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stm32dmaadcstm32ldiscovery

STM32F3 Discovery board ADC DMA transfer not working

I'm using the STM32F303 (Discovery board) and trying to trigger an ADC conversion externally from a timer signal TRGO2 and store it to a buffer through DMA. However, it doesn't appear that anything is being written to that buffer. Could someone please look through my initialization code and let me know if I'm messing something up during the initialization? I know that the timer triggering works because I am able to read the ADC values when I enable the ADC interrupt.

void InitADC(void)
{
     int i;
     ADC_InitTypeDef       ADC_InitStructure;
     ADC_CommonInitTypeDef ADC_CommonInitStructure;
     GPIO_InitTypeDef    GPIO_InitStructure;
     NVIC_InitTypeDef    NVIC_InitStructure;
     DMA_InitTypeDef         DMA_InitStructure;


     RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

     DMA_DeInit(DMA1_Channel1);

     DMA_InitStructure.DMA_BufferSize = 2;
     DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
     DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
     DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)adcBuffer;
     DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
     DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
     DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
     DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&ADC2->DR;
     DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
     DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
     DMA_InitStructure.DMA_Priority = DMA_Priority_High;
     DMA_Init(DMA1_Channel1, &DMA_InitStructure);

     DMA_Cmd(DMA1_Channel1, ENABLE);

     /* Configure the ADC clock */
     RCC_ADCCLKConfig(RCC_ADC12PLLCLK_Div2);

     /* Enable ADC12 clock */
     RCC_AHBPeriphClockCmd(RCC_AHBPeriph_ADC12, ENABLE);

     ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;
     ADC_CommonInitStructure.ADC_Clock = ADC_Clock_SynClkModeDiv1;
     ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_1;
     ADC_CommonInitStructure.ADC_DMAMode = ADC_DMAMode_OneShot;
     ADC_CommonInitStructure.ADC_TwoSamplingDelay = 0;

     ADC_CommonInit(ADC2, &ADC_CommonInitStructure);

     /* GPIOA Periph clock enable */
     RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);

     /* Configure ADC2 Channel1 as analog input */
     GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_5;
     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
     GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
     GPIO_Init(GPIOA, &GPIO_InitStructure);

     ADC_StructInit(&ADC_InitStructure);

     /* Calibration procedure */
     ADC_VoltageRegulatorCmd(ADC2, ENABLE);
     for(i = 0; i < 1000; i++) {}

     ADC_SelectCalibrationMode(ADC2, ADC_CalibrationMode_Single);
     ADC_StartCalibration(ADC2);

     while(ADC_GetCalibrationStatus(ADC2) != RESET );

     ADC_InitStructure.ADC_ContinuousConvMode = ADC_ContinuousConvMode_Disable;
     ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
     ADC_InitStructure.ADC_ExternalTrigConvEvent = ADC_ExternalTrigConvEvent_10;
     ADC_InitStructure.ADC_ExternalTrigEventEdge = ADC_ExternalTrigEventEdge_RisingEdge;
     ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
     ADC_InitStructure.ADC_OverrunMode = ADC_OverrunMode_Disable;
     ADC_InitStructure.ADC_AutoInjMode = ADC_AutoInjec_Disable;
     ADC_InitStructure.ADC_NbrOfRegChannel = 2;
     ADC_Init(ADC2, &ADC_InitStructure);

     /* ADC2 regular channel1 configuration */
     ADC_RegularChannelConfig(ADC2, ADC_Channel_1, 1, ADC_SampleTime_7Cycles5);
     ADC_RegularChannelConfig(ADC2, ADC_Channel_2, 2, ADC_SampleTime_7Cycles5);

     /* Configure and enable DMA interrupt */
     NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel1_IRQn;
     NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
     NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
     NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
     NVIC_Init(&NVIC_InitStructure);

     /* Enable interrupt */
     7DMA_ITConfig(DMA1_Channel1, DMA1_IT_TC1, ENABLE);

     /* Configures the ADC DMA */
     ADC_DMAConfig(ADC2, ADC_DMAMode_Circular);
     /* Enable the ADC DMA */
     ADC_DMACmd(ADC2, ENABLE);

     /* Enable ADC2 */
     ADC_Cmd(ADC2, ENABLE);
     ADC_DMACmd(ADC2, ENABLE);

     /* wait for ADRDY */
     while(!ADC_GetFlagStatus(ADC2, ADC_FLAG_RDY));

     /* Start ADC2 Software Conversion */
     ADC_StartConversion(ADC2);
}

void DMA1_Channel1_IRQHandler(void)
{
     if (DMA_GetFlagStatus(DMA1_FLAG_TC1) != RESET)
     {
         DMA_ClearITPendingBit(DMA1_FLAG_TC1);
         adcBuffer[0] = (adcBuffer[0] * ADC_VREF) >> 12;
         adcBuffer[1] = (adcBuffer[1] * ADC_VREF) >> 12;
     } 
}

Here's the relevant ADC and DMA register content:

ADC2 CR: 0x10000005

ADC2 CFGR: 0x00000683

DMA1_CH1 CCR: 0x000025A3

DMA1_CH1 CNDTR: 0x00000002

DMA1_CH1 CPAR: 0x50000140

DMA1_CH1 CMAR: 0x2000001C

Solution

  • I appear to have solved the issue. Looking further in the datasheet I realized that ADC2 was not connected to DMA1 channel 1:

    enter image description here

    The correct DMA connection to ADC2 is DMA2 Channel 1:

    enter image description here