test.c

一个Linux串口通信小程序.使用时请注意修改MAKEFILE.

#include <stdio.h>		/*标准输入输出定义*/
#include <stdlib.h>		/*标准函数库定义*/
#include <unistd.h>		/*Unix标准函数定义*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>		/*文件控制定义*/
#include <termios.h>	/*PPSIX终端控制定义*/
#include <errno.h>      	/*错误号定义*/

#ifndef TRUE
#define TRUE 1
#endif

#ifndef FALSE
#define FALSE 0
#endif

/***@brief  设置串口通信速率
*@param  fd     类型 int  打开串口的文件句柄
*@param  speed  类型 int  串口速度
*@return  void*/

int speed_arr[] = {B38400,B19200,B9600,B4800,B2400,B1200,B300};
int bps_arr[]  = {38400,19200,9600,4800,2400,1200,300};

void setBps(int fd,int bps)
{
    int i;
    int status;
    struct termios opt;
    tcgetattr(fd,&opt);
    for(i=0;i<sizeof(speed_arr)/sizeof(int);i++)
    {
        if(bps==bps_arr[i])
   	{
            tcflush(fd,TCIOFLUSH);
            cfsetispeed(&opt,speed_arr[i]);
            cfsetospeed(&opt,speed_arr[i]);
            status = tcsetattr(fd,TCSANOW,&opt);
            if(status != 0)
            {
                perror("Set Serial Bps Error");
            }
            return;
        }
        tcflush(fd,TCIOFLUSH);
    }
}

/**
*@brief   设置串口数据位，停止位和效验位
*@param  fd     类型  int  打开的串口文件句柄*
*@param  databits 类型  int 数据位   取值 为 7 或者8*
*@param  stopbits 类型  int 停止位   取值为 1 或者2*
*@param  parity  类型  int  效验类型 取值为N,E,O,,S
*/
int setOption(int fd,int databits,int stopbits,int parity)
{
    struct termios opt;
    if(tcgetattr(fd,&opt) != 0)
    {
        perror("Get Serial Options Error");
        return(FALSE);
    }
    opt.c_cflag &= ~CSIZE;
    //set data bit length
    switch (databits) /*设置数据位数*/
    {
        case 7:
            opt.c_cflag |= CS7;
            break;
  	case 8:
            opt.c_cflag |= CS8;
            break;
	default:
            fprintf(stderr,"Unsupported data size!\n");
            return (FALSE);
    }
    //set parity bit mode
    switch (parity)
    {
        case 'n':
        case 'N':
            opt.c_cflag &= ~PARENB;		/* Clear parity enable */
            opt.c_iflag &= ~INPCK;			/* Disable parity checking */
            break;
        case 'o':
        case 'O':
            opt.c_cflag |= (PARODD|PARENB);	/* 设置为奇效验*/ 
            opt.c_iflag |= INPCK;			/* Enable parity checking */
            break;
        case 'e':
        case 'E':
            opt.c_cflag |= PARENB;     		/* Enable parity */
            opt.c_cflag &= ~PARODD;   		/* 转换为偶效验*/  
            opt.c_iflag |= INPCK;      		/* Enable parity checking */
            break;
        case 's':
        case 'S':  				/*as no parity*/
            opt.c_cflag &= ~PARENB;
            opt.c_cflag &= ~CSTOPB;
            break;
	default:
            fprintf(stderr,"Unsupported parity\n");
            return (FALSE);
    }
    //set stop bit length
    switch (stopbits)
    {
        case 1:
            opt.c_cflag &= ~CSTOPB;
            break;
	case 2:
            opt.c_cflag |= CSTOPB;
            break;
        default:
            fprintf(stderr,"Unsupported stop bits\n");
        return (FALSE);
    }
    //set input parity option
    //if (parity != 'n')
    //{
        //opt.c_iflag |= INPCK;
    //}

    opt.c_lflag &= ~(ECHO|ECHOE|ISIG);	//~(ICANON|ECHO|ECHOE|ISIG);
    opt.c_oflag &= ~OPOST;

    opt.c_cc[VTIME] = 150; // 15 seconds
    opt.c_cc[VMIN] = 0;

    tcflush(fd,TCIFLUSH);			//Update the options and do it NOW
    if (tcsetattr(fd,TCSANOW,&opt) != 0)
    {
        perror("Set Serial Options Error");
        return (FALSE);
    }
    return (TRUE);
}

/**
*@breif 打开串口
*/
int devOpen(char *dev)
{
    int fd = open(dev,O_RDWR);         //|O_NOCTTY|O_NDELAY
    if(fd==-1)
    { 
        perror("Can't Open Serial Port");
    }
    return fd;
}

/**
*@breif 	main()
*/
int main(int argc, char **argv)
{
    int fd;
    int bufsize = 512;
    int rxlen;
    char rxbuf[bufsize];
    char * dev ="/dev/ttyS1";
    fd = devOpen(dev);
    printf("please enter any data to the ttyS1, Enter key to confirm\n");
    if(fd>0)
    {
        setBps(fd,19200);
    }
    else
    {
        printf("Can't Open Serial Port!\n");
        exit(0);
    }
    if(setOption(fd,8,1,'N')==FALSE)
    {
        printf("Set Option Error\n");
        exit(1);
    }
    write(fd,"READY!\n",7);
    while(1)
    {
        rxlen = 0;
        rxlen = read(fd,rxbuf,512);
        if(rxlen>0)
        {
            if(rxbuf[0]=='#')
            {
                break;
            }
            //write(fd,"RE:",3);
            rxbuf[rxlen]='\0';
            write(fd,rxbuf,rxlen);
            //write(fd,"\n",1);
            printf("%s",rxbuf);
        }
    }
    close(fd);
    exit(0);
}