RE: Problem on combining ADC, GPIO, and BLE

user81429 — Mon, 13 Jun 2022 05:36:12 GMT

Wow Thanks, Thorsrud!!

I accepted your first suggestion.

I increased the ADC buffer size, and it was really helpful.

Also, I increased the connection interval, and it makes perfect operation.

Thank you again,.

RE: Problem on combining ADC, GPIO, and BLE

user7377 — Fri, 10 Jun 2022 11:36:07 GMT

Hi,

As you only see this when BLE is in use I assume this is related to SoftDevice interrupts, which have high priority. You can refer to the SoftDevice specification to see for how long the SoftDevice can block the application (Bluetooth Low Energy processor usage patterns). If this causes problems then there are several potential ways around it:

If the SAADC sampling happens for a not too long time, provide a long ADC buffer so that the CPU is only needed to start sampling and process the samples after all samples are collected (I see you already trigger sampling and toggle the GPIOs using a timer and PPI, so that does not involve the CPU).
If you do not need to do the time critical operations continuously, you could consider doing it in timeslots. During that time, you will not get interrupted by the SoftDevice.