the NRF52840 microcontroller enters an unknown state where Bluetooth cannot be detected

[zengbo]

I have a question to ask. After being subjected to interference, the NRF52840 microcontroller enters an unknown state where Bluetooth cannot be detected. The RESET pin grounding for reset does not respond, and even battery depletion followed by recharging does not reset it. It only returns to normal after power is disconnected and then reconnected. Have you encountered this situation before? How can it be resolved?

[Kenneth]

Hello,

After being subjected to interference

Could be interesting to understand a bit more what interference this may be. But the chip will operate normally within the operating conditions, if there are "power spikes" for unknown reason outside the operating conditions, that can cause an invalid state, then it may enter an undefined state which will require a valid power on reset to start operating again (e.g. below <0.3V to above >1.8V within 60ms).

I assume inductors and long wires can be the place to start looking (e.g. shield them or remove) if those are the ones picking up the interference you refer to.

Kenneth