While the Boffintronics Commodore 64 Adapter board can be hooked directly up to the GPIO of the Raspberry Pi, one of the easier ways is to use the PetRockBlock ControlBlock.
The ControlBlock is an add on board for the Raspberry Pi that adds 32 extra inputs for additional joysticks or buttons. The ControlBlock also allows for adding a power switch and LED with intelligent start up and shutdown scripts.
Hooking up the C64 board is fairly simple since standard Commodore and Atari joysticks are just switch closures that ground the corresponding pin on the connector. Each joystick will require 5 connections plus a ground.
The ControlBlock breaks up the inputs so that Player 1 is on one side and Player 2 is on the other.
For Player 1, connect the following wires;
|C64 Board||ControlBlock (Player 1)|
For Player 2, connect the following wires;
|C64 Board||ControlBlock (Player 2)|
If you want to use the power switch and LED functions of the ControlBlock, the instructions can be found here.
You will need to install the drivers for the the Controlblock on your Raspberry Pi which can be found here.
Once the driver is installed, use the arcade button profile. This allows for the best functionality in the C64 emulator VICE.