Triggering ADC from Timer Event & PPI

RE: Triggering ADC from Timer Event & PPI

snoopy20 — Sat, 06 Jun 2020 15:15:07 GMT

Excellent, that could be it!

I also messed up, I need to START and SAMPLE, so two PPI channels.

I do like the auto buffer fill but query how useful RESULT.AMOUNT is. I was hoping I could use it in another interrupt to see which buffer segment holds the latest values, but according to the reference data it can only be queried after a adc DONE event. That would mean the ADC firing an interrupt and copying the RESULT.AMOUNT value into another variable. Or do I have that wrong?

RE: Triggering ADC from Timer Event & PPI

Turbo J — Sat, 06 Jun 2020 10:39:40 GMT

I am 99% sure you wrote the wrong addresses into the PPI.

Correct addresses:

NRF_PPI->CH[CFG_PPI_TASKER_CHANNEL_ADC_START].EEP = (uint32_t)& CFG_TASKER_PIF_TIMER->EVENTS_COMPARE[1]; // wire timer compare
NRF_PPI->CH[CFG_PPI_TASKER_CHANNEL_ADC_START].TEP = (uint32_t)& NRF_SAADC->TASKS_START;