Re: Commodore drives can be controlled on Apple II serial!

[doug.cotton@cmdweb.com (Doug Cotton)]

In article <1998032405360600.AAA10282@ladder03.news.aol.com>,
supertimer@aol.com (Supertimer) wrote:

> >That last bit is interesting... standard Commodore serial I/O only uses
> >three lines... ATN (Attention), CLK (Clock) and DATA (Serial Data). The
> >other three lines on the bus are a ground, reset and SRQ (Service Request).
> >The latter is needed for fast serial only, though schemes like JiffyDOS
> >perform (sometimes outperform) fast serial without even using this line.
> 
> So, based on what David wrote about the SmartPort, can it be used to
> emulate Commodore serial I/O?

It sounds like it at this point. Due to the limited number of lines, I'd
say use them for ATN, CLK, DATA and SRQ. RESET could be done in the 'cable'
with a one-shot, or could be ignored for that matter... isn't an absolute
necessity, though it would be better to have it than not. Is there by any
chance some form of a reset signal on this port already? That would be
another option. Need to pick up a ground too, but hopefully the port has
that. Is there any documentation on this port anywhere?

The low-level software side isn't too bad, but the only other sticking
points I can see are speed of the port, and finding out if interrupts can
be avoided during operation.

-- 
Doug Cotton <doug.cotton@cmdweb.com>

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