Posted By
TLC
on 2007-01-08
17:00:01
|  Re: Plus/4 Expansion port...
Mike: I've checked the images... I'm actually surprised that those can be _that_ simple...
Bionic: well, good theory...  Actually, if the card really works like that, then it must have been reverse-engineered inaccurately... or whatever... according to that sch, A9 would be asserted low as soon as a high (inactive) IRQ' state is latched (amongst other conditions like AEC is high and R/W' is high); the circuit won't wait for IRQ' to drop (thus it could disturb a running code before finally catching an IRQ'...). Neat finding, anyway. The algorithm should certainly be possible (as far as I can see) to implement in a new design.
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