boards: waveshare: Add RP2350 Zero board support #97628

cetola · 2025-10-15T13:26:10Z

Add initial support for the Waveshare RP2350-Zero, a low-cost, high-performance Pico-like development board based on the Raspberry Pi RP2350A microcontroller.

This commit introduces the board definition, devicetree files, pin control configuration, Kconfig options, and board documentation.

The RP2350-Zero’s Arm and RISC-V cores are supported with this port. Basic peripherals (GPIO, UART, I2C) are configured and tested. Verified by building and running the Zephyr "hello_world" sample on the RP2350-Zero / RP2350-One boards, and manually testing the GPIO, I2C, PIO, and RGB LED.

github-actions · 2025-10-15T13:26:50Z

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dsseng

Thank you for your contribution! Please find some suggestions attached

dsseng · 2025-10-15T20:04:35Z

boards/waveshare/rp2350_zero/board.cmake

+board_runner_args(openocd --cmd-pre-init "source [find interface/${RPI_PICO_DEBUG_ADAPTER}.cfg]")
+board_runner_args(openocd --cmd-pre-init "source [find target/rp2350.cfg]")
+
+# The adapter speed is expected to be set by interface configuration.


It's safe to assume probe-rs also works for this target, please consider adding it by copying from other files, like here: https://github.com/zephyrproject-rtos/zephyr/pull/94542/files

Sounds good, added this. I'll see if I can get a probe-rs debug probe and test this out as well.

dsseng · 2025-10-15T20:05:28Z

boards/waveshare/rp2350_zero/doc/index.rst

+
+  west flash
+
+In alternative you can locate the generated file at ``build/zephyr/zephyr.uf2 file`` and simply drag-and-drop to the device after entreing the UF2 flashing mode.


Suggested change

In alternative you can locate the generated file at ``build/zephyr/zephyr.uf2 file`` and simply drag-and-drop to the device after entreing the UF2 flashing mode.

Alternatively, you can locate the generated file at ``build/zephyr/zephyr.uf2 file`` and simply drag-and-drop to the device after entering the UF2 flashing mode.

dsseng · 2025-10-15T20:08:27Z

boards/waveshare/rp2350_zero/doc/index.rst

+   :goals: build
+   :compact:
+
+You must flash the RP2350-Zero with an UF2 file. One option is to use West (Zephyr’s meta-tool). To enter the UF2 flashing mode just keep the ``BOOT`` button pressed while you connect the USB port, it will appear on the host as a mass storage device. In alternative with the board already connected via USB you can keep the ``RESET`` button pressed, press and release ``BOOT``, release ``RESET``. At this point you can flash the image file by running:


uf2 isn't the must option, I'm pretty sure picotool can load elf as well. Also, it seems the button press order should be different:

Suggested change

You must flash the RP2350-Zero with an UF2 file. One option is to use West (Zephyr’s meta-tool). To enter the UF2 flashing mode just keep the ``BOOT`` button pressed while you connect the USB port, it will appear on the host as a mass storage device. In alternative with the board already connected via USB you can keep the ``RESET`` button pressed, press and release ``BOOT``, release ``RESET``. At this point you can flash the image file by running:

You can flash the RP2350-Zero with an UF2 file. One option is to use West (Zephyr’s meta-tool). To enter the UF2 flashing mode just keep the ``BOOT`` button pressed while you connect the USB port, it will appear on the host as a mass storage device. In alternative with the board already connected via USB you can keep the ``BOOT`` button pressed, press and release ``RUN``, release ``BOOT``. At this point you can flash the image file by running:

kartben · 2025-10-16T09:16:32Z

boards/waveshare/rp2350_zero/doc/img/rp2350_zero.jpg

please use this one (it has transparent bg, is cropped to avoid unnecessary white space, and webp so size is smaller)

kartben · 2025-10-16T09:19:40Z

boards/waveshare/rp2350_zero/doc/img/rp2350_zero_pinout.jpg

cwebp rp2350_zero_pinout.jpg -q 50 -o rp2350_zero_pinout.webp -m 6 -af

but fwiw I would rather you link to the product webpage rather than unnecessarily cluttering the Zehpyr git repo with this file

Updated the PR with a link to the product webpage.

Sorry, pushed the wrong rst file. Should be updated now.

nordicjm · 2025-10-16T10:36:24Z

boards/waveshare/rp2350_zero/board.cmake

+# SPDX-License-Identifier: Apache-2.0
+
+if("${RPI_PICO_DEBUG_ADAPTER}" STREQUAL "")
+    set(RPI_PICO_DEBUG_ADAPTER "cmsis-dap")


cmake indent is 2 spaces

nordicjm · 2025-10-16T10:36:46Z

boards/waveshare/rp2350_zero/rp2350_zero-pinctrl.dtsi

+		group1 {
+			pinmux = <UART0_TX_P0>;
+		};
+		group2 {


newline gaps missing e.g. line 11, fix in whole PR

To put some of this in context, take a look at 2d22884 which might help.

Thanks. Funny enough, I fixed the issue and then immediately started looking for a linter. 😆

nordicjm · 2025-10-16T10:36:57Z

boards/waveshare/rp2350_zero/rp2350_zero.dtsi

+			<28 0 &gpio0 28 0>,	/* GP28 */
+			<29 0 &gpio0 29 0>;	/* GP29 */
+	};
+


Suggested change

nordicjm · 2025-10-16T10:37:23Z

boards/waveshare/rp2350_zero/rp2350_zero_rp2350a_hazard3_defconfig

+CONFIG_LED=y
+CONFIG_LED_STRIP=y
+CONFIG_WS2812_STRIP_RPI_PICO_PIO=y


Suggested change

CONFIG_LED=y

CONFIG_LED_STRIP=y

CONFIG_WS2812_STRIP_RPI_PICO_PIO=y

nordicjm · 2025-10-16T10:37:40Z

boards/waveshare/rp2350_zero/rp2350_zero_rp2350a_m33_defconfig

+CONFIG_LED=y
+CONFIG_LED_STRIP=y
+CONFIG_WS2812_STRIP_RPI_PICO_PIO=y


Suggested change

CONFIG_LED=y

CONFIG_LED_STRIP=y

CONFIG_WS2812_STRIP_RPI_PICO_PIO=y

PR updated to remove the LED. Is best practice here to keep the defconfig as minimal as possible?

PR updated to remove the LED. Is best practice here to keep the defconfig as minimal as possible?

https://docs.zephyrproject.org/latest/hardware/porting/board_porting.html#general-recommendations is the best their is, AFAIK.

Extending https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/drivers/led/led_strip/boards might be the way to go.

CONFIG_WS2812_STRIP_RPI_PICO_PIO shouldn't be required, for example, because that'll just sort itself out when the node is enabled in the device tree, (and LED_STRIP is enabled) for example. It does raise an interesting (but beyond the scope of this PR) question: should samples/basic/rgb_led also include RGB LEDs that are driven via a LED 'strip'? To a lot of people (including me) that difference is nuanced.

ajf58

The I2C configuration is the thing that needs the closest attention, IMHO.

ajf58 · 2025-10-16T19:22:17Z

boards/waveshare/rp2350_zero/Kconfig.defconfig

+if I2C_DW
+
+config I2C_DW_CLOCK_SPEED
+	default 125
+
+endif # I2C_DW


Suggested change

if I2C_DW

config I2C_DW_CLOCK_SPEED

default 125

endif # I2C_DW

This doesn't look right, clk_sys runs at 150MHz by default, and clk_peri is derived from that. Is this a copy-paste error from RP2040 code?

I looked through my notes and I cannot find a reason I would have set this, so it is likely a copy/paste error from the RP2040. I used both the RP2040 and the Pico 2 as references.

ajf58 · 2025-10-16T19:27:43Z

boards/waveshare/rp2350_zero/rp2350_zero.dtsi

+&wdt0 {
+	status = "okay";
+};
+


Suggested change

&wdt0 {

status = "okay";

};

Duplicated on line 146, remove.

Add initial support for the Waveshare RP2350-Zero, a low-cost, high-performance Pico-like development board based on the Raspberry Pi RP2350A microcontroller. This commit introduces the board definition, devicetree files, pin control configuration, Kconfig options, and board documentation. The RP2350-Zero’s Arm and RISC-V cores are supported with this port. Basic peripherals (GPIO, UART, I2C) are configured and tested. Verified by building and running the Zephyr "hello_world" sample on the RP2350-Zero / RP2350-One boards, and manually testing the GPIO, I2C, PIO, and RGB LED. Signed-off-by: Stephano Cetola <[email protected]>

sonarqubecloud · 2025-10-16T20:58:48Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

zephyrbot added the area: Boards/SoCs label Oct 15, 2025

cetola force-pushed the rp2350_zero branch 2 times, most recently from 0d202ba to b39093a Compare October 15, 2025 18:53

dsseng added area: Devicetree platform: Raspberry Pi Pico Raspberry Pi Pico (RPi Pico) labels Oct 15, 2025

dsseng self-requested a review October 15, 2025 19:57

dsseng reviewed Oct 15, 2025

View reviewed changes

dsseng requested review from ThreeEights, ajf58, nordicjm and soburi October 15, 2025 20:10

cetola force-pushed the rp2350_zero branch from b39093a to 54dac50 Compare October 15, 2025 20:40

kartben reviewed Oct 16, 2025

View reviewed changes

nordicjm requested changes Oct 16, 2025

View reviewed changes

cetola force-pushed the rp2350_zero branch 3 times, most recently from 76f7ae1 to 314aa51 Compare October 16, 2025 16:13

cetola requested review from kartben and nordicjm October 16, 2025 19:01

ajf58 requested changes Oct 16, 2025

View reviewed changes

cetola force-pushed the rp2350_zero branch 2 times, most recently from 3e4e896 to b1d9842 Compare October 16, 2025 20:54


		west flash

		In alternative you can locate the generated file at ``build/zephyr/zephyr.uf2 file`` and simply drag-and-drop to the device after entreing the UF2 flashing mode.

	In alternative you can locate the generated file at ``build/zephyr/zephyr.uf2 file`` and simply drag-and-drop to the device after entreing the UF2 flashing mode.
	Alternatively, you can locate the generated file at ``build/zephyr/zephyr.uf2 file`` and simply drag-and-drop to the device after entering the UF2 flashing mode.

	CONFIG_LED=y
	CONFIG_LED_STRIP=y
	CONFIG_WS2812_STRIP_RPI_PICO_PIO=y

boards: waveshare: Add RP2350 Zero board support #97628

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boards: waveshare: Add RP2350 Zero board support #97628

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sonarqubecloud bot commented Oct 16, 2025

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