flash storage start and end address

[jonas.woerner]

Hello,

I am trying to find out where to put my persistent storage data in flash.

I have to set start_addr and end_addr, to use fstorage, but I dont know what addresses are free to use. I currently dont have a bootloader, but will add one soon, so I would need to place the data below the coming bootloader, so how do I determine the start and end addresses?

chip is the NRF52832 and S132 softdevice.

thanks a lot,

Jonas

[Vidar Berg]

Hello Jonas,

The bootloader start address will be stored in NRF_UICR->NRFFW[0] (@0x100010014) so you can use that as an upper boundary for your data section, then determine the lower boundary by subtracting the number of flash pages you need from the end address. I would recommend reuse the flash_end_addr() function in fds.c for finding the upper boundary. It will automatically the end of flash if no bootloader is present.

Here's the typical memory layout with softdevice, bootloader and app (source):

Updated link: https://infocenter.nordicsemi.com/topic/sdk_nrf5_v16.0.0/lib_bootloader.htm#lib_bootloader_memory

[jonas.woerner]

Hi,

thanks for your reply, but NRF_UICR->NRFFW[0] is 0xFFFFFFFF ?! NRF_UICR->NRFFW = 0x100010014

and reading the memory at this addres gets me:

J-Link>mem8 0x100010014 4
00010014 = 62 7F 69 1D

which is 1D697F62 as 32bits number

what can I do now?

[Vidar Berg]

Hi,

This is not a valid memory address. Could you try to do a full chip erase then upload the bootloader example again and check register value again?  I'm not sure if Jlink commander supports full chip erase (erase FLASH + UICR). Suggest to use nrfjprog -e  or the Programmer app in nRF Connect desktop if UICR is not being erased. 

[jonas.woerner]

I just tested it, Jlink erase erases the full chip, but the problem doesnt change, however I dont run the bootloader example, I dont have a bootloader on my device, could that be the problem? I guess so.

how can I determine if a bootloader is present, and if not, how do I get the end address without bootloader?

[Vidar Berg]

It should  read 0xFFFFFFFF after a full chip erase, maybe you application uses this register (none of the SDK examples do except for thebootloader)? We use this register to determine if a bootloader is present. If it's 0xFFFFFFFF we assume that there is no bootloader present and use the FICR registers to find the end of flash address, see the flash_end_addr() function I mentioned earlier.

[jonas.woerner]

yes, after the full erase, and when I upload my code it now reads FFFFFFFF, so far so good.

I think now I know what I have to do. I read the register, and if its FF.. I just use the flash size as end address.