ex_RS485Receive.nxc

This is an example of how to use the RS485Control, RS485DataAvailable, RS485Disable, RS485Initialize, RS485Enable, UseRS485, RS485Uart, RS485Status, RS485Read, RS485ReadEx, TextOut, and Wait functions.

// RS-485 receiver program
inline void WaitForMessageToBeSent()
{
  while(RS485SendingData())
    Wait(MS_1);
}

task main()
{
  byte mlen;
  string buffer;
  // configure the S4 port as RS485
  UseRS485(); 
  // make sure the RS485 system is turned on
  RS485Enable(); 
//  // initialize the UART to default values
//  RS485Initialize();
  // configure the UART (this is equivalent to RS485Initialize)
  RS485Uart(HS_BAUD_DEFAULT, HS_MODE_DEFAULT);

  Wait(MS_1); // make sure everything is turned on
  byte ACK[] = {1};
  while (true) {
    // wait for a message to arrive.

    // read the number of bytes message
    until(RS485DataAvailable() >= 5);

    // read the number of bytes
    RS485Read(buffer);
    long cnt = 0;
    UnflattenVar(buffer, cnt);

    // send out ACK
    RS485Write(ACK);
    WaitForMessageToBeSent();

    // now wait for the real message
    until(RS485DataAvailable() >= cnt);

    // now read the actual message
    RS485ReadEx(buffer, cnt);
//    RS485Read(buffer);

    // send out ACK
    RS485Write(ACK);
    WaitForMessageToBeSent();

    // display message
    TextOut(0, LCD_LINE1, buffer);
  }
}