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DMA and multiple ADC channels with different buffer sizes

Liam Mullane

Hi

I'm using DMA with ADC1 channels 12 & 16.
ADC1 Channel_16 is the core temperature.
The code below works ie when the DMA flags the DMA_Buffer contains 800 samples, 400 for Channel_12 400 for Channel_16
However I only need a 4 samples for Channel_16
Is there a way to configure the DMA to retrieve 400 samples on Channel_12 and 4 samples on Channel_16.

Thanks
Liam

#define BUFF_SIZE 800
uint32_t DMA_Buffer[BUFF_SIZE];

void ConfigConductivityADC (void)
{ ADC_InitTypeDef ADC_InitStructure;
RCC_ADCCLKConfig(RCC_PCLK2_Div6);
ADC_DeInit(ADC1);
// ADC1 configuration
ADC_InitStructure.ADC_Mode= ADC_Mode_RegSimult;
ADC_InitStructure.ADC_ScanConvMode= ENABLE;
ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T3_TRGO;
ADC_InitStructure.ADC_DataAlign= ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfChannel= 2;
ADC_Init(ADC1, &ADC_InitStructure);
ADC_TempSensorVrefintCmd(ENABLE);
ADC_DMACmd(ADC1, ENABLE);
ADC_RegularChannelConfig(ADC1, ADC_Channel_12, 1, ADC_SampleTime_239Cycles5);
ADC_RegularChannelConfig(ADC1, ADC_Channel_16, 2, ADC_SampleTime_239Cycles5);
ADC_ExternalTrigConvCmd(ADC1, ENABLE);
ADC_Cmd(ADC1, ENABLE);
ADC_ResetCalibration(ADC1);
while(ADC_GetResetCalibrationStatus(ADC1));
ADC_StartCalibration(ADC1);
while(ADC_GetCalibrationStatus(ADC1));
}

void ConfigConductivityDMA(void)
{ DMA_InitTypeDef DMA_InitStructure;
/* DMA1 channel1 configuration ----------------------------------------------*/
DMA_DeInit(DMA1_Channel1);
DMA_InitStructure.DMA_PeripheralBaseAddr=ADC1_DR_Address;
DMA_InitStructure.DMA_MemoryBaseAddr=(uint32_t)DMA_Buffer;
DMA_InitStructure.DMA_DIR=DMA_DIR_PeripheralSRC;
DMA_InitStructure.DMA_BufferSize=BUFF_SIZE;
DMA_InitStructure.DMA_PeripheralInc=DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc=DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_PeripheralDataSize=DMA_PeripheralDataSize_Word;
DMA_InitStructure.DMA_MemoryDataSize=DMA_MemoryDataSize_Word;
DMA_InitStructure.DMA_Mode=DMA_Mode_Circular;
DMA_InitStructure.DMA_Priority=DMA_Priority_High;
DMA_InitStructure.DMA_M2M=DMA_M2M_Disable;
DMA_Init(DMA1_Channel1, &DMA_InitStructure);
}