JFlash to read nRF52832 serial number

[mike1369]

Hello,

I am developing a solution based on nrf52-DK, using nRF52832.

I am trying to use JFlash to read Device Serial Number.

I could read it with JLink , with command "mem32 0x10000060 2"
I could read it with nrfjprog , with command "nrfjprog --memrd 0x10000060 --n 8"

But I cannot get it with JFlash, I tried "JFlash.exe -openprj nrf52_dk.jflash -readrange 0x10000060 8 -exit"
but nothing is read actually, message shows 0 bytes are actually read : "Target memory read successfully. (0 bytes, 0 ranges) - Completed after 0.185 sec"

Do you have any suggestion on how to read serial number with JFlash  ?

Thanks

[Michal]

Hello,

According to the chapter 5.2 of the J-Flash manual: https://www.segger.com/downloads/jlink/um08003

-readrange<SADDR>,<EADDR>      |    Read specified range of target memory.

You need both the start and end address as the arguments.

Best regards,

Michal

[mike1369]

Yes, sorry, I tried both actually, and made the wrong copy / paste 

JFlash.exe -openprj nrf52_dk.jflash -jflashlogC:\tmp\jflash.log -readrange 0x10000060,0x10000067 -exit

gives the following log : 

- Connected successfully
- Target memory read successfully. (0 bytes, 0 ranges) - Completed after 0.234 sec
J-Flash V8.10a: Target memory read successfully. (0 bytes, 0 ranges) - Completed after 0.234 sec

[mike1369]

Just to confirm that "read successfully. (0 bytes, 0 ranges) " is an issue 

I still cannot read the serial number with JFlash

[Michal]

Can you read anything else successfully using JFlash?

I think that you may actually want to direct that question to the SEGGER forums.

[mike1369]

Yes if I read a flash memory range with :
JFlash.exe -openprj nrf52_dk.jflash -jflashlogC:\tmp\jflash.log -readrange 0x0000060,0x0000067 -exit
that works and I get this log and the data is read: 

- Target memory read successfully. (8 bytes, 1 range) - Completed after 0.349 sec
J-Flash V8.10a: Target memory read successfully. (8 bytes, 1 range) - Completed after 0.349 sec

[Michal]

I did some tests and I think I know the issue.

J-Flash can only read the memory in the flash section, see for example here: https://forum.segger.com/index.php/Thread/5922-SOLVED-How-can-I-use-jflash-to-read-device-memory-and-save-to-file/

If you look into flash bank for this device in J-Flash, you can also see, that the serial number address is outside the flash bank memory space (as it should be).

So unfortunately, it is a limitation of J-Flash.

Best regards,

Michal