Problems with ADC and dma

[Ernesto B]

Posted on January 15, 2017 at 21:34

The original post was too long to process during our migration. Please click on the attachment to read the original post.

https://community.st.com/s/question/0D50X00009XkdduSAB/triggering-adc-in-dual-mode-with-dma-problems

[Ernesto B · Accepted solution]

Posted on January 26, 2017 at 11:59

At the end it seems the problem was this one:

https://community.st.com/0D50X00009XkdfSSAR

Having a look at the code generated by STM32CubeMX, where it says:

hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;�?�?�?�?

Is wrong, it should be:

hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;�?�?�?�?

So STM32CubeMX is not generating the correct initialization code for the chosen options.

Cheers.

[Imen.D]

Posted on April 07, 2017 at 17:29

Hello

Barragan.Ernesto

,

I reported this issue internally to our CubeMx team for further check and investigation.

Thank your for your contribution.

Regards

Imen

[Angus Cunningham-Burley_O]

Posted on August 25, 2017 at 12:37

Hello

Barragan.Ernesto

,

I have tried to reproduce your configuration with CubeMX 4.

HoweverI'm unable to get the same generated code as you for the Peripheral DMA init.

If IactivateUse Fifo (enable FIFOMode), then I obtain:

hdma_adc1.Instance = DMA2_Stream0;

hdma_adc1.Init.Channel = DMA_CHANNEL_0; hdma_adc1.Init.Direction = DMA_PERIPH_TO_MEMORY; hdma_adc1.Init.PeriphInc = DMA_PINC_DISABLE; hdma_adc1.Init.MemInc = DMA_MINC_ENABLE; hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD; hdma_adc1.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD; hdma_adc1.Init.Mode = DMA_NORMAL; hdma_adc1.Init.Priority = DMA_PRIORITY_VERY_HIGH; hdma_adc1.Init.FIFOMode = DMA_FIFOMODE_ENABLE; hdma_adc1.Init.FIFOThreshold = DMA_FIFO_THRESHOLD_HALFFULL; hdma_adc1.Init.MemBurst = DMA_MBURST_SINGLE; hdma_adc1.Init.PeriphBurst = DMA_PBURST_SINGLE;

But if I deactivate Use Fifo (disable FIFOMode), then I get:

hdma_adc1.Instance = DMA2_Stream0;

hdma_adc1.Init.Channel = DMA_CHANNEL_0; hdma_adc1.Init.Direction = DMA_PERIPH_TO_MEMORY; hdma_adc1.Init.PeriphInc = DMA_PINC_DISABLE; hdma_adc1.Init.MemInc = DMA_MINC_ENABLE; hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD; hdma_adc1.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD; hdma_adc1.Init.Mode = DMA_NORMAL; hdma_adc1.Init.Priority = DMA_PRIORITY_VERY_HIGH; hdma_adc1.Init.FIFOMode = DMA_FIFOMODE_DISABLE;

You say that your problem is resolved when you change the source transfer width.

hdma_adc1

.

Init

.

PeriphDataAlignment

=

DMA_PDATAALIGN_WORD

;

If -as your code suggests - the Fifo is disabled (direct mode) then data packing/unpacking is not possible and the source and destination transfer data widths are the same and defined by PeriphDataAlignment (PSIZE). This means that although your 'corrected' source code may read:

hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;

hdma_adc1.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;

the hardware implementationwill beequivalent to:

hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;

hdma_adc1.Init.MemDataAlignment = DMA_MDATAALIGN_WORD;

Can you please confirm whether the Fifo mode is enabled or disabled in you code?

Many thanks,

Angus