ART-PI使用HAL库的DMA进行ADC数据采集问题。

发布于 2021-08-06 18:51:33 浏览：1383 订阅该版

根据官方的HAL库使用adc设备教程可以进行轮询方式下的ADC数据的采集
但使用DMA的方式打开ADC，程序就会卡死。
使用这个函数时程序就会卡死。
```c
HAL_ADC_Start_DMA(ADC_HandleTypeDef *hadc, uint32_t *pData, uint32_t Length)
```
函数原型为：
```c
HAL_StatusTypeDef HAL_ADC_Start_DMA(ADC_HandleTypeDef *hadc, uint32_t *pData, uint32_t Length)
{
  HAL_StatusTypeDef tmp_hal_status;
  uint32_t tmp_multimode_config = LL_ADC_GetMultimode(__LL_ADC_COMMON_INSTANCE(hadc->Instance));

/* Check the parameters */
  assert_param(IS_ADC_ALL_INSTANCE(hadc->Instance));

/* Perform ADC enable and conversion start if no conversion is on going */
  if (LL_ADC_REG_IsConversionOngoing(hadc->Instance) == 0UL)
  {
    /* Process locked */
    __HAL_LOCK(hadc);

/* Ensure that multimode regular conversions are not enabled.   */
    /* Otherwise, dedicated API HAL_ADCEx_MultiModeStart_DMA() must be used.  */
    if ((tmp_multimode_config == LL_ADC_MULTI_INDEPENDENT)
        || (tmp_multimode_config == LL_ADC_MULTI_DUAL_INJ_SIMULT)
        || (tmp_multimode_config == LL_ADC_MULTI_DUAL_INJ_ALTERN)
       )
    {
      /* Enable the ADC peripheral */
      tmp_hal_status = ADC_Enable(hadc);

/* Start conversion if ADC is effectively enabled */
      if (tmp_hal_status == HAL_OK)
      {
        /* Set ADC state                                                        */
        /* - Clear state bitfield related to regular group conversion results   */
        /* - Set state bitfield related to regular operation                    */
        ADC_STATE_CLR_SET(hadc->State,
                          HAL_ADC_STATE_READY | HAL_ADC_STATE_REG_EOC | HAL_ADC_STATE_REG_OVR | HAL_ADC_STATE_REG_EOSMP,
                          HAL_ADC_STATE_REG_BUSY);

/* Reset HAL_ADC_STATE_MULTIMODE_SLAVE bit
          - if ADC instance is master or if multimode feature is not available
          - if multimode setting is disabled (ADC instance slave in independent mode) */
        if ((__LL_ADC_MULTI_INSTANCE_MASTER(hadc->Instance) == hadc->Instance)
            || (tmp_multimode_config == LL_ADC_MULTI_INDEPENDENT)
           )
        {
          CLEAR_BIT(hadc->State, HAL_ADC_STATE_MULTIMODE_SLAVE);
        }

/* Check if a conversion is on going on ADC group injected */
        if ((hadc->State & HAL_ADC_STATE_INJ_BUSY) != 0UL)
        {
          /* Reset ADC error code fields related to regular conversions only */
          CLEAR_BIT(hadc->ErrorCode, (HAL_ADC_ERROR_OVR | HAL_ADC_ERROR_DMA));
        }
        else
        {
          /* Reset all ADC error code fields */
          ADC_CLEAR_ERRORCODE(hadc);
        }

/* Set the DMA transfer complete callback */
        hadc->DMA_Handle->XferCpltCallback = ADC_DMAConvCplt;

/* Set the DMA half transfer complete callback */
        hadc->DMA_Handle->XferHalfCpltCallback = ADC_DMAHalfConvCplt;

/* Set the DMA error callback */
        hadc->DMA_Handle->XferErrorCallback = ADC_DMAError;

/* Manage ADC and DMA start: ADC overrun interruption, DMA start,     */
        /* ADC start (in case of SW start):                                   */

/* Clear regular group conversion flag and overrun flag               */
        /* (To ensure of no unknown state from potential previous ADC         */
        /* operations)                                                        */
        __HAL_ADC_CLEAR_FLAG(hadc, (ADC_FLAG_EOC | ADC_FLAG_EOS | ADC_FLAG_OVR));

/* Process unlocked */
        /* Unlock before starting ADC conversions: in case of potential         */
        /* interruption, to let the process to ADC IRQ Handler.                 */
        __HAL_UNLOCK(hadc);

/* With DMA, overrun event is always considered as an error even if
           hadc->Init.Overrun is set to ADC_OVR_DATA_OVERWRITTEN. Therefore,
           ADC_IT_OVR is enabled. */
        __HAL_ADC_ENABLE_IT(hadc, ADC_IT_OVR);

/* Enable ADC DMA  mode*/
#if defined(ADC_VER_V5_V90)
        if (hadc->Instance == ADC3)
        {
          LL_ADC_REG_SetDMATransferMode(hadc->Instance, ADC3_CFGR_DMACONTREQ((uint32_t)hadc->Init.DMAContinuousRequests));
          LL_ADC_EnableDMAReq(hadc->Instance);
        }
        else
        {
          LL_ADC_REG_SetDataTransferMode(hadc->Instance, ADC_CFGR_DMACONTREQ((uint32_t)hadc->Init.ConversionDataManagement));
        }

#else
        LL_ADC_REG_SetDataTransferMode(hadc->Instance, (uint32_t)hadc->Init.ConversionDataManagement);
#endif

/* Start the DMA channel */
        tmp_hal_status = HAL_DMA_Start_IT(hadc->DMA_Handle, (uint32_t)&hadc->Instance->DR, (uint32_t)pData, Length);

/* Enable conversion of regular group.                                  */
        /* If software start has been selected, conversion starts immediately.  */
        /* If external trigger has been selected, conversion will start at next */
        /* trigger event.                                                       */
        /* Start ADC group regular conversion */

LL_ADC_REG_StartConversion(hadc->Instance);

}
      else
      {
        /* Process unlocked */
        __HAL_UNLOCK(hadc);
      }

}
    else
    {
      tmp_hal_status = HAL_ERROR;
      /* Process unlocked */
      __HAL_UNLOCK(hadc);
    }
  }
  else
  {
    tmp_hal_status = HAL_BUSY;
  }

/* Return function status */
  return tmp_hal_status;
}
```
经过测试发现程序卡在这一句：
```c
  LL_ADC_REG_StartConversion(hadc->Instance);
```

注释掉这句，程序正常运行。

但是采集到数组内的数据为0