Power removal on nRF52832 chip.

[EmanuelePozziNordic]

  Hello,

  I have some questions on power removal on nRF52832 chip.

  I think that some tasks are managed by the application and some other directly from the stack, the
  firsts are under "our" control, the seconds are directly managed by the stack.
  I have not a full understanfing till now of the separation of these task, i do not know eaxcly what is done
  by the softdevice and what is required to be implemented by the application.

  In general the device may be in different statues, i.e. advertisining, connected,... if we remove the power
  from the MCU is there any conditions that can generate an unrecoverable error ?

  I am thinking for example to the pairing where the MCU saves the pairing information in the flash.
  Supposing that the power is removed in the middle of a saving what happen ?
  Is is possible to recover the situation ? (i.e. the last pairing is lost but the previous remains)

  Thanks in advance
  Best regards
  Emanuele

[Simonr]

Hi Emanuele

Due to the Power on reset and the Brownout reset, the device will always be reset in a safe state. A reset, at any point, will not be able to brick the chip/ cause an unrecoverable error as you describe.

Please also read up on the Power supply supervisor for more info.

Best regards,

Simon

[EmanuelePozziNordic]

Hi Simon,

thanks for you reply.

My main point was on corruption of data saved in MCU internal flash. I try to better explain.

During a piaring some data are saved in the flash (by the stack i suppose),if we remove the power during the writing in the flash the flash can be corrupted at next restart (data partially saved, crc mismatch)

I suppose that these data aree saved/managed by the BLE stack (softdevice), is this correct ?

At restart, the device will find unconsistend data, what happen ?

We have an error and we can anyway recover the situation, are API availble ?

Thanks in advance

Best regars

Emanuele

[Simonr]

Hi Emanuele

We had some issues like this early on with the nRF51 series, but I believe this was fixed in the later revisions of that chip. None of the nRF52 series chips should have any problems with the flash being corrupted due to a power outage while doing flash operations, or any other operations for that matter.

Best regards,

Simon

[EmanuelePozziNordic]

Hi SImon,

grat news !

Thanks

Best regards

Emanuele