RS485.hh

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#ifndef COSA_RS485_HH
#define COSA_RS485_HH

#if !defined(BOARD_ATTINY)
#include "Cosa/UART.hh"
#include "Cosa/IOBuffer.hh"
#include "Cosa/OutputPin.hh"

// Default buffer size
#ifndef COSA_RS485_BUFFER_MAX
# define COSA_RS485_BUFFER_MAX 64
#endif

class RS485 : public UART {
public:
  static const uint8_t SOT = 0x01;

  struct header_t {
    uint8_t length;             
    uint8_t dest;               
    uint8_t src;                
    uint8_t crc;                
  };

  static const uint8_t FRAME_MAX = sizeof(header_t) + sizeof(uint16_t) + 1;

  static const uint16_t BUFFER_MAX = COSA_RS485_BUFFER_MAX;

  static const uint8_t BROADCAST = 0;

  static const uint8_t MASTER = 255;

  RS485(uint8_t port, IOStream::Device* ibuf, IOStream::Device* obuf,
        uint16_t size, Board::DigitalPin de, uint8_t addr = MASTER) :
    UART(port, ibuf, obuf),
    PAYLOAD_MAX(size - FRAME_MAX),
    m_de(de),
    m_addr(addr),
    m_state(0)
  {}

  virtual int putchar(char c);

  void address(uint8_t addr = MASTER)
  {
    m_addr = addr;
  }

  int send(const void* buf, size_t len, uint8_t dest = MASTER);

  int broadcast(const void* buf, size_t len)
    __attribute__((always_inline))
  {
    return (send(buf, len, BROADCAST));
  }

  int recv(void* buf, size_t len, uint32_t ms = 0L);

protected:
  const uint16_t PAYLOAD_MAX;

  header_t m_header;

  OutputPin m_de;

  uint8_t m_addr;

  uint8_t m_state;

  virtual void on_udre_interrupt();

  virtual void on_tx_interrupt();

  virtual void on_transmit_completed()
  {
    m_de.clear();
  }
};
#endif
#endif