How to run nrf52 SAADC continuously non-stop without interrupts?

RE: How to run nrf52 SAADC continuously non-stop without interrupts?

sunnyyangfine — Mon, 04 Sep 2017 11:47:47 GMT

Your answer I always can not find the location, can not prompt an exact xx.c xx line position

RE: How to run nrf52 SAADC continuously non-stop without interrupts?

Jørgen Holmefjord — Thu, 02 Feb 2017 12:30:04 GMT

Yes, your solution should work. You would not need the RTC then.

RE: How to run nrf52 SAADC continuously non-stop without interrupts?

DL — Tue, 31 Jan 2017 23:31:54 GMT

That sample has lines:

/************************* STOP SAMPLING AT END EVENT (When buffer is full.) *************************/   
NRF_PPI->CH[2].EEP = (uint32_t)&NRF_SAADC->EVENTS_END;
NRF_PPI->CH[2].TEP = (uint32_t)&NRF_SAADC->TASKS_STOP;
NRF_PPI->CHEN |= PPI_CHENSET_CH2_Enabled << PPI_CHENSET_CH2_Pos;

But I need the opposite: run SAADC non-stop. Can I enter these lines:

NRF_PPI->CH[2].EEP = (uint32_t)&NRF_SAADC->EVENTS_END;
NRF_PPI->CH[2].TEP = (uint32_t)&NRF_SAADC->TASKS_SAMPLE;
NRF_PPI->FORK[2].TEP = (uint32_t)&NRF_SAADC->TASKS_START;
NRF_PPI->CHEN |= PPI_CHENSET_CH2_Enabled << PPI_CHENSET_CH2_Pos;

Would this work? Then I would not need RTC, right?

RE: How to run nrf52 SAADC continuously non-stop without interrupts?

DL — Tue, 31 Jan 2017 03:29:25 GMT

If I understand this sample correctly, RTC starts SSADC 3 times a second (NRF_RTC1->CC[0] = 10000) and SSADC captures 10 samples and stops. But I need to run SSADC continuously, without stops (for the purpose of low limit detection). How to do that?

RE: How to run nrf52 SAADC continuously non-stop without interrupts?

Jørgen Holmefjord — Mon, 30 Jan 2017 10:05:54 GMT

This example might be what you are looking for. It use RTC and PPI to trigger the SAADC, and use double buffering to sample in one buffer while the other register is read.