Support "file-less" configuration by soburi · Pull Request #151 · zephyrproject-rtos/ArduinoCore-zephyr

soburi · 2026-02-01T14:26:20Z

This PR introduce new configuration system without variants/[board].overlay.

Boards that has arduino like connector mostly has define arduino-header.
We can use this information to configure automatically for each boards.
We can support all zephyr supported that has arduino-header.
That means, we make it works for more 200 boards, including Nucleo series.

However, only Blinky works out of the box, and ADC and PWM channels are required.
These should be made into snippets in the future.

Fix #11
Fix #90

Copilot

Pull request overview

This PR introduces a "file-less" configuration system that automatically configures boards using Arduino-compatible header definitions from the device tree, eliminating the need for board-specific overlay files. The system detects supported connector types (arduino_header, arduino_mkr_header, etc.) and automatically maps GPIO pins, enabling support for 200+ Zephyr-supported boards including the Nucleo series.

Changes:

Added automatic board detection using device tree connector labels (arduino_header, pico_header, etc.)
Introduced GPIO port/pin abstraction layer with constexpr helper functions for compile-time pin mapping
Modified tone/noTone implementation to support dynamic timer allocation by tracking pin assignments
Updated PWM and ADC pin mappings to support both legacy and new connector-based configurations

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 21 comments.

File	Description
cores/arduino/Arduino.h	Adds macro definitions for automatic connector detection (ZARD_CONNECTOR, ZARD_ADC_CONNECTOR, ZARD_PWM_CONNECTOR) and updates digital/analog pin enums to support both legacy and connector-based configurations
cores/arduino/zephyrCommon.cpp	Implements GPIO abstraction layer with constexpr functions for pin mapping, updates all GPIO operations to use new abstraction, and modifies tone/noTone for improved timer management

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cores/arduino/zephyrCommon.cpp

cores/arduino/Arduino.h

cores/arduino/zephyrCommon.cpp

Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 5 comments.

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samples/tone_doremi/src/app.cpp

cores/arduino/zephyrCommon.cpp

cores/arduino/Arduino.h

cores/arduino/zephyrCommon.cpp

DhruvaG2000 · 2026-02-09T12:42:05Z

This PR looks quite interesting, will be on my next list of things to review!

DhruvaG2000 · 2026-02-10T06:40:23Z

variants/arduino_uno_r4_r7fa4m1ab3cfm/variant.h

+ * Copyright (c) 2026 TOKITA Hiroshi
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */


If we can get #161 merged before this, then this will no longer be needed.

In preparation for improvements to allow the use of GPIOs without device tree definitions, the interface will be changed to specify port and pin instead of `gpio_dt_spec`. Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

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Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

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cores/arduino/Arduino.h

cores/arduino/zephyrCommon.cpp

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Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

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cores/arduino/Arduino.h

cores/arduino/zephyrCommon.cpp

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cores/arduino/zephyrCommon.cpp

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Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

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cores/arduino/zephyrCommon.cpp

variants/arduino_uno_r4_r7fa4m1ab3cfm/arduino_uno_r4_r7fa4m1ab3cfm.overlay

DhruvaG2000

The commit ("cores: arduino: zephyrCommon: Generate config from connector definition") on it's own is rather too large to review.

I had to stop halfway through reviewing when I realised that a bunch of things have just been grouped together in it while it could definitely be split up in a cleaner more targeted way.

Here's my suggestion on how we need to make this cleaner:

Create a Directory for Connectors (variants/connectors/)
Create variants/connectors/arduino_header_r3.h: Move all R3-specific pin names and ZARD_CONNECTOR definition there.
Create variants/connectors/connector.h: Add the #if DT_NODE_HAS_COMPAT checks to select the right file
Clean cores/arduino/Arduino.h: Replace the mess with #include "connectors/connector.h".

I am open to hearing if you have alternate suggestions on similar lines, I just don't want to overcrowd the Arduino.h

DhruvaG2000 · 2026-02-15T12:11:09Z

documentation/variants.md

+`LED_BUILTIN` to the **global GPIO number**, which matches the numeric pin
+interpretation in that mode.


These 2 lines are not entirely clear, what is "global GPIO number" and what is "the numeric pin
interpretation "?

I've created a chapter in the documentation and included references.

DhruvaG2000 · 2026-02-15T12:39:41Z

cores/arduino/Arduino.h

+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_A_0 A0
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_A_1 A1
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_A_2 A2
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_A_3 A3
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_A_4 A4
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_A_5 A5
+
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_6 D0
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_7 D1
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_8 D2
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_9 D3
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_10 D4
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_11 D5
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_12 D6
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_13 D7
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_14 D8
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_15 D9
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_16 D10
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_17 D11
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_18 D12
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_19 D13
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_20 D14
+#define ZARD_ARDUINO_HEADER_R3_PIN_NAME_D_21 D15
+
+#define ZARD_ARDUINO_HEADER_R3_IS_ANALOG_0 1
+#define ZARD_ARDUINO_HEADER_R3_IS_ANALOG_1 1
+#define ZARD_ARDUINO_HEADER_R3_IS_ANALOG_2 1
+#define ZARD_ARDUINO_HEADER_R3_IS_ANALOG_3 1
+#define ZARD_ARDUINO_HEADER_R3_IS_ANALOG_4 1
+#define ZARD_ARDUINO_HEADER_R3_IS_ANALOG_5 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_6 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_7 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_8 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_9 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_10 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_11 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_12 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_13 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_14 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_15 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_16 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_17 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_18 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_19 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_20 1
+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_21 1


Umm why are we bringing in Arduino R3 pins inside a central file like Arduino.h ?

Create a Directory for Connectors (variants/connectors/)

Create variants/connectors/arduino_header_r3.h: Move all R3-specific pin names and ZARD_CONNECTOR definition there.

Create variants/connectors/connector.h: Add the #if DT_NODE_HAS_COMPAT checks to select the right file

Clean cores/arduino/Arduino.h: Replace the mess with #include "connectors/connector.h".

The domain under variants is where special rules origins from the Arduino IDE apply, so it's best not to put it there.
I agree that it's better to split the files, so I split them into cores/arduino/connectors.

DhruvaG2000 · 2026-02-15T12:41:13Z

cores/arduino/Arduino.h

+#else
+
+#if DT_NODE_EXISTS(DT_NODELABEL(arduino_header))
+#if DT_NODE_HAS_COMPAT(DT_NODELABEL(arduino_header), arduino_header_r3)


https://docs.zephyrproject.org/latest/build/dts/api/bindings/gpio/arduino-header-r3.html

GPIO pins exposed on Arduino Uno (R3) headers.

Please don't bring in board specific implementation inside the Arduino.h file.

DhruvaG2000 · 2026-02-15T12:42:00Z

cores/arduino/Arduino.h

+#define ZARD_ARDUINO_HEADER_R3_IS_DIGITAL_21 1
+
+#else
+#error "Only arduino-header-r3 connector is supported"


No, we definitely can make this approach way better structured, but definitely not including #defines of board over board in a header single file

DhruvaG2000 · 2026-02-15T12:44:08Z

cores/arduino/zephyrCommon.cpp

+#define ADC_PINS_GLOBAL(n, p, i) \
+	ZARD_GLOBAL_GPIO_OFFSET(DT_PHANDLE_BY_IDX(n, p, i)) + DT_PHA_BY_IDX(n, p, i, pin),
 #define ADC_CH_CFG(n,p,i) arduino_adc[i].channel_cfg,
+#define ADC_CONN_CHANNEL_CFG(n, p, i)                                                              \
+	COND_CODE_1(DT_NODE_HAS_STATUS_OKAY(DT_MAP_ENTRY_PARENT_BY_IDX(n, p, i)),                  \
+	            (ADC_CHANNEL_CFG_DT(ADC_CHANNEL_DT_NODE(DT_MAP_ENTRY_PARENT_BY_IDX(n, p, i),   \
+					DT_MAP_ENTRY_PARENT_SPECIFIER_BY_IDX(n, p, i, 0))),),      \
+		    ())
+#define ADC_CONN_CHANNEL_DT(n, p, i)                                                               \
+	COND_CODE_1(DT_NODE_HAS_STATUS_OKAY(DT_MAP_ENTRY_PARENT_BY_IDX(n, p, i)),                  \
+	            (ADC_DT_SPEC_STRUCT(DT_MAP_ENTRY_PARENT_BY_IDX(n, p, i),                       \
+					DT_MAP_ENTRY_PARENT_SPECIFIER_BY_IDX(n, p, i, 0)),),       \
+		    ())
+#define ADC_CONN_PINNUM(n, p, i)                                                                   \
+	COND_CODE_1(DT_NODE_HAS_STATUS_OKAY(DT_MAP_ENTRY_PARENT_BY_IDX(n, p, i)),                  \
+	            (ZARD_CONNECTOR_PIN_NAME_A(DT_NODELABEL(ZARD_CONNECTOR),                       \
+			                       DT_MAP_ENTRY_CHILD_SPECIFIER_BY_IDX(n, p, i, 0)),), \
+		    ())
+
+const struct adc_dt_spec arduino_adc[] = {
+#if DT_NODE_HAS_PROP(DT_PATH(zephyr_user), io_channels)
+  DT_FOREACH_PROP_ELEM(DT_PATH(zephyr_user), io_channels, ADC_DT_SPEC)


All these ADC related changes aren't even really part of the aim of this commit, please split this up into it's own commit

I split the commits into gpio, adc and pwm.

If digital-gpio-pins is not defined, the pin configuration will be generated using the connector definition. This allows ArduinoCore-Zephyr to be used on boards that have arduino-header defined, without requiring specific configuration in ArduinoCore-Zephyr. Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

…nition Like digital pins, PWMs are also defined from connectors. Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

…nition Like digital pins, ADCs are also defined from connectors. Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

Add guide for adding new board configuration and configuration reference. Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

A new configuration method has been adopted, allowing support to be added with less configuration than before. Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

soburi force-pushed the configure_by_connector_def branch from 30e80c9 to 2157ae2 Compare February 1, 2026 15:38

soburi changed the title ~~Configure by connector def~~ Support **file-less** configuration Feb 1, 2026

soburi changed the title ~~Support **file-less** configuration~~ Support "file-less" configuration Feb 1, 2026

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soburi added 4 commits February 21, 2026 00:13

cores: arduino: zephyrCommon: Generate PWM config from connector defi…

1a1f6ac

…nition Like digital pins, PWMs are also defined from connectors. Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

cores: arduino: zephyrCommon: Generate ADC config from connector defi…

8d351cb

…nition Like digital pins, ADCs are also defined from connectors. Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

documentation: Add configuration guide and reference

b95324b

Add guide for adding new board configuration and configuration reference. Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

soburi force-pushed the configure_by_connector_def branch from ebbb62a to 834adb8 Compare February 21, 2026 03:16

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variant: Adds support for Arduino Uno R4.

42996fc

A new configuration method has been adopted, allowing support to be added with less configuration than before. Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

soburi force-pushed the configure_by_connector_def branch from 834adb8 to 42996fc Compare February 21, 2026 07:22

		`LED_BUILTIN` to the global GPIO number, which matches the numeric pin
		interpretation in that mode.

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soburi commented Feb 1, 2026 •

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