Dual Bank DFU in NRF52805 using an external flash

[Dipak]

Hi Nordic,

I have an NRF52805 board [ from Raytech] and I am implementing all my application using SDK v15.1.0.

As of now, I have implemented my application using the ble_app_uart service and it works perfectly with buttonless DFU!

but my problem is NRF52805 has only 192kb of flash and my code size is around 135kb and in near future, I will include more services and it will take more flash size.

and, therefore dual bank is not possible with this amount of flash size. So I have used W25Q32 [4MB NOR Flash] flash IC to store the new image.

I have also successfully tested the basic read-write function in flash using SPI.

Now, I don't know how to store the new image in flash, and

- what kind of and where I have to make changes?

Thanks in advance

Dipak

[Hung Bui]

Hi Dipak, 

We currently don't have an example on how to use external flash for doing DFU. What you need to do is to add a new backend to the fstorage to store data in external flash instead of the internal flash. It's similar to the nrf_fstorage_nvmc.c and the nrf_storage_sd.c . But you need to write your own library to access SPI flash instead. This would require some study on how the DFU bootloader works and how fstorage works. 

But may I ask do you have to use nRF52805 and the W25Q32 in your design ? The DFU dual bank issue can be solve by simply use a nRF52832 which has 512kB of flash. 

[Dipak]

Hi Hung,

Sorry for the late reply!

I have read this thread,

https://devzone.nordicsemi.com/f/nordic-q-a/48961/dfu-with-external-qspi-memory

and after entering into DFU first nrf_dfu_req_handler_init is initialize correct?

if yes, then what kind of changes I have to make in the nrf_dfu_req_handler_init function for the external_SPI_interface _init?

Dipak