Gopper

A Klipper firmware implementation in TinyGo for modern microcontrollers.

Gopper brings the power of Go to 3D printer firmware, providing a modern, type-safe, and maintainable alternative to C-based implementations while maintaining full compatibility with the Klipper protocol.

Features (Planned)

• Full Klipper protocol compatibility
• Written in TinyGo for optimal embedded performance
• Modular architecture for easy customization
• Type-safe implementation with Go's strong typing
• Support for modern microcontrollers (RP2040, STM32, etc.)

Status

⚠️ Early Development - This project is in active development and not yet ready for production use.

Current Progress

Phase 1: Core Protocol (Completed ✅)

• ✅ VLQ encoding/decoding (Klipper-compatible)
• ✅ CRC16 implementation
• ✅ Buffer management (InputBuffer, OutputBuffer, FifoBuffer)
• ✅ Transport layer with message framing
• ✅ Command dispatch system
• ✅ Unit tests for all components

Phase 2: Minimum Viable Commands (Completed ✅)

• ✅ Data dictionary generation system
• ✅ Constants and enumerations registry
• ✅ Core protocol commands:
  • identify / identify_response
  • get_uptime / uptime
  • get_clock / clock
  • get_config / config
  • config_reset
  • finalize_config
  • allocate_oids
  • emergency_stop
• ✅ RP2040 hardware timer integration
• ✅ USB CDC communication (native USB support)
• ✅ Complete main loop with USB I/O

Phase 3: Peripheral Modules (In Progress ⏳)

• ✅ ADC driver infrastructure (RP2040)
  • ✅ Internal temperature sensor support
  • ✅ External ADC channels (ADC0-ADC3)
  • ✅ Klipper analog_in protocol
  • ✅ Pin enumeration system
• ✅ GPIO driver infrastructure (RP2040)
  • ✅ Digital output support
  • ✅ Digital input support (pull-up/pull-down)
  • ✅ Pin enumeration (gpio0-gpio29)
  • ✅ PWM capable outputs
• ✅ PWM driver infrastructure (RP2040)
  • ✅ Hardware PWM support
• ✅ I2C driver infrastructure (RP2040)
• ✅ Stepper driver infrastructure
  • ✅ config_stepper, queue_step, set_next_step_dir, reset_step_clock
  • ✅ stepper_get_position and stepper_position response
  • ✅ stepper_stop_on_trigger for homing
  • ✅ PIO-accelerated backend (500kHz step rate)
  • ✅ GPIO fallback backend (200kHz step rate)
• ✅ Endstop handling
  • ✅ Trigger synchronization (trsync)
  • ✅ Digital and analog endstop support
  • ✅ Coordinated multi-axis homing
• ⏳ Heater/temperature control
• ⏳ TMC driver UART/SPI configuration

Supported Hardware (Planned)

• RP2040 (Raspberry Pi Pico)
• STM32F4 series
• STM32H7 series
• More to come...

Communication

Gopper uses native USB CDC (Communications Device Class) for communication with the Klipper host. This provides:

When you flash Gopper to your board, it will enumerate as a USB serial device:

• Linux: /dev/ttyACM0
• macOS: /dev/tty.usbmodem*
• Windows: COM3 (or similar)

Recommended: Use Persistent Device Path

Instead of /dev/ttyACM0 (which can change if you have multiple USB serial devices), use the persistent /dev/serial/by-id/ path:

# List available USB serial devices by ID
ls -l /dev/serial/by-id/

# Example output:
# lrwxrwxrwx 1 root root 13 Nov 12 10:00 usb-Raspberry_Pi_Pico-if00 -> ../../ttyACM0

# Use this in your printer.cfg:
[mcu]
serial: /dev/serial/by-id/usb-Raspberry_Pi_Pico-if00

## Project Structure

gopper/ ├── protocol/ # Klipper protocol implementation ├── core/ # Core scheduling and command system ├── hardware/ # Hardware abstraction layer ├── motion/ # Motion control and kinematics ├── modules/ # Peripheral modules (steppers, sensors, etc.) ├── targets/ # Target-specific implementations └─ tinycompress/ # TinyCompress compression library (zlib compatible)

## Building

Requirements:
- TinyGo 0.31.0 or later
- Go 1.21 or later

```bash
# Build for RP2040 (Raspberry Pi Pico)
make rp2040

# Build for RP2350 (Raspberry Pi Pico 2)
tinygo build -target=pico2 -o build/gopper-rp2350.uf2 ./targets/rp2040

# Build for STM32F4
make stm32f4

# Run tests
make test

# Clean build artifacts
make clean

Manual Build Commands

# Build for RP2040
tinygo build -target=pico -o build/gopper-rp2040.uf2 ./targets/rp2040

# Build for RP2350
tinygo build -target=pico2 -o build/gopper-rp2350.uf2 ./targets/rp2040

# Build for STM32F4
tinygo build -target=nucleo-f446re -o build/gopper-stm32f4.hex ./targets/stm32f4

# Run tests (protocol package only)
go test -v ./protocol/...

Testing with Klipper

Test protocol without any Klipper installation:

# 1. Install Klipper (if not using Docker)
git clone https://github.com/Klipper3d/klipper
cd klipper && ./scripts/install-octopi.sh

# 2. Flash firmware
cp build/gopper-rp2040.uf2 /media/$USER/RPI-RP2/
#copy the uf2 to the RP2040 in Bootsel mode

# or use this command to flash directly from the RP2040
tinygo flash -target=pico -port=/dev/ttyACM0 build/gopper-rp2040.uf2

# 3. Configure and run Klipper
cp test/klipper-test.cfg ~/printer.cfg
~/klipper/klippy/klippy.py ~/printer.cfg -l /tmp/klippy.log

See test/README.md for detailed testing instructions and troubleshooting.

Contributing

Contributions are welcome! Please see CONTRIBUTING.md for guidelines.

Acknowledgments

• Klipper by Kevin O'Connor
• Anchor for inspiration on protocol implementation
• The TinyGo community

This project is not endorsed or affiliated with Klipper, Anchor, or TinyGo in any way. Please do not contact Klipper, Anchor, or TinyGo for support.

License

MIT License - See LICENSE for details