rtthread串口采用DMA发送死机是为什么？如何解决？

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. 详见代码

//监控主站的软件看门狗





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;

}