HAL_UART_DMAStop不会停止UART RX上的DMA怎么解决？

使用 Nucleo-G431KB 开发板，我玩了一下 UART RX DMA。
我在线性缓冲区上启动了 DMA RX，然后停止并重新启动 DMA。
我刚刚观察到，在接收到几个字节后，HAL_UART_DMAStop 不再停止 UART RX 上的 DMA。HAL_UART_DMAStop 调用不会返回错误，但 HAL_UART_Receive_DMA 会返回错误，因为传输从未停止过。我还观察到字符仍会被接收到 DMA UART RX 缓冲区，确认 DMA 没有停止。
它仅在我在缓冲区中收到几个字节后才会发生。单个字节不会造成任何问题。
我找不到根本原因。
无论如何，仅在循环缓冲区上启动一次 HAL_UART_Receive_DMA 并检查 __HAL_DMA_GET_COUNTER 是输入随机大小的 UART 数据的更好方法。
我只是想知道是否有人也注意到了这一点。
它是 HAL 中的错误吗？
不幸的是，我不再拥有代码，但它只是简单明了，就像在循环中调用一样，大致如下：

uint8_t DataRX[256];
while (1)
{
HAL_UART_Receive_DMA(&huart1, DataRX, sizeof(DataRX))
//Checking length and print buffer (on a different UART)
uint16_t Last_Byte_Index = (uint16_t)(sizeof(DataRX) - __HAL_DMA_GET_COUNTER(huart1.hdmarx));
// ... printing the buffer on another UART
HAL_UART_DMAStop(&huart1);
}

回帖（1）

彭玉林

2023-2-1 14:27:20

我一定是因为一些愚蠢的错误而失明了。我没有保留该代码，所以我不得不重做它，然后似乎没有遇到任何问题。我一定有点老了。
尽管如此，无论如何，启用 uart 中断似乎是最佳实践，如果它只是清除错误标志，例如在连接和断开线路时很容易发生的帧错误。
我想我会分享一些直接的示例供其他（合作）开发人员使用。
在阻塞 HAL_Delay 期间，使用 UART RX 上的 DMA 获取字符。
我们可以使用 UART RTO 中断（以位数表示的接收超时）来检测数据接收的结束（可能在接收 Modbus 时，35 位是 3.5 个字符的超时），或者对接收到的数据进行 pol，或者识别一些特定的接收数据。
请注意，我认为应始终避免阻止呼叫。这只是一个简单的演示示例。
还应该尽可能多地使用硬件来完成，因此尽可能多地使用 DMA 通常是一件好事。MCU 然后可以同时执行其他任务。
第一：Mode = DMA_CIRCULAR，启动一次（我认为最好的解决方案，因为不会遗漏任何字符）
第二：DMA_NORMAL 或 DMA_CIRCULAR，启动/停止

/* Mode = DMA_CIRCULAR, start once */
/* Interrupt Enable */
HAL_NVIC_EnableIRQ(USART1_IRQn);
uint8_t DataRX[256];
if (HAL_UART_Receive_DMA(&huart1, DataRX, sizeof(DataRX)) != HAL_OK)
{
/* Error */
char Error[] = "Error HAL_UART_Receive_DMAn";
HAL_UART_Transmit(&huart2, (uint8_t*)Error, strlen(Error), 100); /* To USB serial port */
}
uint16_t First_Byte_Index = 0;
uint16_t Last_Byte_Index_Previous = 0;
while (1)
{
/* Show what's in the DataRX */
uint16_t Last_Byte_Index = (uint16_t)(sizeof(DataRX) - __HAL_DMA_GET_COUNTER(huart1.hdmarx));
uint16_t DataRX_Length = Last_Byte_Index - Last_Byte_Index_Previous;
First_Byte_Index = Last_Byte_Index - DataRX_Length;
/* If the new Index is greater than Index_old, we received something */
if (DataRX_Length)
{
char Received[] = "Received: ";
HAL_UART_Transmit(&huart2, (uint8_t*)Received, strlen(Received), 100); /* To USB serial port */
for (uint16_t i = 0; i < DataRX_Length; i++)
{
uint16_t DataRX_Index = i + First_Byte_Index;
/* Roll over DataRX_index if necessary */
if (DataRX_Index > sizeof(DataRX))
{
DataRX_Index -= sizeof(DataRX);
}
HAL_UART_Transmit(&huart2, &DataRX[DataRX_Index], 1, 100); /* To USB serial port */
}
char CR[] = "n";
HAL_UART_Transmit(&huart2, (uint8_t*)CR, strlen(CR), 100); /* To USB serial port */
/* Reset Index_old to latest Index */
Last_Byte_Index_Previous = Last_Byte_Index;
}
HAL_UART_Transmit(&huart2, (uint8_t*)Test, strlen(Test), 100); /* To USB serial port */
HAL_Delay(1000);
HAL_IWDG_Refresh(&hiwdg); /* Don't forget to take good care of your watch-dog, feed it! */
}

/* Mode = DMA_NORMAL or DMA_CIRCULAR, start/stop */
/* Interrupt Enable */
HAL_NVIC_EnableIRQ(USART1_IRQn);
uint8_t DataRX[256];
while (1)
{
if (HAL_UART_Receive_DMA(&huart1, DataRX, sizeof(DataRX)) != HAL_OK)
{
/* Error */
char Error[] = "Error HAL_UART_Receive_DMAn";
HAL_UART_Transmit(&huart2, (uint8_t*)Error, strlen(Error), 100); /* To USB serial port */
}
HAL_Delay(1000);
/*Checking length and print buffer (on a different UART) */
uint16_t Last_Byte_Index = (uint16_t)(sizeof(DataRX) - __HAL_DMA_GET_COUNTER(huart1.hdmarx));
/* printing the buffer on another UART */
if (Last_Byte_Index)
{
char Received[] = "Received: ";
HAL_UART_Transmit(&huart2, (uint8_t*)Received, strlen(Received), 100); /* To USB serial port */
for (uint16_t i = 0; i < Last_Byte_Index; i++)
{
HAL_UART_Transmit(&huart2, &DataRX, 1, 100); /* To USB serial port */
}
char CR[] = "n";
HAL_UART_Transmit(&huart2, (uint8_t*)CR, strlen(CR), 100); /* To USB serial port */
}
if (HAL_UART_DMAStop(&huart1) != HAL_OK)
{
/* Error */
char Error[] = "Error HAL_UART_DMAStopn";
HAL_UART_Transmit(&huart2, (uint8_t*)Error, strlen(Error), 100); /* To USB serial port */
}
HAL_IWDG_Refresh(&hiwdg); /* Don't forget to take good care of your watch-dog, feed it! */
}

在 stm32g4xx_it.c 中我们清除了一些错误标志，它们会不会发生。我们可以不检查就清除它们，但也许有人会维护帧和奇偶校验错误计数器。

/**

  * @brief This function handles USART1 global interrupt / USART1 wake-up interrupt through EXTI line 25.

  */

void USART1_IRQHandler(void)

{

  /* USER CODE BEGIN USART1_IRQn 0 */

  /* Noise immunity feature enabled for RS (Modbus-RTU) interfaces */

  /* Clear the errors if they occurred */

  /* UART parity error detected */

  if (__HAL_UART_GET_FLAG(&huart1, UART_FLAG_PE) == SET)

  {

__HAL_UART_CLEAR_PEFLAG(&huart1);

  }

  /* UART frame error detected or break character is detected */

  if (__HAL_UART_GET_FLAG(&huart1, UART_FLAG_FE) == SET)

  {

__HAL_UART_CLEAR_FEFLAG(&huart1);

  }

  /* UART noise error detected */

  if (__HAL_UART_GET_FLAG(&huart1, UART_FLAG_NE) == SET)

  {

__HAL_UART_CLEAR_NEFLAG(&huart1);

  }

  /* UART overrun error detected */

  if (__HAL_UART_GET_FLAG(&huart1, UART_FLAG_ORE) == SET)

  {

__HAL_UART_CLEAR_OREFLAG(&huart1);

  }

  /* UART idle flag */

  if((__HAL_UART_GET_FLAG(&huart1, UART_FLAG_IDLE) != RESET))

  {

__HAL_UART_CLEAR_IDLEFLAG(&huart1);

  }

  /* USER CODE END USART1_IRQn 0 */

  HAL_UART_IRQHandler(&huart1);

  /* USER CODE BEGIN USART1_IRQn 1 */

  /* USER CODE END USART1_IRQn 1 */

}

/* Mode = DMA_CIRCULAR, start once */
/* Interrupt Enable */
HAL_NVIC_EnableIRQ(USART1_IRQn);
uint8_t DataRX[256];
if (HAL_UART_Receive_DMA(&huart1, DataRX, sizeof(DataRX)) != HAL_OK)
{
/* Error */
char Error[] = "Error HAL_UART_Receive_DMAn";
HAL_UART_Transmit(&huart2, (uint8_t*)Error, strlen(Error), 100); /* To USB serial port */
}
uint16_t First_Byte_Index = 0;
uint16_t Last_Byte_Index_Previous = 0;
while (1)
{
/* Show what's in the DataRX */
uint16_t Last_Byte_Index = (uint16_t)(sizeof(DataRX) - __HAL_DMA_GET_COUNTER(huart1.hdmarx));
uint16_t DataRX_Length = Last_Byte_Index - Last_Byte_Index_Previous;
First_Byte_Index = Last_Byte_Index - DataRX_Length;
/* If the new Index is greater than Index_old, we received something */
if (DataRX_Length)
{
char Received[] = "Received: ";
HAL_UART_Transmit(&huart2, (uint8_t*)Received, strlen(Received), 100); /* To USB serial port */
for (uint16_t i = 0; i < DataRX_Length; i++)
{
uint16_t DataRX_Index = i + First_Byte_Index;
/* Roll over DataRX_index if necessary */
if (DataRX_Index > sizeof(DataRX))
{
DataRX_Index -= sizeof(DataRX);
}
HAL_UART_Transmit(&huart2, &DataRX[DataRX_Index], 1, 100); /* To USB serial port */
}
char CR[] = "n";
HAL_UART_Transmit(&huart2, (uint8_t*)CR, strlen(CR), 100); /* To USB serial port */
/* Reset Index_old to latest Index */
Last_Byte_Index_Previous = Last_Byte_Index;
}
HAL_UART_Transmit(&huart2, (uint8_t*)Test, strlen(Test), 100); /* To USB serial port */
HAL_Delay(1000);
HAL_IWDG_Refresh(&hiwdg); /* Don't forget to take good care of your watch-dog, feed it! */
}

/* Mode = DMA_NORMAL or DMA_CIRCULAR, start/stop */
/* Interrupt Enable */
HAL_NVIC_EnableIRQ(USART1_IRQn);
uint8_t DataRX[256];
while (1)
{
if (HAL_UART_Receive_DMA(&huart1, DataRX, sizeof(DataRX)) != HAL_OK)
{
/* Error */
char Error[] = "Error HAL_UART_Receive_DMAn";
HAL_UART_Transmit(&huart2, (uint8_t*)Error, strlen(Error), 100); /* To USB serial port */
}
HAL_Delay(1000);
/*Checking length and print buffer (on a different UART) */
uint16_t Last_Byte_Index = (uint16_t)(sizeof(DataRX) - __HAL_DMA_GET_COUNTER(huart1.hdmarx));
/* printing the buffer on another UART */
if (Last_Byte_Index)
{
char Received[] = "Received: ";
HAL_UART_Transmit(&huart2, (uint8_t*)Received, strlen(Received), 100); /* To USB serial port */
for (uint16_t i = 0; i < Last_Byte_Index; i++)
{
HAL_UART_Transmit(&huart2, &DataRX, 1, 100); /* To USB serial port */
}
char CR[] = "n";
HAL_UART_Transmit(&huart2, (uint8_t*)CR, strlen(CR), 100); /* To USB serial port */
}
if (HAL_UART_DMAStop(&huart1) != HAL_OK)
{
/* Error */
char Error[] = "Error HAL_UART_DMAStopn";
HAL_UART_Transmit(&huart2, (uint8_t*)Error, strlen(Error), 100); /* To USB serial port */
}
HAL_IWDG_Refresh(&hiwdg); /* Don't forget to take good care of your watch-dog, feed it! */
}

更多回帖

吴湛

HAL_UART_DMAStop不会停止UART RX上的DMA怎么解决？

回帖（1）

彭玉林

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