ADC DMA overrun

Here's my DMA IRQ handler

void DMA2_Stream4_IRQHandler ()
{ extern uint16_t ADC_DMA_Buffer [DMA_BUFFER_SIZE]; extern bool dataALCready; extern uint16_t probeALCdata[PERIOD], plusALCdata[PERIOD]; uint16_t probeChan_A, plusChan_B; //Locator probe and UTP log amped TEV signals respectively static uint16_t count = 0; uint8_t i;

if ( DMA_GetITStatus(DMA2_Stream4, DMA_IT_TCIF4) != RESET)//if the stream transfer is complete

{ DMA_ClearITPendingBit(DMA2_Stream4, DMA_IT_TCIF4);

probeChan_A = ADC_DMA_Buffer [0]; //copy DMA contents into globals plusChan_B = ADC_DMA_Buffer [1]; probeTEV [count] = probeChan_A; // Array to store 20ms worth of LP TEV signals plusTEV [count] = plusChan_B; // Array to store 20ms worth of UTP TEV signals count++; if (count == 20) { for ( i = 0; i < count; i++) { probeALCdata [i] = probeTEV [i]; plusALCdata [i] = plusTEV [i]; } count = 0; }

}

}

DMA_InitStruct.DMA_Mode = DMA_Mode_Normal;

You'll need to reinitialize the transfer at every TC, perhaps you should use Circular Mode?

What happens when you get a HT interrupt? If you don't service interrupt you enable the processor will keep entering the interrupt handler.

Consider the use of HT/TC to handle half the buffer at each interrupt, and use of circular so that it keeps going.

worked!
Thanks very much Clive!

Hi Clive, I was wondering if you could be of further assistance at all.

Below is my set up for a regular ADC conversion for channels 12 and 13.
I am using DMA as whon in the previous post to copy the data from the ADC buffer. But I'm having another problem now.

Channel 12 seems to be following channel 13. i.e when I have the analogue input of channel 12 set at around 100 mV and the channel 13 set at say around 600mV, channel 13 reads 600mV okay but the channel 12 reads just short of channel 13's value nothing close to the 100mV value. Any ideas on what I'm doing wrong?

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_112Cycles);  //tocheck
        /*ADC Channel for UTP TEV*/
        ADC_RegularChannelConfig(ADC1, ADC_Channel_13,2,ADC_SampleTime_112Cycles);


        /* 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_Circular;
                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 = 0;
                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*/

        }



void DMA2_Stream4_IRQHandler ()
{
                extern uint16_t ADC_DMA_Buffer [DMA_BUFFER_SIZE];
                extern bool dataALCready;
                extern uint16_t probeALCdata[PERIOD], plusALCdata[PERIOD]; //buffers to store 20 ms worth of raw TEv signals
                uint16_t probeChan_A, plusChan_B;    //Locator probe and UTP log raw TEV signals respectively
                static uint16_t count = 0;
                uint8_t i;
                uint16_t probeTEV[PERIOD];
                uint16_t plusTEV[PERIOD];

                if ( DMA_GetITStatus(DMA2_Stream4, DMA_IT_HTIF4) != RESET)//if the stream transfer is complete

                {
                                probeChan_A = ADC_DMA_Buffer [0];        //copy DMA contents into globals
                                DMA_ClearITPendingBit(DMA2_Stream4, DMA_IT_HTIF4);
                }

                if ( DMA_GetITStatus(DMA2_Stream4, DMA_IT_TCIF4) != RESET)//if the stream transfer is complete

                {
                                plusChan_B = ADC_DMA_Buffer [1];
                                probeTEV [count] = probeChan_A;                   //    Array to store 20ms worth of LP TEV signals
                                plusTEV [count] = plusChan_B;                   // Array to store 20ms worth of UTP TEV signals
                                count++;
                                if (count == 20)
                                {                               for ( i = 0; i < count; i++)
                                        {
                                                probeALCdata [i] = probeTEV [i];
                                                plusALCdata [i] = plusTEV [i];
                                        }
                                        count = 0;
                                }
                DMA_ClearITPendingBit(DMA2_Stream4, DMA_IT_TCIF4);
                }

}