Posted By
BSZ
on 2021-06-08
18:21:49
|  Re: Let’s JoyTest! :)
@Mad: In my opinion, the broken TED is not detectable without any user interaction. But for simple detection enough to press any key. ("Press Any Key to Continue..."  ) Simple detecting code:
LDA #%00000000 ;Select all Keyboard rows
STA $FD30
LDA #%11111111
STA $FF08
CMP $FF08 ;Any key pressed?
BEQ .NoKeypress_DoItAnything
The check comes from here:
LDA #%11111111 ;Deselect all Keyboard rows
STA $FD30
CMP $FF08 ;All Keyboard column released without $FF08 write cycle?
BEQ .BrokenTed ;If yes, TED Keyboard Latch is broken
But... What is this check for..?  Handling a broken TED also works for a good TED, I think. No need to program them separately. Keyboard control is just an idea; probably no problem at this time for a required Joystick.
@MCes: Only good TED is good news!
@MMS: PLA and CPU faliure is significant higher than full faulty TED, at least that's been my experience. If only the latch is bad, we are happy!
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