串口编程--C语言串口读取数据

逃离我推掉我的手 2022-12-25 13:50 187阅读 0赞

### 串口编程 ###

*  1、通讯流程
 *  2、demo

# 1、通讯流程 #

①、打开串口  
②、设置波特率  
③、设置奇偶校验位、停止位、数据位等  
④、读写数据  
⑤、关闭串口

# 2、demo #

本示例串口文件根据自己实际情况打开，方可读写成功，需要注意

#include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <unistd.h>
    #include <sys/types.h> 
    #include <sys/stat.h> 
    #include <fcntl.h>
    #include <termios.h> 
    #include <errno.h>
    #include <curses.h>
    
    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, };
    
    // fd is the open tty ;speed is the rate
    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]);
        	status = tcsetattr(fd, TCSANOW, &Opt);
        	if  (status != 0)
                perror("tcsetattr fd1");
         	return;
        }
        tcflush(fd,TCIOFLUSH);
      }
    }
    
    //set data bit , stop bit and checksum bit 
    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)
      	{ 
      		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); //set as odd check 
    			options.c_iflag |= INPCK;             		//Disnable parity check
    			break;
    		case 'e':
    		case 'E':
    			options.c_cflag |= PARENB;    		//Enable parity 
    			options.c_cflag &= ~PARODD; 
    			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);
    		}
    
     	 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);
     }
    int main(int argc, char **argv)
    { 
    	int fd;
    	int nread;
    	char *ptr=argv[2];
    	char *dev =argv[1]; //根据自己的实际串口打开相应的串口
    	if(argc<3)
    	{ 
    		printf("pls usage %s /dev/ttyS[n] your_message.\n",argv[1]);
    		exit(EXIT_FAILURE);
    	}
    	/*打开串口*/
    	if((fd=open(dev,O_RDWR))==-1)
    	{ 
    		perror("open");
    		exit(EXIT_FAILURE);
    	}  
    	/*设置波特率*/  
    	set_speed(fd,19200);
    	/*设置奇偶校验位、数据位、停止位*/
      	if (set_Parity(fd,8,1,'N')== FALSE)
      	{ 
        		printf("Set Parity Error\n");
        		exit(EXIT_FAILURE);
      	}
      	/*向串口写入数据*/
    	if(write(fd,ptr,strlen(ptr))<0)
    	{ 
    		perror("write");
    		exit(EXIT_FAILURE);
    	}
    	printf("pls check the tty data\n");
    	/*关闭串口*/
        close(fd);
        exit(EXIT_SUCCESS);
    }