code.c

linux环境下的读串口测试程序的简单代码

#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*/

/*
*@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,
                    B38400, B19200, B9600, B4800, B2400, B1200, B300, };

int name_arr[] = {38400,  19200,  9600,  4800,  2400,  1200,  300,
                  38400,  19200,  9600, 4800, 2400, 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]);
			cfsetospeed(&Opt, speed_arr[i]);
			status = tcsetattr(fd, TCSANOW, &Opt);
			if  (status != 0)
				perror("tcsetattr fd1");
			return;
		}
		tcflush(fd,TCIOFLUSH);
	}
}

/*
*@brief   设置串口数据位，停止位和效验位
*@param  fd         int  打开的串口文件句柄*
*@param  databits   int  数据位   取值 为 7 或者8*
*@param  stopbits   int  停止位   取值为 1 或者2*
*@param  parity     int  效验类型 取值为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;

    /*设置数据位数*/
	switch (databits) 
	{
	case 7:
		options.c_cflag |= CS7;
		break;
	case 8:
		options.c_cflag |= CS8;
		break;
	default:
		fprintf(stderr,"Unsupported data size\n");
		return (FALSE);
	}

	/*设置校验位*/
	switch (parity)
	{
	case 'n':
	case 'N':
		options.c_cflag &= ~PARENB;   /* Clear parity enable */
		options.c_iflag &= ~INPCK;     /* Enable parity checking */
		break;
	case 'o':
	case 'O':
		options.c_cflag |= (PARODD | PARENB);  /* 设置为奇效验*/ 
		options.c_iflag |= INPCK;             /* Disnable parity checking */
		break;
	case 'e':
	case 'E':
		options.c_cflag |= PARENB;     /* Enable parity */
		options.c_cflag &= ~PARODD;   /* 转换为偶效验*/  
		options.c_iflag |= INPCK;       /* Disnable parity checking */
		break;
	case 'S':
	case 's':  /*as no parity*/
		options.c_cflag &= ~PARENB;
		options.c_cflag &= ~CSTOPB;
		break;
	default:
		fprintf(stderr,"Unsupported parity\n");
		return (FALSE);
	}

	/* 设置停止位*/   
	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 打开串口
*/
int OpenDev(char *Dev)
{
	int	fd = open( Dev, O_RDWR );         //| O_NOCTTY | O_NDELAY
	if (-1 == fd)
	{
		perror("Can't Open Serial Port");
		return -1;
	}
	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);
}