arduino-smartcard/SoftwareSerial8e1.h

//
// Created by robin on 2/24/17.
//

#ifndef ARDUINOSMARTCARD_SOFTWARESERIAL8E1_H
#define ARDUINOSMARTCARD_SOFTWARESERIAL8E1_H



#include <inttypes.h>
#include <Stream.h>

/******************************************************************************
* Definitions
******************************************************************************/

#ifndef _SS_MAX_RX_BUFF
#define _SS_MAX_RX_BUFF 64 // RX buffer size
#endif

#ifndef GCC_VERSION
#define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
#endif

class SoftwareSerial8e1 : public Stream
{
private:
    // per object data
    uint8_t _receivePin;
    uint8_t _receiveBitMask;
    volatile uint8_t *_receivePortRegister;
    uint8_t _transmitBitMask;
    volatile uint8_t *_transmitPortRegister;
    volatile uint8_t *_pcint_maskreg;
    uint8_t _pcint_maskvalue;

    // Expressed as 4-cycle delays (must never be 0!)
    uint16_t _rx_delay_centering;
    uint16_t _rx_delay_intrabit;
    uint16_t _rx_delay_stopbit;
    uint16_t _tx_delay;

    uint16_t _buffer_overflow:1;
    uint16_t _inverse_logic:1;

    // static data
    static uint8_t _receive_buffer[_SS_MAX_RX_BUFF];
    static volatile uint8_t _receive_buffer_tail;
    static volatile uint8_t _receive_buffer_head;
    static SoftwareSerial8e1 *active_object;

    // private methods
    inline void recv() __attribute__((__always_inline__));
    uint8_t rx_pin_read();
    void setTX(uint8_t transmitPin);
    void setRX(uint8_t receivePin);
    inline void setRxIntMsk(bool enable) __attribute__((__always_inline__));

    // Return num - sub, or 1 if the result would be < 1
    static uint16_t subtract_cap(uint16_t num, uint16_t sub);

    // private static method for timing
    static inline void tunedDelay(uint16_t delay);

public:
    // public methods
    SoftwareSerial8e1(uint8_t receivePin, uint8_t transmitPin, bool inverse_logic = false);
    ~SoftwareSerial8e1();
    void begin(long speed);
    bool listen();
    void end();
    bool isListening() { return this == active_object; }
    bool stopListening();
    bool overflow() { bool ret = _buffer_overflow; if (ret) _buffer_overflow = false; return ret; }
    int peek();

    virtual size_t write(uint8_t byte);
    virtual int read();
    virtual int available();
    virtual void flush();
    operator bool() { return true; }

    using Print::write;

    // public only for easy access by interrupt handlers
    static inline void handle_interrupt() __attribute__((__always_inline__));
};

// Arduino 0012 workaround
#undef int
#undef char
#undef long
#undef byte
#undef float
#undef abs
#undef round

#endif //ARDUINOSMARTCARD_SOFTWARESERIAL8E1_H