nrf52840 locked in reset

RE: nrf52840 locked in reset

Neunz — Tue, 23 Nov 2021 08:54:18 GMT

Thank you for your time I will create a private ticket.

RE: nrf52840 locked in reset

Håkon Alseth — Tue, 23 Nov 2021 08:36:29 GMT

Hi,

[quote user="Neunz"]Q2. We can not reproduce the issue on other board, even on our custom board the issue only happen on some but not every board. [/quote]

Since you do not see this issue on other boards, it is likely that this specific board has been ESD/EOS damaged on this specific pin.

That can happen if the pin is routed for longer instances, and exposed to the "environment" (for instance direct physical handling), without having ESD protection diode / series resistors to handle such scenarios.

I would recommend that you create a private ticket and ask for a hardware layout review, and specifically mention that you have had one board that has been problematic around the P0.18 pin (ESD/EOS).

Kind regards,

Håkon

RE: nrf52840 locked in reset

Neunz — Tue, 23 Nov 2021 08:20:32 GMT

Q1. We use sensor example from nRF5 SDK for Mesh v5.0.0, after the board is bricked the pin stay locked regardless of the firmware on board.

Q2. We can not reproduce the issue on other board, even on our custom board the issue only happen on some but not every board.

RE: nrf52840 locked in reset

Håkon Alseth — Mon, 22 Nov 2021 15:16:21 GMT

Hi,

[quote user="Neunz"]If "CONFIG_GPIO_AS_PINRESET" is removed, the application work fine but not the reset button.[/quote]

Q1: Are you using P0.18 in your firmware?

Q2: Do you see this issue on other boards as well?

Kind regards,

Håkon

RE: nrf52840 locked in reset

Neunz — Mon, 22 Nov 2021 14:55:13 GMT

Hi,

We use it as reset pin.

If "CONFIG_GPIO_AS_PINRESET" is removed, the application work fine but not the reset button.

RE: nrf52840 locked in reset

Håkon Alseth — Mon, 22 Nov 2021 08:15:27 GMT

Hi,

Are you using P0.18 as a generic GPIO in your application?

In the nRF52840, you can use the P0.18 as nRESET or as generic GPIO (via removing "CONFIG_GPIO_AS_PINRESET" in your preprocessor defines).

The default behavior is to use P0.18 as nRESET, so you have to first issue an erase-all (nrfjprog -e or nrfjprog --recover), then flash the device with your own firmware.

Kind regards,

Håkon