a way to read the flash memory over UART without uploading a firmware to the target chip? (nrf52)

[JohnM]

nRF52832 / SDK V15

Hello,

Is there is way to read the nRF52 flash memory (any location if possible) over UART without uploading a program in the flash memory for that? (because there might be already a firmware there

we don't want to alter)

Basically, it's like asking how "nRF Connect/ Programmer" app can display the flash memory map...

My first guess would be to upload and run a small sketch in the RAM of the target chip and only in there.

Thanks.

[Jørgen Holmefjord]

Hi,

There is no way to get anything from flash over UART without uploading a application that reads the data and sends it over UART. You can use nrfjprog to read flash area/data through SWD interface, as long as the APPROTECT register have not been set.

Best regards,
Jørgen

[JohnM]

Well my idea is just to experiment with the Python UART library.  

So, if you say that I'm obliged to upload a little FW in the Flash, it mean nrfjprog (or nRF Connect) does it as well. But how can it manage to put it in an unused flash area in order not to corrupt the FW already present in the target chip?

my guess: nrfproj calculates the flash application size, the actual size of the existing FW and then puts its little FW at the end of the area, am I right?

Thanks. 

[Andy]

nrfjprog works through JLink though, i.e. it uses SWD, not UART.

Which Python UART library are you talking about? I searched the repositories of Nordic and didn't find anything about UART. Do you mean nrfutil by any chance? Or the Python wrapper for nrfjprog? Those are the only two relevant repos I found in GitHub. Or are you talking about something in the SDK?

[JohnM]

ok! so I drop UART and I've just found a Jlink lib in Python: pylink.

So I'll experiment with this library, there must be a function to read a memory location in this lib.

[Andy]

I still don't understand what's your goal with this. If you just want to display the contents on flash somewhere, I'd advise you to just use JLinkExe, use the savebin command and open the bin file in Sublime Text using the HexViewer plugin.

If you're just doing stuff for educational purposes then the pynrfjprog library is fairly easy to use. I've used it in the past to automate flashing of entire panels, writing serial numbers to UICR, etc.

[JohnM]

ok, I didn't know about this pynrfproj! I think that's what I'm looking for.

Yes it's for educational.

Case closed.