[ts-7000] Re: RS232 Questions/Problems

["JD" <>]

I have a simple example, using non blocking read that works _most_ of the time.

It will start reading ok and print out the number of characters read when a stream of data is applied, but after maybe 10 seconds, it stops reading anything (read returns 0) even though data is being sent.

Any ideas on why it would stop?

Code:
#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <string.h>

#include <unistd.h>

#include <termios.h>

#include <sys/ioctl.h>

#include <stdio.h>

#include <stdlib.h>
#include <inttypes.h>


void termConfigRaw(int fd,struct termios *saved,int baud_Enum);

/*------------------------------------------------------------*/
int UART_init(uint8_t port, uint32_t baudrate)
{
  int hCom = -1;
  struct termios oldtio;
  char buffer[100];

  sprintf(buffer,"/dev/ttyS%d", (port));

  printf("try open %d : '%s'\r\n", (int)port, buffer);

  hCom = open(buffer, O_RDWR | O_NOCTTY | O_NDELAY); 
  if (hCom == -1) 
  {
    fprintf(stderr,"OpenSerial: Couldnt open %s:", buffer);
    fflush(stderr);
    perror(NULL);
    return -1;
  }    
  termConfigRaw(hCom,&oldtio,baudrate);

//  fcntl(hCom, F_SETFL, FNDELAY);

  return hCom;
}

/*------------------------------------------------------------*/
void termConfigRaw(int fd,struct termios *saved,int baud_Enum) {
  struct termios newtio;
  int err;

  err = tcgetattr(fd,saved); /* save current port settings */
  printf("tcgetattr: %d\r\n", err);
  perror("tcgetattr:");

  /* Start with old settings, then we'll modify */
  newtio = *saved;

  /* Set baudrate */
  cfsetispeed(&newtio,baud_Enum);
  cfsetospeed(&newtio,baud_Enum);

  newtio.c_cflag |= CREAD;
  newtio.c_cflag &= ~CLOCAL;

  // 8N1

  newtio.c_cflag &= ~PARENB;
  newtio.c_cflag &= ~CSTOPB;
  newtio.c_cflag &= ~CSIZE;
  newtio.c_cflag |= CS8;        /* Set for 8 bits. */

  /* disable hardware flow control. */
  newtio.c_cflag &= ~CRTSCTS;

  /* When we read, we want completely raw access  */
  /* the last two get set by default on ARM but not CYGWIN */
  newtio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG | NOFLSH | TOSTOP);
  newtio.c_lflag = 0;  // We don't believe above signals are set correctly...

  /* ignore flow control, don't do CR/LF translations */
  newtio.c_iflag &= ~(IXON | IXOFF | IXANY | ICRNL | INLCR | IGNCR);

  /* Set output filtering to raw. */
  newtio.c_oflag &= ~(OPOST | ONLCR | OCRNL | ONLRET);

  /* Set readsize and timeout to some reasonable values, just to be safe*/
  newtio.c_cc[VTIME]    = 0;   /* inter-character timer unused */
  newtio.c_cc[VMIN]     = 0;   /* nonblocking read */

  tcflush(fd, TCIFLUSH);
  err = tcsetattr(fd,TCSANOW,&newtio);
  printf("tcsetattr: %d\r\n", err);
  perror("tcsetattr:");
}

int main()
{
  int f = UART_init(0,B57600);
  int ch;
  int len;
  char buff[256];

  if(f == -1)
   perror("No UART!:");
  else
  {
    while(1)
    {
        len = read(f, buff,sizeof(buff));

        if(len != 0) printf("%d\r\n", len);
    }
  }

  return 0;
}


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