DFU internal and external flash used

[Etienne]

Hi everyone, 

I work with an nrf52840 and SDK15.3.0 and SD 140-6.1.1

I have a board with two micro controler, one nrf52840 and one STM32. 

I want to know if it is possible to use the internal flash to update the nrf application during DFU and an external flash for the STM32. 

The stm32 applicationis larger than the available space in the nrf52 bank 1.

Thanks in advance for your response. 

Best Regards, 

Etienne 

[Simonr]

Hi Etienne

Unfortunately we're not experts on the STM32 series devices, so I can't guarantee that you can do DFU from an external flash onto it, but I don't see a reason it should not work. We don't have an example doing something similar to this either unfortunately, but you can use the DFU protocol in the nRF5 SDK and UART DFU master example for reference.

Best regards,

Simon

[Etienne]

Hi Simonr,

Thank for your response. 

I havent explain myself weel I presume. 

The scheme we wanted to use to update the STM is the following: We put the nrf52840 in DFU mode, we transfert the STM firmware over BLE to the external flash and after that the bootloader return to the application and make the transfert to the STM. 

But we have others devices which dodn't have external flash and we want to keep the nrf52840 application download into the internal flash of the NRF during DFU process over BLE. 

Is it possible to do that ? 

Best Regards, 

Etienne  

[Simonr]

Hi

Thank you for the explanation. I think this should indeed be possible, although some changes will be necessary to make in our bootloader to make the external image write to the SPI flash. I'd suggest that you do a check in update_data_addr_get() in the nrf_dfu_validation.c to make sure that DFU_FW_TYPE_EXTERNAL_APPLICATION is written to external flash instead of to the internal flash.

Moving the image to the STM from the application in the nRF52 should be possible as well.

Best regards,

Simon

[Etienne]

Hi, 

Thanks for your response. I will look into those functions.

Best Regards

Etienne