UICR Erase when the Battery is disconnected of the device

RE: UICR Erase when the Battery is disconnected of the device

Julien — Tue, 23 Feb 2021 15:37:13 GMT

Okay, thank you for all the answer, i think it will be preferable to use the Flash rather than UICR register in the futur.

Best Regards,

RE: UICR Erase when the Battery is disconnected of the device

Vidar Berg — Tue, 23 Feb 2021 15:20:28 GMT

Then it will ok to use UICR. I just wanted to make sure you were aware of this behavior.

RE: UICR Erase when the Battery is disconnected of the device

Julien — Tue, 23 Feb 2021 15:09:56 GMT

We did not plan to use the readback protection

RE: UICR Erase when the Battery is disconnected of the device

Vidar Berg — Tue, 23 Feb 2021 09:02:34 GMT

There is also the problem that UICR can't be erased if you plan to enable the debugger readback protection on the device like I mentioned in my first reply. Would it be an option to keep this data in a regular flash page instead?

RE: UICR Erase when the Battery is disconnected of the device

Julien — Mon, 22 Feb 2021 15:12:24 GMT

The UICR update happen at every startup,

For the moment , the UICR is not stored on flash but it could be the good solution.

RE: UICR Erase when the Battery is disconnected of the device

Vidar Berg — Mon, 22 Feb 2021 14:12:52 GMT

Hi,

Does this UICR update always happen on startup, or just the first time the device is started after being programmed in production? Either way, it sounds like maybe the update routine should be made more robust to withstand unexpected resets.

Do you keep a backup of the UICR in flash?

RE: UICR Erase when the Battery is disconnected of the device

Julien — Mon, 22 Feb 2021 13:15:43 GMT

Hi,

Yes, at the start we are erasing the UICR to rewrite data. The problem came from our pcb design where at the startup the power supply takes time to stabilize, and go below the brown-out voltage during this operation.

I tried to use the POFCON register to prevent from writing the NVMC if voltage is to low, but my devies stay blocked in a loop. Maybe i need to read an event or something like that ?

So my solution is to put a delay at the start, in order to let time from the power supply to be stabilized.

Thanks,

RE: UICR Erase when the Battery is disconnected of the device

Vidar Berg — Fri, 19 Feb 2021 14:08:09 GMT

Hi Julien,

This is certainly not expected behavior. Is there anything in your application code that uses the NVMC-> ERASEUICR task? Also, does this always happen after you re-insert the battery, or does it occur more intermittently?

And unlike on the 52832, it's not possible to only erase the UICR after readback protection is enabled (ERASEUICR task is blocked): Access port protection behavior

Best regards,

Vidar