Hello, I have a SPI TX DMA, and I need to do the followingStep 1:start the TX DMA ,Step 2:stop the DMA,Step 3: store the NDTR register,Step 4: modify the size of the DMA SPIStep 5: restart the DMA with the new sizeStep 6: and restore the position of the NDTR register to continue (restart) at the same position as previouslyI guess the last step (6) is not possible ? right ? or is there a way to change the current positionI tried to change it using the __HAL_SET_COUNTER but it is not workingDo I miss something ? Vincent

Senior

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STM32F4x DMA NDTR, need your help

Hello,

I have a SPI TX DMA,

and I need to do the following

Step 1:start the TX DMA ,
Step 2:stop the DMA,
Step 3: store the NDTR register,
Step 4: modify the size of the DMA SPI
Step 5: restart the DMA with the new size
Step 6: and restore the position of the NDTR register to continue (restart) at the same position as previously

I guess the last step (6) is not possible ? right ? or is there a way to change the current position

I tried to change it using the __HAL_SET_COUNTER but it is not working

Do I miss something ?

Vincent

Best answer by TDK

You cannot resume a DMA transfer after changing the size. It always starts at the beginning of the buffer with NDTR at the max/starting value.

TDKBest answer

You cannot resume a DMA transfer after changing the size. It always starts at the beginning of the buffer with NDTR at the max/starting value.

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Senior

This is what I thought as well...

the only way to do it is to shift the memcpy of the new buffer in 2 parts to simulate the resume of the position.

thanks

Vincent