NCS DFU Supported External Flash Devices

[Bryan]

OS: Windows

NCS: 2.2.0

We have discovered that we do not have enough internal flash space to support BLE DFU and need to add an external flash to our nRF52833-based design.

The nRF52840 DK board has an external flash (MX25R64) and BLE DFU is shown to work with the bus configured as SPI or QSPI.

 https://devzone.nordicsemi.com/f/nordic-q-a/82430/ncs-external-flash-ota-change-qspi-to-spi/345238

Our board is very small, so the MX25R64 is simply too physically large, so we are looking at the Gigadevices GD25WD40E/20E.  It is tiny at 1.2x1.2mm and supports SPI bus.

https://www.mouser.com/datasheet/2/870/gd25wd40e_gd25wd20e_datasheet_rev1_1_20221019-3081635.pdf

We have no way of verifying this device without doing another version of the board.  That is a big risk.

1.  Is there a specific memory layout of the flash for NCS DFU to work?  For example, the Gigadevices part's memory layout looks like:

2. Is there a specific list of SPI/QSPI flash devices that work with NCS DFU?

[nordicator_prim3]

Hi Bryan,

This is not an answer to your question but just a tip on what else to look for when trying to find a compatible external flash.

- Make sure if you're going to use QSPI that the quad enable bit is at one of the supported registers. The options are shown in "jedec,jesd216.yaml" dts binding file. The options are: "S2B1v1", "S1B6", "S2B7", "S2B1v4", "S2B1v5", "S2B1v6" where S1B6 would mean the quad enable bit is bit 6 of status register 2. The description in the dts binding file has more information on this.

- Make sure that the read and write commands the the flash driver uses are supported by the chip you're looking at. You'll have to dig through the flash driver or just make sure that the read and write commands on the new chip are the same ones used in the MX25r64.

Just thought I would chime in with those tips - it was very rough trying to find an external flash chip having had no experience with NOR chips before needing to look for one. That and understanding how the flash drivers from nordic/zephyr work and what their limitations were. I would be scared of spinning up a board without verifying it as you said. Is it an option to get a SOP8 breakout to put the chip on to hook up to a devkit?

https://www.digikey.com/en/products/detail/adafruit-industries-llc/1212/5022800?utm_adgroup=Adapter%2C%20Breakout%20Boards&utm_source=google&utm_medium=cpc&utm_campaign=Shopping_Product_Prototyping%2C%20Fabrication%20Products_NEW&utm_term=&utm_content=Adapter%2C%20Breakout%20Boards&gclid=Cj0KCQiA6fafBhC1ARIsAIJjL8mOXW9DWxr5odwyvOOLTX1pvAM80a7WfErRodEIx46s3zjYh15Hqq4aAsnqEALw_wcB

Based on what you said about your board being small I'm guessing you're using the USON form factor though, so that's gonna be hard to find a breakout board for (and to solder).

Good luck!

[Kenneth]

I think getting a breakout board as suggested is a good option to debug/verify this works. The breakout board can be done with a different package type.

That said, I do believe you should be able to make this work. The spi_nor driver is pretty generic.

In terms of how to switch between internal flash, spi flash and qspi flash you can find the driver test for the flash module useful:
https://github.com/nrfconnect/sdk-zephyr/tree/main/tests/drivers/flash

In your case that want to use spi you can find these two files relevant:
boards/nrf52840dk_flash_spi.conf
boards/nrf52840dk_mx25r_high_perf.overlay

By modifying the .overlay file you should hopefully relatively quickly find configuration that works.

Edit, here are the properties that can be set:
https://github.com/nrfconnect/sdk-zephyr/blob/main/dts/bindings/mtd/jedec%2Cspi-nor.yaml 
https://github.com/nrfconnect/sdk-zephyr/blob/main/dts/bindings/mtd/jedec%2Cspi-nor-common.yaml 

"Properties supporting Zephyr spi-nor flash driver (over the Zephyr SPI API) control of serial flash memories using the standard M25P80-based command set."

Kenneth

[Bryan]

Thanks for the feedback.  I think spinning a breakout board and testing with the nRF52833 DK is the best way to go, too.  

[Bryan]

I finally am getting back to this ticket.  Here is what I have done.

1.  The "hello world" DFU over BLE using internal flash is working on the nRF52833 DK.

2. I then ported the project to the nRF52840 DK to use it's external QSPI flash.  This is also working.

3. Now I am trying to add an external SPI flash device on a breakout board to the nRF52833 DK to prove it will work.  The SPI NOR flash I am using is the ISSI IS25LP080D.
www.issi.com/.../25LP-WP080D-040D-020D.pdf

From item #2 above I modified...

Both of these overlay files update the SPI bus (identical content in both files)

• /boards/nrf52833dk_nrf52833.overlay
• /child_image/mcuboot/boards/nrf52833dk_nrf52833.overlay

Both of the these conf files have these lines added to switch from QSPI to SPI

• prj.conf
• /child_image/mcuboot/boards/nrf52833dk_nrf52833.conf

# Additions for DFU external flash

CONFIG_FLASH=y

CONFIG_SPI=y

CONFIG_SPI_NOR=y

 

---

I am seeing two things that are odd.  CONFIG_SPI_NOR in both .conf files has the red/orange squiggly lines under it.  When I highlight it says:

CONFIG_SPI_NOR was assigned the value y, but got the value n. Missing dependencies:
DT_HAS_JEDEC_SPI_NOR_ENABLED

 https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/kconfig/index.html  and searching for "CONFIG_SPI_NOR" shows does have DT_HAS_JEDEC_SPI_NOR_ENABLED as a dependency.

However in my build directory both of the .config files shows CONFIG_DT_HAS_JEDEC_SPI_NOR_ENABLED=y 

• build_nrf52833dk_nrf52833/mcuboot/zephyr/.config
• build_nrf52833dk_nrf52833/zephyr/.config

I suspect this is the root cause of the build error I am getting, but the message doesn't give any real detail.
c:/users/bryan/ncs/toolchains/v2.2.0/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.1.0/../../../../arm-zephyr-eabi/bin/ld.exe: zephyr/drivers/spi/libdrivers__spi.a(spi_nrfx_spi.c.obj): in function `k_sem_give':
C:\Virtuix\nordic\myapps\hello_world_dfu\build_nrf52833dk_nrf52833\mcuboot\zephyr\include\generated\syscalls\kernel.h:1071: undefined reference to `z_impl_k_sem_give'

I have attached my hello_world_dfu project for reference.  The build output log is saved in the root directory (build_output.txt).  I appreciate any help!

hello_world_dfu.zip

[Kenneth]

I did not have time to look into this today, and I am out of office tomorrow. The undefined reference to `z_impl_k_sem_give' error seems to be related to MULTITHREADING is not enabled? Maybe try to delete your build folder and build again.

Kenneth