Sparkfun NRF52840 Mini Breakout Board - Bricked after trying to use UICR register

RE: Sparkfun NRF52840 Mini Breakout Board - Bricked after trying to use UICR register

Simonr — Tue, 19 Mar 2024 09:52:38 GMT

Glad to hear that! Then I guess we can close this case.

Best regards,

Simon

RE: Sparkfun NRF52840 Mini Breakout Board - Bricked after trying to use UICR register

Jagannath — Mon, 18 Mar 2024 13:12:14 GMT

Simonr Thanks for you input. I used OpenOCD and Raspberry Pi to flash the device. There is a small mistake on my side. As the cfg file in raspberry pi is different compared to all online tuitorials, I made a small error. Now I have flashed bootloader and it works fine.

Thanks again Simonr ! 😃

RE: Sparkfun NRF52840 Mini Breakout Board - Bricked after trying to use UICR register

Simonr — Thu, 14 Mar 2024 14:26:38 GMT

What voltage level does the RaspberryPi support the nRF with here? Can it provide 1.8V or 3.0V. Depending on what state your nRRF52840 is locked in, the voltage level of the programmer needs to match the level of the nRF52840 SoC.

Best regards,

Simon

RE: Sparkfun NRF52840 Mini Breakout Board - Bricked after trying to use UICR register

Jagannath — Thu, 14 Mar 2024 12:54:12 GMT

Hi, Thanks for the reply.

I didnt have JLink with me. So I tried OpenOCD in Raspberry Pi.

I am getting external reset detected!

But I didnt press reset button

RE: Sparkfun NRF52840 Mini Breakout Board - Bricked after trying to use UICR register

Simonr — Wed, 13 Mar 2024 13:41:15 GMT

The Sparkfun boards aren't our designs, so I don't know the specifics of it or what the bootloader entails, but since it has a USB bootloader I assume it's somewhat comparable to the nRF52840 Dongle. If you have written something to the UICR without knowing if it overrides the bootloader or not, that is likely what has happened, and why it seems bricked.

You most likely needs to reflash the bootloader somehow. I see the Adafruit bootloader source code is available online, so it should be possible. First you need access to VDD, GND, SWDIO and SWDCLK on the onboard nRF52840. See the HW specifications for how to do so. Then you need a J-Link programmer so you can communicate with the SoC and flash the bootloader back onto it.

Best regards,

Simon