linux 串口接收

  1 #include <stdio.h>

  2 #include <stdlib.h>

  3 #include <unistd.h>

  4 #include <sys/types.h>

  5 #include <sys/stat.h>

  6 #include <fcntl.h> //文件控制定义

  7 #include <termios.h>//终端控制定义

  8 #include <errno.h>

  9 

 10 char *comport;

 11 int bRate = 0;

 12 

 13 int serial_fd = 0;

 14 

 15 //打开串口并初始化设置

 16 int init_serial(void)

 17 {

 18     serial_fd = open(comport, O_RDWR | O_NOCTTY | O_NDELAY);

 19     if (serial_fd < 0) {

 20         perror("open");

 21         return -1;

 22     }

 23     else

 24         printf("open %s success! \n", comport);

 25 

 26     //串口主要设置结构体termios <termios.h>

 27     struct termios options;

 28 

 29     /**1. tcgetattr函数用于获取与终端相关的参数。

 30     *参数fd为终端的文件描述符，返回的结果保存在termios结构体中

 31     */

 32     tcgetattr(serial_fd, &options);

 33     /**2. 修改所获得的参数*/

 34     options.c_cflag |= (CLOCAL | CREAD);//设置控制模式状态，本地连接，接收使能

 35     options.c_cflag &= ~CSIZE;//字符长度，设置数据位之前一定要屏掉这个位

 36     options.c_cflag &= ~CRTSCTS;//无硬件流控

 37     options.c_cflag |= CS8;//8位数据长度

 38     options.c_cflag &= ~CSTOPB;//1位停止位

 39     options.c_iflag |= IGNPAR;//无奇偶检验位

 40     options.c_oflag = 0; //输出模式

 41     options.c_lflag = 0; //不激活终端模式

 42 

 43     switch(bRate)

 44     {

 45     case 9600:cfsetospeed(&options, B9600);break;//设置波特率

 46     case 115200:cfsetospeed(&options, B115200);break;//设置波特率

 47     }

 48 

 49     /**3. 设置新属性，TCSANOW：所有改变立即生效*/

 50     tcflush(serial_fd, TCIFLUSH);//溢出数据可以接收，但不读

 51     tcsetattr(serial_fd, TCSANOW, &options);

 52 

 53     return 0;

 54 }

 55 

 56 void uart_recv(int fd)

 57 {

 58     char data[1024];

 59     int len=0, ret = 0;

 60     fd_set fs_read;

 61     struct timeval tv_timeout;

 62 

 63     FD_ZERO(&fs_read);

 64     FD_SET(fd, &fs_read);

 65     tv_timeout.tv_sec  = 6000;//(10*20/115200+2);

 66     tv_timeout.tv_usec = 0;

 67 

 68     while (1)

 69     {

 70         ret = select(fd+1, &fs_read, NULL, NULL, &tv_timeout);

 71         //printf("ret = %d\n", ret);

 72         if (FD_ISSET(fd, &fs_read)) {

 73             len = read(fd, data, sizeof(data));

 74             printf("len: %d(bytes) recv: %s\n", len, data);

 75         } else {

 76             perror("select");

 77         }

 78     }

 79 }

 80 

 81 int main(int argc, char **argv)

 82 {

 83     comport = (char *)malloc(1024);

 84     memset(comport, '\0', sizeof(comport));

 85     if (argc == 1)

 86     {

 87         comport = "/dev/ttyS6";

 88         bRate = 9600;

 89     }

 90     else if (argc == 3)

 91     {

 92         switch(atoi(argv[1]))

 93         {

 94         case 0:comport = "/dev/ttyS0";break;

 95         case 1:comport = "/dev/ttyS1";break;

 96         case 2:comport = "/dev/ttyS2";break;

 97         case 3:comport = "/dev/ttyS3";break;

 98         case 4:comport = "/dev/ttyS4";break;

 99         case 5:comport = "/dev/ttyS5";break;

100         case 6:comport = "/dev/ttyS6";break;

101         default: printf("argv[0](com port id) should be 0 to 6 !\n");exit(0);

102         }

103         switch(atoi(argv[2]))

104         {

105         case 9600: bRate = 9600; break;

106         case 115200: bRate = 115200; break;

107         default: printf("argv[1](bRate) should be 9600 or 115200 !\n");exit(0);

108         }

109     }

110     else{

111         printf("parameter count error!\n");

112         return 0;

113     }

114 

115     init_serial();

116     printf("current BaudRate is %d\n", bRate);

117     //uart_send(serial_fd, buf, sizeof(buf));

118     uart_recv(serial_fd);

119     free(comport);

120     close(serial_fd);

121     return 0;

122 }