为什么我SPI发送D03E,前面会多出一些高电平数据啊

chensihan123

发送的是1101000000111110
最终得到的应该是这样子的啊。

LcwSwust

看看HAL_SPI_Transmit函数的源代码

chensihan123

LcwSwust 发表于 2022-11-28 20:47
看看HAL_SPI_Transmit函数的源代码

HAL_StatusTypeDef HAL_SPI_Transmit(SPI_HandleTypeDef *hspi, uint8_t *pData, uint16_t Size, uint32_t Timeout)
{
  uint32_t tickstart = 0U;
  HAL_StatusTypeDef errorcode = HAL_OK;

  /* Check Direction parameter */
  assert_param(IS_SPI_DIRECTION_2LINES_OR_1LINE_2LINES_TXONLY(hspi->Init.Direction));

  /* Process Locked */

  __HAL_LOCK(hspi);

  /* Init tickstart for timeout management*/
  tickstart = HAL_GetTick();

  if (hspi->State != HAL_SPI_STATE_READY)
  {
    errorcode = HAL_BUSY;
    __HAL_UNLOCK(hspi);
    return errorcode;
  }

  if ((pData == NULL) || (Size == 0U))
  {
    errorcode = HAL_ERROR;
    __HAL_UNLOCK(hspi);
    return errorcode;
  }

  /* Set the transaction information */
  hspi->State       = HAL_SPI_STATE_BUSY_TX;
  hspi->ErrorCode   = HAL_SPI_ERROR_NONE;
  hspi->pTxBuffPtr  = (uint8_t *)pData;
  hspi->TxXferSize  = Size;
  hspi->TxXferCount = Size;

  /*Init field not used in handle to zero */
  hspi->pRxBuffPtr  = NULL;
  hspi->RxXferSize  = 0U;
  hspi->RxXferCount = 0U;
  hspi->TxISR       = NULL;
  hspi->RxISR       = NULL;

  /* Configure communication direction : 1Line */
  if (hspi->Init.Direction == SPI_DIRECTION_1LINE)
  {
    SPI_1LINE_TX(hspi);
  }

  /* Set the number if data at current transfer */
  MODIFY_REG(hspi->Instance->CR2, SPI_CR2_TSIZE, Size);

  /* Enable SPI peripheral */
  __HAL_SPI_ENABLE(hspi);

  if (hspi->Init.Mode == SPI_MODE_MASTER)
  {
    /* Master transfer start */
    SET_BIT(hspi->Instance->CR1, SPI_CR1_CSTART);//4
  }

  /* Transmit data in 32 Bit mode */
  if (hspi->Init.DataSize > SPI_DATASIZE_16BIT)
  {
    /* Transmit data in 32 Bit mode */
    while (hspi->TxXferCount > 0U)
    {
      /* Wait until TXE flag is set to send data */
      if (__HAL_SPI_GET_FLAG(hspi, SPI_FLAG_TXE))
      {
        *((__IO uint32_t *)&hspi->Instance->TXDR) = *((uint32_t *)hspi->pTxBuffPtr);
        hspi->pTxBuffPtr += sizeof(uint32_t);
        hspi->TxXferCount--;
      }
      else
      {
        /* Timeout management */
        if ((Timeout == 0U) || ((Timeout != HAL_MAX_DELAY) && ((HAL_GetTick() - tickstart) >=  Timeout)))
        {
          /* Call standard close procedure with error check */
          SPI_CloseTransfer(hspi);

          /* Process Unlocked */
          __HAL_UNLOCK(hspi);

          SET_BIT(hspi->ErrorCode, HAL_SPI_ERROR_TIMEOUT);
          hspi->State = HAL_SPI_STATE_READY;
          return HAL_ERROR;
        }
      }
    }
  }
  /* Transmit data in 16 Bit mode */
  else if (hspi->Init.DataSize > SPI_DATASIZE_8BIT)
  {
    /* Transmit data in 16 Bit mode */ //13
    while (hspi->TxXferCount > 0U)
    {
      /* Wait until TXE flag is set to send data */
      if (__HAL_SPI_GET_FLAG(hspi, SPI_FLAG_TXE))//14
      {
        if ( (hspi->TxXferCount > 1U) && (hspi->Init.FifoThreshold > SPI_FIFO_THRESHOLD_01DATA))
        {
          *((__IO uint32_t *)&hspi->Instance->TXDR) = *((uint32_t *)hspi->pTxBuffPtr);
          hspi->pTxBuffPtr += sizeof(uint32_t);
          hspi->TxXferCount-=2;
        }
        else
        {
          *((__IO uint16_t *)&hspi->Instance->TXDR) = *((uint16_t *)hspi->pTxBuffPtr);
          hspi->pTxBuffPtr += sizeof(uint16_t);
          hspi->TxXferCount--;
        }
      }
      else
      {
        /* Timeout management */
        if ((Timeout == 0U) || ((Timeout != HAL_MAX_DELAY) && ((HAL_GetTick() - tickstart) >=  Timeout)))
        {
          /* Call standard close procedure with error check */
          SPI_CloseTransfer(hspi);

          /* Process Unlocked */
          __HAL_UNLOCK(hspi);

          SET_BIT(hspi->ErrorCode, HAL_SPI_ERROR_TIMEOUT);
          hspi->State = HAL_SPI_STATE_READY;
          return HAL_ERROR;
        }
      }
    }
  }
  /* Transmit data in 8 Bit mode */
  else
  {
    while (hspi->TxXferCount > 0U)
    {
      /* Wait until TXE flag is set to send data */
      if (__HAL_SPI_GET_FLAG(hspi, SPI_FLAG_TXE))
      {
        if ((hspi->TxXferCount > 3U) && (hspi->Init.FifoThreshold > SPI_FIFO_THRESHOLD_03DATA))
        {
          *((__IO uint32_t *)&hspi->Instance->TXDR) = *((uint32_t *)hspi->pTxBuffPtr);
          hspi->pTxBuffPtr += sizeof(uint32_t);
          hspi->TxXferCount-=4;
        }
        else if ((hspi->TxXferCount > 1U) && (hspi->Init.FifoThreshold > SPI_FIFO_THRESHOLD_01DATA))
        {
          *((__IO uint16_t *)&hspi->Instance->TXDR) = *((uint16_t *)hspi->pTxBuffPtr);
          hspi->pTxBuffPtr += sizeof(uint16_t);
          hspi->TxXferCount-=2;
        }
        else//17
        {
          *((__IO uint8_t *)&hspi->Instance->TXDR) = *((uint8_t *)hspi->pTxBuffPtr);
          hspi->pTxBuffPtr += sizeof(uint8_t);
          hspi->TxXferCount--;
        }
      }
      else
      {
        /* Timeout management */
        if ((Timeout == 0U) || ((Timeout != HAL_MAX_DELAY) && ((HAL_GetTick() - tickstart) >=  Timeout)))
        {
          /* Call standard close procedure with error check */
          SPI_CloseTransfer(hspi);

          /* Process Unlocked */
          __HAL_UNLOCK(hspi);

          SET_BIT(hspi->ErrorCode, HAL_SPI_ERROR_TIMEOUT);
          hspi->State = HAL_SPI_STATE_READY;
          return HAL_ERROR;
        }
      }
    }
  }

  /* Wait for Tx (and CRC) data to be sent */
  if (SPI_WaitOnFlagUntilTimeout(hspi, SPI_FLAG_EOT, RESET, tickstart, Timeout) != HAL_OK)
  {
    SET_BIT(hspi->ErrorCode, HAL_SPI_ERROR_FLAG);
  }

  /* Call standard close procedure with error check */

  SPI_CloseTransfer(hspi);

  /* Process Unlocked */
  __HAL_UNLOCK(hspi);

  hspi->State = HAL_SPI_STATE_READY;

  if (hspi->ErrorCode != HAL_SPI_ERROR_NONE)
  {
    return HAL_ERROR;
  }
  return HAL_OK;
}


这样的。

jermy_z

开始信号吧   这个得看下时序

LcwSwust

chensihan123 发表于 2022-11-29 17:28
HAL_StatusTypeDef HAL_SPI_Transmit(SPI_HandleTypeDef *hspi, uint8_t *pData, uint16_t Size, uint32_ ...

这么多代码，看着头疼，看起来这函数应该是用于批量传输的。
要不还是参考标准库的函数简化一下吧：

1. //--------------------------------------------------
   
2. //SPI发送数据
   
3. //--------------------------------------------------
   
4. U8 SPI2_SendByte(U8 d)
   
5. {        //等待TXE=1,发送寄存器空
   
6.         while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET);
   
7.         //SPI2->DR=d;
   
8.         SPI_I2S_SendData(SPI2,d); //往寄存器中写入一个字节
   
9.         //等待RXNE=1,接收完成
   
10.         while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == RESET);
    
11.         SPI_I2S_ReceiveData(SPI2);//读数据，清溢出标志，避免错误               
    
12.         return d;
    
13. }

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