System reset while enabling ADC in main loop

[Avadacadabara]

Hi all,

I occurred a weird phenomenon while debugging custom nRF52832 board.

Basic idea is to enable ADC(including nRF52832 ADC module and a LDO powering Analog front-end circuit) while receiving certain command via BLE.

It works properly when testing on 52832 DK, but only 1 out of 5 custom boards work as expected. 

The failure boards act normally until I send the command -- system seems reset immediately. 

Here are what the boards suppose to do after receiving the command:

1. set the GPIO as output and put it high to drive the LDO
2. initiate 52832 ADC module

I tried to set LDO driving pin high in front of the main loop and the failure boards works. But I just can't modify this pin inside the main loop whitout causing system reset.

Since DK and one of the custom boards works well, I assume the problem lies in the hardware. But which part might be the cause?

Thanks,

Ava   

[Avadacadabara]

Updates：

I'm currently using P0.25 as LDO Enable pin. Even if I put the pin configuration in front of main loop, if I switch the status(for instance: set P0.25 as output, pull it high, delay for 100ms, then pull it low), system will crash.

I've also attached enable pin parameters from LDO datasheet.

[JONATHAN LL]

Do you receive any error message when it crashes, could you possibly share a log of what is happening during the crash ?


I can take a look at the HW and see if there is anything iffy going on that could be causing trouble for you. If you could share schematics and HW layout files as GERBER file or a Altium file then i will update you with any feedback on the layout. 

If you don't want to share the files publicly I can make this case private, just say so and I will make it happen. 

Regards,
Jonathan