nRF54L15 flash problem.

[Benson_Lai]

Hi,

I use the nRF54L15-DK flash fimware (.hex) with "nRF Connect for Desktop - Programmer" success.

And I view the schematic, discovered the DK board have flash memory MX25R6435F "U9"

So I have Three Question

Q1: When I use "nRF Connect for Desktop - Programmer" to flashed any firmware to nRF54L15-DK, firmware is update to nRF54L15 or flash memory "U9" ?

Q2: Flash memory "U9" is mandatory in layout ?

Q3:Can we flash fimware to nRF54L15 (layout w/o U9)?

[Bendik Heiskel]

Hi,

Q1: When I use "nRF Connect for Desktop - Programmer" to flashed any firmware to nRF54L15-DK, firmware is update to nRF54L15 or flash memory "U9" ?

The programmer application is only flashing to the nRF54L15 internal flash, not to U9.

Q2: Flash memory "U9" is mandatory in layout ?

No, if you can fit the application within the internal flash a external SPI flash isn't required. One thing to keep in mind is that when using DFU you will effectively halv the available flash, as it needs to fit 2 DFU images, in this case having external flash is beneficial as one of the images can be stored externally.

Q3:Can we flash fimware to nRF54L15 (layout w/o U9)?

Yes, when using a programmer you write directly to the nRF54L15 internal flash.

 

Best regards,

Bendik

[Benson_Lai]

Hi Bendik,
Thanks for you reply!

but I have another question, if U9 isn't mandatory in layout, Why U9 is schematic in nRF54L15-DK?

[Bendik Heiskel]

The external flash is added to the development kit to simplify development for applications where external flash is needed, like when the application is large and DFU is required.

 

If the flash isn't needed the DK can be configured to route the GPIO pins to the pin headers instead, by reconfiguring the solder bridges. Here is a overview of which modifications can be made to disconnect U9:
https://docs.nordicsemi.com/bundle/ug_nrf54l15_dk/page/UG/nRF54L15_DK/hw_desription/external_memory.html