Linux下串口协议控制51单片机(2)

void write_port(void)
{
    int nwrite,i;
    for (i=0;i<14;i++)
    {
        nwrite = write(fd,&ptr[i],2);
        usleep(200000);/*每200ms秒发一次数据*/
    }   
}

void read_port(void)
{   
    fd_set rd;
    int nread,retval;
    unsigned char msg[14];
    struct timeval timeout;
    FD_ZERO(&rd);
    FD_SET(fd,&rd);
    timeout.tv_sec = 1;
    timeout.tv_usec = 0;
    retval = select (fd+1,&rd,NULL,NULL,&timeout);/*select 实现i/o复用*/
    switch (retval)
    {
        case 0:
            printf("no data input within  1 seconds.\n");
            break;
        case -1:
            perror("select");
            break;       
        default:
            if((nread=read(fd,msg,14))>0)
            {
                printf("nread=%d,msg=%s\n",nread,msg);
            }
            break;
    }
}

void *recv_thread(void )
{
    pthread_mutex_lock(&mutex);
    read_port();
    pthread_mutex_unlock(&mutex);
    pthread_exit(NULL);
}

void *send_thread(void )
{
    pthread_mutex_lock(&mutex);
    write_port();
    pthread_mutex_unlock(&mutex);
    pthread_exit(NULL);
}

void create_thread(void )
{
    int temp;
    memset(thread, 0, sizeof(thread));
    if((temp = pthread_create(&thread[0], NULL,(void *)send_thread, NULL)) != 0)
        printf("create send_thread failed!\n");        
    if((temp = pthread_create(&thread[1], NULL,(void *)recv_thread, NULL)) != 0)
        printf("create recev_thread failed!\n");
       
}

void wait_thread(void )
{
    if(thread[0] !=0)
    {
        pthread_join(thread[0],NULL);
        printf("send_thread end\n");
    }
    if(thread[1] !=0)
    {
        pthread_join(thread[1],NULL);
        printf("recev_thread end\n");
    }
}

int  main(void )
{   
    int i;
    if((fd=open_port(fd,1))<0){
        perror("open_port error");
    }
    if((i=set_port(fd,9600,8,'N',1))<0){
        perror("set_opt error");
    }
    /*用默认属性初始化互斥锁*/
    pthread_mutex_init(&mutex,NULL);
    int num = 100;
    while (num)
    {
        create_thread();
        wait_thread();
        num--;
    }
    pthread_mutex_destroy(&mutex);
    close(fd);
    return 0;
}