Changing Flash parameters in overlay file

[CktDesigner]

My project is using nRF52840.   Early software development used an nRF52840-DK to develop most of the software.   Software is based on Zephyr using nRF Connect version 1.6.1.     I'm using the "littlefs" file system.   I got most things working using the nRF52840-DK.     I now have my custom board and it uses a slightly different (and larger) qspi-nor flash device.   

I'm still using the nRF52840-DK board file, but "modify" some of the parameters using an overlay file.    I know I need to change some of the parameters w.r.t. the flash.    I was able to modify the jedec-id for the new device, but am looking for some documentation that defines the parameters (keywords) in the board definition file (what some of them mean and format of values)   

Can you point me to these definitions (so I don't have to read through a lot of code :-))?

Thanks!

[Simonr]

Hi

Just to clarify, the project you're using is the littleFS File System Sample application in Zephyr, correct? I assume you have noticed that on an nRF52840 DK, the file system will be placed in the SoC flash by default. Have you not made any changes to make it use the external flash device except adding the jedec-id in your overlay file?

Best regards,

Simon

[CktDesigner]

Yes, I'm using the project you referenced.

But in main.c at lines 20 through 32 it defines "PARTITION_MODE" which references /lfs1 which is defined in the overlay file.   There, the partition /lfs1_part is referenced which is defined in the &mx25r64, which is the Flash device connected via the qspi bus.   

So by default, the example uses the external flash.    I think to use the SOC flash you have to comment out the definition of PARTITION_MODE on main.c line 20...

I needed to add the jedec-id line to redefine the device id to the one I'm using on my custom board.   When it still didn't work I thought that some other parameter must need to be adjusted but didn't see any concise definitions for these parameters.