An awful lot of questions, but one after the other
Okay, and gflorez had right, as well,
I could read the informations more deeply and I could try to put the informations together for myself, but these things are not too easy ...
But (sooner or later) I will do that, of course.
But now I try to ask more specifically, maybe the answer is shorter for this:
Using (for example) a sega controller through this adapter with the EP ... will it be "under the scope" of this hardware interface, or such a "change" is out of the scope ?
(Maybe with some custom programming of the chips on it, or such ...)
Sega controllers have the same physical connector like C64/Atari/Amiga/CPC/ETC joysticks, but of course probably a different pinout and/or a different protocol.
But these devices have real 3 or more additional buttons to the directions ...
(What buttons will be barely used by EP softwares, but I hope that some EP software is configurable on the full range of inputs of the EP ...)
But (of course) there are many joysticks/controllers,
(using the same physical connector, or only more easy to replace the connector on the wire of the controller than fully recable the device to the EP inputs, not mentioned how problemmatic to get edge connectors with the appropriate size to the EP side),
so there are many controllers, for nintendo, sega, and other computers/consoles what have less than 9 wires, and physically could connect to this interface easilly through the joystick connectors.
The question is the above one: handling different pinouts and/or protocols than the C64's one, is under or above the scope of this device ? (Of course with customization, not "from stock")
Some explanation to the question:
Formerly I hacked together (with the help of the people of this forum, not myself) a PS/2 keyboard interface, what can work along with the EP's internal keyboard.
(I used an arduino micro "board" alone, the wires connect to this board directly, everything is in software, and (of course) the answer times to the EP side are on the edge, using even assembly handled interrupts.)
I very like the different game controllers/joysticks especially those are with many buttons.
Along the keyboard interface, I planned to implement mouse and joystick support as well,
but (thanks to god) the mouse will be handled by your interface, so that problem will be solved by you,
and I would be happy if your hardware would be capable to handle such different type of controllers, too.
In this case, I have not to do anything more, but customize the hardware of you ...