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Problem with ADCs in dual regular mode

Question asked by Gonzo on Sep 23, 2013
Latest reply on Sep 23, 2013 by Gonzo

I’ve have a problem with the ADCs in dual regular simultaneous mode.

I want to measure 3 channels with ADC1 and 3 channels with ADC2. The conversions are started by software. I want to get 32 acquisitions in DMA mode and then stop the ADCs. The conversions will be started by software again.

My code works fine but after several acquisitions I get sometimes wrong results for ADC2.

  // init DMA and ADC
  DMA_DeInit(DMA1_Channel1);                                        // ADC and DMA handling
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC1_DR_Address;
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)ADC_DualConvertedValueTab;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
  DMA_InitStructure.DMA_BufferSize = (32*3);
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Word;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  DMA_Init(DMA1_Channel1, &DMA_InitStructure);
  DMA_ITConfig(DMA1_Channel1, DMA_IT_TC, ENABLE);  
  DMA_Cmd(DMA1_Channel1, ENABLE);
 
  // ADC1 configuration
  ADC_InitStructure.ADC_Mode = ADC_Mode_RegSimult;
  ADC_InitStructure.ADC_ScanConvMode = ENABLE;
  ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
  ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
  ADC_InitStructure.ADC_NbrOfChannel = 3;
  ADC_Init(ADC1, &ADC_InitStructure);
 
  ADC_RegularChannelConfig(ADC1, ADC_Channel_11, 1, ADC_SampleTime_41Cycles5);  
  ADC_RegularChannelConfig(ADC1, ADC_Channel_12, 2, ADC_SampleTime_41Cycles5);  
  ADC_RegularChannelConfig(ADC1, ADC_Channel_10, 3, ADC_SampleTime_41Cycles5);  
 
  ADC_DMACmd(ADC1, ENABLE);

  // ADC2 configuration
  ADC_InitStructure.ADC_Mode = ADC_Mode_RegSimult;
  ADC_InitStructure.ADC_ScanConvMode = ENABLE;
  ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
  ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
  ADC_InitStructure.ADC_NbrOfChannel = 3;
  ADC_Init(ADC2, &ADC_InitStructure);
 
  ADC_RegularChannelConfig(ADC2, ADC_Channel_7, 1, ADC_SampleTime_41Cycles5);   
  ADC_RegularChannelConfig(ADC2, ADC_Channel_6, 2, ADC_SampleTime_41Cycles5);   
  ADC_RegularChannelConfig(ADC2, ADC_Channel_13, 3, ADC_SampleTime_41Cycles5);  
  ADC_ExternalTrigConvCmd(ADC2, ENABLE);

  // calibrate ADC1
  ADC_Cmd(ADC1, ENABLE);
  ADC_ResetCalibration(ADC1);
  while(ADC_GetResetCalibrationStatus(ADC1));
  ADC_StartCalibration(ADC1);
  while(ADC_GetCalibrationStatus(ADC1));

  // calibrate ADC2
  ADC_Cmd(ADC2, ENABLE);
  ADC_ResetCalibration(ADC2);
  while(ADC_GetResetCalibrationStatus(ADC2));
  ADC_StartCalibration(ADC2);
  while(ADC_GetCalibrationStatus(ADC2));
 
   __disable_interrupt();
 
   // DMA1 interrupt
  NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel1_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
 
  __enable_interrupt();
}


void ADC_Start(void)
{
  DMA_Cmd(DMA1_Channel1, ENABLE);
  ADC_Cmd(ADC1, ENABLE);  
  ADC_SoftwareStartConvCmd(ADC1, ENABLE);
}

// DMA Mode
void DMA_ADC1_2_IRQHandler(void)
{
  DMA_Cmd(DMA1_Channel1, DISABLE);                  // ADC and DMA handling
  DMA_ClearFlag(DMA1_FLAG_TC1);
 
  ADC_Cmd(ADC1, DISABLE);
}




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