EzHID Gamecube Controller Firmware


The gcpad module is a firmware package for the EZ-USB device that manages up to four Gamecube controllers. It makes them available as generic gamepads to any computer system that supports the HID class of the USB standard. Modern computer systems should be able to recognize this bundle and to attach it seamlessly to the set of input devices for game control. There should be even no need for specific drivers as the HUT gamepad characteristics are well-defined inside the HID specification. The generic driver of any operating system should do the job.
It has been tested with Linux 2.4.22 so far, which implements joystick handling within the joydev module. In case this module is not loaded automatically, consult the documentation of your distribution on how to activate this module.


Some restrictions apply when using this module. Not everything has been tested yet and I do not know which flaws are still present. The firmware is known to play well with the original controller and certain clones. It definitely works with a "BigBen Interactive" clone.

Compilation and Installing

The file gcpad.ihx contains a compiled version of the firmware based of the released source files. You need the SDCC compiler suite if you want to modify the sources.
Once it is installed, issue


The hex-file can be downloaded directly to the EZ-USB device using your preferred method. The firmware supports both downloading into the device RAM or being bootloaded from a programmed serial I2C EEPROM on the board. In the latter case you'll have to set the variable ROM_FW accordingly in Makefile. After having compiled the source code to suit the needs of the bootloading, run create_ezhid_e2.pl on the compiled hex-file. The output of create_ezhid_e2.pl has the correct format for the onbaord I2C EEPROM.
The benefit of having the firmware permanently in the EEPROM is that you do not have to set up a firmware downloader for every operating system you happen to use on your computer.

Adapter Hardware

The Gamecube controller connector is quite straight forward. It uses three pins for power supply (+5.0V, +3.43V and GND) and one pin for the data signal. Please note that the voltages were measured at two PAL consoles only, so it is a good idea to verify if their values match your paticular console. Here's a schematic how to connect the controllers:
I am not 100% sure about the value of the four resitors. I followed the description on James' page and they worked for me.

Wiring diagram for the Gamecube controller adapter (gcpad.png)

The assignment to the EZ-USB ports is arbitrary. It can be changed by modifying the #define statements in pad_port.h.
Although some references for the Gamecube controller mention the supply voltage to be 3.43V it seems not to be mandatory to stick exactly to this voltage. I use the 3.3V on-board supply which works well with my controllers.
If you are lucky you can find a matching connector and wire this to the EZ-USB device. Alternatively, you can reuse an externsion cable and replace the connector which plugs into the console by a standard male connector. The matching female connector is then connected to the EZ-USB according to the above schematic. 5-Pin DIN connectors are well suited, cheap and provide compatibility with extension cables for old keyboards. You can share the adapter hardware of an N64 controller and add the 5.0V supply to a spare pin.

Once the firmware is downloaded and installed, the HID subsystem should report four new gamepad devices. Each controller has eight axes (analog joystick, analog C-joystick, digital pad, L and R) and 8 buttons. The buttons are assigned in the following way:

Gamecube Button
Gamepad Button

Additional Resources

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