Missing ADC Samples when using double buffer circular DMA on STM32F407VG

[kaihaacks]

Posted on December 19, 2013 at 11:36The original post was too long to process during our migration. Please click on the attachment to read the original post.

[kaihaacks]

Posted on December 19, 2013 at 13:35

I found my problem:

To check the contents of the buffers with the ADC results I set a breakpoint inside the DMA transfer complete interrupt handler and did not stop the ADC. I guess the breakpoint did not stop the ADC and it continued writing samples into the buffer. So the content seems to be a mixture from old and new Samples. If I stop the ADC just before the breakpoint everything works as expected.

[Tesla DeLorean]

Posted on December 19, 2013 at 17:24

Ok, yes the DMA and lots of peripherals operate autonomously of the core, got to watch that, and also that memory used in such a way is known to the compiler as volatile.