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STM32F4 ADC DMA Overrun problem

Question asked by adeyemi.oluwaseun on Dec 3, 2015
Latest reply on Dec 3, 2015 by Clive One

I have been struggling on this over the past few days and its starting to really push my buttons now.

Device: sTM32F405RGTX

Basically I have ADC 1 configured in regular mode Channel 10 and 11, and I am using DMA to get the values from it and pass it onto a global variable.

the ADC is triggered by a timer TIM3_TRGO

The problem I'm facing is on the peripheral viewer, I can see that the ADC is overrunning, i.e OVR register is set high. when i try to debug and run the code, the ADc output is stuck o one value, however when I untick the OVR register in the periph viewer, it (ADC output) updates for a few secs and the OVR goes back high again.

I think it might be something to do with the fact that maybe the DMA isn't somehow configured right. On first run I can see it copies a value into my buffer but then afterwards its just stuck can someone help please?

void Config_ADCtimer_init ()  //Regular ADC Timer{        TIM_TimeBaseInitTypeDef Timer_Struct;        RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //enabling the clock for Timer 3        Timer_Struct.TIM_Period = 16000-1; //scaled to 1000khz        Timer_Struct.TIM_Prescaler = 1000-1;        Timer_Struct.TIM_CounterMode = TIM_CounterMode_Up;        Timer_Struct.TIM_ClockDivision = TIM_CKD_DIV1;        TIM_TimeBaseInit(TIM3, &Timer_Struct);  //Enabling Timer 3        TIM_SelectOutputTrigger(TIM3,TIM_TRGOSource_Update); // ADC_ExternalTrigConv_T2_TRGO        TIM_Cmd(TIM3,ENABLE);}void Config_RegADC_Init(void){        ADC_InitTypeDef ADC_InitStruct;        GPIO_InitTypeDef GPIO_InitStructure;  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);        RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);        //GPIO setups PC3 and  PC4 for the raw TEV signals        GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3|GPIO_Pin_4;        GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;        GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;        GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;        GPIO_Init(GPIOC, &GPIO_InitStructure);        ADC_DeInit(); //Default All ADC settings registers        ADC_InitStruct.ADC_Resolution = ADC_Resolution_12b;        ADC_InitStruct.ADC_DataAlign = ADC_DataAlign_Right;        ADC_InitStruct.ADC_ContinuousConvMode = DISABLE;        ADC_InitStruct.ADC_NbrOfConversion= 2;        ADC_InitStruct.ADC_ScanConvMode= ENABLE;        ADC_InitStruct.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T3_TRGO ;//TIM3 trigger output TIM3 is a 16 bit timer.Reg ADC        ADC_InitStruct.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_Rising;        ADC_Init(ADC1, &ADC_InitStruct);  /* Enable ADC1 DMA */        ADC_DiscModeChannelCountConfig(ADC1, 2);   //Discontinuous Mode configuration        ADC_DiscModeCmd(ADC1, ENABLE);        /*ADC Channel for LP TEV*/        ADC_RegularChannelConfig(ADC1, ADC_Channel_12,1,ADC_SampleTime_56Cycles);  //tocheck        /*ADC Channel for UTP TEV*/        ADC_RegularChannelConfig(ADC1, ADC_Channel_13,2,ADC_SampleTime_56Cycles);        /* Enable DMA request after last transfer (Single-ADC mode) */  ADC_DMARequestAfterLastTransferCmd(ADC1, ENABLE);        ADC_DMACmd(ADC1, ENABLE);        ADC_Cmd(ADC1, ENABLE);}void  RegADC_DMA_Setup ()        {                DMA_InitTypeDef DMA_InitStruct;                NVIC_InitTypeDef   NVIC_ADCRegDMA_InitStruct;          RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE);                DMA_ITConfig (DMA2_Stream4, DMA_IT_TC | DMA_IT_HT, ENABLE);                DMA_InitStruct.DMA_Channel = DMA_Channel_0;                DMA_InitStruct.DMA_PeripheralBaseAddr = (uint32_t)ADC1_DR_ADDRESS;                DMA_InitStruct.DMA_Memory0BaseAddr = (uint32_t)&ADC_DMA_Buffer[0];                DMA_InitStruct.DMA_DIR = DMA_DIR_PeripheralToMemory;                DMA_InitStruct.DMA_BufferSize = DMA_BUFFER_SIZE;                DMA_InitStruct.DMA_PeripheralInc = DMA_PeripheralInc_Disable;                DMA_InitStruct.DMA_MemoryInc = DMA_MemoryInc_Enable;                DMA_InitStruct.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;                DMA_InitStruct.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;                DMA_InitStruct.DMA_Mode = DMA_Mode_Normal;                DMA_InitStruct.DMA_Priority = DMA_Priority_High;                DMA_InitStruct.DMA_FIFOMode = DMA_FIFOMode_Disable;                DMA_InitStruct.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;                DMA_InitStruct.DMA_MemoryBurst = DMA_MemoryBurst_Single;                DMA_InitStruct.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;                DMA_Init(DMA2_Stream4, &DMA_InitStruct); //adc1 is on dma2 channel 0 stream 4                /***NVIC Setup for the DMA***/                NVIC_ADCRegDMA_InitStruct.NVIC_IRQChannel = DMA2_Stream4_IRQn;    //dma 2 stream 4 pertains to ADC1                NVIC_ADCRegDMA_InitStruct.NVIC_IRQChannelPreemptionPriority = 1;                NVIC_ADCRegDMA_InitStruct.NVIC_IRQChannelSubPriority = 0;                NVIC_ADCRegDMA_InitStruct.NVIC_IRQChannelCmd = ENABLE;                NVIC_Init (&NVIC_ADCRegDMA_InitStruct);                DMA_Cmd(DMA2_Stream4, ENABLE);                ADC_DMARequestAfterLastTransferCmd(ADC1, ENABLE);                /*Enabling the DMA interput for a halfway transfer and end of copy transfer*/        }

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