Joystick API

[stevesims]

We have an Agon machine that ships with two 2-button Atari-style joystick ports, the Agon Console8. There are also several interface boards available for other Agon machines that provide joystick ports that at completely compatible with the Console8. It would be good if there was an API in MOS that made reading those ports easy

Ideally a joystick API should allow for future adjustment/augmentation.

To bear in mind here is that there are other options for integrating joysticks and similar interfaces with Agon machines, and we may have other options possible in the future too. There's been a Wii nunchuck interface available for Agon Light 2 machines since long before the Console8 launch. A design exists for connecting joypads with more buttons like a Megadrive controller. (Paddle controllers and mice via a 9-pin port may also be a possibility, although they perhaps would require a different API.) A potential future VDP could perhaps allow USB-based joysticks/joypads to be plugged in and used.

An initial implementation in MOS that only supports Console8 style ports may be an acceptable compromise for now. The API design for getting information on a joystick should, however, be able to work with joysticks of differing capabilities to allow for supporting other interfaces in the future.

(Discussion around providing modular support for other interfaces can be found here: #2 )