if (argc == 2) 
{
    rt_strncpy(uart_name, argv[1], RT_NAME_MAX);
}
else  
{
    rt_strncpy(uart_name, SAMPLE_UART_NAME , RT_NAME_MAX);
}
/* 查找系统中的串口设备*/
serial = rt_device_find(uart_name);
if (!serial) {
    rt_kprintf("find %s failed!\n", uart_name);
    return RT_ERROR;
}
rt_kprintf("==========  test  =========== \n");
rt_sem_init(&rx_sem, "rx_sem", 0, RT_IPC_FLAG_FIFO);
/* 以中断接收及轮询发送模式打开串口设备*/
rt_device_open(serial, RT_DEVICE_FLAG_INT_RX);
// rt_device_open(serial, RT_DEVICE_FLAG_INT_TX);
/* 设置接收回调函数*/
ret = rt_device_set_rx_indicate(serial, uart_input);
if(ret != RT_EOK){
    rt_kprintf("rx_indicate failed !!");
}
/* 设置配置参数 */
config.baud_rate = BAUD_RATE_115200;
config.data_bits = DATA_BITS_8;
config.stop_bits = STOP_BITS_1;
config.parity = PARITY_NONE;
config.bufsz = 2048;        /*can not change buffer size, must be 2048*/
/* 打开设备后才可修改串口配置参数 */
rt_device_control(serial, RT_DEVICE_CTRL_CONFIG, &config);
rt_device_write(serial, 0, str, (sizeof(str) - 1));
rt_thread_t thread = rt_thread_create("serial", serial_thread_entry , RT_NULL,1024, 25, 10);
if (thread != RT_NULL) {
    rt_thread_startup(thread);
}
else {
    ret = RT_ERROR;
}
return ret;