serial_test.ino

/*
 * Serial echo for verifying communication with a PC based program
 * On Galileo or Edison this can talk to a process on the host
 * if you setup socat to create some devices.
 */

#if defined(__ARDUINO_X86__)
  //Galileo or Edison, setup ring buffer and TTYUARTClass
  RingBuffer rx_buffer_S1;
  TTYUARTClass mySerial(&rx_buffer_S1, 3, false); 
#elif
  //all other configuration use the first serial UART
  #define mySerial Serial
#endif

void setup() {
#if defined(__ARDUINO_X86__)
  //for Galileo or Edison specify the host TTY to connect to
  mySerial.init_tty("/root/tty0");
#endif
  //now the mySerial instance can be treated just like any Serial instance
  mySerial.begin(115200);
}

void loop()
{
  mySerial.write("A");
  if(mySerial.available()) {
    char in = mySerial.read();
    if(in == 'A') {
      mySerial.write("$");
    } else {
      mySerial.write("!");
    }
  }
}