示例#1
0
uint8_t
modbus_rxstart(uint8_t *data, uint8_t len, int16_t *recv_len) {
#ifdef MODBUS_CLIENT_SUPPORT
  if (data[0] == MODBUS_ADDRESS || data[0] == MODBUS_BROADCAST) {
    modbus_client_process(data, len, recv_len);
    if (data[0] == MODBUS_ADDRESS)
      return 1;
  }
#endif
  if (modbus_data.crc_len != 0) return 0; /* There is an packet on the way */

  /* enable the transmitter */
  PIN_SET(MODBUS_TX);

  modbus_recv_len_ptr = recv_len;

  modbus_data.crc = modbus_crc_calc(data, len);
  modbus_data.crc_len = 2;

  modbus_data.data = data;
  modbus_data.len = len;

  /* Enable the tx interrupt and send the first character */
  modbus_data.sent = 1;
  usart(UCSR,B) |= _BV(usart(TXCIE));
  usart(UDR) = data[0];

  return 1;
}
示例#2
0
void
modbus_periodic(void)
{
  if (modbus_recv_timer == 0) return;
  modbus_recv_timer--;

  if (!modbus_recv_len_ptr) {
#ifdef MODBUS_CLIENT_SUPPORT
    if (modbus_recv_timer == 0) {
      /* check the crc */
      uint16_t crc = modbus_crc_calc(modbus_client_state.data, modbus_client_state.len - 2);
      uint16_t crc_recv =
        ((modbus_client_state.data[modbus_client_state.len - 1])  << 8)
        | modbus_client_state.data[modbus_client_state.len - 2];
      if (crc != crc_recv) {
        modbus_client_state.len = 0;
        return;
      }
      /* See if we are the receiver */
      if (!(modbus_client_state.data[0] == MODBUS_ADDRESS
          || modbus_client_state.data[0] == MODBUS_BROADCAST))
        return;
      modbus_client_state.len -= 2;
      /* A message for our own modbus stack */
      int16_t recv_len;
      modbus_client_process(modbus_client_state.data, modbus_client_state.len,
                            &recv_len);
      if (recv_len) {
        PIN_SET(MODBUS_TX);
        modbus_data.data = modbus_client_state.data;
        modbus_data.len = recv_len; 

        /* Enable the tx interrupt and send the first character */
        modbus_data.sent = 1;
        usart(UCSR,B) |= _BV(usart(TXCIE));
        usart(UDR) = modbus_client_state.data[0];
      }
      modbus_client_state.len = 0;
    }
#endif
    return;
  }
  if (modbus_recv_timer != 0) return;
  *modbus_recv_len_ptr = modbus_data.len;

  if (*modbus_recv_len_ptr < 2)
      *modbus_recv_len_ptr = -1;

  if (modbus_data.data[0] != modbus_last_address) {
      *modbus_recv_len_ptr = -1;
  }
  modbus_recv_len_ptr = NULL;
}