RT-Thread 串口透传问题

发布于 2017-09-26 14:47:28 浏览：5645 订阅该版

我在用uart2读取数据然后发送到uart3 的时候遇到一个问题：
uart2 读取数据函数 rt_device_read（）返回值是0；
用rt_get_errno();函数读取当前线程错误码返回值也是0，

证明rt_device_read（）函数是成功执行了，也就是没有读取到数据，可是上面的消息队列已经成功过了阻塞状态，
也就是说是有接收中断产生了。好矛盾。

```#include "r_uart2_w_uart3.h"

#include <string.h>
#include <rtthread.h>

static rt_mq_t rx_mq_uart2;
static char msg_pool_uart2[512];
static rx_struct rx2_data;

static struct rt_messagequeue s_your_mq;

rt_err_t uart2_input(rt_device_t dev, rt_size_t size)
{
   static rx_msg_t msg;
    rt_err_t result;
    msg.dev = dev;
    msg.size = size;
    
  
   result = rt_mq_send(rx_mq_uart2, &msg, sizeof(rx_msg_t)); 
   if(result == -RT_EFULL){
		rt_kprintf("msg queue2 is full!
");
		return RT_EFULL;
	}
    return RT_EOK;
}
/**
 * uart3_thread_entry.
 *
 * @param 
 * 
 *
 * @return 
 * @note 
 */
void uart2_thread_entry(void* parameter)
{
	rt_device_t device_uart2, device_uart3;
	static rx_msg_t rx_msg;
	rt_err_t result = RT_EOK;
	rt_err_t myerrno;

device_uart2 = rt_device_find("uart2");
    if(device_uart2 != RT_NULL)
    {
        rt_kprintf("thread1 open uart2 ok
");
     
        rt_device_set_rx_indicate(device_uart2, uart2_input);
        rt_device_open(device_uart2, RT_DEVICE_OFLAG_RDWR|RT_DEVICE_FLAG_DMA_RX);
    }
	rt_mq_init(&s_your_mq,"mq_uart2",&msg_pool_uart2[0],sizeof(rx_msg_t),sizeof(msg_pool_uart2),RT_IPC_FLAG_FIFO);
	rx_mq_uart2 = &s_your_mq;
	
	device_uart3 = rt_device_find("uart3");
	if(device_uart3 != RT_NULL)
	{
		
		rt_device_open(device_uart3, RT_DEVICE_OFLAG_RDWR);
		rt_kprintf("thread1 open uart3 ok
");
	}
	while(1)
	{
		result = rt_mq_recv(rx_mq_uart2, &rx_msg, sizeof(rx_msg_t), RT_WAITING_FOREVER);/*????2??????????·??ò×è????*/
		if(result == RT_EOK)
			rt_kprintf("mq_recv ok!
");
		if (result == RT_EOK) 
        { 
            rt_uint32_t rx_length; 
			/*??????2????????*/ 
			rx_length = rt_device_read(rx_msg.dev, 0, rx2_data.rx_buff, RX_BUFF_SIZE); 
			rx2_data.rx_buff[rx_length] = '�'; 
			if(rx_length == 0)
			{
				myerrno = rt_get_errno();
				rt_kprintf("--------errno: %d
", myerrno);
			}
			rt_kprintf("UART2 recive len: %d
", rx_length);
			/*????????????????????3*/
			if(device_uart3 != RT_NULL)
			{
				rt_device_write(device_uart3, 0, rx2_data.rx_buff, rx_length);
				rt_kprintf("UART2 -> UART3
");
			}
		} 
		rt_thread_delay(50);
	}
}```