GC9D01 Rust Driver

A no_std Rust driver for the GC9D01 LCD display controller with full embedded-graphics support. This driver provides both async and sync APIs, making it suitable for modern embedded frameworks like Embassy as well as traditional blocking applications.

✨ Features

🎯 Complete GC9D01 support - Full manufacturer initialization sequence from official documentation
⚡ Async/Sync APIs - Built for Embassy and other async frameworks, with sync fallback
🎨 embedded-graphics integration - Full DrawTarget implementation for rich graphics
🚀 High-performance rendering - Optimized batch SPI transfers and frame buffer architecture
🌈 RGB565 color format - 16-bit color depth with efficient memory usage
🔧 Hardware abstraction - Works with any embedded-hal SPI implementation
📐 Multiple orientations - Portrait, Landscape, and rotated variants with coordinate transformation
🎪 Display optimized - Designed for GC9D01-based LCD panels
📦 no_std compatible - Perfect for resource-constrained embedded systems

🚀 Quick Start

Add this to your Cargo.toml:

[dependencies]
gc9d01 = "0.1"
embedded-graphics = "0.8"

# For async support
gc9d01 = { version = "0.1", features = ["async"] }

Basic Usage

use gc9d01::{GC9D01, Config, Orientation};
use embedded_graphics::{
    pixelcolor::Rgb565,
    prelude::*,
    primitives::{Circle, PrimitiveStyle},
};

// Create display configuration
let config = Config {
    width: 160,
    height: 40,
    orientation: Orientation::Portrait,
    rgb: false,
    inverted: false,
    dx: 0,
    dy: 0,
};

// Initialize display (async example)
let mut display = GC9D01::new(
    config, spi_device, dc_pin, rst_pin,
    buffer, frame_buffer
);
display.init().await?;

// Draw with embedded-graphics
Circle::new(Point::new(80, 20), 30)
    .into_styled(PrimitiveStyle::with_fill(Rgb565::RED))
    .draw(&mut display)?;

// Flush to screen
display.flush().await?;

📋 Examples

This repository includes comprehensive examples for different use cases:

🎮 STM32G4 Examples

Direct SPI Implementation

Location: examples/stm32g4-direct-spi-90-complex-patterns/
Features: Raw SPI operations, complex pattern rendering, coordinate transformation
Performance: Optimized for maximum speed with chunked rendering

embedded-graphics Integration

Location: examples/stm32g4-embedded-graphics/
Features: Full embedded-graphics support, shapes, text, patterns
Use case: Rich graphics applications with high-level drawing APIs

Basic Display Test

Location: examples/stm32g4/
Features: Simple color cycling, basic functionality verification
Use case: Hardware testing and driver validation

🔧 Hardware Configuration

All examples use this pin configuration:

Function	Pin	Description
SCK	PB3	SPI Clock
MOSI	PA7	SPI Data
CS	PA4	Chip Select (active low)
DC	PB0	Data/Command select
RST	PC4	Reset (active low)

🏃‍♂️ Running Examples

# Basic functionality test
cd examples/stm32g4
cargo run

# embedded-graphics demo
cd examples/stm32g4-embedded-graphics
cargo run

# High-performance patterns
cd examples/stm32g4-direct-spi-90-complex-patterns
cargo run

🎨 embedded-graphics Support

This driver provides full DrawTarget implementation, supporting:

Primitives: Rectangles, circles, triangles, lines
Text rendering: Multiple fonts and styles
Images: Bitmap and raw image support
Custom graphics: Any embedded-graphics compatible drawing
Coordinate transformation: Automatic handling of display orientation

use embedded_graphics::{
    mono_font::{ascii::FONT_6X10, MonoTextStyle},
    pixelcolor::Rgb565,
    prelude::*,
    primitives::{Rectangle, PrimitiveStyle},
    text::Text,
};

// Draw a rectangle
Rectangle::new(Point::new(10, 10), Size::new(50, 30))
    .into_styled(PrimitiveStyle::with_fill(Rgb565::BLUE))
    .draw(&mut display)?;

// Draw text
let text_style = MonoTextStyle::new(&FONT_6X10, Rgb565::WHITE);
Text::new("Hello GC9D01!", Point::new(20, 25), text_style)
    .draw(&mut display)?;

⚙️ Configuration

Display Orientations

The driver supports multiple orientations with automatic coordinate transformation:

use gc9d01::Orientation;

let config = Config {
    orientation: Orientation::Portrait,     // 0°
    // orientation: Orientation::Landscape,    // 90°
    // orientation: Orientation::PortraitSwapped,  // 180°
    // orientation: Orientation::LandscapeSwapped, // 270°
    ..Default::default()
};

Performance Optimization

For maximum performance, use the frame buffer architecture:

// Allocate buffers
static DISPLAY_BUFFER: [u8; gc9d01::BUF_SIZE] = [0; gc9d01::BUF_SIZE];
static FRAME_BUFFER: [Rgb565; 6400] = [Rgb565::BLACK; 6400]; // 160x40

// Create display with frame buffer
let mut display = GC9D01::new(
    config, spi_device, dc_pin, rst_pin,
    &mut DISPLAY_BUFFER, &mut FRAME_BUFFER
);

🔧 Features

Cargo Features

async - Enable async/await support (requires embedded-hal-async)
defmt - Enable defmt logging support

[dependencies]
gc9d01 = { version = "0.1", features = ["async", "defmt"] }

📚 Documentation

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

📄 License

This project is dual-licensed under either:

MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)
Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)

at your option.

🙏 Acknowledgments

Based on the official GC9D01 initialization sequence
Inspired by the embedded-hal ecosystem
Built for the Embassy async framework

gc9d01 0.0.1