STM32F4 DMA doesn't control ADC channels

Question

I'm trying to set up my STM32F407-Discovery board to read multiple ADC channels from ADC1 using the DMA controller. I can easily read the analog value one at a time without using DMA, but as soon as I enable DMA for the ADC, ADC1->DR is always 0, and adc_vals is filled with zeros. Furthermore, it hangs on while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC));.

EDIT: it would appear DMA_GetCmdStatus is returning DISABLED. Any ideas?

Is there a way to start the ADC or something that I'm missing?

//setup adc1: in1,2,3,8,9,15
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1,ENABLE); //adc1 on the apb2 peripheral bus
ADC_InitTypeDef adc;
ADC_DeInit(); //set adc to default state
adc.ADC_DataAlign = ADC_DataAlign_Right;
adc.ADC_Resolution = ADC_Resolution_12b;//12 bit = 4096
adc.ADC_ContinuousConvMode = ENABLE;
adc.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T1_CC1;
adc.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
adc.ADC_NbrOfConversion = NUM_ADC;
adc.ADC_ScanConvMode = ENABLE;
ADC_Init(ADC1,&adc);


ADC_DMACmd(ADC1, ENABLE); //enable adc for dma.  When this line is removed, I see data on ADC1->DR


ADC_Cmd(ADC1,ENABLE);

ADC_RegularChannelConfig(ADC1,ADC_Channel_1,1,ADC_SampleTime_144Cycles);//1:1710, 0
//ADC_RegularChannelConfig(ADC1,ADC_Channel_2,2,ADC_SampleTime_144Cycles);//2:1710, 0
//ADC_RegularChannelConfig(ADC1,ADC_Channel_3,3,ADC_SampleTime_144Cycles);//3:1710, 0
ADC_RegularChannelConfig(ADC1,ADC_Channel_8,4,ADC_SampleTime_144Cycles);//8:3520
ADC_RegularChannelConfig(ADC1,ADC_Channel_9,5,ADC_SampleTime_144Cycles);//9:1000
//ADC_RegularChannelConfig(ADC1,ADC_Channel_15,6,ADC_SampleTime_144Cycles);//15:3920


//DMA for multiple adc channels:
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE); //dma1 clock enable
DMA_InitTypeDef dma;

DMA_DeInit(DMA2_Stream0); //reset DMA2 stream 0 to default values
dma.DMA_Channel = DMA_Channel_0;
dma.DMA_PeripheralBaseAddr = (uint32_t)&(ADC1->DR);
dma.DMA_Memory0BaseAddr = (uint32_t)&adc_vals[0];
dma.DMA_DIR = DMA_DIR_PeripheralToMemory;
dma.DMA_BufferSize = NUM_ADC;
dma.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
dma.DMA_MemoryInc = DMA_MemoryInc_Enable;
dma.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
dma.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
dma.DMA_Mode = DMA_Mode_Circular;
dma.DMA_Priority = DMA_Priority_High;
dma.DMA_FIFOMode = DMA_FIFOMode_Disable;
dma.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
dma.DMA_MemoryBurst = DMA_MemoryBurst_Single;
dma.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
DMA_Init(DMA2_Stream0, &dma);

DMA_ITConfig(DMA2_Stream0, DMA_IT_TC | DMA_IT_HT, ENABLE); //Enable DMA Stream Half / Transfer Complete interrupt

DMA_Cmd(DMA2_Stream0, ENABLE); //DMA2_Stream0 enable

//dma transfer complete interrupt:
NVIC_InitTypeDef nvic;
//Enable DMA1 channel IRQ Channel
nvic.NVIC_IRQChannel = DMA2_Stream0_IRQn;
nvic.NVIC_IRQChannelPreemptionPriority = 0;
nvic.NVIC_IRQChannelSubPriority = 0;
nvic.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&nvic);

ADC_SoftwareStartConv(ADC1);//Start the adc conversion

Well, part of my problem was that dma wasn't set up before the adc. Now, I can read exactly one adc value from ADC1->DR, but it freezes there and is still zero in adc_vals[i] — ethan

Yuriy Yuriy · Accepted Answer · 2017-03-10T22:26:51

At least you can try:

change DMA_PeripheralInc to enable
use ADC_DMARequestAfterLastTransferCmd(ADC, Enable); for dma request after group conversion.
init ADC_CommonInitTypeDef
init GPIO, if not

Moreover enabling ADC before all the configurations is strange.

In my opinion the best way is to copy-paste "ADC_DualModeRegulSimu"example from standard peripherals library. It contains beautiful code exactly for your purpose.

STM32F4 DMA doesn't control ADC channels

3 Answers