Can't change ERASEPROTECT.DISABLE value

[erik.johnson]

If I write a value to ERASEPROTECT.DISABLE -- which itself works, as I'm fully able to perform the mass erase by writing the same value using the debugger -- I can't seem to write a new value to the register during the same boot. It presumably isn't flash-based, since it needs to be written each boot. Is this specifically being prevented by the core? Is there a way to "reset" the value and write a new one, assuming ERASEPROTECT.LOCK hasn't been set?

[erik.johnson]

Hopefully someone will have some more ideas on how to get the nrfjprog programming working.

As for the NVMC fields, I was mostly just talking about NVMC->CONFIGNS and how the NVMC peripheral hadn't been set to Non-Secure (in the SPU->PERIPHID[n].PERM registers). Like I said before, though, even after setting the permission to Non-Secure nrfjprog still isn't working.

Looking at nAN41, it seems like nrfjprog/a debugger should be fully capable of programming the Non-Secure flash using the DAP. I'm definitely not experienced enough with debuggers to be able to quickly put together a custom DAP script to accomplish the programming, so I'll wait to hear what the Nordic team has to say.

Thanks!

[Øyvind]

Hi Erik, 

Our system architecture group reports that you are correct, and that this a Write Once register. Currently no fix available unfortunately. 

Kind regards,
Øyvind

[erik.johnson]

Okay, thanks for confirming the behavior I was seeing.

Any word on the nrfjprog stuff yet? That's a far more important issue for us to get figured out.

[Øyvind]

erik.johnson said:

Any word on the nrfjprog stuff yet? That's a far more important issue for us to get figured out.

 It's a known limitation in nrfjprog, and unfortunately no workaround yet. According to the nrfjprog team there will not be a fix until after next release. 

Sorry for the inconvenience this may cause. 

Kind regards,
Øyvind