Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!usc!apple!oliveb!amiga!cbmvax!daveh
From: daveh@cbmvax.UUCP (Dave Haynie)
Newsgroups: comp.sys.amiga.tech
Subject: Re: State of PD system enhancement (was: Two Amigas)
Message-ID: <7950@cbmvax.UUCP>
Date: 19 Sep 89 16:28:36 GMT
References: <34.filbo@gorn.santa-cruz.ca.us>
Organization: Commodore Technology, West Chester, PA
Lines: 21

in article <34.filbo@gorn.santa-cruz.ca.us>, filbo@gorn.santa-cruz.ca.us (Bela Lubkin) says:
> X-Claimer: I >am< R Pentomino!

> What happens if you Forbid() as the block starts, can you get away with
> cycle counting? 

One big problem is that you never know exactly how long it'll take to write
to the CIA chip.  It's hooked into the system via the 68000's 6800 family
support mechanism.  The CIA runs from a clock that's 6 68000 clocks low,
4 clocks high.  When you access the CIA, the 68000 will synchronize to this 
free running 716kHz clock; depending on where the 68000 cycle is in relation
to the CIA cycle, this can sync-up can vary quite a bit.  So handshaking 
between machines is a requirement.

> Bela Lubkin     * *   filbo@gorn.santa-cruz.ca.us   CIS: 73047,1112
>      @        * *     ...ucbvax!ucscc!gorn!filbo    ^^^  REALLY slow [months]
> R Pentomino     *     Filbo @ Pyrzqxgl (408) 476-4633 & XBBS (408) 476-4945
-- 
Dave Haynie Commodore-Amiga (Systems Engineering) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
                    Too much of everything is just enough