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 }