what's wrong with my ADC DMA initialization?

[G S]

Posted on November 15, 2017 at 22:13

Hello,

I'm trying to trigger an ADC conversion externally from 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?

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);
#warning 'Figure out priority'
/* Configure and enable ADC2 interrupt */
NVIC_InitStructure.NVIC_IRQChannel = ADC1_2_IRQn;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
/* Enable EOS interrupt */
ADC_ITConfig(ADC2, ADC_IT_EOS, 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 ADC1_2_IRQHandler(void)
{
 if(ADC_GetFlagStatus(ADC2, ADC_FLAG_EOS) != RESET)
 {
 /* Clear ADC2 AWD pending interrupt bit */
 ADC_ClearITPendingBit(ADC2, ADC_IT_EOS);
adcBuffer[0] = (adcBuffer[0] * ADC_VREF) >> 12;
adcBuffer[1] = (adcBuffer[1] * ADC_VREF) >> 12;
 }
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Question 2: The schematic I'm working with is using ADC peripheral 1 and ADC peripheral 2 as part of the group of signals I'd like to sample during the TRGO2 event. Do I need to set up a different DMA channel to capture the sample from the other peripheral?

Thanks.

#dma-adc #dma-transfer #stm32f3

[waclawek.jan]

Posted on November 16, 2017 at 00:46

Which mcu?

Did you verify that your trigger source works and the trigger is set properly in timer?

JW

[G S]

Posted on November 16, 2017 at 06:21

Yes, trigger source works. The ADC interrupt is firing and I can read the value directly from there, however the adcBuffer which is the address the DMA is set to is empty.

I'm using the STM32F303VC. 

[waclawek.jan]

Posted on November 16, 2017 at 09:41

Remove (don't enable) the interrupt. Instead, use the transfer complete interrupt from DMA.

Make sure both DMACFG and DMAEN are set in ADCx_CFGR.

JW

[G S]

Posted on November 16, 2017 at 16:13

You mean by calling 

/* Configures the ADC DMA */

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

?

I did that and removed the ADC interrupt, instead added the DMA interrupt using the following function call:

DMA_ITConfig(DMA1_Channel1, DMA1_IT_TC1, ENABLE);

with this handler:

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;

// Debug LEDs: GPIO_SetBits( GPIOE, GPIO_Pin_9 ); GPIO_ResetBits( GPIOE, GPIO_Pin_9 ); } }

But this interrupt is not firing.  The buffer is still empty.

[waclawek.jan]

Posted on November 16, 2017 at 16:42

Read out and post the relevant ADC and DMA register content.

JW

[G S]

Posted on November 16, 2017 at 17:23

Certainly.  Thanks for your help so far!

Here's the register content:

ADC2 CR: 0x10000005

ADC2 CFGR: 0x00000683

DMA1_CH1 CCR: 0x000025A3

DMA1_CH1 CNDTR: 0x00000002

DMA1_CH1 CPAR: 0x50000140

DMA1_CH1 CMAR: 0x2000001C

[G S · Accepted solution]

Posted on November 17, 2017 at 21:17

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

The correct DMA connection to ADC2 is DMA2 Channel 1: