ArduinoCore-API deployment

.github/workflows/Arduino-build.yml

@@ -35,7 +35,9 @@ jobs:
     steps:
     # First of all, clone the repo using the checkout action.
     - name: Checkout
-      uses: actions/checkout@v4
+      uses: actions/checkout@main
+      with:
+        submodules: true
 
     - name: Compilation
       id: Compile

.github/workflows/Cmake.yml

@@ -53,7 +53,9 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@main
+        with:
+          submodules: true
 
       - name: Get latest CMake and Ninja
         uses: lukka/get-cmake@latest

.github/workflows/PIO-build.yml

@@ -38,6 +38,8 @@ jobs:
       # First of all, clone the repo using the checkout action.
     - name: Checkout
       uses: actions/checkout@main
+      with:
+        submodules: true
 
     - name: PlatformIO
       id: Compile

.github/workflows/astyle.yml

@@ -31,7 +31,7 @@ jobs:
     steps:
     # First of all, clone the repo using the checkout action.
     - name: Checkout
-      uses: actions/checkout@v4
+      uses: actions/checkout@v5
 
     - name: Astyle check
       id: Astyle

.gitmodules

@@ -0,0 +1,4 @@
+[submodule "cores/arduino/api"]
+	path = cores/arduino/api
+	url = https://github.com/stm32duino/ArduinoCore-API.git
+	branch = dev

CI/astyle/.astyleignore

@@ -1,4 +1,5 @@
 .git
 BUILD
 CI
-system
+system
+cores/arduino/api

CI/build/examples/BareMinimum/CMakeLists.txt

@@ -7,6 +7,7 @@ cmake_minimum_required(VERSION 3.21)
 # STEP 1: set up bases of environment
 # -----------------------------------------------------------------------------
 
+
 file(REAL_PATH "../../../../" CORE_PATH EXPAND_TILDE)
 file(TO_CMAKE_PATH "${CORE_PATH}" CORE_PATH)
 

CI/codespell/.codespellrc

@@ -1,5 +1,5 @@
 [codespell]
 check-filenames =
 check-hidden =
-skip = ./.git,./CI,./system/Drivers,./system/Middlewares
+skip = ./.git,./CI,./system/Drivers,./system/Middlewares,./cores/arduino/api
 ignore-words = ./CI/codespell/.codespellignore

CI/update/patch/api/0001-docs-update-README-with-STM32duino-integration-infor.patch

@@ -0,0 +1,178 @@
+From 7a2df83c9217c36aa3c871e604d31049f8ab88df Mon Sep 17 00:00:00 2001
+From: Aymane Bahssain <aymane.bahssain@st.com>
+Date: Fri, 23 Jan 2026 16:07:39 +0100
+Subject: [PATCH] docs: update README with STM32duino integration information
+
+Signed-off-by: Aymane Bahssain <aymane.bahssain@st.com>
+---
+ README.md | 123 ++++++++++++++++++++++++++++--------------------------
+ 1 file changed, 64 insertions(+), 59 deletions(-)
+
+diff --git a/README.md b/README.md
+index 506569a..142260e 100644
+--- a/README.md
++++ b/README.md
+@@ -1,95 +1,100 @@
+-# ArduinoCore-API
++# 📚 ArduinoCore-API for STM32duino
+
+-[![Unit Tests](https://github.com/arduino/ArduinoCore-API/workflows/Unit%20Tests/badge.svg)](https://github.com/arduino/ArduinoCore-API/actions?workflow=Unit+Tests)
+-[![codecov](https://codecov.io/gh/arduino/ArduinoCore-API/branch/master/graph/badge.svg)](https://codecov.io/gh/arduino/ArduinoCore-API)
+-[![Spell Check status](https://github.com/arduino/ArduinoCore-API/actions/workflows/spell-check.yml/badge.svg)](https://github.com/arduino/ArduinoCore-API/actions/workflows/spell-check.yml)
++Fork of [`arduino/ArduinoCore-API`](https://github.com/arduino/ArduinoCore-API)  
++Designed to be used as a git submodule in [`stm32duino/Arduino_Core_STM32`](https://github.com/stm32duino/Arduino_Core_STM32)
+
+-This repository hosts the hardware independent layer of Arduino core. In other words it contains the abstract definition of the Arduino core API, consisting of hardware-independent header files that are then included and implemented by the various platform-specific cores.
++---
+
+-Having a single place where the Arduino API is defined means that there is no longer a String implementation within every Arduino core (a String module within ArduinoCore-avr, a String module within ArduinoCore-samd, a String module within ArduinoCore-megaavr …) but rather one String implementation within ArduinoCore-API which all other cores utilise. This has the pleasant side effects that bugs fixed or features added within the ArduinoCore-API String implementation are automatically propagated to all cores utilizing ArduinoCore-API.
++## 🎯 Purpose
+
+-As of now, the following official cores are utilising ArduinoCore-API:
++This repository is a fork which reworks the folder structure to contain only the official Arduino API and hardware‑independent code, in order to simplify Arduino API integration into STM32duino via a git submodule.
+
+-* [megaavr](https://github.com/arduino/ArduinoCore-megaAVR)
+-* [mbed](https://github.com/arduino/ArduinoCore-mbed)
+-* [samd](https://github.com/arduino/ArduinoCore-samd)
+-* [renesas](https://github.com/arduino/ArduinoCore-renesas)
++It will also contain some updates/changes/enhancements/fixes.
+
+-There's an ongoing effort to port the others, while maintainers of third-party cores are strongly invited to follow the same route in order to stay up-to-date with the new language features. For backwards compatibility, every revision of this repo will increase the `ARDUINO_API_VERSION` define.
++---
+
+-## Documentation
++## 📦 What's Included?
+
+-The Arduino API is documented in the official [language reference](https://www.arduino.cc/reference/en/), whose sources are located in [this repository](https://github.com/arduino/reference-en) and are open to contributions from the community.
++- ✅ Official Arduino API files (`api/` folder)
++- ✅ some updates, changes, enhancements and fixes.
+
+-## Support
++---
+
+-This repository is not directly usable by final users. If you need assistance with Arduino, see the [Help Center](https://support.arduino.cc/) and browse the [forum](https://forum.arduino.cc).
++## 🚀 Submodule usage
+
+-## Development
++### 1️⃣ Add the Submodule
+
+-### Bugs & Issues
++In the `Arduino_Core_STM32` repository, run:
+
+-If you want to report an issue with this core, you can submit it to the [issue tracker](https://github.com/arduino/ArduinoCore-API/issues) of this repository. Some rules apply:
+-
+-* If your issue is about a specific hardware platform, report it to its repository. This one is only about discussing the generic API.
+-* Before posting, please check if the same problem has been already reported by someone else to avoid duplicates.
+-* Remember to include as much detail as you can about your hardware set-up, code and steps for reproducing the issue. Make sure you're using an original Arduino board.
+-
+-### Contributions
++```bash
+
+-Contributions are always welcome! You can submit them directly to this repository as Pull Requests. Please provide a detailed description of the problem you're trying to solve. We also appreciate any help in testing issues and patches contributed by other users.
++git submodule add https://github.com/stm32duino/ArduinoCore-API.git cores/arduino/api
++```
++### 2️⃣ Initialize and update
++```bash
++git submodule update --init 
++```
+
+-### Unit testing
++---
+
+-This repository includes a test suite that covers most of the API and that is designed to run on generic hardware, thus not requiring a development board. We call this _host-based unit-testing_. In order to test the features that are only defined but not implemented in this repository, mock implementations are included.
++## 🔗 Official Resources
+
+-Please help us improve the coverage of the test suite!
++| Resource | Link |
++|----------|------|
++| **Official ArduinoCore-API** | https://github.com/arduino/ArduinoCore-API |
++| **STM32duino** | https://github.com/stm32duino/Arduino_Core_STM32 |
+
+-#### To build and run unit tests
++---
+
+-The unit tests are automatically built by GitHub as part of pull request checks (in `.github/workflows/unit-tests.yml`).
++## 📝 License
+
+-To build and run locally:
++This repository is a fork of `arduino/ArduinoCore-API` and maintains the **same license** (LGPL 2.1+).
+
+-**Dependencies**
++See the [LICENSE](License) file in the repository root for details.
+
+-* [CMake](https://cmake.org/)
+-* [GCC](https://gcc.gnu.org/)
++---
+
+-On (Ubuntu) Linux run:
++## 💡 Important Notes
+
+-```bash
+-sudo apt-get install build-essential cmake
+-```
++### ✅ Advantages of Using a Submodule
+
+-From the project root:
++- **Traceability**: Know exactly which version of the API you're using
++- **Easy Updates**: Simple `git submodule update` to sync
++- **Isolation**: API stays in its own code branch
++- **Compatibility**: STM32-specific modifications remain separate
+
+-```bash
+-cd test && mkdir build && cd build
+-cmake ..
+-make && bin/test-ArduinoCore-API
+-```
++### ⚠️ Points to Consider
+
+-### Implementing ArduinoCore-API
++- After cloning **Arduino_Core_STM32**, run:
++  ```bash
++  git submodule update --init --recursive
++  ```
+
+-In order to compile a core which is implementing ArduinoCore-API you'll need to copy/symlink the `api` directory to the target's `cores/arduino` directory as part of your development and release workflow. The most elegant and effective solution is to develop your core with `api` symlinked and produce the distributable archive by telling `tar` to follow symlinks. Example:
++---
+
+-```bash
+-tar --exclude='*.git*' -cjhvf $yourcore-$version.tar.bz2 $yourcore/
+-```
++## 📊 Project Information
+
+-The API is coded to the C++11 standard and the core's compiler must be able to support that version of the language.
++| Property | Value |
++|----------|-------|
++| **Type** | fork |
++| **Use Case** | Submodule for STM32duino |
++| **Language** | C/C++ |
++| **License** | LGPL 2.1+ |
++| **Original Repository** | https://github.com/arduino/ArduinoCore-API |
++---
+
+-Documentation for how to integrate with a Arduino core (which is necessary if you do not download the Arduino core via the Boards Manager) can be found here:
+-* [ArduinoCore-megaavr](https://github.com/arduino/ArduinoCore-megaavr#developing)
+-* [ArduinoCore-mbed](https://github.com/arduino/ArduinoCore-mbed#clone-the-repository-in-sketchbookhardwarearduino-git)
+-* [ArduinoCore-samd](https://github.com/arduino/ArduinoCore-samd/#developing)
++## ✨ Quick Start
+
+-## Donations
++### Clone **Arduino_Core_STM32** with this submodule
+
+-This open source code is maintained by Arduino with the help of the community. We invest a considerable amount of time in testing code, optimizing it and introducing new features. Please consider [donating](https://www.arduino.cc/en/donate/) or [sponsoring](https://github.com/sponsors/arduino) to support our work, as well as [buying original Arduino boards](https://store.arduino.cc) which is the best way to make sure our effort can continue in the long term.
++```bash
++git clone --recurse-submodules https://github.com/stm32duino/Arduino_Core_STM32.git
++```
+
+-## License and credits
++### Update submodule
+
+-This code is licensed under the terms of the GNU LGPL 2.1. If you have questions about licensing please contact us at [license@arduino.cc](mailto:license@arduino.cc).
++```bash
++git submodule update --remote
++```
+
++---
+\ No newline at end of file
+-- 
+2.51.2.windows.1
+

CI/update/patch/api/0001-feat-implement-weak-_write-hook-for-Print.patch

@@ -0,0 +1,65 @@
+From ed7ffc8cc475b05bf50fed6ef91007c3d75f0393 Mon Sep 17 00:00:00 2001
+From: Aymane Bahssain <aymane.bahssain@st.com>
+Date: Fri, 23 Jan 2026 17:05:29 +0100
+Subject: [PATCH] feat: implement weak _write() hook for Print
+
+Signed-off-by: Aymane Bahssain <aymane.bahssain@st.com>
+---
+ api/Print.cpp | 34 ++++++++++++++++++++++++++++++++++
+ 1 file changed, 34 insertions(+)
+
+diff --git a/api/Print.cpp b/api/Print.cpp
+index d827f2e..54319f1 100644
+--- a/api/Print.cpp
++++ b/api/Print.cpp
+@@ -24,6 +24,14 @@
+
+ #include "Print.h"
+
++#ifdef ARDUINO_ARCH_STM32
++#include <unistd.h>
++#include "uart.h"
++#if defined (VIRTIO_LOG)
++  #include "virtio_log.h"
++#endif
++#endif
++
+ using namespace arduino;
+
+ // Public Methods //////////////////////////////////////////////////////////////
+@@ -248,6 +256,32 @@ size_t Print::println(const Printable& x)
+   return n;
+ }
+
++#ifdef ARDUINO_ARCH_STM32
++extern "C" {
++  __attribute__((weak))
++  int _write(int file, char *ptr, int len)
++  {
++    switch (file) {
++      case STDOUT_FILENO:
++      case STDERR_FILENO:
++        /* Used for core_debug() */
++#if defined (VIRTIO_LOG)
++        virtio_log((uint8_t *)ptr, (uint32_t)len);
++#elif defined(HAL_UART_MODULE_ENABLED) && !defined(HAL_UART_MODULE_ONLY)
++        uart_debug_write((uint8_t *)ptr, (uint32_t)len);
++#endif
++        break;
++      case STDIN_FILENO:
++        break;
++      default:
++        ((class Print *)file)->write((uint8_t *)ptr, len);
++        break;
++    }
++    return len;
++  }
++}
++#endif
++
+ int Print::printf(const char *format, ...)
+ {
+   va_list ap;
+-- 
+2.51.2.windows.1
+