10 rtthread串口采用DMA发送死机问题.

发布于 2022-06-09 16:08:25 浏览：659 订阅该版

代码与我的另一个贴子差不多. 现在的问题不一样, 目前碰到的问题是串口采用DMA发送时会死机.(我查询了很多贴子, 都提到DMA接收问题, 没有用DMA发送例子) 详见代码

//监控主站的软件看门狗
```c
static void profibus_watchdog_proc(void)
{
	m_rtUsart2ProfibusErrCnt++;
	//超时则重新初始化状态		
	if (m_rtUsart2ProfibusErrCnt > m_rtUsart2WatchDogTime)
	{
		m_rtUsart2ProfibusErrCnt = 0;
                ..........
		}
	}
}

// @brief   dma_tx回调函数

static rt_err_t uart2_dma_tx_callback(rt_device_t dev, void * dataBuf)
{
	rt_err_t result;
	rt_pin_write(RS485_RX_TX_EN, PIN_LOW);
	
        return result;
}
 
//@brief   dma回调函数

static rt_err_t uart2_dma_rx_callback(rt_device_t dev, rt_size_t size)
{
	/* 串口接收到数据后产生中断，调用此回调函数，然后发送接收信号量 */
	struct rx_msg msg;
    rt_err_t result;
    msg.dev = dev;
    msg.size = size;

result = rt_mq_send(&profidp_rx_mq, &msg, sizeof(msg));
    if ( result == -RT_EFULL)
    {
        /* 消息队列满 */
        rt_kprintf("message queue full！\n");
    }
    return result;
}

// @brief   串口接收线程

static void serial_thread_entry(void *parameter)
{
	struct rx_msg msg;

rt_err_t result;
    rt_uint16_t rx_length;

while (1)
    {
		if (m_rtUsart2TxToRxUs > 0)
		{
			rt_thread_mdelay(1);
			m_rtUsart2TxToRxUs--;
		}
		else
		{
			rt_pin_write(RS485_RX_TX_EN, PIN_LOW);
		}

rt_memset(&msg, 0, sizeof(msg));
		rt_memset(m_rtUsart2RxBuf, 0x00, sizeof(m_rtUsart2RxBuf));
		profibus_watchdog_proc();
		
        /* 从消息队列中读取消息*/
        result = rt_mq_recv(&profidp_rx_mq, &msg, sizeof(msg), RT_WAITING_NO/*RT_WAITING_NO RT_WAITING_FOREVER*/);
        if (result == RT_EOK)
        {
            /* 从串口读取数据*/
            rx_length = rt_device_read(msg.dev, 0, m_rtUsart2RxBuf, msg.size);
			if (rx_length >= 6 && rx_length <= PROFIDP_RX_BUF_LEN)
			{
				//发送使能
				rt_pin_write(RS485_RX_TX_EN, PIN_HIGH);
				hw_profibusdp_rx_proc(m_rtUsart2RxBuf, rx_length);
				hw_profibusdp_auto_tx_proc();
				m_rtUsart2TxToRxUs = 20;

}
		}
		
    }
}
 
* @brief   串口初始化

int profibus_uart_init(void)
{
	rt_err_t open_result = RT_EOK;
	rt_pin_mode(RS485_RX_TX_EN, PIN_MODE_OUTPUT);	
	rt_pin_write(RS485_RX_TX_EN, PIN_LOW);
	
	profibusdp_serial=rt_device_find(DP_UART_PORT_NAME);
	if(RT_NULL == profibusdp_serial)
	{
		rt_kprintf("uart2 find failed !\n");
	}
	else
	{
		hw_profibusdp_init();
		rt_mq_init(&profidp_rx_mq, "profidp_rx_mq" ,msg_pool, sizeof(struct rx_msg), sizeof(msg_pool), RT_IPC_FLAG_PRIO);	//RT_IPC_FLAG_PRIO | RT_IPC_FLAG_FIFO);
		profibusdp_uart_config.baud_rate = BAUD_RATE_9600;   
		profibusdp_uart_config.data_bits = DATA_BITS_9;          
		profibusdp_uart_config.stop_bits = STOP_BITS_1;
		profibusdp_uart_config.bufsz     = PROFIDP_RX_BUF_LEN;                  
		profibusdp_uart_config.parity    = PARITY_EVEN;      
		
		
		rt_device_control(profibusdp_serial, RT_DEVICE_CTRL_CONFIG, &profibusdp_uart_config);
		
		open_result = rt_device_open(profibusdp_serial, RT_DEVICE_OFLAG_RDWR | RT_DEVICE_FLAG_DMA_RX | RT_DEVICE_FLAG_DMA_TX);
		RT_ASSERT(open_result == RT_EOK);
		
		rt_device_set_rx_indicate(profibusdp_serial, uart2_dma_rx_callback);
		
		rt_device_set_tx_complete(profibusdp_serial, uart2_dma_tx_callback);
	}
	rt_thread_t thread = rt_thread_create("profidp_serial", serial_thread_entry, RT_NULL, 1024, 1, 10);
    if (thread != RT_NULL)
    {
        rt_thread_startup(thread);
    }
 
    return RT_EOK;
}
```