This project demonstrates how to use Swift in an embedded environment with ESP32C6, featuring a rotating 3D cube animation on an OLED display.

. ├── CMakeLists.txt # Main CMake configuration ├── main/ │ ├── CMakeLists.txt # Component CMake configuration │ ├── Package.swift # Swift package manifest │ └── Source/ │ ├── App/ # Main application code │ └── Support/ # Support code and fonts └── sdkconfig # ESP-IDF configuration 

• Swift embedded programming on ESP32C6
• OLED display support using U8g2
• 3D graphics rendering
• I2C communication

To integrate Swift Package Manager with CMake in an embedded environment:

1. Create a Package.swift file in your component directory:

// swift-tools-version: 6.1 import PackageDescription let package = Package( name: "App", products: [ .library( name: "App", type: .static, targets: ["App"]), ], dependencies: [ .package(url: "https://github.com/CmST0us/U8g2Kit", branch: "main", traits: ["Embedded"]), ], targets: [ .target( name: "App", dependencies: [ "Support", .product(name: "U8g2Kit", package: "U8g2Kit"), .product(name: "CU8g2", package: "U8g2Kit")], swiftSettings: [ .swiftLanguageMode(.v5), .enableExperimentalFeature("Embedded"), ]), .target(name: "Support", swiftSettings: [ .swiftLanguageMode(.v5), .enableExperimentalFeature("Embedded"), ]), ] )

2. Configure CMakeLists.txt to build Swift code:

Thanks to https://github.com/anders0nmat/swift-embedded-pm

Add custom command to run swift build to make embedded libApp.a

add_custom_target(swift-archive COMMAND # Remove the archive. Swift does not overwrite this on building but merges them. # If the file with app_main gets renamed, both objectfiles (old and new) will be in the archive, potentially causing problems	rm -f ${SWIFT_PRODUCT_ARCHIVE}	&& ${SWIFT_TOOLCHAIN}/swift package update	--package-path ${COMPONENT_DIR}	&& ${SWIFT_TOOLCHAIN}/swift build	-c release	--package-path ${COMPONENT_DIR}	--triple ${SWIFT_TARGET}	-Xswiftc -target -Xswiftc riscv32-none-none-eabi	-Xswiftc -enable-experimental-feature -Xswiftc Embedded	-Xswiftc -wmo	-Xswiftc -parse-as-library	-Xswiftc -Osize	-Xswiftc -Xfrontend -Xswiftc -function-sections	-Xswiftc -Xfrontend -Xswiftc -enable-single-module-llvm-emission	-Xlinker -lgcc	-Xlinker -lm	-Xswiftc -pch-output-dir -Xswiftc /tmp	-Xcc ${march_flag}	-Xcc ${mabi_flag}	-Xcc -fno-pic	-Xcc -fno-pie # Get includes for C-std libraries and extra components ${SWIFT_INCLUDES_LIST} $$\( echo '$<TARGET_PROPERTY:__idf_main,INCLUDE_DIRECTORIES>' | tr '\;' '\\n' | sed -e 's/\\\(.*\\\)/-Xcc -I\\1/g' \) BYPRODUCTS ${SWIFT_PRODUCT_ARCHIVE} )

When working with Swift->C->ESP-IDF symbols (e.g., i2c_driver_install), you might encounter linking errors. To resolve this:

// Reference to ESP32U8g2Driver.swift init() { super.init(u8g2_Setup_ssd1306_i2c_128x64_noname_f, &U8g2Kit.u8g2_cb_r0) // Mask use this, otherwise i2c_driver_install will not found let installHandler = i2c_driver_install } 

To reduce binary size when using U8g2 fonts:

1. Extract required fonts to a separate C file:

// font.c #include "font.h" const uint8_t *default_font_5x7 = "..."; // Font data

2. Include only necessary fonts in your build.

Currently, SourceKit-LSP doesn't work properly in the embedded Swift environment. This affects:

• Code completion
• Symbol navigation
• Error reporting

Potential workarounds:

1. Use a text editor with basic syntax highlighting
2. Maintain a separate Swift package for development
3. Use command-line tools for building and debugging

1. Install ESP-IDF and Swift toolchain
2. Configure the project:

idf.py set-target esp32c6 idf.py menuconfig

3. Build and flash:

idf.py build idf.py -p (PORT) flash

Contributions are welcome! Please feel free to submit a Pull Request.

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.