Posted on January 24, 2014 at 23:48
I have used counters and the result can be seen in the picture below. There are two almost identical codes running in the same program that use a separate DMA, TIM and ADC. The ADC sample on TIM CC and DMA transfers the adc samples and signals when transfer is complete.
Sometimes when waiting for the DMA transfer complete interrupt (in a while-loop), it never gets signaled. This is the case for both the DMA ISRs I have in my program.
In the picture below one of them (
DMA2_Channel4_5_IRQHandler
)
suddently did not fire the 11438th time. The timer that belongs to DM2CH4_5 (
TIM8_CC_IRQHandler
) continues to fire interrupts, butI can not confirm if the ADCstilldoes sample. The DMA does increment the pointer to the memory location to save the sampled data, but I can not see that any of the data in thesample buffer is every overwritten.
This might mean there is a problem with the ADC and/or the DMA. Any suggestions on how to debug this further?
I do have some thoughts about the value that is being read continuously in the while loop. This value is written in the DMA ISR. To make sure they do not access the global variable at the same time I have currently done this:
bool_t DMA_IsTransferDone(DMA_t * dma)
{
bool_t temp;
__disable_irq();
temp = dma->isTransferDone;
__enable_irq();
return temp;
}
Could this cause any problems? (I will at a later time onlydisablethe ISRsaccessing this variable).
Image link:
http://itinypic.com/mczxo6.png
