Click here to Skip to main content
15,885,366 members
Please Sign up or sign in to vote.
0.00/5 (No votes)
See more:
i want read and write data from serial port in Ubuntu
Download port Driver Form this side
https://www.silabs.com/products/mcu/Pages/USBtoUARTBridgeVCPDrivers.aspx

write Code in c


XML
#include <stdio.h>
#include <string.h>
#include <unistd.h> //UNIX Standard function definitions
#include <fcntl.h> //File control
#include <errno.h> //Error number def
#include <termios.h> //POSIX terminal control
#include <termio.h>

int open_port(){ //-1 is a error
  int port = open("/dev/ttyUSB0", O_RDWR | O_NOCTTY | O_NDELAY);
  /*O_RDWR POSIX read write
  O_NOCTTY: not a "controlling terminal"
  O_NDELAY": Ignore DCD signal state*/

  if(port == -1){
    perror("open_port: Unable to open /dev/ttyS0 - ");
  }else fcntl(port, F_SETFL, 0);
  return (port);
}

int set_port(int port){
  struct termios options;
  tcgetattr(port, &options);

  cfsetispeed(&options, B9600); //Typical way of setting baud rate. Actual baud rate are contained in the c_ispeed and c_ospeed members
  cfsetospeed(&options, B9600);
  options.c_cflag |= (CLOCAL|CREAD);

  options.c_cflag &= ~CSIZE;
  options.c_cflag &= ~CSTOPB;
  options.c_cflag &= ~PARENB;
  options.c_cflag |= CS8;     //No parity, 8bits, 1 stop bit (8N1)
  options.c_cflag &= ~CRTSCTS;//CNEW_RTSCTS; //Turn off flow control

  options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); //Make sure that Canonical input is off (raw input data)

  options.c_iflag &= ~(IXON | IXOFF | IXANY); //Turn off software control flow

  options.c_oflag &= ~OPOST; //Raw output data

  options.c_cc[VMIN] = 0;
  options.c_cc[VTIME] = 10;

  return tcsetattr (port, TCSANOW, &options); //Make changes now without waiting for data to complete.
}

int main(){
  int fd, n;
  unsigned char byte = 0x0F;
  unsigned char buff[255];
  int ready;

  fd = open_port();
  set_port(fd);
  //n = write(fd, &byte, 1);
  n = write(fd, ":010317D1000A0A\0", 16);
  if (n < 0) fputs("write() failed!\n", stderr);

  usleep(1000000); //Wait for 1 sec

  ioctl(fd, FIONREAD, &ready);
  printf("Bytes in input buffer: %d\n\n", ready);


  fcntl(fd, F_SETFL, FNDELAY); //Return read immidiatly
  n = read(fd, buff, 255);
  printf("Byte Read: %d\nByte received: %d %d %d\n\n", n, buff[0], buff[1], buff[2]);

  close(fd);
  return 0;
}




code is Note Working properly

Write data is ":010311B900010A"
Read data like that ="1021012001201020000012ADFF0000"

Thanx in advance
Posted
Comments
CPallini 1-Apr-15 8:42am    
What is expected as 'read data'? Have you a loopback?
Richard MacCutchan 1-Apr-15 9:49am    
What device is connected to the port?

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)



CodeProject, 20 Bay Street, 11th Floor Toronto, Ontario, Canada M5J 2N8 +1 (416) 849-8900