使用RTT 的stm32F103bsp 串口数据丢失问题

发布于 2018-09-03 10:09:20 浏览：3576 订阅该版

RTT版本3.0.3正式版，使用官方的串口驱动框架，
串口发送接收代码参考 《编程手册-IO设备驱动》，
具体 如下：

1、串口接收发代码
```c
/********************************************
* Defines *
********************************************/
#define APPUART_FIFO_SIZE        1<<6
#define APPUART_SEND_INTERVAL    (RT_TICK_PER_SECOND*10)  //1S

#define BL_ATOI(c)              ((c>='A')?(c-'A'+10):((c>='a')?(c-'a'+10):(c-'0')))

/* uart events define */
#define APPUART_SEND_EVENT          (1<<0)
#define APPUART_RECV_EVENT          (1<<1)

#define APPUART_EVENTS              (APPUART_SEND_EVENT|APPUART_RECV_EVENT)

/********************************************
* Private typedef *
********************************************/
/* 设备控制块 */
static	rt_device_t uart_device = RT_NULL;

/* 线程控制块 */
static rt_thread_t appuart_thread;

/* 事件控制块 */
static struct rt_event appuart_event;

rt_size_t length = 0;
char inc;

/********************************************
* Private variables *
********************************************/

static char uart_rx_buf[APPUART_FIFO_SIZE];

/********************************************
* Private functions *
********************************************/
static rt_err_t app_uart_intput (rt_device_t dev, rt_size_t size);

static rt_err_t app_uart_set_device(const char *name)
{
	rt_err_t res;
	
	uart_device = rt_device_find(name); 
	
	if(uart_device != RT_NULL)
	{	
			
		res = rt_device_set_rx_indicate(uart_device, app_uart_intput);				
		
		res = rt_device_open(uart_device,RT_DEVICE_OFLAG_RDWR|RT_DEVICE_FLAG_INT_RX);	
		
		if(res != RT_EOK)
		{
			rt_kprintf("open %s device error.%d<br>",name,res);
			
            return -RT_ERROR;
		}

rt_event_init(&appuart_event, "APP_UART_event", RT_IPC_FLAG_FIFO);		
	}
	else
	{
		rt_kprintf("can't find %s device.<br>",name);
			
        return -RT_ERROR;	
	}
		
	return RT_EOK;
}

static void rt_thread_app_uart_entry(void * parameter)
{	
	const char *gps_cfg="Hello Word!";	
		
	rt_err_t res;
	
	res = app_uart_set_device(YI_POS_SERIAL);
	
	if(res != RT_EOK)	
		return;	
	memset(&uart_rx_buf, 0, sizeof(uart_rx_buf));
	
	rt_event_send(&appuart_event, APPUART_SEND_EVENT);

while(1)
	{
		rt_uint32_t event;
		
		res = rt_event_recv(&appuart_event, APPUART_EVENTS, RT_EVENT_FLAG_OR|RT_EVENT_FLAG_CLEAR, RT_WAITING_FOREVER, &event);

if(res != RT_EOK)
			continue;
		
		if(event & APPUART_SEND_EVENT)
		{       
			rt_device_write(uart_device, 0, gps_cfg, rt_strlen(gps_cfg));
		}
		
		if(event & APPUART_RECV_EVENT)
		{
			length = rt_device_read(uart_device, 0, &uart_rx_buf, length);
			if(length != 0)	
			{
					rt_device_write(uart_device, 0, uart_rx_buf, length);
					rt_device_write(uart_device, 0, &inc, sizeof(inc));
				    inc = 0;
					length = 0;
			}
		}					
	}
}

void app_uart_init(void)
{
	appuart_thread = rt_thread_create("app_uart", 
	                                   rt_thread_app_uart_entry,RT_NULL,
									   1024,
									   3,
									   21);
	
	if(appuart_thread != RT_NULL)
		rt_thread_startup(appuart_thread);
	else
	{	
		rt_device_close(uart_device);	
		
		rt_kprintf("Create Thread Failed!");	
	}		
}

static rt_err_t app_uart_intput (rt_device_t dev, rt_size_t size) 
{	
	length = size;
    rt_event_send(&appuart_event, APPUART_RECV_EVENT);
		
    return RT_EOK;
}
```
以上代码没啥功能：将串口收到的数据，缓存到buf再发出来。

2 app_uart_init是在main()中调用，main是系统开设的一个线程。inc是我加的一个中断计数器，用于判断进了几次中断

3 实际单次发送5、10、15、20不等的字节，串口收到的数据不等但是都有丢包(除非单字节发送，不会丢)，inc中断计数正常分别为5、10、15....，
说明硬件上是有全部收到的并且触发了中断。inc计数在中断处理函数位置，如下：
```c
void USART1_IRQHandler(void)
{
    /* enter interrupt */
    rt_interrupt_enter();
	inc++;
    uart_isr(&serial1);

/* leave interrupt */
    rt_interrupt_leave();
}
```
4 将inc放到  `uart_isr(&serial1);`  函数中(位置如下)，
实际测试inc计数值与串口收到的字节数一置。说明其中没有通过 
`USART_GetITStatus(uart->uart_device, USART_IT_RXNE)`这个条件。
```c
static void uart_isr(struct rt_serial_device *serial) {
    struct stm32_uart *uart = (struct stm32_uart *) serial->parent.user_data;

RT_ASSERT(uart != RT_NULL);

if(USART_GetITStatus(uart->uart_device, USART_IT_RXNE) != RESET)
    {
		**inc ++;**
		if(USART_GetFlagStatus(uart->uart_device, USART_FLAG_PE) == RESET)
		{
			rt_hw_serial_isr(serial, RT_SERIAL_EVENT_RX_IND);
		}
        /* clear interrupt */
        USART_ClearITPendingBit(uart->uart_device, USART_IT_RXNE);
    }
    if(USART_GetITStatus(uart->uart_device, USART_IT_IDLE) != RESET)
    {
        dma_uart_rx_idle_isr(serial);
    }
    if (USART_GetITStatus(uart->uart_device, USART_IT_TC) != RESET)
    {
        /* clear interrupt */
        if(serial->parent.open_flag & RT_DEVICE_FLAG_INT_TX)
        {
            rt_hw_serial_isr(serial, RT_SERIAL_EVENT_TX_DONE);
        }
        USART_ITConfig(uart->uart_device, USART_IT_TC, DISABLE);
        USART_ClearITPendingBit(uart->uart_device, USART_IT_TC);
    }
    if (USART_GetFlagStatus(uart->uart_device, USART_FLAG_ORE) == SET)
    {
        stm32_getc(serial);
    }
}
```
5 如果换成裸机，串口中断那边也是这么写，但从来没有出现这种情况，所以应该和RTT使用或者配置有问题，请教大神解答吧，在线等。