linux 串口接收

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h> //文件控制定义
#include <termios.h>//终端控制定义
#include <errno.h>

char *comport;
int bRate = 0;

int serial_fd = 0;

//打开串口并初始化设置
int init_serial(void)
{
    serial_fd = open(comport, O_RDWR | O_NOCTTY | O_NDELAY);
    if (serial_fd < 0) {
        perror("open");
        return -1;
    }
    else
        printf("open %s success! 
", comport);

    //串口主要设置结构体termios <termios.h>
    struct termios options;

    /**1. tcgetattr函数用于获取与终端相关的参数。
    *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
    */
    tcgetattr(serial_fd, &options);
    /**2. 修改所获得的参数*/
    options.c_cflag |= (CLOCAL | CREAD);//设置控制模式状态，本地连接，接收使能
    options.c_cflag &= ~CSIZE;//字符长度，设置数据位之前一定要屏掉这个位
    options.c_cflag &= ~CRTSCTS;//无硬件流控
    options.c_cflag |= CS8;//8位数据长度
    options.c_cflag &= ~CSTOPB;//1位停止位
    options.c_iflag |= IGNPAR;//无奇偶检验位
    options.c_oflag = 0; //输出模式
    options.c_lflag = 0; //不激活终端模式

    switch(bRate)
    {
    case 9600:cfsetospeed(&options, B9600);break;//设置波特率
    case 115200:cfsetospeed(&options, B115200);break;//设置波特率
    }

    /**3. 设置新属性，TCSANOW：所有改变立即生效*/
    tcflush(serial_fd, TCIFLUSH);//溢出数据可以接收，但不读
    tcsetattr(serial_fd, TCSANOW, &options);

    return 0;
}

void uart_recv(int fd)
{
    char data[1024];
    int len=0, ret = 0;
    fd_set fs_read;
    struct timeval tv_timeout;

    FD_ZERO(&fs_read);
    FD_SET(fd, &fs_read);
    tv_timeout.tv_sec  = 6000;//(10*20/115200+2);
    tv_timeout.tv_usec = 0;

    while (1)
    {
        ret = select(fd+1, &fs_read, NULL, NULL, &tv_timeout);
        //printf("ret = %d
", ret);
        if (FD_ISSET(fd, &fs_read)) {
            len = read(fd, data, sizeof(data));
            printf("len: %d(bytes) recv: %s
", len, data);
        } else {
            perror("select");
        }
    }
}

int main(int argc, char **argv)
{
    comport = (char *)malloc(1024);
    memset(comport, '', sizeof(comport));
    if (argc == 1)
    {
        comport = "/dev/ttyS6";
        bRate = 9600;
    }
    else if (argc == 3)
    {
        switch(atoi(argv[1]))
        {
        case 0:comport = "/dev/ttyS0";break;
        case 1:comport = "/dev/ttyS1";break;
        case 2:comport = "/dev/ttyS2";break;
        case 3:comport = "/dev/ttyS3";break;
        case 4:comport = "/dev/ttyS4";break;
        case 5:comport = "/dev/ttyS5";break;
        case 6:comport = "/dev/ttyS6";break;
        default: printf("argv[0](com port id) should be 0 to 6 !
");exit(0);
        }
        switch(atoi(argv[2]))
        {
        case 9600: bRate = 9600; break;
        case 115200: bRate = 115200; break;
        default: printf("argv[1](bRate) should be 9600 or 115200 !
");exit(0);
        }
    }
    else{
        printf("parameter count error!
");
        return 0;
    }

    init_serial();
    printf("current BaudRate is %d
", bRate);
    //uart_send(serial_fd, buf, sizeof(buf));
    uart_recv(serial_fd);
    free(comport);
    close(serial_fd);
    return 0;
}