Posted By
gerliczer
on 2021-06-03
11:39:09
|  Re: Let’s JoyTest! :)
As far as I understood, you are mistaken Mad. STA $FF08 is superfluous because latch control is damaged therefore you can't use it in those TEDs. You put the row select value into the TED idle byte $FFFF (which is a bit inconvenient) then wait for a TED idle fetch. That is a similar mechanism as VIC-II idle fetch from $3FFF/$7FFF/$BFFF/$FFFF depending on the VIC-II bank. That idle fetch will trigger the latch properly so LDA $FF08 will read from the joystick. You have to be careful to time it in such a way that memory refresh will not interfere with the idle fetch that sets up the latch.
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