STM32CubeMX Hal库的一些坑

世上最美丽的裤头 · 发表于 2017-4-12 10:20:54

本帖最后由世上最美丽的裤头于 2017-4-13 11:24 编辑

使用的是stm32f103 V1.40版本的库

UART DMA发送的问题

发送函数
HAL_StatusTypeDef HAL_UART_Transmit_DMA(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size);
发送完毕之后成功的回调函数也正常，可是再次发送的时候就发不出去了。一直返回错误。
我们看下这个函数的代码

[mw_shl_code=applescript,true]HAL_StatusTypeDef HAL_UART_Transmit_DMA(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size)
{
  uint32_t *tmp;
  uint32_t tmp_state = 0;

  tmp_state = huart->State;
  if((tmp_state == HAL_UART_STATE_READY) || (tmp_state == HAL_UART_STATE_BUSY_RX))
  {
if((pData == NULL ) || (Size == 0))
{
   return HAL_ERROR;
}

/* Process Locked */
__HAL_LOCK(huart);

huart->pTxBuffPtr = pData;
huart->TxXferSize = Size;
huart->TxXferCount = Size;

huart->ErrorCode = HAL_UART_ERROR_NONE;
/* Check if a receive process is ongoing or not */
if(huart->State == HAL_UART_STATE_BUSY_RX)
{
   huart->State = HAL_UART_STATE_BUSY_TX_RX;
}
else
{
   huart->State = HAL_UART_STATE_BUSY_TX;
}

/* Set the UART DMA transfer complete callback */
huart->hdmatx->XferCpltCallback = UART_DMATransmitCplt;

/* Set the UART DMA Half transfer complete callback */
huart->hdmatx->XferHalfCpltCallback = UART_DMATxHalfCplt;

/* Set the DMA error callback */
huart->hdmatx->XferErrorCallback = UART_DMAError;

/* Enable the UART transmit DMA channel */
tmp = (uint32_t*)&pData;
HAL_DMA_Start_IT(huart->hdmatx, *(uint32_t*)tmp, (uint32_t)&huart->Instance->DR, Size);

/* Clear the TC flag in the SR register by writing 0 to it */
__HAL_UART_CLEAR_FLAG(huart, UART_FLAG_TC);

/* Enable the DMA transfer for transmit request by setting the DMAT bit
   in the UART CR3 register */
SET_BIT(huart->Instance->CR3, USART_CR3_DMAT);

/* Process Unlocked */
__HAL_UNLOCK(huart);

return HAL_OK;
  }
  else
  {
return HAL_BUSY;
  }
}[/mw_shl_code]

代码中可以看出，发送之前先判断状态标志，不是在发送状态才进行发送，这也正常。但是，发送一次之后，状态就被至为发送状态，发送完毕也没有清楚，这就导致了下次再发送，判断为忙，就发不出去了。我们看下他发送成功的处理部分。

[mw_shl_code=applescript,true]static void UART_DMATransmitCplt(DMA_HandleTypeDef *hdma)
{
  UART_HandleTypeDef* huart = ( UART_HandleTypeDef* )((DMA_HandleTypeDef* )hdma)->Parent;
  /* DMA Normal mode*/
  if ( HAL_IS_BIT_CLR(hdma->Instance->CCR, DMA_CCR_CIRC) )
  {
huart->TxXferCount = 0;

/* Disable the DMA transfer for transmit request by setting the DMAT bit
   in the UART CR3 register */
CLEAR_BIT(huart->Instance->CR3, USART_CR3_DMAT);

/* Enable the UART Transmit Complete Interrupt */
__HAL_UART_ENABLE_IT(huart, UART_IT_TC);
  }
  /* DMA Circular mode */
  else
  {
HAL_UART_TxCpltCallback(huart);
  }[/mw_shl_code]

代码中可以看到，并没有清除发送的状态，这就导致了下次发送不成功的问题。
难道要自己发送之前清除一下状态，我想这应该不是库函数的本意。
我们对比看下接收成功是如何处理的

[mw_shl_code=applescript,true]static void UART_DMAReceiveCplt(DMA_HandleTypeDef *hdma)
{
  UART_HandleTypeDef* huart = ( UART_HandleTypeDef* )((DMA_HandleTypeDef* )hdma)->Parent;
  /* DMA Normal mode*/
  if ( HAL_IS_BIT_CLR(hdma->Instance->CCR, DMA_CCR_CIRC) )
  {
huart->RxXferCount = 0;

/* Disable the DMA transfer for the receiver request by setting the DMAR bit
   in the UART CR3 register */
CLEAR_BIT(huart->Instance->CR3, USART_CR3_DMAR);

/* Check if a transmit process is ongoing or not */
if(huart->State == HAL_UART_STATE_BUSY_TX_RX)
{
   huart->State = HAL_UART_STATE_BUSY_TX;
}
else
{
   huart->State = HAL_UART_STATE_READY;
}
  }
  HAL_UART_RxCpltCallback(huart);
}[/mw_shl_code]

接收成功之后有正确清除状态标志，发送成功应该也是同样的，所以可能是漏掉了。我们加上即可

[mw_shl_code=applescript,true]static void UART_DMATransmitCplt(DMA_HandleTypeDef *hdma)
{
  UART_HandleTypeDef* huart = ( UART_HandleTypeDef* )((DMA_HandleTypeDef* )hdma)->Parent;
  /* DMA Normal mode*/
  if ( HAL_IS_BIT_CLR(hdma->Instance->CCR, DMA_CCR_CIRC) )
  {
huart->TxXferCount = 0;

/* Disable the DMA transfer for transmit request by setting the DMAT bit
   in the UART CR3 register */
CLEAR_BIT(huart->Instance->CR3, USART_CR3_DMAT);

/* Enable the UART Transmit Complete Interrupt */
__HAL_UART_ENABLE_IT(huart, UART_IT_TC);

    /* Check if a transmit process is ongoing or not */
if(huart->State == HAL_UART_STATE_BUSY_TX_RX) //这里是增加的代码
{
   huart->State = HAL_UART_STATE_BUSY_RX;
}
else
{
   huart->State = HAL_UART_STATE_READY;
}
  }
  /* DMA Circular mode */
  else    //普通模式没有回调发送成功，注释掉次else则修改为发送完成回调
  {
HAL_UART_TxCpltCallback(huart);
  }
}[/mw_shl_code]

测试，可以正常发送了····