NRF52840DK SPI Flash (w25q64) Device showing not ready

RE: NRF52840DK SPI Flash (w25q64) Device showing not ready

bpolito8 — Wed, 17 Dec 2025 03:49:39 GMT

Hi there,

First, thank you so much for all the help so far!

I’ve done a ton of testing in the last few days and identified a few issues with my setup.

First, I had the wrong DK selected as the build target in the build configuration. I had selected one of the other NRF52840 dk’s (nrf21540dk_nrf52840 I think), but not the NRF52840DK_NRF52840 configuration I should have been using.

Second, some of the jumper cables that I am using appear to be faulty. I’ve swapped them out and the read/erase/write tests from spi_flash sample are now working!

That being said, I believe I am at a similar starting point to the ticket you linked, where the flash operations work but the device still does not show ready. I’ve tried adding a 1 second delay (longer than necessary I imagine) to the beginning of main.c so the flash has time to power up before checking device_is_ready, but this did not work. I see the user’s solution was to “add a snippet to turn on the voltage before the jedec ID is checked,” but I’m unsure how to do that.

RE: NRF52840DK SPI Flash (w25q64) Device showing not ready

Amanda Hsieh — Tue, 16 Dec 2025 18:36:37 GMT

Could you check if this post can help or not?

RE: NRF52840DK SPI Flash (w25q64) Device showing not ready

bpolito8 — Mon, 15 Dec 2025 17:16:40 GMT

Hi,

Yes I edited the overlay for w25q64 based on the example. Here is that overlay after the change:

/*
 * Copyright (c) 2022-2023 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: Apache-2.0
 */

// /delete-node/ &mx25r64;

&qspi {
	status = "disabled";
};

/* The mx25, on nrf52840dk_nrf52840, uses pins for spi0, spi1, spi2 and spi3
 * to provide quad-spi feature. In individual specifications each of the spi
 * notes define own clock source (SCK), but spi2 shares the same clock source
 * as qspi configuration, which is pin (0,19). That is why spi2 is used here
 * to communicate with mx25, when qspi is not used, to avoid rerouting clock
 * pin.
 */
&spi2 {
	compatible = "nordic,nrf-spi";
	status = "okay";
	cs-gpios = <&gpio0 17 GPIO_ACTIVE_LOW>;
	pinctrl-0 = <&spi2_default>;
	pinctrl-1 = <&spi2_sleep>;
	pinctrl-names = "default", "sleep";
	w25q64_spi: spi-nor-flash@0 {
		compatible = "jedec,spi-nor";
		reg = <0>;
		spi-max-frequency = <24000000>;
		size = <DT_SIZE_M(64)>; /* 64 Mbits */
		status = "okay";
		jedec-id = [ef 40 17];
		has-dpd;
		t-enter-dpd = <3500>;
		t-exit-dpd = <3500>;
	};
};

The only other edits to the sample are adding the nrf52840dk_nrf52840_spi.conf file and editing main.c to point to the updated w25q64_spi device from the overlay.

# nrf52840dk_nrf52840_spi.conf
CONFIG_SPI=y
CONFIG_SPI_NOR=y

I am still using the same wiring for spi2 as described above. I tried swapping the MOSI/MISO pins too, with no luck.

I have also tried a different (identical) w25q64 module, and have tested one of the modules with a Arduino and simple sketch successfully.

Unfortunately I am still seeing `spi-nor-flash@0: device not ready.` with the spi_flash sample and these changes.

RE: NRF52840DK SPI Flash (w25q64) Device showing not ready

Amanda Hsieh — Mon, 15 Dec 2025 15:20:34 GMT

Got it.

[quote user="Amanda"]You can refer to https://github.com/nrfconnect/sdk-zephyr/blob/ncs-v3.1.1/samples/drivers/spi_flash/boards/blackpill_f411ce.overlay#L21-L30 for the w25q64. [/quote]

Do you update the overlay for the w25q64?

RE: NRF52840DK SPI Flash (w25q64) Device showing not ready

bpolito8 — Fri, 12 Dec 2025 00:20:37 GMT

Apologies for making things unnecessarily confusing, as mentioned in that quoted section I renamed the device in the overlay to `spi_flash0` in the spi_flash sample. In both samples I've made sure the DEVICE_DT_GET(DT_NODELABEL()) call matches the name of the device from the overlay, as they will not build if there is a mismatch.

RE: NRF52840DK SPI Flash (w25q64) Device showing not ready

Amanda Hsieh — Thu, 11 Dec 2025 21:13:13 GMT

[quote user="bpolito8"]In spi_flash I also named the device `spi_flash0` commented out the `/delete-node/ &mx25r64;` line from the overlay, and used DT_NODELABEL instead of DT_ALIAS when getting the device from devicetree in main.c. [/quote]

If you use DT_NODELABEL , the code should be like this

const struct device *flash_dev = DEVICE_DT_GET(DT_NODELABEL(mx25r64)); // if you don't rename for mx25q64

You can refer to https://github.com/nrfconnect/sdk-zephyr/blob/ncs-v3.1.1/samples/drivers/spi_flash/boards/blackpill_f411ce.overlay#L21-L30 for the w25q64.

RE: NRF52840DK SPI Flash (w25q64) Device showing not ready

bpolito8 — Thu, 11 Dec 2025 02:59:51 GMT

Hi, thank you for the response!

I've tried this overlay with both the jesd16 and spi_flash samples, no luck with either. In both cases I edited the overlay slightly to have the matching jedec-id and size as the w25q64 flash. I've also made sure to include this overlay and the relevant .conf file in the build configurations for both projects. I made no changes to main.c in the jesd16 sample.

In spi_flash I also named the device `spi_flash0` commented out the `/delete-node/ &mx25r64;` line from the overlay, and used DT_NODELABEL instead of DT_ALIAS when getting the device from devicetree in main.c. I've also moved the flash pins to match the pins for spi2.

jesd216 overlay:

main.c for spi_flash:

Module Pin	DK Pin
VCC	VCC
GND	GND
CS	P0.17
MOSI/DI	P0.20
MISO/DO	P0.21
SCLK	P0.19

spi_flash output:

jesd216 output:

Is there anything else I could be missing?

RE: NRF52840DK SPI Flash (w25q64) Device showing not ready

Amanda Hsieh — Wed, 10 Dec 2025 15:01:00 GMT

Hi,

You can refer to https://github.com/nrfconnect/sdk-zephyr/blob/main/samples/drivers/jesd216/boards/nrf52840dk_nrf52840_spi.overlay for the overlay to test with the unmodified the spi_flash sample.

Regards,
Amanda H.