This project uses an Arduino to exchange data with a Nintendo 64 controller. Data passed to the Arduino over its serial interface is transmitted to the controller, then the controller's response is returned over the serial interface. A Python script is included for interacting in certain ways with devices in the controller's expansion port; it includes (and uses) a class with methods wrapping each known raw command and providing some functionality on top of that for interacting with expansion devices.

To use the Arduino part, once the code is uploaded connect the N64 controller's 3.3V and ground lines to the expected places, connect the data line to pin 2 (changeable in param.h), and open the serial interface at 115200 8N1. Transmit a two-byte header (length of raw command and length of expected response) and the raw command to be sent to the controller, and the controller's response will be sent back, with no header. You will always get the number of response bytes you indicated you were expecting; bytes beyond the number that the controller actually sent are undefined.

(For example, to query the controller's buttons, send 01 04 01, and you will get back the four bytes the controller sends back.)

The main difference between this and other projects I found for interacting with N64 controllers is that this implements only the bare minimum that is necessary on the Arduino and leaves everything else to the host machine. I feel that this has advantages over doing everything on the Arduino, especially when it comes to flexibility, testing, and interactive experimentation with the controller.

Building

The Makefile includes Arduino.mk from the path where the Debian arduino-mk package puts it. This path may need to be modified.

BOARD_TAG is not set in the Makefile because this should be able to work with many Arduino boards. Specify it on the command line - something like:

make BOARD_TAG=mega2560 upload

The Arduino used must be AVR-based with a clock rate of 16 MHz; this is checked at compile time. Patches making it work at other clock rates are welcome.

My use case

I did this project mainly to read and write savefiles from Game Boy cartridges through a Transfer Pak. This was part of the setup for shenanagans_' Pokémon glitch showcase at AGDQ 2016, whose finale involved a specially preconstructed savefile made by luckytyphlosion. For more information, see:

To do

The Python script probably has many bugs, especially in fully handling expansion devices. I don't have a Rumble Pak, so I can't test that it can really distinguish those from Controller Paks and Transfer Paks (which I do have); I went by what other code does.