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?

[Bryan]

Kenneth,

I keep getting shifted onto other tasks.  Sorry for the delay.

CONFIG_PM_OVERRIDE_EXTERNAL_DRIVER_CHECK=y  was not the root cause.

I ported the https://github.com/nrfconnect/sdk-zephyr/tree/main/tests/drivers/flash project to the nRF52833DK with the external SPI NOR Flash wired to it and got it working.

*** Booting Zephyr OS build v3.2.99-ncs1 ***
Running TESTSUITE flash_driver
===================================================================
START - test_read_unaligned_address
PASS - test_read_unaligned_address in 0.047 seconds
===================================================================
TESTSUITE flash_driver succeeded

------ TESTSUITE SUMMARY START ------

SUITE PASS - 100.00% [flash_driver]: pass = 1, fail = 0, skip = 0, total = 1 duration = 0.047 seconds
- PASS - [flash_driver.test_read_unaligned_address] duration = 0.047 seconds

------ TESTSUITE SUMMARY END ------

===================================================================
PROJECT EXECUTION SUCCESSFUL

I can confirm it is working by simply lifting the power pin to the SPI NOR Flash.

E: Device id ff ff ff does not match config 9d 60 14
*** Booting Zephyr OS build v3.2.99-ncs1 ***
Running TESTSUITE flash_driver
===================================================================

Assertion failed at ../src/main.c:59: flash_driver_setup: device_is_ready(flash_dev) is false

START - test_read_unaligned_address
FAIL - test_read_unaligned_address in 0.001 seconds
===================================================================
TESTSUITE flash_driver failed.

------ TESTSUITE SUMMARY START ------

SUITE FAIL - 0.00% [flash_driver]: pass = 0, fail = 1, skip = 0, total = 1 duration = 0.001 seconds
- FAIL - [flash_driver.test_read_unaligned_address] duration = 0.001 seconds

------ TESTSUITE SUMMARY END ------

===========================

I now have the nRF52833DK with external SPI NOR flash working, too.  The key was to use the exact same nrf52833dk_nrf52833.overlay file from the flash test above in /boards and /child_image/mcuboot/boards.

The only difference between what works and what caused issues is the first five lines in the overlay file.

from the flash test that works

/ {
    aliases {
       spi-flash0 = &is25lp080d;
    };
};

what I was trying to use, which was based on the nRF52840DK external flash overlay file.
/ {
    chosen {
       nordic,pm-ext-flash = &is25lp080d;
    };
};

Kenneth - Two final questions.

1.  I am not understanding what it hated about nordic,pm-ext-flash = &is25lp080d; This is the exact syntax used in the hello_world_dfu_840DK_ext_flash project overlay files.

2.  I used spi-flash0 in the flash test because it was the exact same syntax as /boards/nrf52840dk_mx25l51245g.overlay

I honestly didn't expect it to work in the DFU project.  It seems that spi-flash0 is standard label in Zephyr to define a external spi flash device.  It is used in a lot of zephyr/boards/*.dts files.  Am I understanding this correctly?

I have attached all three of the projects for everyone's reference.

hello_world_dfu_840DK_ext_flash.zip

6153.flash.ziphello_world_dfu_833DK_ext_flash.zip

[Kenneth]

Hello,

You should use both alias and chosen, ref:

/ { 	
	aliases 
	{ spi-flash0 = &is25lp080d; }; 
	chosen 
	{ nordic,pm-ext-flash = &is25lp080d; }; 
};

Looks like nRF52840DK already have the spi-flash0 defined in the board file:
https://github.com/nrfconnect/sdk-zephyr/blob/main/boards/arm/nrf52840dk_nrf52840/nrf52840dk_nrf52840.dts#L129

Well spotted this was the problem!

Kenneth

[Bryan]

Kenneth,

Once again I was switched off this and onto something else.  I never got to test adding "chosen".  Without "chosen" it is still using internal flash.

I have upgraded to the latest NCS 2.3.0.  I am back to getting this output when it boots.

*** Booting Zephyr OS build v3.2.99-ncs2 ***
I: Starting bootloader
W: Cannot upgrade: not a compatible amount of sectors
I: Bootloader chainload address offset: 0xf000
*** Booting Zephyr OS build v3.2.99-ncs2 ***
Hello World 1! nrf52833dk_nrf52833

Since it had been awhile, I reconfirmed that the  https://github.com/nrfconnect/sdk-zephyr/tree/main/tests/drivers/flash test still works.  

from the file ncs\v2.3.0\bootloader\mcuboot\boot\bootutil\src\swap_move.c

num_sectors_pri = boot_img_num_sectors(state, BOOT_PRIMARY_SLOT);
num_sectors_sec = boot_img_num_sectors(state, BOOT_SECONDARY_SLOT);
if ((num_sectors_pri != num_sectors_sec) &&
(num_sectors_pri != (num_sectors_sec + 1))) {
       BOOT_LOG_WRN("Cannot upgrade: not a compatible amount of sectors");
       return 0;
}

However, if I look at the partition manager report it shows primary and secondary are exactly the same size.

PS C:\Virtuix\nordic\myapps\hello_world_dfu_833DK_ext_flash\build> west build -t partition_manager_report
-- west build: running target partition_manager_report
[1/1] cmd.exe /C "cd /D C:\Virtuix\nordic\myapps\hello_w...ps/hello_world_dfu_833DK_ext_flash/build/partitions.yml"
external_flash (0x100000 - 1024kB):
+-------------------------------------------+
| 0x0: mcuboot_secondary (0x71000 - 452kB) |
| 0x71000: external_flash (0x8f000 - 572kB) |
+-------------------------------------------+

flash_primary (0x80000 - 512kB):
+-------------------------------------------------+
| 0x0: mcuboot (0xf000 - 60kB) |
+---0xf000: mcuboot_primary (0x71000 - 452kB)-----+
| 0xf000: mcuboot_pad (0x200 - 512B) |
+---0xf200: mcuboot_primary_app (0x70e00 - 451kB)-+
| 0xf200: app (0x70e00 - 451kB) |
+-------------------------------------------------+

sram_primary (0x20000 - 128kB):
+--------------------------------------------+
| 0x20000000: sram_primary (0x20000 - 128kB) |
+--------------------------------------------+

PS C:\Virtuix\nordic\myapps\hello_world_dfu_833DK_ext_flash\build>

What I am missing?

8463.hello_world_dfu_833DK_ext_flash.zip

[Kenneth]

Hello,

I can see you are getting help in a private case. I suggest you continue there, but please share your findings for anyone experiencing the same that find this public case.

Kenneth

[Bryan]

Kenneth,

My private case is for our custom board that has two spi busses, so it is more complex.  This one is just to get the basic external flash DFU working.