AnsweredAssumed Answered

STM32 F4 Discovery adc / dma setup for 4 channels

Question asked by Goebel.Vincent on Oct 17, 2013
Latest reply on Oct 17, 2013 by Clive One
Hi,
based on the example in the peripheral lib i tried to expand the code to read 4 different pins. Googling around i managed to get values, but the problem is: the first (adc channel 11) is working fine, but the second  (adc channel 12) has an effect on all channels (or at least the values in the array). channel 14 and 15 don't have any effect on the array. I skipped 13 because its already in use on the STM32F4Discovery.
Since the Values at the Pins are fine ( checked with multimeter ) the problem has to be my init code. I would be really thankful for advice.


*edit : fixed clives remarks
My init-code:

__IO uint16_t ADC3ConvertedValue[4];
__IO uint32_t ADC3ConvertedVoltage[4];

void ADC3_CH12_DMA_Config(void)
{
  ADC_InitTypeDef       ADC_InitStructure;
  ADC_CommonInitTypeDef ADC_CommonInitStructure;
  DMA_InitTypeDef       DMA_InitStructure;
  GPIO_InitTypeDef      GPIO_InitStructure;

  /* Enable ADC3, DMA2 and GPIO clocks ****************************************/
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2 | RCC_AHB1Periph_GPIOC, ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC3, ENABLE);

  /* DMA2 Stream0 channel0 configuration **************************************/
  DMA_DeInit(DMA2_Stream0);
  DMA_InitStructure.DMA_Channel = DMA_Channel_2;
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC3_DR_ADDRESS;
  DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&ADC3ConvertedValue[0];
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
  DMA_InitStructure.DMA_BufferSize = 4;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; // orig dis
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; //orig dis
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;
  DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
  DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
  DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
  DMA_Init(DMA2_Stream0, &DMA_InitStructure);
  DMA_Cmd(DMA2_Stream0, ENABLE);

  /* Configure ADC3 Channel12 pin as analog input ******************************/
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1|GPIO_Pin_2|GPIO_Pin_4|GPIO_Pin_5;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
  GPIO_Init(GPIOC, &GPIO_InitStructure);

  /* ADC Common Init **********************************************************/
  ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;
  ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div2;
  ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_Disabled; // Orig dis
  ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;
  ADC_CommonInit(&ADC_CommonInitStructure);

  /* ADC3 Init ****************************************************************/
  ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
  ADC_InitStructure.ADC_ScanConvMode = ENABLE; //orig disable
  ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
  ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
  ADC_InitStructure.ADC_NbrOfConversion = 4;
  ADC_Init(ADC3, &ADC_InitStructure);

  /* ADC3 regular channel12 configuration *************************************/
  ADC_RegularChannelConfig(ADC3, ADC_Channel_11, 1, ADC_SampleTime_15Cycles);
  ADC_RegularChannelConfig(ADC3, ADC_Channel_12, 2, ADC_SampleTime_15Cycles);
  ADC_RegularChannelConfig(ADC3, ADC_Channel_14, 3, ADC_SampleTime_15Cycles);
  ADC_RegularChannelConfig(ADC3, ADC_Channel_15, 4, ADC_SampleTime_15Cycles);

 /* Enable DMA request after last transfer (Single-ADC mode) */
  ADC_DMARequestAfterLastTransferCmd(ADC3, ENABLE);

  /* Enable ADC3 DMA */
  ADC_DMACmd(ADC3, ENABLE);

  /* Enable ADC3 */
  ADC_Cmd(ADC3, ENABLE);
}

Outcomes