How to read the command Get Moving Status

Support Servo controllers and servos
16

Okay, I think I have a linux solution for you. You need to put the terminal into “raw mode” using the tcsetattr() function so that it does not wait for a newline character before actually sending the bytes. Here is a complete program that works for me:

#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <termios.h>

int main()
{
  int fd = open("/dev/ttyACM0", O_RDWR | O_NOCTTY);
  char message[] = {161};
  unsigned char buf[2];
  struct termios options;

  if (fd == -1)
  {
    fprintf(stderr, "error opening");
    exit(1);
  }

  tcgetattr(fd, &options);
  options.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
  options.c_oflag &= ~(ONLCR | OCRNL);
  tcsetattr(fd, TCSANOW, &options);

  if(write(fd,message,4) == EOF)
  {
    fprintf(stderr, "error writing");
    exit(1);
  }

  int bytes_read = read(fd,buf,2);
  if(bytes_read != 2)
  {
    fprintf(stderr, "error reading: %d bytes read", bytes_read);
    exit(1);
  }

  printf("Received: 0x%02x 0x%02x\n",buf[0],buf[1]);

  exit(0);
}

As for your question - no, the device does not return a special final character. It does not even append a CRC when it is in CRC mode.

-Paul

Edit: c_oflag line added by David.