Posted By
siz
on 2021-07-13
07:27:28
|  Re: Joypad for plus/4
Following up TLC's ideas I have my own(?) protocol suggestion: the gamepad itself could be switched between traditional (4 directions and all fire buttons connected to the same wire) and extended mode where the select line of the joystick port would toggle between state read from the joystick:
1) read joystick state returns the 4 directions AND fire as being high to indicate that directions are read
2) second joystick state returns fire=low and the directions contain the state of up to 4 buttons.
This would require 2 subsequent joystick reads for the same port but IMHO this is simple enough to implement. Of course all the programs should be aware of this extended gamepad so it must be selected as a different control method but that's the price to use the extra buttons.
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