Joystick connection (C64/Amiga)

[Zac67]

There's no way to detect a joystick if it's not used.

An Atari style joystick consists of five switches - four directional, one fire button (possibly two). Each switch connects the according sense line to ground when activated. Without moving the stick or pressing the button all sense lines are pulled high and there's no difference between an inactive stick and none present.

[Zac67]

That's right - there are two perils when 'hot' plugging devices:
- shorting powered pins to ground (causing a fuse or track to burn) or an I/O pin that can't cope with it (destroying some active component)
- static electricity: even when not noticable to humans, static buildup (of a non-earthed device or body) of a few hundred to several thousand!(!) volts can instantly destroy electronics

While the Amiga's joystick/mouse ports are explicitly hardened against the latter danger (see manual) there still is some danger, so handle with care!