pixel artist friend of mine wanted a mouse to try his skills on a real C64. I thought I could help him by making an adapter that would allow a regular PS/2 mouse to be used with a Commodore 64. The most popular and supported C64 mouse is 1351 mouse which uses analog capabilities of joystick control ports to send movement data. Same mouse also has a joystick compatibility mode that emulates joystick tilt in response to mouse movements. A PS/2 mouse uses a serial protocol to send digital packets that contain information about current counter values and status of the buttons. A 1351 mouse sends information in the form that C64 analog inputs can read. [M]ouse, the coupling device, communicates with a PS/2 mouse on one side and presents itself as a 1351 mouse to the other side.