[Serial port of Embedded Development Technology] serial port Host Program in Linux

Author: gnuhpc
Source: http://www.cnblogs.com/gnuhpc/

# Include <stdio. h>/* standard input/output definition */# include <stdlib. h>/* standard function library definition */# include <unistd. h>/* UNIX standard function definition */# include <sys/types. h>/**/# include <sys/STAT. h>/**/# include <fcntl. h>/* file control definition */# include <termios. h>/* ppsix terminal control definition */# include <errno. h>/* Error Code definition * // *** @ brief sets the serial communication rate * @ Param FD type int opens the serial port file handle * @ Param Speed Type int serial port speed *@ return void */INT speed_arr [] = {b38400, b19200, b9600, b4800, b2400, b1200, b300, b38 400, b19200, b9600, b4800, b2400, b1200, b300,}; int name_arr [] = {38400,192 00, 9600,480 0, 2400,120 0, 300,384 00, 19200,960 0, 4800,240 0, 0, 1200,300 ,}; void set_speed (int fd, int speed) {int I; int status; struct termios OPT; tcgetattr (FD, & OPT); for (I = 0; I <sizeof (speed_arr)/sizeof (INT); I ++) {If (speed = name_arr [I]) {tcflush (FD, tcioflush); cfsetispeed (& OPT, speed_arr [I]); cfsetospe Ed (& OPT, speed_arr [I]); status = tcsetattr (FD, tcsanow, & OPT); If (status! = 0) perror ("tcsetattr fd1"); return;} tcflush (FD, tcioflush) ;}/ *** @ brief sets the serial data bit, stop bits and check bits * @ Param FD type int open serial port file handle ** @ Param databits type int data bits value is 7 or 8 ** @ Param stopbits type int Stop bits value is 1 or 2 ** @ Param parity type int verification type value: N, e, O, S */INT set_parity (int fd, int databits, int stopbits, int parity) {struct termios options; If (tcgetattr (FD, & options )! = 0) {perror ("setupserial 1"); Return (false);} options. c_cflag & = ~ Csize; Switch (databits)/* set the number of digits */{Case 7: options. c_cflag | = cs7; break; case 8: options. c_cflag | = cs8; break; default: fprintf (stderr, "unsupported data size/N"); Return (false);} switch (parity) {Case 'N ': case 'N': options. c_cflag & = ~ Parenb;/* clear parity enable */options. c_iflag & = ~ Inpck;/* enable parity checking */break; Case 'O': options. c_cflag | = (parodd | parenb);/* set it to an odd test */options. c_iflag | = inpck;/* disnable parity checking */break; Case 'E': options. c_cflag | = parenb;/* enable parity */options. c_cflag & = ~ Parodd;/* convert to an even test */options. c_iflag | = inpck;/* disnable parity checking */break; Case's ':/* as no parity */options. c_cflag & = ~ Parenb; options. c_cflag & = ~ Cstopb; break; default: fprintf (stderr, "unsupported parity/N"); Return (false) ;}/ * set the stop bit */switch (stopbits) {Case 1: options. c_cflag & = ~ Cstopb; break; Case 2: options. c_cflag | = cstopb; break; default: fprintf (stderr, "unsupported Stop bits/N"); Return (false);}/* set input parity option */If (parity! = 'N') options. c_iflag | = inpck; options. c_cc [vtime] = 150; // 15 seconds options. c_cc [Vmin] = 0; tcflush (FD, tciflush);/* update the options and do it now */If (tcsetattr (FD, tcsanow, & options )! = 0) {perror ("setupserial 3"); Return (false);} return (true );} /*** @ breif open the serial port */INT opendev (char * Dev) {int FD = open (Dev, o_rdwr ); // | o_noctty | o_ndelay if (-1 = FD) {/* set the number of data digits */perror ("can't open serial port"); Return-1 ;} else return FD;}/*** @ breif main () */INT main (INT argc, char ** argv) {int FD; int nread; char buff [512]; char * Dev = "/dev/ttys1"; FD = opendev (Dev); If (FD> 0) set_speed (FD, 19200); else {printf ("can't open serial port! /N "); exit (0);} If (set_parity (FD, 8, 1, 'n') = false) {printf (" set parity error/N "); exit (1);} while (1) {While (nread = read (FD, buff, 512)> 0) {printf ("/nlen % d/N ", nread); buff [nread + 1] = '/0'; printf ("/n % s", buff) ;}// close (FD ); // exit (0 );}