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Amken USA edited this page Nov 19, 2025 · 2 revisions

Gopper

Gopper_Logo.png

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.

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