pymcu-plugin-sdk

Shared base classes and plugin protocol for PyMCU backend and toolchain packages.
Part of the PyMCU project.

pymcu-sdk is the stable API surface that all PyMCU backend and toolchain plugins depend on. It ships two parallel components that plugin authors reference in their own packages:

Component	Artifact	Language	Description
pymcu-plugin-sdk	Python wheel	Python ≥ 3.11	ABCs and entry-point protocol for backend & toolchain plugins
PyMCU.Backend.SDK	NuGet library	.NET 10 (AOT)	C# abstract types for codegen backend binaries bundled in backend plugins

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Repository layout

pymcu-sdk/
├── src/
│   ├── python/
│   │   └── pymcu/
│   │       ├── backend/sdk/      # BackendPlugin ABC + LicenseStatus
│   │       └── toolchain/sdk/    # ToolchainPlugin, ExternalToolchain, HardwareProgrammer ABCs
│   └── csharp/
│       └── PyMCU.Backend.SDK/    # CodeGen, IBackendProvider, IR types, stack allocator
├── pyproject.toml                # Python build config (Hatchling)
├── PyMCU.SDK.slnx                # .NET solution (Rider / dotnet CLI)
└── .github/
    └── workflows/
        ├── build-python.yml      # CI: build Python wheel
        └── build-csharp.yml      # CI: build C# NuGet package

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Requirements

Python component

• Python ≥ 3.11
• Hatch ≥ 1.25

pip install hatch

C# component

• .NET SDK 10.0

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Building locally

Python wheel

hatch build
# Artifacts are written to dist/
#   dist/pymcu_plugin_sdk-<version>-py3-none-any.whl
#   dist/pymcu_plugin_sdk-<version>.tar.gz

C# NuGet package

dotnet build src/csharp/PyMCU.Backend.SDK.csproj -c Release
dotnet pack  src/csharp/PyMCU.Backend.SDK.csproj -c Release --no-build -o artifacts/
# Artifact: artifacts/PyMCU.Backend.SDK.<version>.nupkg

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Plugin development

Backend plugin (Python)

Implement BackendPlugin and register it under the pymcu.backends entry-point group:

# pyproject.toml of your backend package
[project.entry-points."pymcu.backends"]
avr = "pymcu.backend.avr:AvrBackendPlugin"

from pymcu.backend.sdk import BackendPlugin, LicenseStatus
from pathlib import Path

class AvrBackendPlugin(BackendPlugin):
    family = "avr"
    description = "AVR backend for PyMCU"
    version = "1.0.0"
    supported_arches = ["atmega", "attiny", "at90"]

    @classmethod
    def get_backend_binary(cls) -> Path:
        return Path(__file__).parent / "bin" / "pymcuc-avr"

Toolchain plugin (Python)

Implement ToolchainPlugin and register it under pymcu.toolchains:

[project.entry-points."pymcu.toolchains"]
avr = "pymcu.toolchain.avr:AvrToolchainPlugin"

from pymcu.toolchain.sdk import ToolchainPlugin, ExternalToolchain
from rich.console import Console

class AvrToolchainPlugin(ToolchainPlugin):
    family = "avr"
    description = "AVR-GCC toolchain for PyMCU"
    version = "14.1.0"
    default_chip = "atmega328p"

    @classmethod
    def supports(cls, chip: str) -> bool:
        return chip.lower().startswith(("atmega", "attiny", "at90"))

    @classmethod
    def get_toolchain(cls, console: Console, chip: str) -> ExternalToolchain:
        ...

Backend codegen binary (C#)

Reference the NuGet package in your .csproj and subclass CodeGen:

<PackageReference Include="PyMCU.Backend.SDK" Version="1.0.0-beta1" />

using PyMCU.Backend;
using PyMCU.IR;

public sealed class AvrCodeGen : CodeGen
{
    public override void Compile(ProgramIR program, TextWriter output) { ... }
    public override void EmitContextSave()    { ... }
    public override void EmitContextRestore() { ... }
    public override void EmitInterruptReturn(){ ... }
}

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CI / Build pipelines

Artifacts are built automatically on every push and pull-request to main:

Workflow	Trigger	Artifact
build-python	push / PR → main	pymcu_plugin_sdk-*.whl + sdist
build-csharp	push / PR → main	PyMCU.Backend.SDK.*.nupkg

Artifacts are uploaded to the GitHub Actions run summary and are not published to PyPI / NuGet.org.

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License

MIT — © 2026 Ivan Montiel Cardona and the PyMCU Project Authors.
See SPDX-License-Identifier: MIT.

Safety notice: This software is not designed for use in hazardous environments requiring fail-safe performance (nuclear facilities, aircraft navigation, life-support systems, weapons systems, etc.).