * The value "3" above is valid for IAR 4.10B/W32
+ */
+#   define argLen   r18 /* argument 2 */
+#   define argPtrL  r16 /* argument 1 */
+#   define argPtrH  r17 /* argument 1 */
+
+#   define resCrcL  r16 /* result */
+#   define resCrcH  r17 /* result */
+
+#   define ptrL     ZL
+#   define ptrH     ZH
+#   define ptr      Z
+#   define byte     r22
+#   define bitCnt   r19
+#   define polyL    r20
+#   define polyH    r21
+#   define scratch  r23
+
+#else  /* __IAR_SYSTEMS_ASM__ */ 
+/* Register assignments for usbCrc16 on gcc */
+/* Calling conventions on gcc:
+ * First parameter passed in r24/r25, second in r22/23 and so on.
+ * Callee must preserve r1-r17, r28/r29
+ * Result is passed in r24/r25
+ */
+#   define argLen   r22 /* argument 2 */
+#   define argPtrL  r24 /* argument 1 */
+#   define argPtrH  r25 /* argument 1 */
+
+#   define resCrcL  r24 /* result */
+#   define resCrcH  r25 /* result */
+
+#   define ptrL     XL
+#   define ptrH     XH
+#   define ptr      x
+#   define byte     r18
+#   define bitCnt   r19
+#   define polyL    r20
+#   define polyH    r21
+#   define scratch  r23
+
+#endif
+
+#if USB_USE_FAST_CRC
+
+; This implementation is faster, but has bigger code size
+; Thanks to Slawomir Fras (BoskiDialer) for this code!
+; It implements the following C pseudo-code:
+; unsigned table(unsigned char x)
+; {
+; unsigned    value;
+; 
+;     value = (unsigned)x << 6;
+;     value ^= (unsigned)x << 7;
+;     if(parity(x))
+;         value ^= 0xc001;
+;     return value;
+; }
+; unsigned usbCrc16(unsigned char *argPtr, unsigned char argLen)
+; {
+; unsigned crc = 0xffff;
+; 
+;     while(argLen--)
+;         crc = table(lo8(crc) ^ *argPtr++) ^ hi8(crc);
+;     return ~crc;
+; }
+
+; extern unsigned usbCrc16(unsigned char *argPtr, unsigned char argLen);
+;   argPtr  r24+25 / r16+r17
+;   argLen  r22 / r18
+; temp variables:
+;   byte    r18 / r22
+;   scratch r23
+;   resCrc  r24+r25 / r16+r17
+;   ptr     X / Z
+usbCrc16:
+    mov     ptrL, argPtrL
+    mov     ptrH, argPtrH
+    ldi     resCrcL, 0xFF
+    ldi     resCrcH, 0xFF
+    rjmp    usbCrc16LoopTest
+usbCrc16ByteLoop:
+    ld      byte, ptr+
+    eor     resCrcL, byte   ; resCrcL is now 'x' in table()
+    mov     byte, resCrcL   ; compute parity of 'x'
+    swap    byte
+    eor     byte, resCrcL
+    mov     scratch, byte
+    lsr     byte
+    lsr     byte
+    eor     byte, scratch
+    inc     byte
+    lsr     byte
+    andi    byte, 1         ; byte is now parity(x)
+    mov     scratch, resCrcL
+    mov     resCrcL, resCrcH
+    eor     resCrcL, byte   ; low byte of if(parity(x)) value ^= 0xc001;
+    neg     byte
+    andi    byte, 0xc0
+    mov     resCrcH, byte   ; high byte of if(parity(x)) value ^= 0xc001;
+    clr     byte
+    lsr     scratch
+    ror     byte
+    eor     resCrcH, scratch
+    eor     resCrcL, byte
+    lsr     scratch
+    ror     byte
+    eor     resCrcH, scratch
+    eor     resCrcL, byte
+usbCrc16LoopTest:
+    subi    argLen, 1
+    brsh    usbCrc16ByteLoop
+    com     resCrcL
+    com     resCrcH
+    ret
+
+#else   /* USB_USE_FAST_CRC */
+
+; This implementation is slower, but has less code size
+;
+; extern unsigned usbCrc16(unsigned char *argPtr, unsigned char argLen);
+;   argPtr  r24+25 / r16+r17
+;   argLen  r22 / r18
+; temp variables:
+;   byte    r18 / r22
+;   bitCnt  r19
+;   poly    r20+r21
+;   scratch r23
+;   resCrc  r24+r25 / r16+r17
+;   ptr     X / Z
+usbCrc16:
+    mov     ptrL, argPtrL
+    mov     ptrH, argPtrH
+    ldi     resCrcL, 0
+    ldi     resCrcH, 0
+    ldi     polyL, lo8(0xa001)
+    ldi     polyH, hi8(0xa001)
+    com     argLen      ; argLen = -argLen - 1: modified loop to ensure that carry is set
+    ldi     bitCnt, 0   ; loop counter with starnd condition = end condition
+    rjmp    usbCrcLoopEntry
+usbCrcByteLoop:
+    ld      byte, ptr+
+    eor     resCrcL, byte
+usbCrcBitLoop:
+    ror     resCrcH     ; carry is always set here (see brcs jumps to here)
+    ror     resCrcL
+    brcs    usbCrcNoXor
+    eor     resCrcL, polyL
+    eor     resCrcH, polyH
+usbCrcNoXor:
+    subi    bitCnt, 224 ; (8 * 224) % 256 = 0; this loop iterates 8 times
+    brcs    usbCrcBitLoop
+usbCrcLoopEntry:
+    subi    argLen, -1
+    brcs    usbCrcByteLoop
+usbCrcReady:
+    ret
+; Thanks to Reimar Doeffinger for optimizing this CRC routine!
+
+#endif /* USB_USE_FAST_CRC */
+
+; extern unsigned usbCrc16Append(unsigned char *data, unsigned char len);
+usbCrc16Append:
+    rcall   usbCrc16
+    st      ptr+, resCrcL
+    st      ptr+, resCrcH
+    ret
+
+#undef argLen
+#undef argPtrL
+#undef argPtrH
+#undef resCrcL
+#undef resCrcH
+#undef ptrL
+#undef ptrH
+#undef ptr
+#undef byte
+#undef bitCnt
+#undef polyL
+#undef polyH
+#undef scratch
+
+
+#if USB_CFG_HAVE_MEASURE_FRAME_LENGTH
+#ifdef __IAR_SYSTEMS_ASM__
+/* Register assignments for usbMeasureFrameLength on IAR cc */
+/* Calling conventions on IAR:
+ * First parameter passed in r16/r17, second in r18/r19 and so on.
+ * Callee must preserve r4-r15, r24-r29 (r28/r29 is frame pointer)
+ * Result is passed in r16/r17
+ * In case of the "tiny" memory model, pointers are only 8 bit with no
+ * padding. We therefore pass argument 1 as "16 bit unsigned".
+ */
+#   define resL     r16
+#   define resH     r17
+#   define cnt16L   r30
+#   define cnt16H   r31
+#   define cntH     r18
+
+#else  /* __IAR_SYSTEMS_ASM__ */ 
+/* Register assignments for usbMeasureFrameLength on gcc */
+/* Calling conventions on gcc:
+ * First parameter passed in r24/r25, second in r22/23 and so on.
+ * Callee must preserve r1-r17, r28/r29
+ * Result is passed in r24/r25
+ */
+#   define resL     r24
+#   define resH     r25
+#   define cnt16L   r24
+#   define cnt16H   r25
+#   define cntH     r26
+#endif
+#   define cnt16    cnt16L
+
+; extern unsigned usbMeasurePacketLength(void);
+; returns time between two idle strobes in multiples of 7 CPU clocks
+.global usbMeasureFrameLength
+usbMeasureFrameLength:
+    ldi     cntH, 6         ; wait ~ 10 ms for D- == 0
+    clr     cnt16L
+    clr     cnt16H
+usbMFTime16:
+    dec     cntH
+    breq    usbMFTimeout
+usbMFWaitStrobe:            ; first wait for D- == 0 (idle strobe)
+    sbiw    cnt16, 1        ;[0] [6]
+    breq    usbMFTime16     ;[2]
+    sbic    USBIN, USBMINUS ;[3]
+    rjmp    usbMFWaitStrobe ;[4]
+usbMFWaitIdle:              ; then wait until idle again
+    sbis    USBIN, USBMINUS ;1 wait for D- == 1
+    rjmp    usbMFWaitIdle   ;2
+    ldi     cnt16L, 1       ;1 represents cycles so far
+    clr     cnt16H          ;1
+usbMFWaitLoop:
+    in      cntH, USBIN     ;[0] [7]
+    adiw    cnt16, 1        ;[1]
+    breq    usbMFTimeout    ;[3]
+    andi    cntH, USBMASK   ;[4]
+    brne    usbMFWaitLoop   ;[5]
+usbMFTimeout:
+#if resL != cnt16L
+    mov     resL, cnt16L
+    mov     resH, cnt16H
+#endif
+    ret
+
+#undef resL
+#undef resH
+#undef cnt16
+#undef cnt16L
+#undef cnt16H
+#undef cntH
+
+#endif  /* USB_CFG_HAVE_MEASURE_FRAME_LENGTH */
+
+;----------------------------------------------------------------------------
+; Now include the clock rate specific code
+;----------------------------------------------------------------------------
+
+#ifndef USB_CFG_CLOCK_KHZ
+#   define USB_CFG_CLOCK_KHZ 12000
+#endif
+
+#if USB_CFG_CHECK_CRC   /* separate dispatcher for CRC type modules */
+#   if USB_CFG_CLOCK_KHZ == 18000
+#       include "usbdrvasm18-crc.inc"
+#   else
+#       error "USB_CFG_CLOCK_KHZ is not one of the supported crc-rates!"
+#   endif
+#else   /* USB_CFG_CHECK_CRC */
+#   if USB_CFG_CLOCK_KHZ == 12000
+#       include "usbdrvasm12.inc"
+#   elif USB_CFG_CLOCK_KHZ == 12800
+#       include "usbdrvasm128.inc"
+#   elif USB_CFG_CLOCK_KHZ == 15000
+#       include "usbdrvasm15.inc"
+#   elif USB_CFG_CLOCK_KHZ == 16000
+#       include "usbdrvasm16.inc"
+#   elif USB_CFG_CLOCK_KHZ == 16500
+#       include "usbdrvasm165.inc"
+#   elif USB_CFG_CLOCK_KHZ == 20000
+#       include "usbdrvasm20.inc"
+#   else
+#       error "USB_CFG_CLOCK_KHZ is not one of the supported non-crc-rates!"
+#   endif
+#endif /* USB_CFG_CHECK_CRC */

usbdrvasm.asm

@@ -0,0 +1,21 @@
+/* Name: usbdrvasm.asm
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2006-03-01
+ * Tabsize: 4
+ * Copyright: (c) 2006 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * This Revision: $Id$
+ */
+
+/*
+General Description:
+The IAR compiler/assembler system prefers assembler files with file extension
+".asm". We simply provide this file as an alias for usbdrvasm.S.
+
+Thanks to Oleg Semyonov for his help with the IAR tools port!
+*/
+
+#include "usbdrvasm.S"
+
+end

usbdrvasm12.inc

@@ -0,0 +1,393 @@
+/* Name: usbdrvasm12.inc
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2004-12-29
+ * Tabsize: 4
+ * Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * This Revision: $Id: usbdrvasm12.inc 740 2009-04-13 18:23:31Z cs $
+ */
+
+/* Do not link this file! Link usbdrvasm.S instead, which includes the
+ * appropriate implementation!
+ */
+
+/*
+General Description:
+This file is the 12 MHz version of the asssembler part of the USB driver. It
+requires a 12 MHz crystal (not a ceramic resonator and not a calibrated RC
+oscillator).
+
+See usbdrv.h for a description of the entire driver.
+
+Since almost all of this code is timing critical, don't change unless you
+really know what you are doing! Many parts require not only a maximum number
+of CPU cycles, but even an exact number of cycles!
+
+
+Timing constraints according to spec (in bit times):
+timing subject                                      min max    CPUcycles
+---------------------------------------------------------------------------
+EOP of OUT/SETUP to sync pattern of DATA0 (both rx) 2   16     16-128
+EOP of IN to sync pattern of DATA0 (rx, then tx)    2   7.5    16-60
+DATAx (rx) to ACK/NAK/STALL (tx)                    2   7.5    16-60
+*/
+
+;Software-receiver engine. Strict timing! Don't change unless you can preserve timing!
+;interrupt response time: 4 cycles + insn running = 7 max if interrupts always enabled
+;max allowable interrupt latency: 34 cycles -> max 25 cycles interrupt disable
+;max stack usage: [ret(2), YL, SREG, YH, shift, x1, x2, x3, cnt, x4] = 11 bytes
+;Numbers in brackets are maximum cycles since SOF.
+USB_INTR_VECTOR:
+;order of registers pushed: YL, SREG [sofError], YH, shift, x1, x2, x3, cnt
+    push    YL              ;2 [35] push only what is necessary to sync with edge ASAP
+    in      YL, SREG        ;1 [37]
+    push    YL              ;2 [39]
+;----------------------------------------------------------------------------
+; Synchronize with sync pattern:
+;----------------------------------------------------------------------------
+;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
+;sync up with J to K edge during sync pattern -- use fastest possible loops
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
+waitForJ:
+    inc     YL
+    sbis    USBIN, USBMINUS
+    brne    waitForJ        ; just make sure we have ANY timeout
+waitForK:
+;The following code results in a sampling window of 1/4 bit which meets the spec.
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+#if USB_COUNT_SOF
+    lds     YL, usbSofCount
+    inc     YL
+    sts     usbSofCount, YL
+#endif  /* USB_COUNT_SOF */
+#ifdef USB_SOF_HOOK
+    USB_SOF_HOOK
+#endif
+    rjmp    sofError
+foundK:
+;{3, 5} after falling D- edge, average delay: 4 cycles [we want 4 for center sampling]
+;we have 1 bit time for setup purposes, then sample again. Numbers in brackets
+;are cycles from center of first sync (double K) bit after the instruction
+    push    YH                  ;2 [2]
+    lds     YL, usbInputBufOffset;2 [4]
+    clr     YH                  ;1 [5]
+    subi    YL, lo8(-(usbRxBuf));1 [6]
+    sbci    YH, hi8(-(usbRxBuf));1 [7]
+
+    sbis    USBIN, USBMINUS ;1 [8] we want two bits K [sample 1 cycle too early]
+    rjmp    haveTwoBitsK    ;2 [10]
+    pop     YH              ;2 [11] undo the push from before
+    rjmp    waitForK        ;2 [13] this was not the end of sync, retry
+haveTwoBitsK:
+;----------------------------------------------------------------------------
+; push more registers and initialize values while we sample the first bits:
+;----------------------------------------------------------------------------
+    push    shift           ;2 [16]
+    push    x1              ;2 [12]
+    push    x2              ;2 [14]
+
+    in      x1, USBIN       ;1 [17] <-- sample bit 0
+    ldi     shift, 0xff     ;1 [18]
+    bst     x1, USBMINUS    ;1 [19]
+    bld     shift, 0        ;1 [20]
+    push    x3              ;2 [22]
+    push    cnt             ;2 [24]
+    
+    in      x2, USBIN       ;1 [25] <-- sample bit 1
+    ser     x3              ;1 [26] [inserted init instruction]
+    eor     x1, x2          ;1 [27]
+    bst     x1, USBMINUS    ;1 [28]
+    bld     shift, 1        ;1 [29]
+    ldi     cnt, USB_BUFSIZE;1 [30] [inserted init instruction]
+    rjmp    rxbit2          ;2 [32]
+
+;----------------------------------------------------------------------------
+; Receiver loop (numbers in brackets are cycles within byte after instr)
+;----------------------------------------------------------------------------
+
+unstuff0:               ;1 (branch taken)
+    andi    x3, ~0x01   ;1 [15]
+    mov     x1, x2      ;1 [16] x2 contains last sampled (stuffed) bit
+    in      x2, USBIN   ;1 [17] <-- sample bit 1 again
+    ori     shift, 0x01 ;1 [18]
+    rjmp    didUnstuff0 ;2 [20]
+
+unstuff1:               ;1 (branch taken)
+    mov     x2, x1      ;1 [21] x1 contains last sampled (stuffed) bit
+    andi    x3, ~0x02   ;1 [22]
+    ori     shift, 0x02 ;1 [23]
+    nop                 ;1 [24]
+    in      x1, USBIN   ;1 [25] <-- sample bit 2 again
+    rjmp    didUnstuff1 ;2 [27]
+
+unstuff2:               ;1 (branch taken)
+    andi    x3, ~0x04   ;1 [29]
+    ori     shift, 0x04 ;1 [30]
+    mov     x1, x2      ;1 [31] x2 contains last sampled (stuffed) bit
+    nop                 ;1 [32]
+    in      x2, USBIN   ;1 [33] <-- sample bit 3
+    rjmp    didUnstuff2 ;2 [35]
+
+unstuff3:               ;1 (branch taken)
+    in      x2, USBIN   ;1 [34] <-- sample stuffed bit 3 [one cycle too late]
+    andi    x3, ~0x08   ;1 [35]
+    ori     shift, 0x08 ;1 [36]
+    rjmp    didUnstuff3 ;2 [38]
+
+unstuff4:               ;1 (branch taken)
+    andi    x3, ~0x10   ;1 [40]
+    in      x1, USBIN   ;1 [41] <-- sample stuffed bit 4
+    ori     shift, 0x10 ;1 [42]
+    rjmp    didUnstuff4 ;2 [44]
+
+unstuff5:               ;1 (branch taken)
+    andi    x3, ~0x20   ;1 [48]
+    in      x2, USBIN   ;1 [49] <-- sample stuffed bit 5
+    ori     shift, 0x20 ;1 [50]
+    rjmp    didUnstuff5 ;2 [52]
+
+unstuff6:               ;1 (branch taken)
+    andi    x3, ~0x40   ;1 [56]
+    in      x1, USBIN   ;1 [57] <-- sample stuffed bit 6
+    ori     shift, 0x40 ;1 [58]
+    rjmp    didUnstuff6 ;2 [60]
+
+; extra jobs done during bit interval:
+; bit 0:    store, clear [SE0 is unreliable here due to bit dribbling in hubs]
+; bit 1:    se0 check
+; bit 2:    overflow check
+; bit 3:    recovery from delay [bit 0 tasks took too long]
+; bit 4:    none
+; bit 5:    none
+; bit 6:    none
+; bit 7:    jump, eor
+rxLoop:
+    eor     x3, shift   ;1 [0] reconstruct: x3 is 0 at bit locations we changed, 1 at others
+    in      x1, USBIN   ;1 [1] <-- sample bit 0
+    st      y+, x3      ;2 [3] store data
+    ser     x3          ;1 [4]
+    nop                 ;1 [5]
+    eor     x2, x1      ;1 [6]
+    bst     x2, USBMINUS;1 [7]
+    bld     shift, 0    ;1 [8]
+    in      x2, USBIN   ;1 [9] <-- sample bit 1 (or possibly bit 0 stuffed)
+    andi    x2, USBMASK ;1 [10]
+    breq    se0         ;1 [11] SE0 check for bit 1
+    andi    shift, 0xf9 ;1 [12]
+didUnstuff0:
+    breq    unstuff0    ;1 [13]
+    eor     x1, x2      ;1 [14]
+    bst     x1, USBMINUS;1 [15]
+    bld     shift, 1    ;1 [16]
+rxbit2:
+    in      x1, USBIN   ;1 [17] <-- sample bit 2 (or possibly bit 1 stuffed)
+    andi    shift, 0xf3 ;1 [18]
+    breq    unstuff1    ;1 [19] do remaining work for bit 1
+didUnstuff1:
+    subi    cnt, 1      ;1 [20]
+    brcs    overflow    ;1 [21] loop control
+    eor     x2, x1      ;1 [22]
+    bst     x2, USBMINUS;1 [23]
+    bld     shift, 2    ;1 [24]
+    in      x2, USBIN   ;1 [25] <-- sample bit 3 (or possibly bit 2 stuffed)
+    andi    shift, 0xe7 ;1 [26]
+    breq    unstuff2    ;1 [27]
+didUnstuff2:
+    eor     x1, x2      ;1 [28]
+    bst     x1, USBMINUS;1 [29]
+    bld     shift, 3    ;1 [30]
+didUnstuff3:
+    andi    shift, 0xcf ;1 [31]
+    breq    unstuff3    ;1 [32]
+    in      x1, USBIN   ;1 [33] <-- sample bit 4
+    eor     x2, x1      ;1 [34]
+    bst     x2, USBMINUS;1 [35]
+    bld     shift, 4    ;1 [36]
+didUnstuff4:
+    andi    shift, 0x9f ;1 [37]
+    breq    unstuff4    ;1 [38]
+    nop2                ;2 [40]
+    in      x2, USBIN   ;1 [41] <-- sample bit 5
+    eor     x1, x2      ;1 [42]
+    bst     x1, USBMINUS;1 [43]
+    bld     shift, 5    ;1 [44]
+didUnstuff5:
+    andi    shift, 0x3f ;1 [45]
+    breq    unstuff5    ;1 [46]
+    nop2                ;2 [48]
+    in      x1, USBIN   ;1 [49] <-- sample bit 6
+    eor     x2, x1      ;1 [50]
+    bst     x2, USBMINUS;1 [51]
+    bld     shift, 6    ;1 [52]
+didUnstuff6:
+    cpi     shift, 0x02 ;1 [53]
+    brlo    unstuff6    ;1 [54]
+    nop2                ;2 [56]
+    in      x2, USBIN   ;1 [57] <-- sample bit 7
+    eor     x1, x2      ;1 [58]
+    bst     x1, USBMINUS;1 [59]
+    bld     shift, 7    ;1 [60]
+didUnstuff7:
+    cpi     shift, 0x04 ;1 [61]
+    brsh    rxLoop      ;2 [63] loop control
+unstuff7:
+    andi    x3, ~0x80   ;1 [63]
+    ori     shift, 0x80 ;1 [64]
+    in      x2, USBIN   ;1 [65] <-- sample stuffed bit 7
+    nop                 ;1 [66]
+    rjmp    didUnstuff7 ;2 [68]
+
+macro POP_STANDARD ; 12 cycles
+    pop     cnt
+    pop     x3
+    pop     x2
+    pop     x1
+    pop     shift
+    pop     YH
+    endm
+macro POP_RETI     ; 5 cycles
+    pop     YL
+    out     SREG, YL
+    pop     YL
+    endm
+
+#include "asmcommon.inc"
+
+;----------------------------------------------------------------------------
+; Transmitting data
+;----------------------------------------------------------------------------
+
+txByteLoop:
+txBitloop:
+stuffN1Delay:                   ;     [03]
+    ror     shift               ;[-5] [11] [59]
+    brcc    doExorN1            ;[-4]      [60]
+    subi    x4, 1               ;[-3]
+    brne    commonN1            ;[-2]
+    lsl     shift               ;[-1] compensate ror after rjmp stuffDelay
+    nop                         ;[00] stuffing consists of just waiting 8 cycles
+    rjmp    stuffN1Delay        ;[01] after ror, C bit is reliably clear
+
+sendNakAndReti:                 ;0 [-19] 19 cycles until SOP
+    ldi     x3, USBPID_NAK      ;1 [-18]
+    rjmp    usbSendX3           ;2 [-16]
+sendAckAndReti:                 ;0 [-19] 19 cycles until SOP
+    ldi     x3, USBPID_ACK      ;1 [-18]
+    rjmp    usbSendX3           ;2 [-16]
+sendCntAndReti:                 ;0 [-17] 17 cycles until SOP
+    mov     x3, cnt             ;1 [-16]
+usbSendX3:                      ;0 [-16]
+    ldi     YL, 20              ;1 [-15] 'x3' is R20
+    ldi     YH, 0               ;1 [-14]
+    ldi     cnt, 2              ;1 [-13]
+;   rjmp    usbSendAndReti      fallthrough
+
+; USB spec says:
+; idle = J
+; J = (D+ = 0), (D- = 1) or USBOUT = 0x01
+; K = (D+ = 1), (D- = 0) or USBOUT = 0x02
+; Spec allows 7.5 bit times from EOP to SOP for replies (= 60 cycles)
+
+;usbSend:
+;pointer to data in 'Y'
+;number of bytes in 'cnt' -- including sync byte
+;uses: x1...x2, x4, shift, cnt, Y [x1 = mirror USBOUT, x2 = USBMASK, x4 = bitstuff cnt]
+;Numbers in brackets are time since first bit of sync pattern is sent (start of instruction)
+usbSendAndReti:
+    in      x2, USBDDR          ;[-12] 12 cycles until SOP
+    ori     x2, USBMASK         ;[-11]
+    sbi     USBOUT, USBMINUS    ;[-10] prepare idle state; D+ and D- must have been 0 (no pullups)
+    out     USBDDR, x2          ;[-8] <--- acquire bus
+    in      x1, USBOUT          ;[-7] port mirror for tx loop
+    ldi     shift, 0x40         ;[-6] sync byte is first byte sent (we enter loop after ror)
+    ldi     x2, USBMASK         ;[-5]
+    push    x4                  ;[-4]
+doExorN1:
+    eor     x1, x2              ;[-2] [06] [62]
+    ldi     x4, 6               ;[-1] [07] [63]
+commonN1:
+stuffN2Delay:
+    out     USBOUT, x1          ;[00] [08] [64] <--- set bit
+    ror     shift               ;[01]
+    brcc    doExorN2            ;[02]
+    subi    x4, 1               ;[03]
+    brne    commonN2            ;[04]
+    lsl     shift               ;[05] compensate ror after rjmp stuffDelay
+    rjmp    stuffN2Delay        ;[06] after ror, C bit is reliably clear
+doExorN2:
+    eor     x1, x2              ;[04] [12]
+    ldi     x4, 6               ;[05] [13]
+commonN2:
+    nop                         ;[06] [14]
+    subi    cnt, 171            ;[07] [15] trick: (3 * 171) & 0xff = 1
+    out     USBOUT, x1          ;[08] [16] <--- set bit
+    brcs    txBitloop           ;[09]      [25] [41]
+
+stuff6Delay:
+    ror     shift               ;[42] [50]
+    brcc    doExor6             ;[43]
+    subi    x4, 1               ;[44]
+    brne    common6             ;[45]
+    lsl     shift               ;[46] compensate ror after rjmp stuffDelay
+    nop                         ;[47] stuffing consists of just waiting 8 cycles
+    rjmp    stuff6Delay         ;[48] after ror, C bit is reliably clear
+doExor6:
+    eor     x1, x2              ;[45] [53]
+    ldi     x4, 6               ;[46]
+common6:
+stuff7Delay:
+    ror     shift               ;[47] [55]
+    out     USBOUT, x1          ;[48] <--- set bit
+    brcc    doExor7             ;[49]
+    subi    x4, 1               ;[50]
+    brne    common7             ;[51]
+    lsl     shift               ;[52] compensate ror after rjmp stuffDelay
+    rjmp    stuff7Delay         ;[53] after ror, C bit is reliably clear
+doExor7:
+    eor     x1, x2              ;[51] [59]
+    ldi     x4, 6               ;[52]
+common7:
+    ld      shift, y+           ;[53]
+    tst     cnt                 ;[55]
+    out     USBOUT, x1          ;[56] <--- set bit
+    brne    txByteLoop          ;[57]
+
+;make SE0:
+    cbr     x1, USBMASK         ;[58] prepare SE0 [spec says EOP may be 15 to 18 cycles]
+    lds     x2, usbNewDeviceAddr;[59]
+    lsl     x2                  ;[61] we compare with left shifted address
+    subi    YL, 2 + 20          ;[62] Only assign address on data packets, not ACK/NAK in x3
+    sbci    YH, 0               ;[63]
+    out     USBOUT, x1          ;[00] <-- out SE0 -- from now 2 bits = 16 cycles until bus idle
+;2006-03-06: moved transfer of new address to usbDeviceAddr from C-Code to asm:
+;set address only after data packet was sent, not after handshake
+    breq    skipAddrAssign      ;[01]
+    sts     usbDeviceAddr, x2   ; if not skipped: SE0 is one cycle longer
+skipAddrAssign:
+;end of usbDeviceAddress transfer
+    ldi     x2, 1<<USB_INTR_PENDING_BIT;[03] int0 occurred during TX -- clear pending flag
+    USB_STORE_PENDING(x2)       ;[04]
+    ori     x1, USBIDLE         ;[05]
+    in      x2, USBDDR          ;[06]
+    cbr     x2, USBMASK         ;[07] set both pins to input
+    mov     x3, x1              ;[08]
+    cbr     x3, USBMASK         ;[09] configure no pullup on both pins
+    pop     x4                  ;[10]
+    nop2                        ;[12]
+    nop2                        ;[14]
+    out     USBOUT, x1          ;[16] <-- out J (idle) -- end of SE0 (EOP signal)
+    out     USBDDR, x2          ;[17] <-- release bus now
+    out     USBOUT, x3          ;[18] <-- ensure no pull-up resistors are active
+    rjmp    doReturn

usbdrvasm128.inc

@@ -0,0 +1,750 @@
+/* Name: usbdrvasm128.inc
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2008-10-11
+ * Tabsize: 4
+ * Copyright: (c) 2008 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * This Revision: $Id: usbdrvasm128.inc 758 2009-08-06 10:12:54Z cs $
+ */
+
+/* Do not link this file! Link usbdrvasm.S instead, which includes the
+ * appropriate implementation!
+ */
+
+/*
+General Description:
+This file is the 12.8 MHz version of the USB driver. It is intended for use
+with the internal RC oscillator. Although 12.8 MHz is outside the guaranteed
+calibration range of the oscillator, almost all AVRs can reach this frequency.
+This version contains a phase locked loop in the receiver routine to cope with
+slight clock rate deviations of up to +/- 1%.
+
+See usbdrv.h for a description of the entire driver.
+
+LIMITATIONS
+===========
+Although it may seem very handy to save the crystal and use the internal
+RC oscillator of the CPU, this method (and this module) has some serious
+limitations:
+(1) The guaranteed calibration range of the oscillator is only 8.1 MHz.
+They typical range is 14.5 MHz and most AVRs can actually reach this rate.
+(2) Writing EEPROM and Flash may be unreliable (short data lifetime) since
+the write procedure is timed from the RC oscillator.
+(3) End Of Packet detection (SE0) should be in bit 1, bit it is only checked
+if bits 0 and 1 both read as 0 on D- and D+ read as 0 in the middle. This may
+cause problems with old hubs which delay SE0 by up to one cycle.
+(4) Code size is much larger than that of the other modules.
+
+Since almost all of this code is timing critical, don't change unless you
+really know what you are doing! Many parts require not only a maximum number
+of CPU cycles, but even an exact number of cycles!
+
+Implementation notes:
+======================
+min frequency: 67 cycles for 8 bit -> 12.5625 MHz
+max frequency: 69.286 cycles for 8 bit -> 12.99 MHz
+nominal frequency: 12.77 MHz ( = sqrt(min * max))
+
+sampling positions: (next even number in range [+/- 0.5])
+cycle index range: 0 ... 66
+bits:
+.5, 8.875, 17.25, 25.625, 34, 42.375, 50.75, 59.125
+[0/1], [9], [17], [25/+26], [34], [+42/43], [51], [59]
+
+bit number:     0   1   2   3   4   5   6   7
+spare cycles    1   2   1   2   1   1   1   0
+
+operations to perform:      duration cycle
+                            ----------------
+    eor     fix, shift          1 -> 00
+    andi    phase, USBMASK      1 -> 08
+    breq    se0                 1 -> 16 (moved to 11)
+    st      y+, data            2 -> 24, 25
+    mov     data, fix           1 -> 33
+    ser     data                1 -> 41
+    subi    cnt, 1              1 -> 49
+    brcs    overflow            1 -> 50
+
+layout of samples and operations:
+[##] = sample bit
+<##> = sample phase
+*##* = operation
+
+0:  *00* [01]  02   03   04  <05>  06   07
+1:  *08* [09]  10   11   12  <13>  14   15  *16*
+2:  [17]  18   19   20  <21>  22   23
+3:  *24* *25* [26]  27   28   29  <30>  31   32
+4:  *33* [34]  35   36   37  <38>  39   40
+5:  *41* [42]  43   44   45  <46>  47   48
+6:  *49* *50* [51]  52   53   54  <55>  56   57   58
+7:  [59]  60   61   62  <63>  64   65   66
+*****************************************************************************/
+
+/* we prefer positive expressions (do if condition) instead of negative
+ * (skip if condition), therefore use defines for skip instructions:
+ */
+#define ifioclr sbis
+#define ifioset sbic
+#define ifrclr  sbrs
+#define ifrset  sbrc
+
+/* The registers "fix" and "data" swap their meaning during the loop. Use
+ * defines to keep their name constant.
+ */
+#define fix     x2
+#define data    x1
+#undef phase        /* phase has a default definition to x4 */
+#define phase   x3
+
+
+USB_INTR_VECTOR:
+;order of registers pushed: YL, SREG [sofError], YH, shift, x1, x2, x3, cnt, r0
+    push    YL              ;2 push only what is necessary to sync with edge ASAP
+    in      YL, SREG        ;1
+    push    YL              ;2
+;----------------------------------------------------------------------------
+; Synchronize with sync pattern:
+;----------------------------------------------------------------------------
+;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
+;sync up with J to K edge during sync pattern -- use fastest possible loops
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
+waitForJ:
+    inc     YL
+    sbis    USBIN, USBMINUS
+    brne    waitForJ        ; just make sure we have ANY timeout
+waitForK:
+;The following code results in a sampling window of 1/4 bit which meets the spec.
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS ;[0]
+    rjmp    foundK          ;[1]
+#if USB_COUNT_SOF
+    lds     YL, usbSofCount
+    inc     YL
+    sts     usbSofCount, YL
+#endif  /* USB_COUNT_SOF */
+#ifdef USB_SOF_HOOK
+    USB_SOF_HOOK
+#endif
+    rjmp    sofError
+
+foundK:
+;{3, 5} after falling D- edge, average delay: 4 cycles [we want 4 for center sampling]
+;we have 1 bit time for setup purposes, then sample again. Numbers in brackets
+;are cycles from center of first sync (double K) bit after the instruction
+    push    YH                  ;[2]
+    lds     YL, usbInputBufOffset;[4]
+    clr     YH                  ;[6]
+    subi    YL, lo8(-(usbRxBuf));[7]
+    sbci    YH, hi8(-(usbRxBuf));[8]
+
+    sbis    USBIN, USBMINUS     ;[9] we want two bits K [we want to sample at 8 + 4 - 1.5 = 10.5]
+    rjmp    haveTwoBitsK        ;[10]
+    pop     YH                  ;[11] undo the push from before
+    rjmp    waitForK            ;[13] this was not the end of sync, retry
+haveTwoBitsK:
+;----------------------------------------------------------------------------
+; push more registers and initialize values while we sample the first bits:
+;----------------------------------------------------------------------------
+#define fix     x2
+#define data    x1
+
+    push    shift               ;[12]
+    push    x1                  ;[14]
+    push    x2                  ;[16]
+    ldi     shift, 0x80         ;[18] prevent bit-unstuffing but init low bits to 0
+    ifioset USBIN, USBMINUS     ;[19] [01] <--- bit 0 [10.5 + 8 = 18.5]
+    ori     shift, 1<<0         ;[02]
+    push    x3                  ;[03]
+    push    cnt                 ;[05]
+    push    r0                  ;[07]
+    ifioset USBIN, USBMINUS     ;[09] <--- bit 1
+    ori     shift, 1<<1         ;[10]
+    ser     fix                 ;[11]
+    ldi     cnt, USB_BUFSIZE    ;[12]
+    mov     data, shift         ;[13]
+    lsl     shift               ;[14]
+    nop2                        ;[15]
+    ifioset USBIN, USBMINUS     ;[17] <--- bit 2
+    ori     data, 3<<2          ;[18] store in bit 2 AND bit 3
+    eor     shift, data         ;[19] do nrzi decoding
+    andi    data, 1<<3          ;[20]
+    in      phase, USBIN        ;[21] <- phase
+    brne    jumpToEntryAfterSet ;[22] if USBMINS at bit 3 was 1
+    nop                         ;[23]
+    rjmp    entryAfterClr       ;[24]
+jumpToEntryAfterSet:
+    rjmp    entryAfterSet       ;[24]
+
+;----------------------------------------------------------------------------
+; Receiver loop (numbers in brackets are cycles within byte after instr)
+;----------------------------------------------------------------------------
+#undef  fix
+#define  fix    x1
+#undef  data
+#define data    x2
+
+bit7IsSet:
+    ifrclr  phase, USBMINUS     ;[62] check phase only if D- changed
+    lpm                         ;[63]
+    in      phase, USBIN        ;[64] <- phase (one cycle too late)
+    ori     shift, 1 << 7       ;[65]
+    nop                         ;[66]
+;;;;rjmp    bit0AfterSet        ; -> [00] == [67] moved block up to save jump
+bit0AfterSet:
+    eor     fix, shift          ;[00]
+#undef  fix
+#define fix     x2
+#undef  data
+#define data    x1  /* we now have result in data, fix is reset to 0xff */
+    ifioclr USBIN, USBMINUS     ;[01] <--- sample 0
+    rjmp    bit0IsClr           ;[02]
+    andi    shift, ~(7 << 0)    ;[03]
+    breq    unstuff0s           ;[04]
+    in      phase, USBIN        ;[05] <- phase
+    rjmp    bit1AfterSet        ;[06]
+unstuff0s:
+    in      phase, USBIN        ;[06] <- phase (one cycle too late)
+    andi    fix, ~(1 << 0)      ;[07]
+    ifioclr USBIN, USBMINUS     ;[00]
+    ifioset USBIN, USBPLUS      ;[01]
+    rjmp    bit0IsClr           ;[02] executed if first expr false or second true
+se0AndStore:                    ; executed only if both bits 0
+    st      y+, x1              ;[15/17] cycles after start of byte
+    rjmp    se0                 ;[17/19]
+
+bit0IsClr:
+    ifrset  phase, USBMINUS     ;[04] check phase only if D- changed
+    lpm                         ;[05]
+    in      phase, USBIN        ;[06] <- phase (one cycle too late)
+    ori     shift, 1 << 0       ;[07]
+bit1AfterClr:
+    andi    phase, USBMASK      ;[08]
+    ifioset USBIN, USBMINUS     ;[09] <--- sample 1
+    rjmp    bit1IsSet           ;[10]
+    breq    se0AndStore         ;[11] if D- was 0 in bits 0 AND 1 and D+ was 0 in between, we have SE0
+    andi    shift, ~(7 << 1)    ;[12]
+    in      phase, USBIN        ;[13] <- phase
+    breq    unstuff1c           ;[14]
+    rjmp    bit2AfterClr        ;[15]
+unstuff1c:
+    andi    fix, ~(1 << 1)      ;[16]
+    nop2                        ;[08]
+    nop2                        ;[10]
+bit1IsSet:
+    ifrclr  phase, USBMINUS     ;[12] check phase only if D- changed
+    lpm                         ;[13]
+    in      phase, USBIN        ;[14] <- phase (one cycle too late)
+    ori     shift, 1 << 1       ;[15]
+    nop                         ;[16]
+bit2AfterSet:
+    ifioclr USBIN, USBMINUS     ;[17] <--- sample 2
+    rjmp    bit2IsClr           ;[18]
+    andi    shift, ~(7 << 2)    ;[19]
+    breq    unstuff2s           ;[20]
+    in      phase, USBIN        ;[21] <- phase
+    rjmp    bit3AfterSet        ;[22]
+unstuff2s:
+    in      phase, USBIN        ;[22] <- phase (one cycle too late)
+    andi    fix, ~(1 << 2)      ;[23]
+    nop2                        ;[16]
+    nop2                        ;[18]
+bit2IsClr:
+    ifrset  phase, USBMINUS     ;[20] check phase only if D- changed
+    lpm                         ;[21]
+    in      phase, USBIN        ;[22] <- phase (one cycle too late)
+    ori     shift, 1 << 2       ;[23]
+bit3AfterClr:
+    st      y+, data            ;[24]
+entryAfterClr:
+    ifioset USBIN, USBMINUS     ;[26] <--- sample 3
+    rjmp    bit3IsSet           ;[27]
+    andi    shift, ~(7 << 3)    ;[28]
+    breq    unstuff3c           ;[29]
+    in      phase, USBIN        ;[30] <- phase
+    rjmp    bit4AfterClr        ;[31]
+unstuff3c:
+    in      phase, USBIN        ;[31] <- phase (one cycle too late)
+    andi    fix, ~(1 << 3)      ;[32]
+    nop2                        ;[25]
+    nop2                        ;[27]
+bit3IsSet:
+    ifrclr  phase, USBMINUS     ;[29] check phase only if D- changed
+    lpm                         ;[30]
+    in      phase, USBIN        ;[31] <- phase (one cycle too late)
+    ori     shift, 1 << 3       ;[32]
+bit4AfterSet:
+    mov     data, fix           ;[33] undo this move by swapping defines
+#undef  fix
+#define fix     x1
+#undef  data
+#define data    x2
+    ifioclr USBIN, USBMINUS     ;[34] <--- sample 4
+    rjmp    bit4IsClr           ;[35]
+    andi    shift, ~(7 << 4)    ;[36]
+    breq    unstuff4s           ;[37]
+    in      phase, USBIN        ;[38] <- phase
+    rjmp    bit5AfterSet        ;[39]
+unstuff4s:
+    in      phase, USBIN        ;[39] <- phase (one cycle too late)
+    andi    fix, ~(1 << 4)      ;[40]
+    nop2                        ;[33]
+    nop2                        ;[35]
+bit4IsClr:
+    ifrset  phase, USBMINUS     ;[37] check phase only if D- changed
+    lpm                         ;[38]
+    in      phase, USBIN        ;[39] <- phase (one cycle too late)
+    ori     shift, 1 << 4       ;[40]
+bit5AfterClr:
+    ser     data                ;[41]
+    ifioset USBIN, USBMINUS     ;[42] <--- sample 5
+    rjmp    bit5IsSet           ;[43]
+    andi    shift, ~(7 << 5)    ;[44]
+    breq    unstuff5c           ;[45]
+    in      phase, USBIN        ;[46] <- phase
+    rjmp    bit6AfterClr        ;[47]
+unstuff5c:
+    in      phase, USBIN        ;[47] <- phase (one cycle too late)
+    andi    fix, ~(1 << 5)      ;[48]
+    nop2                        ;[41]
+    nop2                        ;[43]
+bit5IsSet:
+    ifrclr  phase, USBMINUS     ;[45] check phase only if D- changed
+    lpm                         ;[46]
+    in      phase, USBIN        ;[47] <- phase (one cycle too late)
+    ori     shift, 1 << 5       ;[48]
+bit6AfterSet:
+    subi    cnt, 1              ;[49]
+    brcs    jumpToOverflow      ;[50]
+    ifioclr USBIN, USBMINUS     ;[51] <--- sample 6
+    rjmp    bit6IsClr           ;[52]
+    andi    shift, ~(3 << 6)    ;[53]
+    cpi     shift, 2            ;[54]
+    in      phase, USBIN        ;[55] <- phase
+    brlt    unstuff6s           ;[56]
+    rjmp    bit7AfterSet        ;[57]
+
+jumpToOverflow:
+    rjmp    overflow
+
+unstuff6s:
+    andi    fix, ~(1 << 6)      ;[50]
+    lpm                         ;[51]
+bit6IsClr:
+    ifrset  phase, USBMINUS     ;[54] check phase only if D- changed
+    lpm                         ;[55]
+    in      phase, USBIN        ;[56] <- phase (one cycle too late)
+    ori     shift, 1 << 6       ;[57]
+    nop                         ;[58]
+bit7AfterClr:
+    ifioset USBIN, USBMINUS     ;[59] <--- sample 7
+    rjmp    bit7IsSet           ;[60]
+    andi    shift, ~(1 << 7)    ;[61]
+    cpi     shift, 4            ;[62]
+    in      phase, USBIN        ;[63] <- phase
+    brlt    unstuff7c           ;[64]
+    rjmp    bit0AfterClr        ;[65] -> [00] == [67]
+unstuff7c:
+    andi    fix, ~(1 << 7)      ;[58]
+    nop                         ;[59]
+    rjmp    bit7IsSet           ;[60]
+
+bit7IsClr:
+    ifrset  phase, USBMINUS     ;[62] check phase only if D- changed
+    lpm                         ;[63]
+    in      phase, USBIN        ;[64] <- phase (one cycle too late)
+    ori     shift, 1 << 7       ;[65]
+    nop                         ;[66]
+;;;;rjmp    bit0AfterClr        ; -> [00] == [67] moved block up to save jump
+bit0AfterClr:
+    eor     fix, shift          ;[00]
+#undef  fix
+#define fix     x2
+#undef  data
+#define data    x1  /* we now have result in data, fix is reset to 0xff */
+    ifioset USBIN, USBMINUS     ;[01] <--- sample 0
+    rjmp    bit0IsSet           ;[02]
+    andi    shift, ~(7 << 0)    ;[03]
+    breq    unstuff0c           ;[04]
+    in      phase, USBIN        ;[05] <- phase
+    rjmp    bit1AfterClr        ;[06]
+unstuff0c:
+    in      phase, USBIN        ;[06] <- phase (one cycle too late)
+    andi    fix, ~(1 << 0)      ;[07]
+    ifioclr USBIN, USBMINUS     ;[00]
+    ifioset USBIN, USBPLUS      ;[01]
+    rjmp    bit0IsSet           ;[02] executed if first expr false or second true
+    rjmp    se0AndStore         ;[03] executed only if both bits 0
+bit0IsSet:
+    ifrclr  phase, USBMINUS     ;[04] check phase only if D- changed
+    lpm                         ;[05]
+    in      phase, USBIN        ;[06] <- phase (one cycle too late)
+    ori     shift, 1 << 0       ;[07]
+bit1AfterSet:
+    andi    shift, ~(7 << 1)    ;[08] compensated by "ori shift, 1<<1" if bit1IsClr
+    ifioclr USBIN, USBMINUS     ;[09] <--- sample 1
+    rjmp    bit1IsClr           ;[10]
+    breq    unstuff1s           ;[11]
+    nop2                        ;[12] do not check for SE0 if bit 0 was 1
+    in      phase, USBIN        ;[14] <- phase (one cycle too late)
+    rjmp    bit2AfterSet        ;[15]
+unstuff1s:
+    in      phase, USBIN        ;[13] <- phase
+    andi    fix, ~(1 << 1)      ;[14]
+    lpm                         ;[07]
+    nop2                        ;[10]
+bit1IsClr:
+    ifrset  phase, USBMINUS     ;[12] check phase only if D- changed
+    lpm                         ;[13]
+    in      phase, USBIN        ;[14] <- phase (one cycle too late)
+    ori     shift, 1 << 1       ;[15]
+    nop                         ;[16]
+bit2AfterClr:
+    ifioset USBIN, USBMINUS     ;[17] <--- sample 2
+    rjmp    bit2IsSet           ;[18]
+    andi    shift, ~(7 << 2)    ;[19]
+    breq    unstuff2c           ;[20]
+    in      phase, USBIN        ;[21] <- phase
+    rjmp    bit3AfterClr        ;[22]
+unstuff2c:
+    in      phase, USBIN        ;[22] <- phase (one cycle too late)
+    andi    fix, ~(1 << 2)      ;[23]
+    nop2                        ;[16]
+    nop2                        ;[18]
+bit2IsSet:
+    ifrclr  phase, USBMINUS     ;[20] check phase only if D- changed
+    lpm                         ;[21]
+    in      phase, USBIN        ;[22] <- phase (one cycle too late)
+    ori     shift, 1 << 2       ;[23]
+bit3AfterSet:
+    st      y+, data            ;[24]
+entryAfterSet:
+    ifioclr USBIN, USBMINUS     ;[26] <--- sample 3
+    rjmp    bit3IsClr           ;[27]
+    andi    shift, ~(7 << 3)    ;[28]
+    breq    unstuff3s           ;[29]
+    in      phase, USBIN        ;[30] <- phase
+    rjmp    bit4AfterSet        ;[31]
+unstuff3s:
+    in      phase, USBIN        ;[31] <- phase (one cycle too late)
+    andi    fix, ~(1 << 3)      ;[32]
+    nop2                        ;[25]
+    nop2                        ;[27]
+bit3IsClr:
+    ifrset  phase, USBMINUS     ;[29] check phase only if D- changed
+    lpm                         ;[30]
+    in      phase, USBIN        ;[31] <- phase (one cycle too late)
+    ori     shift, 1 << 3       ;[32]
+bit4AfterClr:
+    mov     data, fix           ;[33] undo this move by swapping defines
+#undef  fix
+#define fix     x1
+#undef  data
+#define data    x2
+    ifioset USBIN, USBMINUS     ;[34] <--- sample 4
+    rjmp    bit4IsSet           ;[35]
+    andi    shift, ~(7 << 4)    ;[36]
+    breq    unstuff4c           ;[37]
+    in      phase, USBIN        ;[38] <- phase
+    rjmp    bit5AfterClr        ;[39]
+unstuff4c:
+    in      phase, USBIN        ;[39] <- phase (one cycle too late)
+    andi    fix, ~(1 << 4)      ;[40]
+    nop2                        ;[33]
+    nop2                        ;[35]
+bit4IsSet:
+    ifrclr  phase, USBMINUS     ;[37] check phase only if D- changed
+    lpm                         ;[38]
+    in      phase, USBIN        ;[39] <- phase (one cycle too late)
+    ori     shift, 1 << 4       ;[40]
+bit5AfterSet:
+    ser     data                ;[41]
+    ifioclr USBIN, USBMINUS     ;[42] <--- sample 5
+    rjmp    bit5IsClr           ;[43]
+    andi    shift, ~(7 << 5)    ;[44]
+    breq    unstuff5s           ;[45]
+    in      phase, USBIN        ;[46] <- phase
+    rjmp    bit6AfterSet        ;[47]
+unstuff5s:
+    in      phase, USBIN        ;[47] <- phase (one cycle too late)
+    andi    fix, ~(1 << 5)      ;[48]
+    nop2                        ;[41]
+    nop2                        ;[43]
+bit5IsClr:
+    ifrset  phase, USBMINUS     ;[45] check phase only if D- changed
+    lpm                         ;[46]
+    in      phase, USBIN        ;[47] <- phase (one cycle too late)
+    ori     shift, 1 << 5       ;[48]
+bit6AfterClr:
+    subi    cnt, 1              ;[49]
+    brcs    overflow            ;[50]
+    ifioset USBIN, USBMINUS     ;[51] <--- sample 6
+    rjmp    bit6IsSet           ;[52]
+    andi    shift, ~(3 << 6)    ;[53]
+    cpi     shift, 2            ;[54]
+    in      phase, USBIN        ;[55] <- phase
+    brlt    unstuff6c           ;[56]
+    rjmp    bit7AfterClr        ;[57]
+unstuff6c:
+    andi    fix, ~(1 << 6)      ;[50]
+    lpm                         ;[51]
+bit6IsSet:
+    ifrclr  phase, USBMINUS     ;[54] check phase only if D- changed
+    lpm                         ;[55]
+    in      phase, USBIN        ;[56] <- phase (one cycle too late)
+    ori     shift, 1 << 6       ;[57]
+bit7AfterSet:
+    ifioclr USBIN, USBMINUS     ;[59] <--- sample 7
+    rjmp    bit7IsClr           ;[60]
+    andi    shift, ~(1 << 7)    ;[61]
+    cpi     shift, 4            ;[62]
+    in      phase, USBIN        ;[63] <- phase
+    brlt    unstuff7s           ;[64]
+    rjmp    bit0AfterSet        ;[65] -> [00] == [67]
+unstuff7s:
+    andi    fix, ~(1 << 7)      ;[58]
+    nop                         ;[59]
+    rjmp    bit7IsClr           ;[60]
+
+macro POP_STANDARD ; 14 cycles
+    pop     r0
+    pop     cnt
+    pop     x3
+    pop     x2
+    pop     x1
+    pop     shift
+    pop     YH
+    endm
+macro POP_RETI     ; 5 cycles
+    pop     YL
+    out     SREG, YL
+    pop     YL
+    endm
+
+#include "asmcommon.inc"
+
+;----------------------------------------------------------------------------
+; Transmitting data
+;----------------------------------------------------------------------------
+
+txByteLoop:
+txBitloop:
+stuffN1Delay:                   ;     [03]
+    ror     shift               ;[-5] [11] [63]
+    brcc    doExorN1            ;[-4]      [64]
+    subi    x3, 1               ;[-3]
+    brne    commonN1            ;[-2]
+    lsl     shift               ;[-1] compensate ror after rjmp stuffDelay
+    nop                         ;[00] stuffing consists of just waiting 8 cycles
+    rjmp    stuffN1Delay        ;[01] after ror, C bit is reliably clear
+
+sendNakAndReti:
+    ldi     cnt, USBPID_NAK ;[-19]
+    rjmp    sendCntAndReti  ;[-18]
+sendAckAndReti:
+    ldi     cnt, USBPID_ACK ;[-17]
+sendCntAndReti:
+    mov     r0, cnt         ;[-16]
+    ldi     YL, 0           ;[-15] R0 address is 0
+    ldi     YH, 0           ;[-14]
+    ldi     cnt, 2          ;[-13]
+;   rjmp    usbSendAndReti      fallthrough
+
+; USB spec says:
+; idle = J
+; J = (D+ = 0), (D- = 1) or USBOUT = 0x01
+; K = (D+ = 1), (D- = 0) or USBOUT = 0x02
+; Spec allows 7.5 bit times from EOP to SOP for replies (= 60 cycles)
+
+;usbSend:
+;pointer to data in 'Y'
+;number of bytes in 'cnt' -- including sync byte
+;uses: x1...x3, shift, cnt, Y [x1 = mirror USBOUT, x2 = USBMASK, x3 = bitstuff cnt]
+;Numbers in brackets are time since first bit of sync pattern is sent (start of instruction)
+usbSendAndReti:
+    in      x2, USBDDR          ;[-10] 10 cycles until SOP
+    ori     x2, USBMASK         ;[-9]
+    sbi     USBOUT, USBMINUS    ;[-8] prepare idle state; D+ and D- must have been 0 (no pullups)
+    out     USBDDR, x2          ;[-6] <--- acquire bus
+    in      x1, USBOUT          ;[-5] port mirror for tx loop
+    ldi     shift, 0x40         ;[-4] sync byte is first byte sent (we enter loop after ror)
+    ldi     x2, USBMASK         ;[-3]
+doExorN1:
+    eor     x1, x2              ;[-2] [06] [62]
+    ldi     x3, 6               ;[-1] [07] [63]
+commonN1:
+stuffN2Delay:
+    out     USBOUT, x1          ;[00] [08] [64] <--- set bit
+    ror     shift               ;[01]
+    brcc    doExorN2            ;[02]
+    subi    x3, 1               ;[03]
+    brne    commonN2            ;[04]
+    lsl     shift               ;[05] compensate ror after rjmp stuffDelay
+    rjmp    stuffN2Delay        ;[06] after ror, C bit is reliably clear
+doExorN2:
+    eor     x1, x2              ;[04] [12]
+    ldi     x3, 6               ;[05] [13]
+commonN2:
+    nop2                        ;[06] [14]
+    subi    cnt, 171            ;[08] [16] trick: (3 * 171) & 0xff = 1
+    out     USBOUT, x1          ;[09] [17] <--- set bit
+    brcs    txBitloop           ;[10]      [27] [44]
+
+stuff6Delay:
+    ror     shift               ;[45] [53]
+    brcc    doExor6             ;[46]
+    subi    x3, 1               ;[47]
+    brne    common6             ;[48]
+    lsl     shift               ;[49] compensate ror after rjmp stuffDelay
+    nop                         ;[50] stuffing consists of just waiting 8 cycles
+    rjmp    stuff6Delay         ;[51] after ror, C bit is reliably clear
+doExor6:
+    eor     x1, x2              ;[48] [56]
+    ldi     x3, 6               ;[49]
+common6:
+stuff7Delay:
+    ror     shift               ;[50] [58]
+    out     USBOUT, x1          ;[51] <--- set bit
+    brcc    doExor7             ;[52]
+    subi    x3, 1               ;[53]
+    brne    common7             ;[54]
+    lsl     shift               ;[55] compensate ror after rjmp stuffDelay
+    rjmp    stuff7Delay         ;[56] after ror, C bit is reliably clear
+doExor7:
+    eor     x1, x2              ;[54] [62]
+    ldi     x3, 6               ;[55]
+common7:
+    ld      shift, y+           ;[56]
+    nop                         ;[58]
+    tst     cnt                 ;[59]
+    out     USBOUT, x1          ;[60] [00]<--- set bit
+    brne    txByteLoop          ;[61] [01]
+;make SE0:
+    cbr     x1, USBMASK         ;[02] prepare SE0 [spec says EOP may be 15 to 18 cycles]
+    lds     x2, usbNewDeviceAddr;[03]
+    lsl     x2                  ;[05] we compare with left shifted address
+    subi    YL, 2 + 0           ;[06] Only assign address on data packets, not ACK/NAK in r0
+    sbci    YH, 0               ;[07]
+    out     USBOUT, x1          ;[00] <-- out SE0 -- from now 2 bits = 16 cycles until bus idle
+;2006-03-06: moved transfer of new address to usbDeviceAddr from C-Code to asm:
+;set address only after data packet was sent, not after handshake
+    breq    skipAddrAssign      ;[01]
+    sts     usbDeviceAddr, x2   ; if not skipped: SE0 is one cycle longer
+skipAddrAssign:
+;end of usbDeviceAddress transfer
+    ldi     x2, 1<<USB_INTR_PENDING_BIT;[03] int0 occurred during TX -- clear pending flag
+    USB_STORE_PENDING(x2)       ;[04]
+    ori     x1, USBIDLE         ;[05]
+    in      x2, USBDDR          ;[06]
+    cbr     x2, USBMASK         ;[07] set both pins to input
+    mov     x3, x1              ;[08]
+    cbr     x3, USBMASK         ;[09] configure no pullup on both pins
+    lpm                         ;[10]
+    lpm                         ;[13]
+    out     USBOUT, x1          ;[16] <-- out J (idle) -- end of SE0 (EOP signal)
+    out     USBDDR, x2          ;[17] <-- release bus now
+    out     USBOUT, x3          ;[18] <-- ensure no pull-up resistors are active
+    rjmp    doReturn
+
+
+
+/*****************************************************************************
+The following PHP script generates a code skeleton for the receiver routine:
+
+<?php
+
+function printCmdBuffer($thisBit)
+{
+global $cycle;
+
+    $nextBit = ($thisBit + 1) % 8;
+    $s = ob_get_contents();
+    ob_end_clean();
+    $s = str_replace("#", $thisBit, $s);
+    $s = str_replace("@", $nextBit, $s);
+    $lines = explode("\n", $s);
+    for($i = 0; $i < count($lines); $i++){
+        $s = $lines[$i];
+        if(ereg("\\[([0-9-][0-9])\\]", $s, $regs)){
+            $c = $cycle + (int)$regs[1];
+            $s = ereg_replace("\\[[0-9-][0-9]\\]", sprintf("[%02d]", $c), $s);
+        }
+        if(strlen($s) > 0)
+            echo "$s\n";
+    }
+}
+
+function printBit($isAfterSet, $bitNum)
+{
+    ob_start();
+    if($isAfterSet){
+?>
+    ifioclr USBIN, USBMINUS     ;[00] <--- sample
+    rjmp    bit#IsClr           ;[01]
+    andi    shift, ~(7 << #)    ;[02]
+    breq    unstuff#s           ;[03]
+    in      phase, USBIN        ;[04] <- phase
+    rjmp    bit@AfterSet        ;[05]
+unstuff#s:
+    in      phase, USBIN        ;[05] <- phase (one cycle too late)
+    andi    fix, ~(1 << #)      ;[06]
+    nop2                        ;[-1]
+    nop2                        ;[01]
+bit#IsClr:
+    ifrset  phase, USBMINUS     ;[03] check phase only if D- changed
+    lpm                         ;[04]
+    in      phase, USBIN        ;[05] <- phase (one cycle too late)
+    ori     shift, 1 << #       ;[06]
+<?php
+    }else{
+?>
+    ifioset USBIN, USBMINUS     ;[00] <--- sample
+    rjmp    bit#IsSet           ;[01]
+    andi    shift, ~(7 << #)    ;[02]
+    breq    unstuff#c           ;[03]
+    in      phase, USBIN        ;[04] <- phase
+    rjmp    bit@AfterClr        ;[05]
+unstuff#c:
+    in      phase, USBIN        ;[05] <- phase (one cycle too late)
+    andi    fix, ~(1 << #)      ;[06]
+    nop2                        ;[-1]
+    nop2                        ;[01]
+bit#IsSet:
+    ifrclr  phase, USBMINUS     ;[03] check phase only if D- changed
+    lpm                         ;[04]
+    in      phase, USBIN        ;[05] <- phase (one cycle too late)
+    ori     shift, 1 << #       ;[06]
+<?php
+    }
+    printCmdBuffer($bitNum);
+}
+
+$bitStartCycles = array(1, 9, 17, 26, 34, 42, 51, 59);
+for($i = 0; $i < 16; $i++){
+    $bit = $i % 8;
+    $emitClrCode = ($i + (int)($i / 8)) % 2;
+    $cycle = $bitStartCycles[$bit];
+    if($emitClrCode){
+        printf("bit%dAfterClr:\n", $bit);
+    }else{
+        printf("bit%dAfterSet:\n", $bit);
+    }
+    ob_start();
+    echo "    *****                       ;[-1]\n";
+    printCmdBuffer($bit);
+    printBit(!$emitClrCode, $bit);
+    if($i == 7)
+        echo "\n";
+}
+
+?>
+*****************************************************************************/

usbdrvasm15.inc

@@ -0,0 +1,423 @@
+/* Name: usbdrvasm15.inc
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: contributed by V. Bosch
+ * Creation Date: 2007-08-06
+ * Tabsize: 4
+ * Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * Revision: $Id: usbdrvasm15.inc 740 2009-04-13 18:23:31Z cs $
+ */
+
+/* Do not link this file! Link usbdrvasm.S instead, which includes the
+ * appropriate implementation!
+ */
+
+/*
+General Description:
+This file is the 15 MHz version of the asssembler part of the USB driver. It
+requires a 15 MHz crystal (not a ceramic resonator and not a calibrated RC
+oscillator).
+
+See usbdrv.h for a description of the entire driver.
+
+Since almost all of this code is timing critical, don't change unless you
+really know what you are doing! Many parts require not only a maximum number
+of CPU cycles, but even an exact number of cycles!
+*/
+
+;max stack usage: [ret(2), YL, SREG, YH, bitcnt, shift, x1, x2, x3, x4, cnt] = 12 bytes
+;nominal frequency: 15 MHz -> 10.0 cycles per bit, 80.0 cycles per byte
+; Numbers in brackets are clocks counted from center of last sync bit
+; when instruction starts
+
+;----------------------------------------------------------------------------
+; order of registers pushed: 
+;	YL, SREG [sofError] YH, shift, x1, x2, x3, bitcnt, cnt, x4
+;----------------------------------------------------------------------------
+USB_INTR_VECTOR:              
+    push    YL                   ;2 	push only what is necessary to sync with edge ASAP
+    in      YL, SREG             ;1 
+    push    YL                   ;2 
+;----------------------------------------------------------------------------
+; Synchronize with sync pattern:
+;
+;   sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
+;   sync up with J to K edge during sync pattern -- use fastest possible loops
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
+waitForJ:
+    inc     YL
+    sbis    USBIN, USBMINUS
+    brne    waitForJ        ; just make sure we have ANY timeout
+;-------------------------------------------------------------------------------
+; The following code results in a sampling window of < 1/4 bit 
+;	which meets the spec.
+;-------------------------------------------------------------------------------
+waitForK:			 ;- 
+    sbis    USBIN, USBMINUS      ;1 [00] <-- sample
+    rjmp    foundK               ;2 [01]
+    sbis    USBIN, USBMINUS	 ;	 <-- sample
+    rjmp    foundK
+    sbis    USBIN, USBMINUS	 ;	 <-- sample
+    rjmp    foundK
+    sbis    USBIN, USBMINUS	 ;	 <-- sample
+    rjmp    foundK
+    sbis    USBIN, USBMINUS	 ;	 <-- sample
+    rjmp    foundK
+    sbis    USBIN, USBMINUS	 ;	 <-- sample
+    rjmp    foundK
+#if USB_COUNT_SOF
+    lds     YL, usbSofCount
+    inc     YL
+    sts     usbSofCount, YL
+#endif  /* USB_COUNT_SOF */
+#ifdef USB_SOF_HOOK
+    USB_SOF_HOOK
+#endif
+    rjmp    sofError
+;------------------------------------------------------------------------------
+; {3, 5} after falling D- edge, average delay: 4 cycles [we want 5 for 
+;	center sampling] 
+; 	we have 1 bit time for setup purposes, then sample again. 
+;	Numbers in brackets are cycles from center of first sync (double K) 
+;	bit after the instruction
+;------------------------------------------------------------------------------
+foundK:                          ;- [02]
+    lds     YL, usbInputBufOffset;2 [03+04]	tx loop
+    push    YH                   ;2 [05+06]
+    clr     YH                   ;1 [07]
+    subi    YL, lo8(-(usbRxBuf)) ;1 [08] 	[rx loop init]
+    sbci    YH, hi8(-(usbRxBuf)) ;1 [09] 	[rx loop init]
+    push    shift                ;2 [10+11]
+    ser	    shift		 ;1 [12]
+    sbis    USBIN, USBMINUS      ;1 [-1] [13] <--sample:we want two bits K (sample 1 cycle too early)
+    rjmp    haveTwoBitsK         ;2 [00] [14]
+    pop     shift                ;2 	 [15+16] undo the push from before
+    pop     YH 			 ;2 	 [17+18] undo the push from before
+    rjmp    waitForK             ;2 	 [19+20] this was not the end of sync, retry
+; The entire loop from waitForK until rjmp waitForK above must not exceed two
+; bit times (= 20 cycles).
+
+;----------------------------------------------------------------------------
+; push more registers and initialize values while we sample the first bits:
+;----------------------------------------------------------------------------
+haveTwoBitsK:			;- [01]
+    push    x1              	;2 [02+03]
+    push    x2              	;2 [04+05]
+    push    x3              	;2 [06+07]
+    push    bitcnt              ;2 [08+09]	
+    in      x1, USBIN       	;1 [00] [10] <-- sample bit 0
+    bst     x1, USBMINUS    	;1 [01]
+    bld     shift, 0        	;1 [02]
+    push    cnt             	;2 [03+04]
+    ldi     cnt, USB_BUFSIZE	;1 [05] 
+    push    x4              	;2 [06+07] tx loop
+    rjmp    rxLoop          	;2 [08]
+;----------------------------------------------------------------------------
+; Receiver loop (numbers in brackets are cycles within byte after instr)
+;----------------------------------------------------------------------------
+unstuff0:               	;- [07] (branch taken)
+    andi    x3, ~0x01   	;1 [08]
+    mov     x1, x2      	;1 [09] x2 contains last sampled (stuffed) bit
+    in      x2, USBIN   	;1 [00] [10] <-- sample bit 1 again
+    andi    x2, USBMASK 	;1 [01]
+    breq    se0Hop         	;1 [02] SE0 check for bit 1 
+    ori     shift, 0x01 	;1 [03] 0b00000001
+    nop				;1 [04]
+    rjmp    didUnstuff0 	;2 [05]
+;-----------------------------------------------------
+unstuff1:               	;- [05] (branch taken)
+    mov     x2, x1      	;1 [06] x1 contains last sampled (stuffed) bit
+    andi    x3, ~0x02   	;1 [07]
+    ori     shift, 0x02 	;1 [08] 0b00000010
+    nop                 	;1 [09]
+    in      x1, USBIN   	;1 [00] [10] <-- sample bit 2 again
+    andi    x1, USBMASK 	;1 [01]
+    breq    se0Hop         	;1 [02] SE0 check for bit 2 
+    rjmp    didUnstuff1 	;2 [03]
+;-----------------------------------------------------
+unstuff2:               	;- [05] (branch taken)
+    andi    x3, ~0x04   	;1 [06]
+    ori     shift, 0x04 	;1 [07] 0b00000100
+    mov     x1, x2      	;1 [08] x2 contains last sampled (stuffed) bit
+    nop                 	;1 [09]
+    in      x2, USBIN   	;1 [00] [10] <-- sample bit 3
+    andi    x2, USBMASK 	;1 [01]
+    breq    se0Hop         	;1 [02] SE0 check for bit 3 
+    rjmp    didUnstuff2 	;2 [03]
+;-----------------------------------------------------
+unstuff3:               	;- [00] [10]  (branch taken)
+    in      x2, USBIN   	;1 [01] [11] <-- sample stuffed bit 3 one cycle too late
+    andi    x2, USBMASK 	;1 [02]
+    breq    se0Hop         	;1 [03] SE0 check for stuffed bit 3 
+    andi    x3, ~0x08   	;1 [04]
+    ori     shift, 0x08 	;1 [05] 0b00001000
+    rjmp    didUnstuff3 	;2 [06]
+;----------------------------------------------------------------------------
+; extra jobs done during bit interval:
+;
+; bit 0:    store, clear [SE0 is unreliable here due to bit dribbling in hubs], 
+; 		overflow check, jump to the head of rxLoop
+; bit 1:    SE0 check
+; bit 2:    SE0 check, recovery from delay [bit 0 tasks took too long]
+; bit 3:    SE0 check, recovery from delay [bit 0 tasks took too long]
+; bit 4:    SE0 check, none
+; bit 5:    SE0 check, none
+; bit 6:    SE0 check, none
+; bit 7:    SE0 check, reconstruct: x3 is 0 at bit locations we changed, 1 at others
+;----------------------------------------------------------------------------
+rxLoop:				;- [09]
+    in      x2, USBIN   	;1 [00] [10] <-- sample bit 1 (or possibly bit 0 stuffed)
+    andi    x2, USBMASK 	;1 [01]
+    brne    SkipSe0Hop		;1 [02]
+se0Hop:				;- [02]
+    rjmp    se0         	;2 [03] SE0 check for bit 1 
+SkipSe0Hop:			;- [03]
+    ser     x3          	;1 [04]
+    andi    shift, 0xf9 	;1 [05] 0b11111001
+    breq    unstuff0    	;1 [06]
+didUnstuff0:			;- [06]
+    eor     x1, x2      	;1 [07]
+    bst     x1, USBMINUS	;1 [08]
+    bld     shift, 1    	;1 [09] 
+    in      x1, USBIN   	;1 [00] [10] <-- sample bit 2 (or possibly bit 1 stuffed)
+    andi    x1, USBMASK 	;1 [01]
+    breq    se0Hop         	;1 [02] SE0 check for bit 2 
+    andi    shift, 0xf3 	;1 [03] 0b11110011
+    breq    unstuff1    	;1 [04] do remaining work for bit 1
+didUnstuff1:			;- [04]
+    eor     x2, x1      	;1 [05]
+    bst     x2, USBMINUS	;1 [06]
+    bld     shift, 2    	;1 [07]
+    nop2			;2 [08+09]
+    in      x2, USBIN   	;1 [00] [10] <-- sample bit 3 (or possibly bit 2 stuffed)
+    andi    x2, USBMASK 	;1 [01]
+    breq    se0Hop         	;1 [02] SE0 check for bit 3 
+    andi    shift, 0xe7 	;1 [03] 0b11100111
+    breq    unstuff2    	;1 [04]
+didUnstuff2:			;- [04]
+    eor     x1, x2      	;1 [05]
+    bst     x1, USBMINUS	;1 [06]
+    bld     shift, 3    	;1 [07]
+didUnstuff3:			;- [07]
+    andi    shift, 0xcf 	;1 [08] 0b11001111
+    breq    unstuff3    	;1 [09]
+    in      x1, USBIN   	;1 [00] [10] <-- sample bit 4
+    andi    x1, USBMASK 	;1 [01]
+    breq    se0Hop         	;1 [02] SE0 check for bit 4
+    eor     x2, x1      	;1 [03]
+    bst     x2, USBMINUS	;1 [04]
+    bld     shift, 4    	;1 [05]
+didUnstuff4:			;- [05]
+    andi    shift, 0x9f 	;1 [06] 0b10011111
+    breq    unstuff4    	;1 [07]
+    nop2			;2 [08+09]
+    in      x2, USBIN   	;1 [00] [10] <-- sample bit 5
+    andi    x2, USBMASK 	;1 [01]
+    breq    se0         	;1 [02] SE0 check for bit 5
+    eor     x1, x2      	;1 [03]
+    bst     x1, USBMINUS	;1 [04]
+    bld     shift, 5    	;1 [05]
+didUnstuff5:			;- [05]
+    andi    shift, 0x3f 	;1 [06] 0b00111111
+    breq    unstuff5    	;1 [07]
+    nop2			;2 [08+09]
+    in      x1, USBIN   	;1 [00] [10] <-- sample bit 6
+    andi    x1, USBMASK 	;1 [01]
+    breq    se0         	;1 [02] SE0 check for bit 6
+    eor     x2, x1      	;1 [03]
+    bst     x2, USBMINUS	;1 [04]
+    bld     shift, 6   	 	;1 [05]
+didUnstuff6:			;- [05]
+    cpi     shift, 0x02 	;1 [06] 0b00000010
+    brlo    unstuff6    	;1 [07]
+    nop2			;2 [08+09]
+    in      x2, USBIN   	;1 [00] [10] <-- sample bit 7
+    andi    x2, USBMASK 	;1 [01]
+    breq    se0         	;1 [02] SE0 check for bit 7
+    eor     x1, x2      	;1 [03]
+    bst     x1, USBMINUS	;1 [04]
+    bld     shift, 7    	;1 [05]
+didUnstuff7:			;- [05] 
+    cpi     shift, 0x04 	;1 [06] 0b00000100
+    brlo    unstuff7		;1 [07]
+    eor     x3, shift   	;1 [08] reconstruct: x3 is 0 at bit locations we changed, 1 at others
+    nop				;1 [09]
+    in      x1, USBIN   	;1 [00]	[10] <-- sample bit 0
+    st      y+, x3      	;2 [01+02] store data
+    eor     x2, x1      	;1 [03]
+    bst     x2, USBMINUS	;1 [04]
+    bld     shift, 0    	;1 [05]
+    subi    cnt, 1		;1 [06]
+    brcs    overflow	;1 [07]
+    rjmp    rxLoop		;2 [08]
+;-----------------------------------------------------
+unstuff4:               	;- [08] 
+    andi    x3, ~0x10   	;1 [09]
+    in      x1, USBIN   	;1 [00] [10] <-- sample stuffed bit 4
+    andi    x1, USBMASK 	;1 [01]
+    breq    se0         	;1 [02] SE0 check for stuffed bit 4
+    ori     shift, 0x10 	;1 [03]
+    rjmp    didUnstuff4 	;2 [04]
+;-----------------------------------------------------
+unstuff5:               	;- [08] 
+    ori     shift, 0x20 	;1 [09]
+    in      x2, USBIN   	;1 [00] [10] <-- sample stuffed bit 5
+    andi    x2, USBMASK 	;1 [01]
+    breq    se0         	;1 [02] SE0 check for stuffed bit 5
+    andi    x3, ~0x20   	;1 [03]
+    rjmp    didUnstuff5		;2 [04]
+;-----------------------------------------------------
+unstuff6:               	;- [08] 
+    andi    x3, ~0x40   	;1 [09]
+    in      x1, USBIN   	;1 [00] [10] <-- sample stuffed bit 6
+    andi    x1, USBMASK 	;1 [01]
+    breq    se0         	;1 [02] SE0 check for stuffed bit 6
+    ori     shift, 0x40 	;1 [03]
+    rjmp    didUnstuff6 	;2 [04]
+;-----------------------------------------------------
+unstuff7:			;- [08]
+    andi    x3, ~0x80   	;1 [09]
+    in      x2, USBIN   	;1 [00] [10] <-- sample stuffed bit 7
+    andi    x2, USBMASK 	;1 [01]
+    breq    se0         	;1 [02] SE0 check for stuffed bit 7
+    ori     shift, 0x80 	;1 [03]
+    rjmp    didUnstuff7 	;2 [04]
+    
+macro POP_STANDARD ; 16 cycles
+    pop     x4    
+    pop     cnt
+    pop     bitcnt
+    pop     x3
+    pop     x2
+    pop     x1
+    pop     shift
+    pop     YH
+    endm
+macro POP_RETI     ; 5 cycles
+    pop     YL
+    out     SREG, YL
+    pop     YL
+    endm
+
+#include "asmcommon.inc"
+
+;---------------------------------------------------------------------------
+; USB spec says:
+; idle = J
+; J = (D+ = 0), (D- = 1)
+; K = (D+ = 1), (D- = 0)
+; Spec allows 7.5 bit times from EOP to SOP for replies
+;---------------------------------------------------------------------------
+bitstuffN:		    	;- [04]
+    eor     x1, x4          	;1 [05]
+    clr	    x2			;1 [06]
+    nop				;1 [07]
+    rjmp    didStuffN       	;1 [08]
+;---------------------------------------------------------------------------    
+bitstuff6:		    	;- [04]
+    eor     x1, x4          	;1 [05]
+    clr	    x2			;1 [06]
+    rjmp    didStuff6       	;1 [07]
+;---------------------------------------------------------------------------
+bitstuff7:		    	;- [02]
+    eor     x1, x4          	;1 [03]
+    clr	    x2			;1 [06]
+    nop			    	;1 [05]
+    rjmp    didStuff7       	;1 [06]
+;---------------------------------------------------------------------------
+sendNakAndReti:			;- [-19]
+    ldi     x3, USBPID_NAK  	;1 [-18]
+    rjmp    sendX3AndReti   	;1 [-17]
+;---------------------------------------------------------------------------
+sendAckAndReti:			;- [-17]
+    ldi     cnt, USBPID_ACK 	;1 [-16]
+sendCntAndReti:			;- [-16]
+    mov     x3, cnt         	;1 [-15]
+sendX3AndReti:			;- [-15]
+    ldi     YL, 20          	;1 [-14] x3==r20 address is 20
+    ldi     YH, 0           	;1 [-13]
+    ldi     cnt, 2          	;1 [-12]
+;   rjmp    usbSendAndReti      fallthrough
+;---------------------------------------------------------------------------
+;usbSend:
+;pointer to data in 'Y'
+;number of bytes in 'cnt' -- including sync byte [range 2 ... 12]
+;uses: x1...x4, btcnt, shift, cnt, Y
+;Numbers in brackets are time since first bit of sync pattern is sent
+;We need not to match the transfer rate exactly because the spec demands 
+;only 1.5% precision anyway.
+usbSendAndReti:             	;- [-13] 13 cycles until SOP
+    in      x2, USBDDR      	;1 [-12]
+    ori     x2, USBMASK     	;1 [-11]
+    sbi     USBOUT, USBMINUS	;2 [-09-10] prepare idle state; D+ and D- must have been 0 (no pullups)
+    in      x1, USBOUT      	;1 [-08] port mirror for tx loop
+    out     USBDDR, x2      	;1 [-07] <- acquire bus
+	; need not init x2 (bitstuff history) because sync starts with 0 
+    ldi     x4, USBMASK     	;1 [-06] 	exor mask
+    ldi     shift, 0x80     	;1 [-05] 	sync byte is first byte sent
+    ldi     bitcnt, 6    	;1 [-04] 
+txBitLoop:		    	;- [-04] [06]
+    sbrs    shift, 0        	;1 [-03] [07]
+    eor     x1, x4          	;1 [-02] [08] 
+    ror     shift           	;1 [-01] [09]  
+didStuffN:		    	;-       [09]
+    out     USBOUT, x1      	;1 [00]  [10] <-- out N
+    ror     x2              	;1 [01]
+    cpi     x2, 0xfc        	;1 [02]
+    brcc    bitstuffN       	;1 [03]
+    dec     bitcnt          	;1 [04]
+    brne    txBitLoop       	;1 [05]
+    sbrs    shift, 0        	;1 [06]
+    eor     x1, x4          	;1 [07]
+    ror     shift           	;1 [08]
+didStuff6:			;- [08]
+    nop				;1 [09]
+    out     USBOUT, x1      	;1 [00] [10] <-- out 6
+    ror     x2              	;1 [01] 
+    cpi     x2, 0xfc        	;1 [02]
+    brcc    bitstuff6       	;1 [03]
+    sbrs    shift, 0        	;1 [04]
+    eor     x1, x4          	;1 [05]
+    ror     shift           	;1 [06]
+    ror     x2              	;1 [07]
+didStuff7:			;- [07]
+    ldi     bitcnt, 6    	;1 [08]
+    cpi     x2, 0xfc        	;1 [09]
+    out     USBOUT, x1      	;1 [00] [10] <-- out 7
+    brcc    bitstuff7       	;1 [01]
+    ld      shift, y+       	;2 [02+03]
+    dec     cnt             	;1 [04]
+    brne    txBitLoop      	;1 [05]
+makeSE0:
+    cbr     x1, USBMASK     	;1 [06] 	prepare SE0 [spec says EOP may be 19 to 23 cycles]
+    lds     x2, usbNewDeviceAddr;2 [07+08]
+    lsl     x2                  ;1 [09] we compare with left shifted address
+;2006-03-06: moved transfer of new address to usbDeviceAddr from C-Code to asm:
+;set address only after data packet was sent, not after handshake
+    out     USBOUT, x1      	;1 [00] [10] <-- out SE0-- from now 2 bits==20 cycl. until bus idle
+    subi    YL, 20 + 2          ;1 [01] Only assign address on data packets, not ACK/NAK in x3
+    sbci    YH, 0           	;1 [02]
+    breq    skipAddrAssign  	;1 [03]
+    sts     usbDeviceAddr, x2	;2 [04+05] if not skipped: SE0 is one cycle longer
+;----------------------------------------------------------------------------
+;end of usbDeviceAddress transfer
+skipAddrAssign:				;- [03/04]
+    ldi     x2, 1<<USB_INTR_PENDING_BIT	;1 [05] int0 occurred during TX -- clear pending flag
+    USB_STORE_PENDING(x2)           ;1 [06]
+    ori     x1, USBIDLE     		;1 [07]
+    in      x2, USBDDR      		;1 [08]
+    cbr     x2, USBMASK     		;1 [09] set both pins to input
+    mov     x3, x1          		;1 [10]
+    cbr     x3, USBMASK     		;1 [11] configure no pullup on both pins
+    ldi     x4, 3           		;1 [12]
+se0Delay:				;- [12] [15] 
+    dec     x4              		;1 [13] [16] 
+    brne    se0Delay        		;1 [14] [17] 
+    nop2				;2      [18+19]
+    out     USBOUT, x1      		;1      [20] <--out J (idle) -- end of SE0 (EOP sig.)
+    out     USBDDR, x2      		;1      [21] <--release bus now
+    out     USBOUT, x3      		;1      [22] <--ensure no pull-up resistors are active
+    rjmp    doReturn			;1	[23]
+;---------------------------------------------------------------------------

usbdrvasm16.inc

@@ -0,0 +1,346 @@
+/* Name: usbdrvasm16.inc
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2007-06-15
+ * Tabsize: 4
+ * Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * Revision: $Id: usbdrvasm16.inc 760 2009-08-09 18:59:43Z cs $
+ */
+
+/* Do not link this file! Link usbdrvasm.S instead, which includes the
+ * appropriate implementation!
+ */
+
+/*
+General Description:
+This file is the 16 MHz version of the asssembler part of the USB driver. It
+requires a 16 MHz crystal (not a ceramic resonator and not a calibrated RC
+oscillator).
+
+See usbdrv.h for a description of the entire driver.
+
+Since almost all of this code is timing critical, don't change unless you
+really know what you are doing! Many parts require not only a maximum number
+of CPU cycles, but even an exact number of cycles!
+*/
+
+;max stack usage: [ret(2), YL, SREG, YH, bitcnt, shift, x1, x2, x3, x4, cnt] = 12 bytes
+;nominal frequency: 16 MHz -> 10.6666666 cycles per bit, 85.333333333 cycles per byte
+; Numbers in brackets are clocks counted from center of last sync bit
+; when instruction starts
+
+USB_INTR_VECTOR:
+;order of registers pushed: YL, SREG YH, [sofError], bitcnt, shift, x1, x2, x3, x4, cnt
+    push    YL                  ;[-25] push only what is necessary to sync with edge ASAP
+    in      YL, SREG            ;[-23]
+    push    YL                  ;[-22]
+    push    YH                  ;[-20]
+;----------------------------------------------------------------------------
+; Synchronize with sync pattern:
+;----------------------------------------------------------------------------
+;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
+;sync up with J to K edge during sync pattern -- use fastest possible loops
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
+waitForJ:
+    inc     YL
+    sbis    USBIN, USBMINUS
+    brne    waitForJ        ; just make sure we have ANY timeout
+waitForK:
+;The following code results in a sampling window of < 1/4 bit which meets the spec.
+    sbis    USBIN, USBMINUS     ;[-15]
+    rjmp    foundK              ;[-14]
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+#if USB_COUNT_SOF
+    lds     YL, usbSofCount
+    inc     YL
+    sts     usbSofCount, YL
+#endif  /* USB_COUNT_SOF */
+#ifdef USB_SOF_HOOK
+    USB_SOF_HOOK
+#endif
+    rjmp    sofError
+foundK:                         ;[-12]
+;{3, 5} after falling D- edge, average delay: 4 cycles [we want 5 for center sampling]
+;we have 1 bit time for setup purposes, then sample again. Numbers in brackets
+;are cycles from center of first sync (double K) bit after the instruction
+    push    bitcnt              ;[-12]
+;   [---]                       ;[-11]
+    lds     YL, usbInputBufOffset;[-10]
+;   [---]                       ;[-9]
+    clr     YH                  ;[-8]
+    subi    YL, lo8(-(usbRxBuf));[-7] [rx loop init]
+    sbci    YH, hi8(-(usbRxBuf));[-6] [rx loop init]
+    push    shift               ;[-5]
+;   [---]                       ;[-4]
+    ldi     bitcnt, 0x55        ;[-3] [rx loop init]
+    sbis    USBIN, USBMINUS     ;[-2] we want two bits K (sample 2 cycles too early)
+    rjmp    haveTwoBitsK        ;[-1]
+    pop     shift               ;[0] undo the push from before
+    pop     bitcnt              ;[2] undo the push from before
+    rjmp    waitForK            ;[4] this was not the end of sync, retry
+; The entire loop from waitForK until rjmp waitForK above must not exceed two
+; bit times (= 21 cycles).
+
+;----------------------------------------------------------------------------
+; push more registers and initialize values while we sample the first bits:
+;----------------------------------------------------------------------------
+haveTwoBitsK:
+    push    x1              ;[1]
+    push    x2              ;[3]
+    push    x3              ;[5]
+    ldi     shift, 0        ;[7]
+    ldi     x3, 1<<4        ;[8] [rx loop init] first sample is inverse bit, compensate that
+    push    x4              ;[9] == leap
+
+    in      x1, USBIN       ;[11] <-- sample bit 0
+    andi    x1, USBMASK     ;[12]
+    bst     x1, USBMINUS    ;[13]
+    bld     shift, 7        ;[14]
+    push    cnt             ;[15]
+    ldi     leap, 0         ;[17] [rx loop init]
+    ldi     cnt, USB_BUFSIZE;[18] [rx loop init]
+    rjmp    rxbit1          ;[19] arrives at [21]
+
+;----------------------------------------------------------------------------
+; Receiver loop (numbers in brackets are cycles within byte after instr)
+;----------------------------------------------------------------------------
+
+; duration of unstuffing code should be 10.66666667 cycles. We adjust "leap"
+; accordingly to approximate this value in the long run.
+
+unstuff6:
+    andi    x2, USBMASK ;[03]
+    ori     x3, 1<<6    ;[04] will not be shifted any more
+    andi    shift, ~0x80;[05]
+    mov     x1, x2      ;[06] sampled bit 7 is actually re-sampled bit 6
+    subi    leap, -1    ;[07] total duration = 11 bits -> subtract 1/3
+    rjmp    didUnstuff6 ;[08]
+
+unstuff7:
+    ori     x3, 1<<7    ;[09] will not be shifted any more
+    in      x2, USBIN   ;[00] [10]  re-sample bit 7
+    andi    x2, USBMASK ;[01]
+    andi    shift, ~0x80;[02]
+    subi    leap, 2     ;[03] total duration = 10 bits -> add 1/3
+    rjmp    didUnstuff7 ;[04]
+
+unstuffEven:
+    ori     x3, 1<<6    ;[09] will be shifted right 6 times for bit 0
+    in      x1, USBIN   ;[00] [10]
+    andi    shift, ~0x80;[01]
+    andi    x1, USBMASK ;[02]
+    breq    se0         ;[03]
+    subi    leap, -1    ;[04] total duration = 11 bits -> subtract 1/3
+    nop2                ;[05]
+    rjmp    didUnstuffE ;[06]
+
+unstuffOdd:
+    ori     x3, 1<<5    ;[09] will be shifted right 4 times for bit 1
+    in      x2, USBIN   ;[00] [10]
+    andi    shift, ~0x80;[01]
+    andi    x2, USBMASK ;[02]
+    breq    se0         ;[03]
+    subi    leap, -1    ;[04] total duration = 11 bits -> subtract 1/3
+    nop2                ;[05]
+    rjmp    didUnstuffO ;[06]
+
+rxByteLoop:
+    andi    x1, USBMASK ;[03]
+    eor     x2, x1      ;[04]
+    subi    leap, 1     ;[05]
+    brpl    skipLeap    ;[06]
+    subi    leap, -3    ;1 one leap cycle every 3rd byte -> 85 + 1/3 cycles per byte
+    nop                 ;1
+skipLeap:
+    subi    x2, 1       ;[08]
+    ror     shift       ;[09]
+didUnstuff6:
+    cpi     shift, 0xfc ;[10]
+    in      x2, USBIN   ;[00] [11] <-- sample bit 7
+    brcc    unstuff6    ;[01]
+    andi    x2, USBMASK ;[02]
+    eor     x1, x2      ;[03]
+    subi    x1, 1       ;[04]
+    ror     shift       ;[05]
+didUnstuff7:
+    cpi     shift, 0xfc ;[06]
+    brcc    unstuff7    ;[07]
+    eor     x3, shift   ;[08] reconstruct: x3 is 1 at bit locations we changed, 0 at others
+    st      y+, x3      ;[09] store data
+rxBitLoop:
+    in      x1, USBIN   ;[00] [11] <-- sample bit 0/2/4
+    andi    x1, USBMASK ;[01]
+    eor     x2, x1      ;[02]
+    andi    x3, 0x3f    ;[03] topmost two bits reserved for 6 and 7
+    subi    x2, 1       ;[04]
+    ror     shift       ;[05]
+    cpi     shift, 0xfc ;[06]
+    brcc    unstuffEven ;[07]
+didUnstuffE:
+    lsr     x3          ;[08]
+    lsr     x3          ;[09]
+rxbit1:
+    in      x2, USBIN   ;[00] [10] <-- sample bit 1/3/5
+    andi    x2, USBMASK ;[01]
+    breq    se0         ;[02]
+    eor     x1, x2      ;[03]
+    subi    x1, 1       ;[04]
+    ror     shift       ;[05]
+    cpi     shift, 0xfc ;[06]
+    brcc    unstuffOdd  ;[07]
+didUnstuffO:
+    subi    bitcnt, 0xab;[08] == addi 0x55, 0x55 = 0x100/3
+    brcs    rxBitLoop   ;[09]
+
+    subi    cnt, 1      ;[10]
+    in      x1, USBIN   ;[00] [11] <-- sample bit 6
+    brcc    rxByteLoop  ;[01]
+    rjmp    overflow
+
+macro POP_STANDARD ; 14 cycles
+    pop     cnt
+    pop     x4
+    pop     x3
+    pop     x2
+    pop     x1
+    pop     shift
+    pop     bitcnt
+    endm
+macro POP_RETI     ; 7 cycles
+    pop     YH
+    pop     YL
+    out     SREG, YL
+    pop     YL
+    endm
+
+#include "asmcommon.inc"
+
+; USB spec says:
+; idle = J
+; J = (D+ = 0), (D- = 1)
+; K = (D+ = 1), (D- = 0)
+; Spec allows 7.5 bit times from EOP to SOP for replies
+
+bitstuffN:
+    eor     x1, x4          ;[5]
+    ldi     x2, 0           ;[6]
+    nop2                    ;[7]
+    nop                     ;[9]
+    out     USBOUT, x1      ;[10] <-- out
+    rjmp    didStuffN       ;[0]
+    
+bitstuff6:
+    eor     x1, x4          ;[5]
+    ldi     x2, 0           ;[6] Carry is zero due to brcc
+    rol     shift           ;[7] compensate for ror shift at branch destination
+    rjmp    didStuff6       ;[8]
+
+bitstuff7:
+    ldi     x2, 0           ;[2] Carry is zero due to brcc
+    rjmp    didStuff7       ;[3]
+
+
+sendNakAndReti:
+    ldi     x3, USBPID_NAK  ;[-18]
+    rjmp    sendX3AndReti   ;[-17]
+sendAckAndReti:
+    ldi     cnt, USBPID_ACK ;[-17]
+sendCntAndReti:
+    mov     x3, cnt         ;[-16]
+sendX3AndReti:
+    ldi     YL, 20          ;[-15] x3==r20 address is 20
+    ldi     YH, 0           ;[-14]
+    ldi     cnt, 2          ;[-13]
+;   rjmp    usbSendAndReti      fallthrough
+
+;usbSend:
+;pointer to data in 'Y'
+;number of bytes in 'cnt' -- including sync byte [range 2 ... 12]
+;uses: x1...x4, btcnt, shift, cnt, Y
+;Numbers in brackets are time since first bit of sync pattern is sent
+;We don't match the transfer rate exactly (don't insert leap cycles every third
+;byte) because the spec demands only 1.5% precision anyway.
+usbSendAndReti:             ; 12 cycles until SOP
+    in      x2, USBDDR      ;[-12]
+    ori     x2, USBMASK     ;[-11]
+    sbi     USBOUT, USBMINUS;[-10] prepare idle state; D+ and D- must have been 0 (no pullups)
+    in      x1, USBOUT      ;[-8] port mirror for tx loop
+    out     USBDDR, x2      ;[-7] <- acquire bus
+; need not init x2 (bitstuff history) because sync starts with 0
+    ldi     x4, USBMASK     ;[-6] exor mask
+    ldi     shift, 0x80     ;[-5] sync byte is first byte sent
+txByteLoop:
+    ldi     bitcnt, 0x35    ;[-4] [6] binary 0011 0101
+txBitLoop:
+    sbrs    shift, 0        ;[-3] [7]
+    eor     x1, x4          ;[-2] [8]
+    out     USBOUT, x1      ;[-1] [9] <-- out N
+    ror     shift           ;[0] [10]
+    ror     x2              ;[1]
+didStuffN:
+    cpi     x2, 0xfc        ;[2]
+    brcc    bitstuffN       ;[3]
+    lsr     bitcnt          ;[4]
+    brcc    txBitLoop       ;[5]
+    brne    txBitLoop       ;[6]
+
+    sbrs    shift, 0        ;[7]
+    eor     x1, x4          ;[8]
+didStuff6:
+    out     USBOUT, x1      ;[-1] [9] <-- out 6
+    ror     shift           ;[0] [10]
+    ror     x2              ;[1]
+    cpi     x2, 0xfc        ;[2]
+    brcc    bitstuff6       ;[3]
+    ror     shift           ;[4]
+didStuff7:
+    ror     x2              ;[5]
+    sbrs    x2, 7           ;[6]
+    eor     x1, x4          ;[7]
+    nop                     ;[8]
+    cpi     x2, 0xfc        ;[9]
+    out     USBOUT, x1      ;[-1][10] <-- out 7
+    brcc    bitstuff7       ;[0] [11]
+    ld      shift, y+       ;[1]
+    dec     cnt             ;[3]
+    brne    txByteLoop      ;[4]
+;make SE0:
+    cbr     x1, USBMASK     ;[5] prepare SE0 [spec says EOP may be 21 to 25 cycles]
+    lds     x2, usbNewDeviceAddr;[6]
+    lsl     x2              ;[8] we compare with left shifted address
+    subi    YL, 20 + 2      ;[9] Only assign address on data packets, not ACK/NAK in x3
+    sbci    YH, 0           ;[10]
+    out     USBOUT, x1      ;[11] <-- out SE0 -- from now 2 bits = 22 cycles until bus idle
+;2006-03-06: moved transfer of new address to usbDeviceAddr from C-Code to asm:
+;set address only after data packet was sent, not after handshake
+    breq    skipAddrAssign  ;[0]
+    sts     usbDeviceAddr, x2; if not skipped: SE0 is one cycle longer
+skipAddrAssign:
+;end of usbDeviceAddress transfer
+    ldi     x2, 1<<USB_INTR_PENDING_BIT;[2] int0 occurred during TX -- clear pending flag
+    USB_STORE_PENDING(x2)   ;[3]
+    ori     x1, USBIDLE     ;[4]
+    in      x2, USBDDR      ;[5]
+    cbr     x2, USBMASK     ;[6] set both pins to input
+    mov     x3, x1          ;[7]
+    cbr     x3, USBMASK     ;[8] configure no pullup on both pins
+    ldi     x4, 4           ;[9]
+se0Delay:
+    dec     x4              ;[10] [13] [16] [19]
+    brne    se0Delay        ;[11] [14] [17] [20]
+    out     USBOUT, x1      ;[21] <-- out J (idle) -- end of SE0 (EOP signal)
+    out     USBDDR, x2      ;[22] <-- release bus now
+    out     USBOUT, x3      ;[23] <-- ensure no pull-up resistors are active
+    rjmp    doReturn

usbdrvasm165.inc

@@ -0,0 +1,453 @@
+/* Name: usbdrvasm165.inc
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2007-04-22
+ * Tabsize: 4
+ * Copyright: (c) 2007 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * Revision: $Id: usbdrvasm165.inc 740 2009-04-13 18:23:31Z cs $
+ */
+
+/* Do not link this file! Link usbdrvasm.S instead, which includes the
+ * appropriate implementation!
+ */
+
+/*
+General Description:
+This file is the 16.5 MHz version of the USB driver. It is intended for the
+ATTiny45 and similar controllers running on 16.5 MHz internal RC oscillator.
+This version contains a phase locked loop in the receiver routine to cope with
+slight clock rate deviations of up to +/- 1%.
+
+See usbdrv.h for a description of the entire driver.
+
+Since almost all of this code is timing critical, don't change unless you
+really know what you are doing! Many parts require not only a maximum number
+of CPU cycles, but even an exact number of cycles!
+*/
+
+;Software-receiver engine. Strict timing! Don't change unless you can preserve timing!
+;interrupt response time: 4 cycles + insn running = 7 max if interrupts always enabled
+;max allowable interrupt latency: 59 cycles -> max 52 cycles interrupt disable
+;max stack usage: [ret(2), r0, SREG, YL, YH, shift, x1, x2, x3, x4, cnt] = 12 bytes
+;nominal frequency: 16.5 MHz -> 11 cycles per bit
+; 16.3125 MHz < F_CPU < 16.6875 MHz (+/- 1.1%)
+; Numbers in brackets are clocks counted from center of last sync bit
+; when instruction starts
+
+
+USB_INTR_VECTOR:
+;order of registers pushed: YL, SREG [sofError], r0, YH, shift, x1, x2, x3, x4, cnt
+    push    YL                  ;[-23] push only what is necessary to sync with edge ASAP
+    in      YL, SREG            ;[-21]
+    push    YL                  ;[-20]
+;----------------------------------------------------------------------------
+; Synchronize with sync pattern:
+;----------------------------------------------------------------------------
+;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
+;sync up with J to K edge during sync pattern -- use fastest possible loops
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
+waitForJ:
+    inc     YL
+    sbis    USBIN, USBMINUS
+    brne    waitForJ        ; just make sure we have ANY timeout
+waitForK:
+;The following code results in a sampling window of < 1/4 bit which meets the spec.
+    sbis    USBIN, USBMINUS     ;[-15]
+    rjmp    foundK              ;[-14]
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+#if USB_COUNT_SOF
+    lds     YL, usbSofCount
+    inc     YL
+    sts     usbSofCount, YL
+#endif  /* USB_COUNT_SOF */
+#ifdef USB_SOF_HOOK
+    USB_SOF_HOOK
+#endif
+    rjmp    sofError
+foundK:                         ;[-12]
+;{3, 5} after falling D- edge, average delay: 4 cycles [we want 5 for center sampling]
+;we have 1 bit time for setup purposes, then sample again. Numbers in brackets
+;are cycles from center of first sync (double K) bit after the instruction
+    push    r0                  ;[-12]
+;   [---]                       ;[-11]
+    push    YH                  ;[-10]
+;   [---]                       ;[-9]
+    lds     YL, usbInputBufOffset;[-8]
+;   [---]                       ;[-7]
+    clr     YH                  ;[-6]
+    subi    YL, lo8(-(usbRxBuf));[-5] [rx loop init]
+    sbci    YH, hi8(-(usbRxBuf));[-4] [rx loop init]
+    mov     r0, x2              ;[-3] [rx loop init]
+    sbis    USBIN, USBMINUS     ;[-2] we want two bits K (sample 2 cycles too early)
+    rjmp    haveTwoBitsK        ;[-1]
+    pop     YH                  ;[0] undo the pushes from before
+    pop     r0                  ;[2]
+    rjmp    waitForK            ;[4] this was not the end of sync, retry
+; The entire loop from waitForK until rjmp waitForK above must not exceed two
+; bit times (= 22 cycles).
+
+;----------------------------------------------------------------------------
+; push more registers and initialize values while we sample the first bits:
+;----------------------------------------------------------------------------
+haveTwoBitsK:               ;[1]
+    push    shift           ;[1]
+    push    x1              ;[3]
+    push    x2              ;[5]
+    push    x3              ;[7]
+    ldi     shift, 0xff     ;[9] [rx loop init]
+    ori     x3, 0xff        ;[10] [rx loop init] == ser x3, clear zero flag
+
+    in      x1, USBIN       ;[11] <-- sample bit 0
+    bst     x1, USBMINUS    ;[12]
+    bld     shift, 0        ;[13]
+    push    x4              ;[14] == phase
+;   [---]                   ;[15]
+    push    cnt             ;[16]
+;   [---]                   ;[17]
+    ldi     phase, 0        ;[18] [rx loop init]
+    ldi     cnt, USB_BUFSIZE;[19] [rx loop init]
+    rjmp    rxbit1          ;[20]
+;   [---]                   ;[21]
+
+;----------------------------------------------------------------------------
+; Receiver loop (numbers in brackets are cycles within byte after instr)
+;----------------------------------------------------------------------------
+/*
+byte oriented operations done during loop:
+bit 0: store data
+bit 1: SE0 check
+bit 2: overflow check
+bit 3: catch up
+bit 4: rjmp to achieve conditional jump range
+bit 5: PLL
+bit 6: catch up
+bit 7: jump, fixup bitstuff
+; 87 [+ 2] cycles
+------------------------------------------------------------------
+*/
+continueWithBit5:
+    in      x2, USBIN       ;[055] <-- bit 5
+    eor     r0, x2          ;[056]
+    or      phase, r0       ;[057]
+    sbrc    phase, USBMINUS ;[058]
+    lpm                     ;[059] optional nop3; modifies r0
+    in      phase, USBIN    ;[060] <-- phase
+    eor     x1, x2          ;[061]
+    bst     x1, USBMINUS    ;[062]
+    bld     shift, 5        ;[063]
+    andi    shift, 0x3f     ;[064]
+    in      x1, USBIN       ;[065] <-- bit 6
+    breq    unstuff5        ;[066] *** unstuff escape
+    eor     phase, x1       ;[067]
+    eor     x2, x1          ;[068]
+    bst     x2, USBMINUS    ;[069]
+    bld     shift, 6        ;[070]
+didUnstuff6:                ;[   ]
+    in      r0, USBIN       ;[071] <-- phase
+    cpi     shift, 0x02     ;[072]
+    brlo    unstuff6        ;[073] *** unstuff escape
+didUnstuff5:                ;[   ]
+    nop2                    ;[074]
+;   [---]                   ;[075]
+    in      x2, USBIN       ;[076] <-- bit 7
+    eor     x1, x2          ;[077]
+    bst     x1, USBMINUS    ;[078]
+    bld     shift, 7        ;[079]
+didUnstuff7:                ;[   ]
+    eor     r0, x2          ;[080]
+    or      phase, r0       ;[081]
+    in      r0, USBIN       ;[082] <-- phase
+    cpi     shift, 0x04     ;[083]
+    brsh    rxLoop          ;[084]
+;   [---]                   ;[085]
+unstuff7:                   ;[   ]
+    andi    x3, ~0x80       ;[085]
+    ori     shift, 0x80     ;[086]
+    in      x2, USBIN       ;[087] <-- sample stuffed bit 7
+    nop                     ;[088]
+    rjmp    didUnstuff7     ;[089]
+;   [---]                   ;[090]
+                            ;[080]
+
+unstuff5:                   ;[067]
+    eor     phase, x1       ;[068]
+    andi    x3, ~0x20       ;[069]
+    ori     shift, 0x20     ;[070]
+    in      r0, USBIN       ;[071] <-- phase
+    mov     x2, x1          ;[072]
+    nop                     ;[073]
+    nop2                    ;[074]
+;   [---]                   ;[075]
+    in      x1, USBIN       ;[076] <-- bit 6
+    eor     r0, x1          ;[077]
+    or      phase, r0       ;[078]
+    eor     x2, x1          ;[079]
+    bst     x2, USBMINUS    ;[080]
+    bld     shift, 6        ;[081] no need to check bitstuffing, we just had one
+    in      r0, USBIN       ;[082] <-- phase
+    rjmp    didUnstuff5     ;[083]
+;   [---]                   ;[084]
+                            ;[074]
+
+unstuff6:                   ;[074]
+    andi    x3, ~0x40       ;[075]
+    in      x1, USBIN       ;[076] <-- bit 6 again
+    ori     shift, 0x40     ;[077]
+    nop2                    ;[078]
+;   [---]                   ;[079]
+    rjmp    didUnstuff6     ;[080]
+;   [---]                   ;[081]
+                            ;[071]
+
+unstuff0:                   ;[013]
+    eor     r0, x2          ;[014]
+    or      phase, r0       ;[015]
+    andi    x2, USBMASK     ;[016] check for SE0
+    in      r0, USBIN       ;[017] <-- phase
+    breq    didUnstuff0     ;[018] direct jump to se0 would be too long
+    andi    x3, ~0x01       ;[019]
+    ori     shift, 0x01     ;[020]
+    mov     x1, x2          ;[021] mov existing sample
+    in      x2, USBIN       ;[022] <-- bit 1 again
+    rjmp    didUnstuff0     ;[023]
+;   [---]                   ;[024]
+                            ;[014]
+
+unstuff1:                   ;[024]
+    eor     r0, x1          ;[025]
+    or      phase, r0       ;[026]
+    andi    x3, ~0x02       ;[027]
+    in      r0, USBIN       ;[028] <-- phase
+    ori     shift, 0x02     ;[029]
+    mov     x2, x1          ;[030]
+    rjmp    didUnstuff1     ;[031]
+;   [---]                   ;[032]
+                            ;[022]
+
+unstuff2:                   ;[035]
+    eor     r0, x2          ;[036]
+    or      phase, r0       ;[037]
+    andi    x3, ~0x04       ;[038]
+    in      r0, USBIN       ;[039] <-- phase
+    ori     shift, 0x04     ;[040]
+    mov     x1, x2          ;[041]
+    rjmp    didUnstuff2     ;[042]
+;   [---]                   ;[043]
+                            ;[033]
+
+unstuff3:                   ;[043]
+    in      x2, USBIN       ;[044] <-- bit 3 again
+    eor     r0, x2          ;[045]
+    or      phase, r0       ;[046]
+    andi    x3, ~0x08       ;[047]
+    ori     shift, 0x08     ;[048]
+    nop                     ;[049]
+    in      r0, USBIN       ;[050] <-- phase
+    rjmp    didUnstuff3     ;[051]
+;   [---]                   ;[052]
+                            ;[042]
+
+unstuff4:                   ;[053]
+    andi    x3, ~0x10       ;[054]
+    in      x1, USBIN       ;[055] <-- bit 4 again
+    ori     shift, 0x10     ;[056]
+    rjmp    didUnstuff4     ;[057]
+;   [---]                   ;[058]
+                            ;[048]
+
+rxLoop:                     ;[085]
+    eor     x3, shift       ;[086] reconstruct: x3 is 0 at bit locations we changed, 1 at others
+    in      x1, USBIN       ;[000] <-- bit 0
+    st      y+, x3          ;[001]
+;   [---]                   ;[002]
+    eor     r0, x1          ;[003]
+    or      phase, r0       ;[004]
+    eor     x2, x1          ;[005]
+    in      r0, USBIN       ;[006] <-- phase
+    ser     x3              ;[007]
+    bst     x2, USBMINUS    ;[008]
+    bld     shift, 0        ;[009]
+    andi    shift, 0xf9     ;[010]
+rxbit1:                     ;[   ]
+    in      x2, USBIN       ;[011] <-- bit 1
+    breq    unstuff0        ;[012] *** unstuff escape
+    andi    x2, USBMASK     ;[013] SE0 check for bit 1
+didUnstuff0:                ;[   ] Z only set if we detected SE0 in bitstuff
+    breq    se0             ;[014]
+    eor     r0, x2          ;[015]
+    or      phase, r0       ;[016]
+    in      r0, USBIN       ;[017] <-- phase
+    eor     x1, x2          ;[018]
+    bst     x1, USBMINUS    ;[019]
+    bld     shift, 1        ;[020]
+    andi    shift, 0xf3     ;[021]
+didUnstuff1:                ;[   ]
+    in      x1, USBIN       ;[022] <-- bit 2
+    breq    unstuff1        ;[023] *** unstuff escape
+    eor     r0, x1          ;[024]
+    or      phase, r0       ;[025]
+    subi    cnt, 1          ;[026] overflow check
+    brcs    overflow        ;[027]
+    in      r0, USBIN       ;[028] <-- phase
+    eor     x2, x1          ;[029]
+    bst     x2, USBMINUS    ;[030]
+    bld     shift, 2        ;[031]
+    andi    shift, 0xe7     ;[032]
+didUnstuff2:                ;[   ]
+    in      x2, USBIN       ;[033] <-- bit 3
+    breq    unstuff2        ;[034] *** unstuff escape
+    eor     r0, x2          ;[035]
+    or      phase, r0       ;[036]
+    eor     x1, x2          ;[037]
+    bst     x1, USBMINUS    ;[038]
+    in      r0, USBIN       ;[039] <-- phase
+    bld     shift, 3        ;[040]
+    andi    shift, 0xcf     ;[041]
+didUnstuff3:                ;[   ]
+    breq    unstuff3        ;[042] *** unstuff escape
+    nop                     ;[043]
+    in      x1, USBIN       ;[044] <-- bit 4
+    eor     x2, x1          ;[045]
+    bst     x2, USBMINUS    ;[046]
+    bld     shift, 4        ;[047]
+didUnstuff4:                ;[   ]
+    eor     r0, x1          ;[048]
+    or      phase, r0       ;[049]
+    in      r0, USBIN       ;[050] <-- phase
+    andi    shift, 0x9f     ;[051]
+    breq    unstuff4        ;[052] *** unstuff escape
+    rjmp    continueWithBit5;[053]
+;   [---]                   ;[054]
+
+macro POP_STANDARD ; 16 cycles
+    pop     cnt
+    pop     x4
+    pop     x3
+    pop     x2
+    pop     x1
+    pop     shift
+    pop     YH
+    pop     r0
+    endm
+macro POP_RETI     ; 5 cycles
+    pop     YL
+    out     SREG, YL
+    pop     YL
+    endm
+
+#include "asmcommon.inc"
+
+
+; USB spec says:
+; idle = J
+; J = (D+ = 0), (D- = 1)
+; K = (D+ = 1), (D- = 0)
+; Spec allows 7.5 bit times from EOP to SOP for replies
+
+bitstuff7:
+    eor     x1, x4          ;[4]
+    ldi     x2, 0           ;[5]
+    nop2                    ;[6] C is zero (brcc)
+    rjmp    didStuff7       ;[8]
+
+bitstuffN:
+    eor     x1, x4          ;[5]
+    ldi     x2, 0           ;[6]
+    lpm                     ;[7] 3 cycle NOP, modifies r0
+    out     USBOUT, x1      ;[10] <-- out
+    rjmp    didStuffN       ;[0]
+
+#define bitStatus   x3
+
+sendNakAndReti:
+    ldi     cnt, USBPID_NAK ;[-19]
+    rjmp    sendCntAndReti  ;[-18]
+sendAckAndReti:
+    ldi     cnt, USBPID_ACK ;[-17]
+sendCntAndReti:
+    mov     r0, cnt         ;[-16]
+    ldi     YL, 0           ;[-15] R0 address is 0
+    ldi     YH, 0           ;[-14]
+    ldi     cnt, 2          ;[-13]
+;   rjmp    usbSendAndReti      fallthrough
+
+;usbSend:
+;pointer to data in 'Y'
+;number of bytes in 'cnt' -- including sync byte [range 2 ... 12]
+;uses: x1...x4, shift, cnt, Y
+;Numbers in brackets are time since first bit of sync pattern is sent
+usbSendAndReti:             ; 12 cycles until SOP
+    in      x2, USBDDR      ;[-12]
+    ori     x2, USBMASK     ;[-11]
+    sbi     USBOUT, USBMINUS;[-10] prepare idle state; D+ and D- must have been 0 (no pullups)
+    in      x1, USBOUT      ;[-8] port mirror for tx loop
+    out     USBDDR, x2      ;[-7] <- acquire bus
+; need not init x2 (bitstuff history) because sync starts with 0
+    ldi     x4, USBMASK     ;[-6] exor mask
+    ldi     shift, 0x80     ;[-5] sync byte is first byte sent
+    ldi     bitStatus, 0xff ;[-4] init bit loop counter, works for up to 12 bytes
+byteloop:
+bitloop:
+    sbrs    shift, 0        ;[8] [-3]
+    eor     x1, x4          ;[9] [-2]
+    out     USBOUT, x1      ;[10] [-1] <-- out
+    ror     shift           ;[0]
+    ror     x2              ;[1]
+didStuffN:
+    cpi     x2, 0xfc        ;[2]
+    brcc    bitstuffN       ;[3]
+    nop                     ;[4]
+    subi    bitStatus, 37   ;[5] 256 / 7 ~=~ 37
+    brcc    bitloop         ;[6] when we leave the loop, bitStatus has almost the initial value
+    sbrs    shift, 0        ;[7]
+    eor     x1, x4          ;[8]
+    ror     shift           ;[9]
+didStuff7:
+    out     USBOUT, x1      ;[10] <-- out
+    ror     x2              ;[0]
+    cpi     x2, 0xfc        ;[1]
+    brcc    bitstuff7       ;[2]
+    ld      shift, y+       ;[3]
+    dec     cnt             ;[5]
+    brne    byteloop        ;[6]
+;make SE0:
+    cbr     x1, USBMASK     ;[7] prepare SE0 [spec says EOP may be 21 to 25 cycles]
+    lds     x2, usbNewDeviceAddr;[8]
+    lsl     x2              ;[10] we compare with left shifted address
+    out     USBOUT, x1      ;[11] <-- out SE0 -- from now 2 bits = 22 cycles until bus idle
+;2006-03-06: moved transfer of new address to usbDeviceAddr from C-Code to asm:
+;set address only after data packet was sent, not after handshake
+    subi    YL, 2           ;[0] Only assign address on data packets, not ACK/NAK in r0
+    sbci    YH, 0           ;[1]
+    breq    skipAddrAssign  ;[2]
+    sts     usbDeviceAddr, x2; if not skipped: SE0 is one cycle longer
+skipAddrAssign:
+;end of usbDeviceAddress transfer
+    ldi     x2, 1<<USB_INTR_PENDING_BIT;[4] int0 occurred during TX -- clear pending flag
+    USB_STORE_PENDING(x2)   ;[5]
+    ori     x1, USBIDLE     ;[6]
+    in      x2, USBDDR      ;[7]
+    cbr     x2, USBMASK     ;[8] set both pins to input
+    mov     x3, x1          ;[9]
+    cbr     x3, USBMASK     ;[10] configure no pullup on both pins
+    ldi     x4, 4           ;[11]
+se0Delay:
+    dec     x4              ;[12] [15] [18] [21]
+    brne    se0Delay        ;[13] [16] [19] [22]
+    out     USBOUT, x1      ;[23] <-- out J (idle) -- end of SE0 (EOP signal)
+    out     USBDDR, x2      ;[24] <-- release bus now
+    out     USBOUT, x3      ;[25] <-- ensure no pull-up resistors are active
+    rjmp    doReturn
+

usbdrvasm18-crc.inc

@@ -0,0 +1,707 @@
+/* Name: usbdrvasm18.inc
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Lukas Schrittwieser (based on 20 MHz usbdrvasm20.inc by Jeroen Benschop)
+ * Creation Date: 2009-01-20
+ * Tabsize: 4
+ * Copyright: (c) 2008 by Lukas Schrittwieser and OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * Revision: $Id: usbdrvasm18-crc.inc 740 2009-04-13 18:23:31Z cs $
+ */
+
+/* Do not link this file! Link usbdrvasm.S instead, which includes the
+ * appropriate implementation!
+ */
+
+/*
+General Description:
+This file is the 18 MHz version of the asssembler part of the USB driver. It
+requires a 18 MHz crystal (not a ceramic resonator and not a calibrated RC
+oscillator).
+
+See usbdrv.h for a description of the entire driver.
+
+Since almost all of this code is timing critical, don't change unless you
+really know what you are doing! Many parts require not only a maximum number
+of CPU cycles, but even an exact number of cycles!
+*/
+
+
+;max stack usage: [ret(2), YL, SREG, YH, [sofError], bitcnt(x5), shift, x1, x2, x3, x4, cnt, ZL, ZH] = 14 bytes
+;nominal frequency: 18 MHz -> 12 cycles per bit
+; Numbers in brackets are clocks counted from center of last sync bit
+; when instruction starts
+;register use in receive loop to receive the data bytes:
+; shift assembles the byte currently being received
+; x1 holds the D+ and D- line state
+; x2 holds the previous line state
+; cnt holds the number of bytes left in the receive buffer
+; x3 holds the higher crc byte (see algorithm below)
+; x4 is used as temporary register for the crc algorithm
+; x5 is used for unstuffing: when unstuffing the last received bit is inverted in shift (to prevent further
+;    unstuffing calls. In the same time the corresponding bit in x5 is cleared to mark the bit as beening iverted
+; zl lower crc value and crc table index
+; zh used for crc table accesses
+
+;--------------------------------------------------------------------------------------------------------------
+; CRC mods:
+;  table driven crc checker, Z points to table in prog space
+;   ZL is the lower crc byte, x3 is the higher crc byte
+;	x4 is used as temp register to store different results
+;	the initialization of the crc register is not 0xFFFF but 0xFE54. This is because during the receipt of the
+;	first data byte an virtual zero data byte is added to the crc register, this results in the correct initial
+;	value of 0xFFFF at beginning of the second data byte before the first data byte is added to the crc.
+;	The magic number 0xFE54 results form the crc table: At tabH[0x54] = 0xFF = crcH (required) and
+;	tabL[0x54] = 0x01  ->  crcL = 0x01 xor 0xFE = 0xFF
+;  bitcnt is renamed to x5 and is used for unstuffing purposes, the unstuffing works like in the 12MHz version
+;--------------------------------------------------------------------------------------------------------------
+; CRC algorithm:
+;	The crc register is formed by x3 (higher byte) and ZL (lower byte). The algorithm uses a 'reversed' form
+;	i.e. that it takes the least significant bit first and shifts to the right. So in fact the highest order
+;	bit seen from the polynomial devision point of view is the lsb of ZL. (If this sounds strange to you i
+;	propose a research on CRC :-) )
+;	Each data byte received is xored to ZL, the lower crc byte. This byte now builds the crc
+;	table index. Next the new high byte is loaded from the table and stored in x4 until we have space in x3
+;	(its destination).
+;	Afterwards the lower table is loaded from the table and stored in ZL (the old index is overwritten as
+;	we don't need it anymore. In fact this is a right shift by 8 bits.) Now the old crc high value is xored
+;	to ZL, this is the second shift of the old crc value. Now x4 (the temp reg) is moved to x3 and the crc
+; 	calculation is done.
+;	Prior to the first byte the two CRC register have to be initialized to 0xFFFF (as defined in usb spec)
+;	however the crc engine also runs during the receipt of the first byte, therefore x3 and zl are initialized
+;	to a magic number which results in a crc value of 0xFFFF after the first complete byte.
+;
+;	This algorithm is split into the extra cycles of the different bits:
+;	bit7:	XOR the received byte to ZL
+;	bit5:	load the new high byte to x4
+;	bit6:	load the lower xor byte from the table, xor zl and x3, store result in zl (=the new crc low value)
+;			move x4 (the new high byte) to x3, the crc value is ready
+;
+
+
+macro POP_STANDARD ; 18 cycles
+    pop		ZH
+    pop		ZL
+	pop     cnt
+    pop     x5
+    pop     x3
+    pop     x2
+    pop     x1
+    pop     shift
+    pop     x4
+    endm
+macro POP_RETI     ; 7 cycles
+    pop     YH
+    pop     YL
+    out     SREG, YL
+    pop     YL
+    endm
+
+macro CRC_CLEANUP_AND_CHECK
+	; the last byte has already been xored with the lower crc byte, we have to do the table lookup and xor
+	; x3 is the higher crc byte, zl the lower one
+	ldi		ZH, hi8(usbCrcTableHigh);[+1] get the new high byte from the table
+	lpm		x2, Z				;[+2][+3][+4]
+	ldi		ZH, hi8(usbCrcTableLow);[+5] get the new low xor byte from the table
+	lpm		ZL, Z				;[+6][+7][+8]
+	eor		ZL, x3				;[+7] xor the old high byte with the value from the table, x2:ZL now holds the crc value
+	cpi		ZL, 0x01			;[+8] if the crc is ok we have a fixed remainder value of 0xb001 in x2:ZL (see usb spec)
+	brne	ignorePacket		;[+9] detected a crc fault -> paket is ignored and retransmitted by the host
+	cpi		x2, 0xb0			;[+10]
+	brne	ignorePacket		;[+11] detected a crc fault -> paket is ignored and retransmitted by the host
+    endm
+
+
+USB_INTR_VECTOR:
+;order of registers pushed: YL, SREG, YH, [sofError], x4, shift, x1, x2, x3, x5, cnt, ZL, ZH
+    push    YL                  ;[-28] push only what is necessary to sync with edge ASAP
+    in      YL, SREG            ;[-26]
+    push    YL                  ;[-25]
+    push    YH                  ;[-23]
+;----------------------------------------------------------------------------
+; Synchronize with sync pattern:
+;----------------------------------------------------------------------------
+;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
+;sync up with J to K edge during sync pattern -- use fastest possible loops
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
+waitForJ:
+    inc     YL
+    sbis    USBIN, USBMINUS
+    brne    waitForJ        ; just make sure we have ANY timeout
+waitForK:
+;The following code results in a sampling window of < 1/4 bit which meets the spec.
+    sbis    USBIN, USBMINUS     ;[-17]
+    rjmp    foundK              ;[-16]
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+#if USB_COUNT_SOF
+    lds     YL, usbSofCount
+    inc     YL
+    sts     usbSofCount, YL
+#endif  /* USB_COUNT_SOF */
+#ifdef USB_SOF_HOOK
+    USB_SOF_HOOK
+#endif
+    rjmp    sofError
+foundK:                         ;[-15]
+;{3, 5} after falling D- edge, average delay: 4 cycles
+;bit0 should be at 30  (2.5 bits) for center sampling. Currently at 4 so 26 cylces till bit 0 sample
+;use 1 bit time for setup purposes, then sample again. Numbers in brackets
+;are cycles from center of first sync (double K) bit after the instruction
+    push    x4                  ;[-14]
+;   [---]                       ;[-13]
+    lds     YL, usbInputBufOffset;[-12] used to toggle the two usb receive buffers
+;   [---]                       ;[-11]
+    clr     YH                  ;[-10]
+    subi    YL, lo8(-(usbRxBuf));[-9] [rx loop init]
+    sbci    YH, hi8(-(usbRxBuf));[-8] [rx loop init]
+    push    shift               ;[-7]
+;   [---]                       ;[-6]
+    ldi		shift, 0x80			;[-5] the last bit is the end of byte marker for the pid receiver loop
+    clc			      	      	;[-4] the carry has to be clear for receipt of pid bit 0
+    sbis    USBIN, USBMINUS     ;[-3] we want two bits K (sample 3 cycles too early)
+    rjmp    haveTwoBitsK        ;[-2]
+    pop     shift               ;[-1] undo the push from before
+    pop     x4                  ;[1]
+    rjmp    waitForK            ;[3] this was not the end of sync, retry
+; The entire loop from waitForK until rjmp waitForK above must not exceed two
+; bit times (= 24 cycles).
+
+;----------------------------------------------------------------------------
+; push more registers and initialize values while we sample the first bits:
+;----------------------------------------------------------------------------
+haveTwoBitsK:
+    push    x1                  ;[0]
+    push    x2                  ;[2]
+    push    x3                  ;[4] crc high byte
+    ldi     x2, 1<<USBPLUS      ;[6] [rx loop init] current line state is K state. D+=="1", D-=="0"
+    push    x5                  ;[7]
+    push    cnt                 ;[9]
+    ldi     cnt, USB_BUFSIZE    ;[11]
+
+
+;--------------------------------------------------------------------------------------------------------------
+; receives the pid byte
+; there is no real unstuffing algorithm implemented here as a stuffing bit is impossible in the pid byte.
+; That's because the last four bits of the byte are the inverted of the first four bits. If we detect a
+; unstuffing condition something went wrong and abort
+; shift has to be initialized to 0x80
+;--------------------------------------------------------------------------------------------------------------
+
+; pid bit 0 - used for even more register saving (we need the z pointer)
+	in      x1, USBIN           ;[0] sample line state
+    andi    x1, USBMASK         ;[1] filter only D+ and D- bits
+    eor		x2, x1				;[2] generate inverted of actual bit
+	sbrc	x2, USBMINUS		;[3] if the bit is set we received a zero
+	sec							;[4]
+	ror		shift				;[5] we perform no unstuffing check here as this is the first bit
+	mov		x2, x1				;[6]
+	push	ZL					;[7]
+								;[8]
+	push	ZH					;[9]
+								;[10]
+	ldi		x3, 0xFE			;[11] x3 is the high order crc value
+
+
+bitloopPid:						
+	in      x1, USBIN           ;[0] sample line state
+   	andi    x1, USBMASK         ;[1] filter only D+ and D- bits
+    breq    nse0                ;[2] both lines are low so handle se0	
+	eor		x2, x1				;[3] generate inverted of actual bit
+	sbrc	x2, USBMINUS		;[4] set the carry if we received a zero
+	sec							;[5]
+	ror		shift				;[6]
+	ldi		ZL, 0x54			;[7] ZL is the low order crc value
+	ser		x4					;[8] the is no bit stuffing check here as the pid bit can't be stuffed. if so
+								; some error occured. In this case the paket is discarded later on anyway.
+	mov		x2, x1				;[9] prepare for the next cycle
+	brcc	bitloopPid			;[10] while 0s drop out of shift we get the next bit
+	eor		x4, shift			;[11] invert all bits in shift and store result in x4
+
+;--------------------------------------------------------------------------------------------------------------
+; receives data bytes and calculates the crc
+; the last USBIN state has to be in x2
+; this is only the first half, due to branch distanc limitations the second half of the loop is near the end
+; of this asm file
+;--------------------------------------------------------------------------------------------------------------
+
+rxDataStart:
+    in      x1, USBIN           ;[0] sample line state (note: a se0 check is not useful due to bit dribbling)
+    ser		x5					;[1] prepare the unstuff marker register
+    eor		x2, x1             	;[2] generates the inverted of the actual bit
+    bst		x2, USBMINUS       	;[3] copy the bit from x2
+    bld		shift, 0	        ;[4] and store it in shift
+    mov		x2, shift	     	;[5] make a copy of shift for unstuffing check
+    andi	x2, 0xF9	      	;[6] mask the last six bits, if we got six zeros (which are six ones in fact)
+    breq	unstuff0	      	;[7] then Z is set now and we branch to the unstuffing handler
+didunstuff0:
+	subi    cnt, 1         		;[8] cannot use dec because it doesn't affect the carry flag
+    brcs    nOverflow    		;[9] Too many bytes received. Ignore packet							
+    st		Y+, x4				;[10] store the last received byte
+								;[11] st needs two cycles
+
+; bit1							
+	in		x2, USBIN			;[0] sample line state
+    andi	x1, USBMASK			;[1] check for se0 during bit 0
+    breq	nse0				;[2]
+    andi	x2, USBMASK			;[3] check se0 during bit 1
+    breq	nse0				;[4]
+	eor		x1, x2				;[5]
+    bst		x1, USBMINUS		;[6]
+    bld 	shift, 1	 		;[7]
+    mov		x1, shift			;[8]
+    andi	x1, 0xF3			;[9]
+    breq	unstuff1			;[10]
+didunstuff1:
+	nop							;[11]	
+
+; bit2
+	in      x1, USBIN           ;[0] sample line state
+    andi	x1, USBMASK			;[1] check for se0 (as there is nothing else to do here
+	breq	nOverflow	 		;[2]
+    eor		x2, x1              ;[3] generates the inverted of the actual bit
+    bst		x2, USBMINUS		;[4]
+    bld		shift, 2			;[5] store the bit
+    mov		x2, shift			;[6]
+    andi	x2, 0xE7			;[7] if we have six zeros here (which means six 1 in the stream)
+    breq	unstuff2			;[8] the next bit is a stuffing bit
+didunstuff2:
+	nop2						;[9]
+								;[10]
+	nop							;[11]					
+					
+; bit3							
+	in		x2, USBIN			;[0] sample line state
+    andi	x2, USBMASK			;[1] check for se0
+    breq	nOverflow           ;[2]
+    eor		x1, x2				;[3]
+    bst		x1, USBMINUS		;[4]
+    bld 	shift, 3	 		;[5]
+    mov		x1, shift			;[6]
+    andi	x1, 0xCF			;[7]
+    breq	unstuff3			;[8]
+didunstuff3:
+	nop							;[9]
+	rjmp 	rxDataBit4			;[10]
+								;[11]				
+
+; the avr branch instructions allow an offset of +63 insturction only, so we need this
+; 'local copy' of se0
+nse0:		
+	rjmp	se0					;[4]
+								;[5]
+; the same same as for se0 is needed for overflow and StuffErr
+nOverflow:
+stuffErr:
+	rjmp	overflow
+
+
+unstuff0:						;[8] this is the branch delay of breq unstuffX
+	andi	x1, USBMASK			;[9] do an se0 check here (if the last crc byte ends with 5 one's we might end up here
+	breq	didunstuff0			;[10] event tough the message is complete -> jump back and store the byte
+	ori		shift, 0x01			;[11] invert the last received bit to prevent furhter unstuffing
+	in		x2, USBIN			;[0] we have some free cycles so we could check for bit stuffing errors
+	andi	x5, 0xFE			;[1] mark this bit as inverted (will be corrected before storing shift)
+	eor		x1, x2				;[2] x1 and x2 have to be different because the stuff bit is always a zero
+	andi	x1, USBMASK			;[3] mask the interesting bits
+	breq	stuffErr			;[4] if the stuff bit is a 1-bit something went wrong
+	mov 	x1, x2				;[5] the next bit expects the last state to be in x1
+	rjmp 	didunstuff0			;[6]
+								;[7] jump delay of rjmp didunstuffX	
+
+unstuff1:						;[11] this is the jump delay of breq unstuffX
+	in		x1, USBIN			;[0] we have some free cycles so we could check for bit stuffing errors
+	ori		shift, 0x02			;[1] invert the last received bit to prevent furhter unstuffing
+	andi	x5, 0xFD			;[2] mark this bit as inverted (will be corrected before storing shift)
+	eor		x2, x1				;[3] x1 and x2 have to be different because the stuff bit is always a zero
+	andi	x2, USBMASK			;[4] mask the interesting bits
+	breq	stuffErr			;[5] if the stuff bit is a 1-bit something went wrong
+	mov 	x2, x1				;[6] the next bit expects the last state to be in x2
+	nop2						;[7]
+								;[8]
+	rjmp 	didunstuff1			;[9]
+								;[10] jump delay of rjmp didunstuffX		
+
+unstuff2:						;[9] this is the jump delay of breq unstuffX
+	ori		shift, 0x04			;[10] invert the last received bit to prevent furhter unstuffing
+	andi	x5, 0xFB			;[11] mark this bit as inverted (will be corrected before storing shift)
+	in		x2, USBIN			;[0] we have some free cycles so we could check for bit stuffing errors
+	eor		x1, x2				;[1] x1 and x2 have to be different because the stuff bit is always a zero
+	andi	x1, USBMASK			;[2] mask the interesting bits
+	breq	stuffErr			;[3] if the stuff bit is a 1-bit something went wrong
+	mov 	x1, x2				;[4] the next bit expects the last state to be in x1
+	nop2						;[5]
+								;[6]
+	rjmp 	didunstuff2			;[7]
+								;[8] jump delay of rjmp didunstuffX	
+
+unstuff3:						;[9] this is the jump delay of breq unstuffX
+	ori		shift, 0x08			;[10] invert the last received bit to prevent furhter unstuffing
+	andi	x5, 0xF7			;[11] mark this bit as inverted (will be corrected before storing shift)
+	in		x1, USBIN			;[0] we have some free cycles so we could check for bit stuffing errors
+	eor		x2, x1				;[1] x1 and x2 have to be different because the stuff bit is always a zero
+	andi	x2, USBMASK			;[2] mask the interesting bits
+	breq	stuffErr			;[3] if the stuff bit is a 1-bit something went wrong
+	mov 	x2, x1				;[4] the next bit expects the last state to be in x2
+	nop2						;[5]
+								;[6]
+	rjmp 	didunstuff3			;[7]
+								;[8] jump delay of rjmp didunstuffX			
+
+
+
+; the include has to be here due to branch distance restirctions
+#define __USE_CRC__
+#include "asmcommon.inc"
+
+	
+
+; USB spec says:
+; idle = J
+; J = (D+ = 0), (D- = 1)
+; K = (D+ = 1), (D- = 0)
+; Spec allows 7.5 bit times from EOP to SOP for replies
+; 7.5 bit times is 90 cycles. ...there is plenty of time
+
+
+sendNakAndReti:
+    ldi     x3, USBPID_NAK  ;[-18]
+    rjmp    sendX3AndReti   ;[-17]
+sendAckAndReti:
+    ldi     cnt, USBPID_ACK ;[-17]
+sendCntAndReti:
+    mov     x3, cnt         ;[-16]
+sendX3AndReti:
+    ldi     YL, 20          ;[-15] x3==r20 address is 20
+    ldi     YH, 0           ;[-14]
+    ldi     cnt, 2          ;[-13]
+;   rjmp    usbSendAndReti      fallthrough
+
+;usbSend:
+;pointer to data in 'Y'
+;number of bytes in 'cnt' -- including sync byte [range 2 ... 12]
+;uses: x1...x4, btcnt, shift, cnt, Y
+;Numbers in brackets are time since first bit of sync pattern is sent
+
+usbSendAndReti:             ; 12 cycles until SOP
+    in      x2, USBDDR      ;[-12]
+    ori     x2, USBMASK     ;[-11]
+    sbi     USBOUT, USBMINUS;[-10] prepare idle state; D+ and D- must have been 0 (no pullups)
+    in      x1, USBOUT      ;[-8] port mirror for tx loop
+    out     USBDDR, x2      ;[-6] <- acquire bus
+	ldi		x2, 0			;[-6] init x2 (bitstuff history) because sync starts with 0
+    ldi     x4, USBMASK     ;[-5] exor mask
+    ldi     shift, 0x80     ;[-4] sync byte is first byte sent
+txByteLoop:
+    ldi     bitcnt, 0x40    ;[-3]=[9]     binary 01000000
+txBitLoop:					; the loop sends the first 7 bits of the byte
+    sbrs    shift, 0        ;[-2]=[10] if we have to send a 1 don't change the line state
+    eor     x1, x4          ;[-1]=[11]
+    out     USBOUT, x1      ;[0]
+    ror     shift           ;[1]
+    ror     x2              ;[2] transfers the last sent bit to the stuffing history
+didStuffN:
+    nop	                    ;[3]
+    nop                     ;[4]
+    cpi     x2, 0xfc        ;[5] if we sent six consecutive ones
+    brcc    bitstuffN       ;[6]
+    lsr     bitcnt          ;[7]
+    brne    txBitLoop       ;[8] restart the loop while the 1 is still in the bitcount
+
+; transmit bit 7
+    sbrs    shift, 0        ;[9]
+    eor     x1, x4          ;[10]
+didStuff7:
+    ror     shift           ;[11]
+	out     USBOUT, x1      ;[0] transfer bit 7 to the pins
+    ror     x2              ;[1] move the bit into the stuffing history	
+    cpi     x2, 0xfc        ;[2]
+    brcc    bitstuff7       ;[3]
+    ld      shift, y+       ;[4] get next byte to transmit
+    dec     cnt             ;[5] decrement byte counter
+    brne    txByteLoop      ;[7] if we have more bytes start next one
+    						;[8] branch delay
+    						
+;make SE0:
+    cbr     x1, USBMASK     ;[8] 		prepare SE0 [spec says EOP may be 25 to 30 cycles]
+    lds     x2, usbNewDeviceAddr;[9]
+    lsl     x2              ;[11] 		we compare with left shifted address
+    out     USBOUT, x1      ;[0] 		<-- out SE0 -- from now 2 bits = 24 cycles until bus idle
+    subi    YL, 20 + 2      ;[1] 		Only assign address on data packets, not ACK/NAK in x3
+    sbci    YH, 0           ;[2]
+;2006-03-06: moved transfer of new address to usbDeviceAddr from C-Code to asm:
+;set address only after data packet was sent, not after handshake
+    breq    skipAddrAssign  ;[3]
+    sts     usbDeviceAddr, x2		; if not skipped: SE0 is one cycle longer
+skipAddrAssign:
+;end of usbDeviceAddress transfer
+    ldi     x2, 1<<USB_INTR_PENDING_BIT;[5] int0 occurred during TX -- clear pending flag
+    USB_STORE_PENDING(x2)   ;[6]
+    ori     x1, USBIDLE     ;[7]
+    in      x2, USBDDR      ;[8]
+    cbr     x2, USBMASK     ;[9] set both pins to input
+    mov     x3, x1          ;[10]
+    cbr     x3, USBMASK     ;[11] configure no pullup on both pins
+    ldi     x4, 4           ;[12]
+se0Delay:
+    dec     x4              ;[13] [16] [19] [22]
+    brne    se0Delay        ;[14] [17] [20] [23]
+    out     USBOUT, x1      ;[24] <-- out J (idle) -- end of SE0 (EOP signal)
+    out     USBDDR, x2      ;[25] <-- release bus now
+    out     USBOUT, x3      ;[26] <-- ensure no pull-up resistors are active
+    rjmp    doReturn
+
+bitstuffN:
+    eor     x1, x4          ;[8] generate a zero
+    ldi     x2, 0           ;[9] reset the bit stuffing history
+    nop2                    ;[10]
+    out     USBOUT, x1      ;[0] <-- send the stuffing bit
+    rjmp    didStuffN       ;[1]
+
+bitstuff7:
+    eor     x1, x4          ;[5]
+    ldi     x2, 0           ;[6] reset bit stuffing history
+    clc						;[7] fill a zero into the shift register
+    rol     shift           ;[8] compensate for ror shift at branch destination
+    rjmp    didStuff7       ;[9]
+    						;[10] jump delay
+
+;--------------------------------------------------------------------------------------------------------------
+; receives data bytes and calculates the crc
+; second half of the data byte receiver loop
+; most parts of the crc algorithm are here
+;--------------------------------------------------------------------------------------------------------------
+
+nOverflow2:
+	rjmp overflow
+
+rxDataBit4:
+	in      x1, USBIN           ;[0] sample line state
+    andi	x1, USBMASK			;[1] check for se0
+    breq	nOverflow2			;[2]
+    eor		x2, x1              ;[3]
+    bst		x2, USBMINUS		;[4]
+    bld		shift, 4			;[5]
+    mov		x2, shift			;[6]
+    andi	x2, 0x9F			;[7]
+    breq	unstuff4			;[8]
+didunstuff4:
+	nop2						;[9][10]
+	nop							;[11]
+
+; bit5							
+	in		x2, USBIN			;[0] sample line state
+    ldi		ZH, hi8(usbCrcTableHigh);[1] use the table for the higher byte
+    eor		x1, x2				;[2]
+    bst		x1, USBMINUS		;[3]
+    bld 	shift, 5	 		;[4]
+    mov		x1, shift			;[5]
+    andi	x1, 0x3F			;[6]
+    breq	unstuff5			;[7]
+didunstuff5:
+	lpm		x4, Z				;[8] load the higher crc xor-byte and store it for later use
+								;[9] lpm needs 3 cycles
+								;[10]			
+	ldi		ZH, hi8(usbCrcTableLow);[11] load the lower crc xor byte adress
+
+; bit6	    					
+	in      x1, USBIN           ;[0] sample line state
+    eor		x2, x1              ;[1]
+    bst		x2, USBMINUS		;[2]
+    bld		shift, 6			;[3]
+    mov		x2, shift			;[4]
+    andi	x2, 0x7E			;[5]
+    breq	unstuff6			;[6]
+didunstuff6:
+	lpm		ZL, Z				;[7] load the lower xor crc byte
+								;[8] lpm needs 3 cycles
+	    						;[9]
+	eor		ZL, x3				;[10] xor the old high crc byte with the low xor-byte
+	mov		x3, x4				;[11] move the new high order crc value from temp to its destination
+			
+; bit7							
+	in		x2, USBIN			;[0] sample line state
+    eor		x1, x2				;[1]
+    bst		x1, USBMINUS		;[2]
+    bld 	shift, 7	 		;[3] now shift holds the complete but inverted data byte
+    mov		x1, shift			;[4]
+    andi	x1, 0xFC			;[5]
+    breq	unstuff7			;[6]
+didunstuff7:
+	eor		x5, shift			;[7] x5 marks all bits which have not been inverted by the unstuffing subs
+	mov		x4, x5				;[8] keep a copy of the data byte it will be stored during next bit0
+	eor		ZL, x4				;[9] feed the actual byte into the crc algorithm
+	rjmp	rxDataStart			;[10] next byte
+								;[11] during the reception of the next byte this one will be fed int the crc algorithm
+
+unstuff4:						;[9] this is the jump delay of rjmp unstuffX
+	ori		shift, 0x10			;[10] invert the last received bit to prevent furhter unstuffing
+	andi	x5, 0xEF			;[11] mark this bit as inverted (will be corrected before storing shift)
+	in		x2, USBIN			;[0] we have some free cycles so we could check for bit stuffing errors
+	eor		x1, x2				;[1] x1 and x2 have to be different because the stuff bit is always a zero
+	andi	x1, USBMASK			;[2] mask the interesting bits
+	breq	stuffErr2			;[3] if the stuff bit is a 1-bit something went wrong
+	mov 	x1, x2				;[4] the next bit expects the last state to be in x1
+	nop2						;[5]
+								;[6]
+	rjmp 	didunstuff4			;[7]
+								;[8] jump delay of rjmp didunstuffX	
+
+unstuff5:						;[8] this is the jump delay of rjmp unstuffX
+	nop							;[9]
+	ori		shift, 0x20			;[10] invert the last received bit to prevent furhter unstuffing
+	andi	x5, 0xDF			;[11] mark this bit as inverted (will be corrected before storing shift)
+	in		x1, USBIN			;[0] we have some free cycles so we could check for bit stuffing errors
+	eor		x2, x1				;[1] x1 and x2 have to be different because the stuff bit is always a zero
+	andi	x2, USBMASK			;[2] mask the interesting bits
+	breq	stuffErr2			;[3] if the stuff bit is a 1-bit something went wrong
+	mov 	x2, x1				;[4] the next bit expects the last state to be in x2
+	nop							;[5]
+	rjmp 	didunstuff5			;[6]
+								;[7] jump delay of rjmp didunstuffX													
+
+unstuff6:						;[7] this is the jump delay of rjmp unstuffX
+	nop2						;[8]
+								;[9]
+	ori		shift, 0x40			;[10] invert the last received bit to prevent furhter unstuffing
+	andi	x5, 0xBF			;[11] mark this bit as inverted (will be corrected before storing shift)
+	in		x2, USBIN			;[0] we have some free cycles so we could check for bit stuffing errors
+	eor		x1, x2				;[1] x1 and x2 have to be different because the stuff bit is always a zero
+	andi	x1, USBMASK			;[2] mask the interesting bits
+	breq	stuffErr2			;[3] if the stuff bit is a 1-bit something went wrong
+	mov 	x1, x2				;[4] the next bit expects the last state to be in x1
+	rjmp 	didunstuff6			;[5]
+								;[6] jump delay of rjmp didunstuffX	
+
+unstuff7:						;[7] this is the jump delay of rjmp unstuffX
+	nop							;[8]
+	nop							;[9]
+	ori		shift, 0x80			;[10] invert the last received bit to prevent furhter unstuffing
+	andi	x5, 0x7F			;[11] mark this bit as inverted (will be corrected before storing shift)
+	in		x1, USBIN			;[0] we have some free cycles so we could check for bit stuffing errors
+	eor		x2, x1				;[1] x1 and x2 have to be different because the stuff bit is always a zero
+	andi	x2, USBMASK			;[2] mask the interesting bits
+	breq	stuffErr2			;[3] if the stuff bit is a 1-bit something went wrong
+	mov 	x2, x1				;[4] the next bit expects the last state to be in x2
+	rjmp 	didunstuff7			;[5]
+								;[6] jump delay of rjmp didunstuff7
+
+; local copy of the stuffErr desitnation for the second half of the receiver loop
+stuffErr2:
+	rjmp	stuffErr
+
+;--------------------------------------------------------------------------------------------------------------
+; The crc table follows. It has to be aligned to enable a fast loading of the needed bytes.
+; There are two tables of 256 entries each, the low and the high byte table.
+; Table values were generated with the following C code:
+/*
+#include <stdio.h>
+int main (int argc, char **argv)
+{
+	int i, j;
+	for (i=0; i<512; i++){
+		unsigned short crc = i & 0xff;
+		for(j=0; j<8; j++) crc = (crc >> 1) ^ ((crc & 1) ? 0xa001 : 0);
+		if((i & 7) == 0) printf("\n.byte ");
+		printf("0x%02x, ", (i > 0xff ? (crc >> 8) : crc) & 0xff);
+		if(i == 255) printf("\n");
+	}
+	return 0;
+}
+
+// Use the following algorithm to compute CRC values:
+ushort computeCrc(uchar *msg, uchar msgLen)
+{
+    uchar i;
+	ushort crc = 0xffff;
+	for(i = 0; i < msgLen; i++)
+		crc = usbCrcTable16[lo8(crc) ^ msg[i]] ^ hi8(crc);
+    return crc;
+}
+*/
+
+.balign 256
+usbCrcTableLow:	
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41
+.byte 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+
+; .balign 256
+usbCrcTableHigh:
+.byte 0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2
+.byte 0xC6, 0x06, 0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04
+.byte 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E
+.byte 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, 0x08, 0xC8
+.byte 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A
+.byte 0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC
+.byte 0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6
+.byte 0xD2, 0x12, 0x13, 0xD3, 0x11, 0xD1, 0xD0, 0x10
+.byte 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, 0xF2, 0x32
+.byte 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4
+.byte 0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE
+.byte 0xFA, 0x3A, 0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38
+.byte 0x28, 0xE8, 0xE9, 0x29, 0xEB, 0x2B, 0x2A, 0xEA
+.byte 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED, 0xEC, 0x2C
+.byte 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26
+.byte 0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0
+.byte 0xA0, 0x60, 0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62
+.byte 0x66, 0xA6, 0xA7, 0x67, 0xA5, 0x65, 0x64, 0xA4
+.byte 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F, 0x6E, 0xAE
+.byte 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68
+.byte 0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA
+.byte 0xBE, 0x7E, 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C
+.byte 0xB4, 0x74, 0x75, 0xB5, 0x77, 0xB7, 0xB6, 0x76
+.byte 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 0x70, 0xB0
+.byte 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92
+.byte 0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54
+.byte 0x9C, 0x5C, 0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E
+.byte 0x5A, 0x9A, 0x9B, 0x5B, 0x99, 0x59, 0x58, 0x98
+.byte 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B, 0x8A, 0x4A
+.byte 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C
+.byte 0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86
+.byte 0x82, 0x42, 0x43, 0x83, 0x41, 0x81, 0x80, 0x40	
+

usbdrvasm20.inc

@@ -0,0 +1,360 @@
+/* Name: usbdrvasm20.inc
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Jeroen Benschop
+ * Based on usbdrvasm16.inc from Christian Starkjohann
+ * Creation Date: 2008-03-05
+ * Tabsize: 4
+ * Copyright: (c) 2008 by Jeroen Benschop and OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * Revision: $Id: usbdrvasm20.inc 740 2009-04-13 18:23:31Z cs $
+ */
+
+/* Do not link this file! Link usbdrvasm.S instead, which includes the
+ * appropriate implementation!
+ */
+
+/*
+General Description:
+This file is the 20 MHz version of the asssembler part of the USB driver. It
+requires a 20 MHz crystal (not a ceramic resonator and not a calibrated RC
+oscillator).
+
+See usbdrv.h for a description of the entire driver.
+
+Since almost all of this code is timing critical, don't change unless you
+really know what you are doing! Many parts require not only a maximum number
+of CPU cycles, but even an exact number of cycles!
+*/
+
+#define leap2   x3
+#ifdef __IAR_SYSTEMS_ASM__
+#define nextInst    $+2
+#else
+#define nextInst    .+0
+#endif
+
+;max stack usage: [ret(2), YL, SREG, YH, bitcnt, shift, x1, x2, x3, x4, cnt] = 12 bytes
+;nominal frequency: 20 MHz -> 13.333333 cycles per bit, 106.666667 cycles per byte
+; Numbers in brackets are clocks counted from center of last sync bit
+; when instruction starts
+;register use in receive loop:
+; shift assembles the byte currently being received
+; x1 holds the D+ and D- line state
+; x2 holds the previous line state
+; x4 (leap)  is used to add a leap cycle once every three bytes received
+; X3 (leap2) is used to add a leap cycle once every three stuff bits received
+; bitcnt is used to determine when a stuff bit is due
+; cnt holds the number of bytes left in the receive buffer
+
+USB_INTR_VECTOR:
+;order of registers pushed: YL, SREG YH, [sofError], bitcnt, shift, x1, x2, x3, x4, cnt
+    push    YL                  ;[-28] push only what is necessary to sync with edge ASAP
+    in      YL, SREG            ;[-26]
+    push    YL                  ;[-25]
+    push    YH                  ;[-23]
+;----------------------------------------------------------------------------
+; Synchronize with sync pattern:
+;----------------------------------------------------------------------------
+;sync byte (D-) pattern LSb to MSb: 01010100 [1 = idle = J, 0 = K]
+;sync up with J to K edge during sync pattern -- use fastest possible loops
+;The first part waits at most 1 bit long since we must be in sync pattern.
+;YL is guarenteed to be < 0x80 because I flag is clear. When we jump to
+;waitForJ, ensure that this prerequisite is met.
+waitForJ:
+    inc     YL
+    sbis    USBIN, USBMINUS
+    brne    waitForJ        ; just make sure we have ANY timeout
+waitForK:
+;The following code results in a sampling window of < 1/4 bit which meets the spec.
+    sbis    USBIN, USBMINUS     ;[-19]
+    rjmp    foundK              ;[-18]
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+    sbis    USBIN, USBMINUS
+    rjmp    foundK
+#if USB_COUNT_SOF
+    lds     YL, usbSofCount
+    inc     YL
+    sts     usbSofCount, YL
+#endif  /* USB_COUNT_SOF */
+#ifdef USB_SOF_HOOK
+    USB_SOF_HOOK
+#endif
+    rjmp    sofError
+foundK:                         ;[-16]
+;{3, 5} after falling D- edge, average delay: 4 cycles
+;bit0 should be at 34 for center sampling. Currently at 4 so 30 cylces till bit 0 sample
+;use 1 bit time for setup purposes, then sample again. Numbers in brackets
+;are cycles from center of first sync (double K) bit after the instruction
+    push    bitcnt              ;[-16]
+;   [---]                       ;[-15]
+    lds     YL, usbInputBufOffset;[-14]
+;   [---]                       ;[-13]
+    clr     YH                  ;[-12]
+    subi    YL, lo8(-(usbRxBuf));[-11] [rx loop init]
+    sbci    YH, hi8(-(usbRxBuf));[-10] [rx loop init]
+    push    shift               ;[-9]
+;   [---]                       ;[-8]
+    ldi     shift,0x40          ;[-7] set msb to "1" so processing bit7 can be detected
+    nop2                        ;[-6]
+;   [---]                       ;[-5]
+    ldi     bitcnt, 5           ;[-4] [rx loop init]
+    sbis    USBIN, USBMINUS     ;[-3] we want two bits K (sample 3 cycles too early)
+    rjmp    haveTwoBitsK        ;[-2]
+    pop     shift               ;[-1] undo the push from before
+    pop     bitcnt              ;[1] 
+    rjmp    waitForK            ;[3] this was not the end of sync, retry
+; The entire loop from waitForK until rjmp waitForK above must not exceed two
+; bit times (= 27 cycles).
+
+;----------------------------------------------------------------------------
+; push more registers and initialize values while we sample the first bits:
+;----------------------------------------------------------------------------
+haveTwoBitsK:
+    push    x1                  ;[0]
+    push    x2                  ;[2]
+    push    x3                  ;[4] (leap2)
+    ldi     leap2, 0x55         ;[6] add leap cycle on 2nd,5th,8th,... stuff bit
+    push    x4                  ;[7] == leap
+    ldi     leap, 0x55          ;[9] skip leap cycle on 2nd,5th,8th,... byte received
+    push    cnt                 ;[10]
+    ldi     cnt, USB_BUFSIZE    ;[12] [rx loop init]
+    ldi     x2, 1<<USBPLUS      ;[13] current line state is K state. D+=="1", D-=="0"
+bit0:       
+    in      x1, USBIN           ;[0] sample line state
+    andi    x1, USBMASK         ;[1] filter only D+ and D- bits
+    rjmp    handleBit           ;[2] make bit0 14 cycles long
+
+;----------------------------------------------------------------------------
+; Process bit7. However, bit 6 still may need unstuffing.
+;----------------------------------------------------------------------------
+
+b6checkUnstuff:
+    dec     bitcnt              ;[9]
+    breq    unstuff6            ;[10]
+bit7:
+    subi    cnt, 1              ;[11] cannot use dec becaus it does not affect the carry flag
+    brcs    overflow            ;[12] Too many bytes received. Ignore packet
+    in      x1, USBIN           ;[0] sample line state
+    andi    x1, USBMASK         ;[1] filter only D+ and D- bits
+    cpse    x1, x2              ;[2] when previous line state equals current line state, handle "1"
+    rjmp    b7handle0           ;[3] when line state differs, handle "0"
+    sec                         ;[4]
+    ror     shift               ;[5] shift "1" into the data
+    st      y+, shift           ;[6] store the data into the buffer
+    ldi     shift, 0x40         ;[7] reset data for receiving the next byte
+    subi    leap, 0x55          ;[9] trick to introduce a leap cycle every 3 bytes
+    brcc    nextInst            ;[10 or 11] it will fail after 85 bytes. However low speed can only receive 11
+    dec     bitcnt              ;[11 or 12]
+    brne    bit0                ;[12 or 13]
+    ldi     x1, 1               ;[13 or 14] unstuffing bit 7
+    in      bitcnt, USBIN       ;[0] sample stuff bit
+    rjmp    unstuff             ;[1]
+
+b7handle0:
+    mov     x2,x1               ;[5] Set x2 to current line state
+    ldi     bitcnt, 6           ;[6]
+    lsr     shift               ;[7] shift "0" into the data
+    st      y+, shift           ;[8] store data into the buffer
+    ldi     shift, 0x40         ;[10] reset data for receiving the next byte
+    subi    leap, 0x55          ;[11] trick to introduce a leap cycle every 3 bytes
+    brcs    bit0                ;[12] it will fail after 85 bytes. However low speed can only receive 11
+    rjmp    bit0                ;[13]
+
+
+;----------------------------------------------------------------------------
+; Handle unstuff
+; x1==0xFF indicate unstuffing bit6
+;----------------------------------------------------------------------------
+
+unstuff6:
+    ldi     x1,0xFF             ;[12] indicate unstuffing bit 6
+    in      bitcnt, USBIN       ;[0]  sample stuff bit
+    nop                         ;[1]  fix timing
+unstuff:                        ;b0-5  b6   b7
+    mov     x2,bitcnt           ;[3]  [2]  [3]  Set x2 to match line state
+    subi    leap2, 0x55         ;[4]  [3]  [4]  delay loop
+    brcs    nextInst            ;[5]  [4]  [5]  add one cycle every three stuff bits
+    sbci    leap2,0             ;[6]  [5]  [6]
+    ldi     bitcnt,6            ;[7]  [6]  [7]  reset bit stuff counter
+    andi    x2, USBMASK         ;[8]  [7]  [8] only keep D+ and D-
+    cpi     x1,0                ;[9]  [8]  [9]
+    brmi    bit7                ;[10] [9]  [10] finished unstuffing bit6 When x1<0
+    breq    bitloop             ;[11] ---  [11] finished unstuffing bit0-5 when x1=0
+    nop                         ;---  ---  [12]
+    in      x1, USBIN           ;---  ---  [0] sample line state for bit0
+    andi    x1, USBMASK         ;---  ---  [1] filter only D+ and D- bits
+    rjmp    handleBit           ;---  ---  [2] make bit0 14 cycles long
+
+;----------------------------------------------------------------------------
+; Receiver loop (numbers in brackets are cycles within byte after instr)
+;----------------------------------------------------------------------------
+bitloop:
+    in      x1, USBIN           ;[0] sample line state
+    andi    x1, USBMASK         ;[1] filter only D+ and D- bits
+    breq    se0                 ;[2] both lines are low so handle se0
+handleBit:
+    cpse    x1, x2              ;[3] when previous line state equals current line state, handle "1"
+    rjmp    handle0             ;[4] when line state differs, handle "0"
+    sec                         ;[5]
+    ror     shift               ;[6] shift "1" into the data
+    brcs    b6checkUnstuff      ;[7] When after shift C is set, next bit is bit7
+    nop2                        ;[8]
+    dec     bitcnt              ;[10]
+    brne    bitloop             ;[11]
+    ldi     x1,0                ;[12] indicate unstuff for bit other than bit6 or bit7
+    in      bitcnt, USBIN       ;[0] sample stuff bit
+    rjmp    unstuff             ;[1]
+
+handle0:
+    mov     x2, x1              ;[6] Set x2 to current line state
+    ldi     bitcnt, 6           ;[7] reset unstuff counter. 
+    lsr     shift               ;[8] shift "0" into the data
+    brcs    bit7                ;[9] When after shift C is set, next bit is bit7
+    nop                         ;[10]
+    rjmp    bitloop             ;[11] 
+    
+;----------------------------------------------------------------------------
+; End of receive loop. Now start handling EOP
+;----------------------------------------------------------------------------
+
+macro POP_STANDARD ; 14 cycles
+    pop     cnt
+    pop     x4
+    pop     x3
+    pop     x2
+    pop     x1
+    pop     shift
+    pop     bitcnt
+    endm
+macro POP_RETI     ; 7 cycles
+    pop     YH
+    pop     YL
+    out     SREG, YL
+    pop     YL
+    endm
+
+
+
+#include "asmcommon.inc"
+
+; USB spec says:
+; idle = J
+; J = (D+ = 0), (D- = 1)
+; K = (D+ = 1), (D- = 0)
+; Spec allows 7.5 bit times from EOP to SOP for replies
+; 7.5 bit times is 100 cycles. This implementation arrives a bit later at se0
+; then specified in the include file but there is plenty of time
+
+bitstuffN:
+    eor     x1, x4          ;[8]
+    ldi     x2, 0           ;[9]
+    nop2                    ;[10]
+    out     USBOUT, x1      ;[12] <-- out
+    rjmp    didStuffN       ;[0]
+    
+bitstuff7:
+    eor     x1, x4          ;[6]
+    ldi     x2, 0           ;[7] Carry is zero due to brcc
+    rol     shift           ;[8] compensate for ror shift at branch destination
+    nop2                    ;[9]
+    rjmp    didStuff7       ;[11]
+
+sendNakAndReti:
+    ldi     x3, USBPID_NAK  ;[-18]
+    rjmp    sendX3AndReti   ;[-17]
+sendAckAndReti:
+    ldi     cnt, USBPID_ACK ;[-17]
+sendCntAndReti:
+    mov     x3, cnt         ;[-16]
+sendX3AndReti:
+    ldi     YL, 20          ;[-15] x3==r20 address is 20
+    ldi     YH, 0           ;[-14]
+    ldi     cnt, 2          ;[-13]
+;   rjmp    usbSendAndReti      fallthrough
+
+;usbSend:
+;pointer to data in 'Y'
+;number of bytes in 'cnt' -- including sync byte [range 2 ... 12]
+;uses: x1...x4, btcnt, shift, cnt, Y
+;Numbers in brackets are time since first bit of sync pattern is sent
+;We don't match the transfer rate exactly (don't insert leap cycles every third
+;byte) because the spec demands only 1.5% precision anyway.
+usbSendAndReti:             ; 12 cycles until SOP
+    in      x2, USBDDR      ;[-12]
+    ori     x2, USBMASK     ;[-11]
+    sbi     USBOUT, USBMINUS;[-10] prepare idle state; D+ and D- must have been 0 (no pullups)
+    in      x1, USBOUT      ;[-8] port mirror for tx loop
+    out     USBDDR, x2      ;[-7] <- acquire bus
+; need not init x2 (bitstuff history) because sync starts with 0
+    ldi     x4, USBMASK     ;[-6] exor mask
+    ldi     shift, 0x80     ;[-5] sync byte is first byte sent
+txByteLoop:
+    ldi     bitcnt, 0x49    ;[-4]        [10] binary 01001001
+txBitLoop:
+    sbrs    shift, 0        ;[-3] [10]   [11]
+    eor     x1, x4          ;[-2] [11]   [12]
+    out     USBOUT, x1      ;[-1] [12]   [13]   <-- out N
+    ror     shift           ;[0]  [13]   [14]
+    ror     x2              ;[1]
+didStuffN:
+    nop2                    ;[2]
+    nop                     ;[4]
+    cpi     x2, 0xfc        ;[5]
+    brcc    bitstuffN       ;[6]
+    lsr     bitcnt          ;[7]
+    brcc    txBitLoop       ;[8]
+    brne    txBitLoop       ;[9]
+
+    sbrs    shift, 0        ;[10]
+    eor     x1, x4          ;[11]
+didStuff7:
+    out     USBOUT, x1      ;[-1] [13] <-- out 7
+    ror     shift           ;[0] [14]
+    ror     x2              ;[1]
+    nop                     ;[2]
+    cpi     x2, 0xfc        ;[3]
+    brcc    bitstuff7       ;[4]
+    ld      shift, y+       ;[5]
+    dec     cnt             ;[7]
+    brne    txByteLoop      ;[8]
+;make SE0:
+    cbr     x1, USBMASK     ;[9] prepare SE0 [spec says EOP may be 25 to 30 cycles]
+    lds     x2, usbNewDeviceAddr;[10]
+    lsl     x2              ;[12] we compare with left shifted address
+    out     USBOUT, x1      ;[13] <-- out SE0 -- from now 2 bits = 22 cycles until bus idle
+    subi    YL, 20 + 2      ;[0] Only assign address on data packets, not ACK/NAK in x3
+    sbci    YH, 0           ;[1]
+;2006-03-06: moved transfer of new address to usbDeviceAddr from C-Code to asm:
+;set address only after data packet was sent, not after handshake
+    breq    skipAddrAssign  ;[2]
+    sts     usbDeviceAddr, x2; if not skipped: SE0 is one cycle longer
+skipAddrAssign:
+;end of usbDeviceAddress transfer
+    ldi     x2, 1<<USB_INTR_PENDING_BIT;[4] int0 occurred during TX -- clear pending flag
+    USB_STORE_PENDING(x2)   ;[5]
+    ori     x1, USBIDLE     ;[6]
+    in      x2, USBDDR      ;[7]
+    cbr     x2, USBMASK     ;[8] set both pins to input
+    mov     x3, x1          ;[9]
+    cbr     x3, USBMASK     ;[10] configure no pullup on both pins
+    ldi     x4, 5           ;[11]
+se0Delay:
+    dec     x4              ;[12] [15] [18] [21] [24]
+    brne    se0Delay        ;[13] [16] [19] [22] [25]
+    out     USBOUT, x1      ;[26] <-- out J (idle) -- end of SE0 (EOP signal)
+    out     USBDDR, x2      ;[27] <-- release bus now
+    out     USBOUT, x3      ;[28] <-- ensure no pull-up resistors are active
+    rjmp    doReturn

usbportability.h

@@ -0,0 +1,140 @@
+/* Name: usbportability.h
+ * Project: V-USB, virtual USB port for Atmel's(r) AVR(r) microcontrollers
+ * Author: Christian Starkjohann
+ * Creation Date: 2008-06-17
+ * Tabsize: 4
+ * Copyright: (c) 2008 by OBJECTIVE DEVELOPMENT Software GmbH
+ * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
+ * This Revision: $Id: usbportability.h 740 2009-04-13 18:23:31Z cs $
+ */
+
+/*
+General Description:
+This header is intended to contain all (or at least most of) the compiler
+and library dependent stuff. The C code is written for avr-gcc and avr-libc.
+The API of other development environments is converted to gcc's and avr-libc's
+API by means of defines.
+
+This header also contains all system includes since they depend on the
+development environment.
+
+Thanks to Oleg Semyonov for his help with the IAR tools port!
+*/
+
+#ifndef __usbportability_h_INCLUDED__
+#define __usbportability_h_INCLUDED__
+
+/* We check explicitly for IAR and CodeVision. Default is avr-gcc/avr-libc. */
+
+/* ------------------------------------------------------------------------- */
+#if defined __IAR_SYSTEMS_ICC__ || defined __IAR_SYSTEMS_ASM__  /* check for IAR */
+/* ------------------------------------------------------------------------- */
+
+#ifndef ENABLE_BIT_DEFINITIONS
+#   define ENABLE_BIT_DEFINITIONS	1   /* Enable bit definitions */
+#endif
+
+/* Include IAR headers */
+#include <ioavr.h>
+#ifndef __IAR_SYSTEMS_ASM__
+#   include <inavr.h>
+#endif
+
+#define __attribute__(arg)  /* not supported on IAR */
+
+#ifdef __IAR_SYSTEMS_ASM__
+#   define __ASSEMBLER__    /* IAR does not define standard macro for asm */
+#endif
+
+#ifdef __HAS_ELPM__
+#   define PROGMEM __farflash
+#else
+#   define PROGMEM __flash
+#endif
+
+#define USB_READ_FLASH(addr)    (*(PROGMEM char *)(addr))
+
+/* The following definitions are not needed by the driver, but may be of some
+ * help if you port a gcc based project to IAR.
+ */
+#define cli()       __disable_interrupt()
+#define sei()       __enable_interrupt()
+#define wdt_reset() __watchdog_reset()
+#define _BV(x)      (1 << (x))
+
+/* assembler compatibility macros */
+#define nop2    rjmp    $+2 /* jump to next instruction */
+#define XL      r26
+#define XH      r27
+#define YL      r28
+#define YH      r29
+#define ZL      r30
+#define ZH      r31
+#define lo8(x)  LOW(x)
+#define hi8(x)  (((x)>>8) & 0xff)   /* not HIGH to allow XLINK to make a proper range check */
+
+/* Depending on the device you use, you may get problems with the way usbdrv.h
+ * handles the differences between devices. Since IAR does not use #defines
+ * for MCU registers, we can't check for the existence of a particular
+ * register with an #ifdef. If the autodetection mechanism fails, include
+ * definitions for the required USB_INTR_* macros in your usbconfig.h. See
+ * usbconfig-prototype.h and usbdrv.h for details.
+ */
+
+/* ------------------------------------------------------------------------- */
+#elif __CODEVISIONAVR__ /* check for CodeVision AVR */
+/* ------------------------------------------------------------------------- */
+/* This port is not working (yet) */
+
+/* #define F_CPU   _MCU_CLOCK_FREQUENCY_    seems to be defined automatically */
+
+#include <io.h>
+#include <delay.h>
+
+#define __attribute__(arg)  /* not supported on IAR */
+
+#define PROGMEM                 __flash
+#define USB_READ_FLASH(addr)    (*(PROGMEM char *)(addr))
+
+#ifndef __ASSEMBLER__
+static inline void  cli(void)
+{
+    #asm("cli");
+}
+static inline void  sei(void)
+{
+    #asm("sei");
+}
+#endif
+#define _delay_ms(t)    delay_ms(t)
+#define _BV(x)          (1 << (x))
+#define USB_CFG_USE_SWITCH_STATEMENT 1  /* macro for if() cascase fails for unknown reason */
+
+#define macro   .macro
+#define endm    .endmacro
+#define nop2    rjmp    .+0 /* jump to next instruction */
+
+/* ------------------------------------------------------------------------- */
+#else   /* default development environment is avr-gcc/avr-libc */
+/* ------------------------------------------------------------------------- */
+
+#include <avr/io.h>
+#ifdef __ASSEMBLER__
+#   define _VECTOR(N)   __vector_ ## N   /* io.h does not define this for asm */
+#else
+#   include <avr/pgmspace.h>
+#endif
+
+#define USB_READ_FLASH(addr)    pgm_read_byte(addr)
+
+#define macro   .macro
+#define endm    .endm
+#define nop2    rjmp    .+0 /* jump to next instruction */
+
+#endif  /* development environment */
+
+/* for conveniecne, ensure that PRG_RDB exists */
+#ifndef PRG_RDB
+#   define PRG_RDB(addr)    USB_READ_FLASH(addr)
+#endif
+#endif  /* __usbportability_h_INCLUDED__ */