USB Adapter for GameCube Controllers

Open-source 4-port USB GameCube Controller Adapter, a drop-in replacement for Nintendo's official adapter (WUP-028).

Just like the official adapter, this reads up to four GameCube controllers over the Joybus protocol and exposes them to a USB host over its own custom HID interface.

Built using libjoybus and TinyUSB. Implementations are provided for ESP32-S3 and Raspberry Pi Pico (RP2040/RP2350).

Features

• Up to 4 GameCube controllers
• Rumble support
• WaveBird receiver support (unlike the Mayflash clones)
• 1 kHz polling end to end for low input latency
• Recognized as the official Nintendo adapter on Wii U, Switch, Switch 2, and Dolphin

Installation

Pre-built firmware files are available for Raspberry Pi Pico, Raspberry Pi Pico 2, Waveshare RP2040-Zero, Waveshare RP2350-Zero, and Waveshare ESP32-S3-Zero boards. You can find them on the releases page.

Raspberry Pi Pico / Pico 2

Enter bootloader mode by holding the BOOTSEL button while plugging in the Pico. Then copy the firmware uf2 file to the RPI-RP2 drive that appears.

ESP32-S3

To flash the ESP32-S3 firmware, you'll need to install esptool.

Enter bootloader mode by holding the BOOT button, pressing and releasing the RST button, then releasing the BOOT button. The flash the firmware using esptool as follows:

esptool write-flash 0x0 <path_to_firmware>

Wiring

• GameCube controller 5V to the board's 5V rail
• GameCube controller 3.3V to the board's 3.3V pin
• GameCube controller GND to a GND pin
• Pull-up resistors are required on each data line - the recommended value is 750Ω
• Each controller's Joybus data line to the configured GPIO

The pre-built firmwares map the four controller ports to the following GPIOs:

Board	Port 1	Port 2	Port 3	Port 4
Waveshare RP2040-Zero	GP29	GP28	GP27	GP26
Waveshare RP2350-Zero	GP29	GP28	GP27	GP26
Raspberry Pi Pico	GP2	GP3	GP4	GP5
Raspberry Pi Pico 2	GP2	GP3	GP4	GP5
Waveshare ESP32-S3-Zero	GP1	GP2	GP3	GP4

Building from Source

Raspberry Pi Pico / Pico 2 Boards

Install the Pico SDK and set the PICO_SDK_PATH environment variable to the path of your installation.

You can build for one of the pre-configured boards using the cmake presets as follows:

cd ports/rp2xxx
cmake --preset rp2040-zero
cmake --build --preset rp2040-zero

Alternatively, you can do a custom build by passing your own configuration options to cmake directly:

cmake -B build \
  -DPICO_BOARD=pico \
  -DGCCA_JOYBUS_GPIO_CH0=1 \
  -DGCCA_JOYBUS_GPIO_CH1=2 \
  -DGCCA_JOYBUS_GPIO_CH2=3 \
  -DGCCA_JOYBUS_GPIO_CH3=4

ESP32-S3 Boards

Install the ESP-IDF toolchain.

You can build for one of the pre-configured boards by specifying the defaults file for that board as follows:

cd ports/esp32
idf.py set-target esp32s3
idf.py -D SDKCONFIG_DEFAULTS="sdkconfig.defaults;boards/esp32-s3-zero.defaults" build

For a custom build, you can configure the port GPIOs under the GameCube Controller Adapter inside idf.py menuconfig, and then build with idf.py build.