nRF52840 DK wont turn on

RE: nRF52840 DK wont turn on

brianreinhold — Mon, 15 Nov 2021 09:25:52 GMT

No one does OOBs on purpose! But they are bound to happen when developing new code that is working with individual bytes as one often does in transport protocols. It's scary that I can permanently brick my board doing an out of band write. I have trashed my code doing OOBs but this kind of trashing is a first!

RE: nRF52840 DK wont turn on

Simonr — Mon, 15 Nov 2021 09:14:24 GMT

If you overwrite I.E the UICR that can indeed cause the board to get into this state. It is not recommended to do OOB writes, as the behavior when doing so will be undefined, and may even break it to a point where a reset like this no longer works. I'm glad you got it working again.

Best regards,

Simon

RE: nRF52840 DK wont turn on

brianreinhold — Fri, 12 Nov 2021 15:02:25 GMT

I used the Segger IDE to flash the project. It had to be something I did in code because the project worked and then this happened after many code changes. Device manager in WIndows no longer showed the com port.

What I ended up doing was reverting the project (was in GIt) and that worked. After a few hours I got back to where I wanted to be and everything was good. Whatever mistake I made the first time did not repeat. Would an out-of-bounds write kill the firmware? I have made out of bounds writes before but I never crashed the board!

RE: nRF52840 DK wont turn on

Simonr — Fri, 12 Nov 2021 14:20:52 GMT

Can you provide some more details on what this project you install is? Is any SDK example causing your device to disconnect from PuTTY and "mess up the board" or is just one specific example causing this? One reason I could think of is that the UART pins are configured differently in this other project causing the PuTTY interface to disconnect. Also, what IDE are you using to build and flash your projects?

Best regards,

Simon