nRF52 Flash Protection

RE: nRF52 Flash Protection

Adam Varga — Wed, 24 Aug 2016 09:24:42 GMT

That did the trick, thank you so much! For anyone with the same issue: look for NVMC CONFIG register and WEN.

RE: nRF52 Flash Protection

RK — Tue, 23 Aug 2016 23:39:55 GMT

Did you do a reset? The UICR contents is only loaded after a reset. And thinking about it, if UICR counts as flash, you need to enable the NVMC for flash writes before you write it.

RE: nRF52 Flash Protection

Adam Varga — Tue, 23 Aug 2016 14:42:47 GMT

When I write 0xFFFFFF00 to that register and I read it back after that, I get 0x47004800. When I read in the first place I get the reset value (0xFFFFFFFF).

Anyways, I can still read back the whole memory after writing the given values to the APPROTECT register. What do I do wrong?

RE: nRF52 Flash Protection

Adam Sillye — Mon, 22 Aug 2016 15:23:58 GMT

Ahh... thank you! :) It's there indeed... We'll put it right in the beginning.

RE: nRF52 Flash Protection

RK — Mon, 22 Aug 2016 12:11:01 GMT

This is in section 14.1.62 of the product spec, the description for the APPPROTECT register which tells you to write 0x00 to the lowest 8 bits of that register to disable SWD access.

You can do that any way you please, by putting it in the code image, by setting it afterwards with a debugger (thus disabling that debugger from then on) or having the code check and write it the first time it runs.