Auto-rebooting firmware after flashing

[mlac]

Hi there,

After flashing the firmware of the nRF52840 with JLink, I'd expect it to restart, but it gets stuck, and I have to power-cycle my board every time after flashing it.

Is this normal, and how to auto-restart the firmware after flashing it from Visual Studio Code?

[Vidar Berg]

Hello,

Yes, the board should normally be reset after the programming is complete. Are you developing on a DK or a custom board? Maybe PINRESET is not supported on the board you're using?

Best regards,

Vidar 

[mlac]

Hi Vidar,

I'm developing on a custom board. How should I implement the mentioned PINRESET functionality?

[Vidar Berg]

Please see my answer in this post:  Pin reset with nrfjprog has no effect . You can change the default reset type in your board file from pinreset to softreset if pinreset is not available on your board. 

[mlac]

Thanks, adding `board_runner_args(nrfjprog "--softreset")` to board.cmake worked!

Why is it not added by default? Or, in other words, why wouldn't one want to reset the board after flashing it?

[Vidar Berg]

The board should always be reset after programming. However, the default reset type is --pinreset, which only works if the reset line is routed to the debug header on the board, like on the nRF52480 DK. Therefore, when the reset pin is unavailable, the board file must be modified to set the default reset type to a soft reset.