nRF52832 SAADC and BLE

RE: nRF52832 SAADC and BLE

Kenneth — Mon, 13 May 2019 10:02:59 GMT

Priority 0 is the absolute highest priority (and should not be used), it would make more sense if timer use for instance 7 and adc use 6. Ref:

https://infocenter.nordicsemi.com/topic/sds_s140/SDS/s1xx/processor_avail_interrupt_latency/exception_mgmt_sd.html?cp=3_4_2_0_15_1

RE: nRF52832 SAADC and BLE

Aftab — Fri, 10 May 2019 07:59:26 GMT

I changed my code to use Timer 4 to call ADC conversions through PPI instead of calling from APP_TIMER.

I can see the function works fine when called from "while" loop of main. But this causes unwanted delays in other BLE functions. So I called it from Timer 4 (used for ADC as well) after, say 2 sec. Also set the priority like: NVIC_SetPriority(TIMER4_IRQn, 0);

But it still doesn't work.

Kenneth

RE: nRF52832 SAADC and BLE

Kenneth — Wed, 08 May 2019 12:41:33 GMT

If you are calling the function from an app_timer or other peripheral interrupt, then you would need to check the interrupt priority level of the app_timer or peripheral interrupt you set during initialization. If you are calling the function from a while()-loop in main(), then it's not running from an interrupt.

RE: nRF52832 SAADC and BLE

Aftab — Wed, 08 May 2019 08:26:04 GMT

How to check the priority level of a function?

Kenneth

RE: nRF52832 SAADC and BLE

Kenneth — Mon, 06 May 2019 18:43:49 GMT

Can it be a interrupt priority issue, where you are trying to wait for a saadc callback from a function that is at the same interrupt priority level? In such case it is not possible for a interrupt to preempt an interrupt of same priority level.

RE: nRF52832 SAADC and BLE

Aftab — Mon, 06 May 2019 13:29:55 GMT

awneil, I am having a different issue all together in the same code. Unfortunately the thread you are referring does not answer my question.

My issue is not SAADC basic function, rather SAADC is working in certain conditions while not working in other conditions. There are two places from where I'm calling saadc_voltage_get_drive().

1. main() function at startup, when saadc_voltage_get_drive() is called, I can clearly see saadc_callback() being called and I can clearly see ADC values.

2. But I call the same saadc_voltage_get_drive() from another function periodically, saadc_callback() does not fire. It seems like ADC buffer full event takes infinite time to complete, hence I don't get right values, instead previously converted value is returned.

So my problem is why saadc_callback() behaves differently when called from different function, periodically.

RE: nRF52832 SAADC and BLE

awneil — Tue, 30 Apr 2019 08:53:04 GMT

You've already posted this in another thread:

https://devzone.nordicsemi.com/f/nordic-q-a/45259/nrf52832-saadc/184285#184285