serial.c

linux 串口的配置,波特率,数据位,校验位,停止位,等等,以及串口的接收程序

#include     <stdio.h>      /*标准输入输出定义*/
#include     <stdlib.h>     /*标准函数库定义*/
#include     <termios.h>    /*PPSIX 终端控制定义*/
#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     <errno.h>      /*错误号定义*/

#define FALSE  -1
#define TRUE   0
#define NCC 19 

struct termio
{	unsigned short  c_iflag;		/* 输入模式标志 */	
	unsigned short  c_oflag;		/* 输出模式标志 */	
	unsigned short  c_cflag;		/* 控制模式标志*/	
	unsigned short  c_lflag;		/* local mode flags */	
	unsigned char  	c_line;		  /* line discipline */	
	unsigned char  	c_cc[NCC];  /* control characters */
};

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, };



/**
*@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
*/

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     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 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) /*设置数据位数*/
	{   
	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':   
	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; 
tcflush(fd,TCIFLUSH);
options.c_cc[VTIME] = 150; /* 设置超时15 seconds*/   
options.c_cc[VMIN] = 0; /* Update the options and do it NOW */
if (tcsetattr(fd,TCSANOW,&options) != 0)   
{ 
	perror("SetupSerial 3");   
	return (FALSE);  
} 
return (TRUE);  
}



int OpenDev(char *Dev)
{
	int	fd = open( Dev, O_RDWR );         //| O_NOCTTY | O_NDELAY	
	if (-1 == fd)	
	{ 			
		perror("Can't Open Serial Port\r\n");
		return -1;		
	}	
	else	
	{
		printf("already open com port!!\r\n");
	}
		return fd;
}


int main(int argc, char **argv)
{
	int fd;
	int nread;
	char buff[512];
	char *dev  = "/dev/ttyS0";
	
	printf("hello!!\r\n");
	fd = OpenDev(dev);
	printf("Open --> /dev/ttyS0\r\n");
	set_speed(fd,19200);
	if (set_Parity(fd,8,1,'N') == FALSE)  {
		printf("Set Parity Error\n");
		exit (0);
	}
	while (1) //循环读取数据
	{   
		while((nread = read(fd, buff, 512))>0)
		{ 
			printf("\nLen %d\n",nread); 
			buff[nread+1] = '\0';   
			printf( "\n%s", buff);   
		}
	}
	//close(fd);  
	// exit (0);
}