Hello,
I will use stm32g473VC ADC2 working together with DMA.
I configure ADC2, Input3 at Pin PA6
and DMA2 Channel1 to read 100 Samples from ADC after Start.
At first call after cpu reset I receive the expected result:
ADC:Value 4034 for Items 0->99, as you can see in following output. (what is a correct value)
Item0: 4034
Item1: 4034
Item2: 4034
Item3: 4036
Item98: 4034
Item99: 4034
But at the 2nd and following starts of DMA, the first received value is 0.
Item0: 0
Item1: 4035
Item2: 4035
Item3: 4035
Item98: 4035
Item99: 4035
At every start I call the following functions:
LL_ADC_ClearFlag_EOC(ADC2);
LL_ADC_ClearFlag_EOS(ADC2);
LL_ADC_ClearFlag_EOSMP(ADC2);
LL_ADC_ClearFlag_OVR(ADC2);
LL_DMA_SetDataLength(DMA2, LL_DMA_CHANNEL_1, 100U);
LL_ADC_REG_StartConversion(ADC2);
LL_DMA_EnableChannel(DMA2, LL_DMA_CHANNEL_1);
while (LL_DMA_GetDataLength(DMA2, LL_DMA_CHANNEL_1) > 0U)
{
}
LL_ADC_REG_StopConversion(ADC2);
LL_DMA_DisableChannel(DMA2, LL_DMA_CHANNEL_1);
Comparing ADC2 and DMA registers at first and 2nd call.
FirstCall:
ADC2->ISR: 0x1
ADC2->IER: 0x0
ADC2->CR: 0x10000001
ADC2->CFGR: 0x80003001
ADC2->CFGR2: 0x0
ADC2->SQR1: 0xc0
ADC2->SQR2: 0x0
DMA2_Channel1->CCR: 0x2580
DMA2_Channel1->CPAR: 0x50000140
DMA2_Channel1->CMAR: 0x200003b4
Exactly the same at 2nd and consecutive calls:
ADC2->ISR: 0x1
ADC2->IER: 0x0
ADC2->CR: 0x10000001
ADC2->CFGR: 0x80003001
ADC2->CFGR2: 0x0
ADC2->SQR1: 0xc0
ADC2->SQR2: 0x0
DMA2_Channel1->CCR: 0x2580
DMA2_Channel1->CPAR: 0x50000140
DMA2_Channel1->CMAR: 0x200003b4
At startup I do following configurations:
LL_ADC_REG_SetContinuousMode(ADC2, LL_ADC_REG_CONV_CONTINUOUS);
LL_ADC_REG_SetDMATransfer(ADC2, LL_ADC_REG_DMA_TRANSFER_LIMITED); LL_DMA_SetPeriphRequest(DMA2, LL_DMA_CHANNEL_1, LL_DMAMUX_REQ_ADC2);
LL_DMA_ConfigAddresses(DMA2, LL_DMA_CHANNEL_1,
LL_ADC_DMA_GetRegAddr(ADC2, LL_ADC_DMA_REG_REGULAR_DATA),
reinterpret_cast<uint32_t>(&ReceiveBuffer[0]),
LL_DMA_DIRECTION_PERIPH_TO_MEMORY);
LL_DMA_SetDataTransferDirection(DMA2, LL_DMA_CHANNEL_1, LL_DMA_DIRECTION_PERIPH_TO_MEMORY);
LL_DMA_SetChannelPriorityLevel(DMA2, LL_DMA_CHANNEL_1, LL_DMA_PRIORITY_HIGH);
LL_DMA_SetMode(DMA2, LL_DMA_CHANNEL_1, LL_DMA_MODE_NORMAL);
LL_DMA_SetPeriphIncMode(DMA2, LL_DMA_CHANNEL_1, LL_DMA_PERIPH_NOINCREMENT);
LL_DMA_SetMemoryIncMode(DMA2, LL_DMA_CHANNEL_1, LL_DMA_MEMORY_INCREMENT);
LL_DMA_SetPeriphSize(DMA2, LL_DMA_CHANNEL_1, LL_DMA_PDATAALIGN_HALFWORD);
LL_DMA_SetMemorySize(DMA2, LL_DMA_CHANNEL_1, LL_DMA_MDATAALIGN_HALFWORD);
I have no more idea, what I'm doing wrong.
Maybe you can help me.
Thanks in advance
Best regares johann
