[A83] Re: Direct Input...
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[A83] Re: Direct Input...
All code I've seen uses 2-4 nops between the out and the in. I've always
used 2 in my code and haven't ever seen any problems on the real hardware.
The code in the ROM for both the 83 and 86 uses 4. The relevant portion of
the ROM (same on both calcs) is shown below:
out (1),a
nop \ nop \ nop \ nop
in a,(1)
ld b,a
ld a,$ff
out (1),a
I don't remember ever having to reset the port when reading keys (but maybe
I never read more than the arrows using the ports).
> With 'Direct Input' you have to reset the keyboard (via outputting $FF
> trough port 1), do you have to wait a little for the hardware to react? Or
> can you just go on with the next output (to actually switch the the
> groups)?
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