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From: blochowi@cat28.CS.WISC.EDU (Jason Blochowiak)
Newsgroups: comp.sys.apple
Subject: Re: WordStar
Keywords: CP/M, INH
Message-ID: <2412@puff.cs.wisc.edu>
Date: 8 Mar 89 18:55:04 GMT
References: <1206@wpi.wpi.edu>
Sender: news@puff.cs.wisc.edu
Reply-To: blochowi@cat28.CS.WISC.EDU (Jason Blochowiak)
Organization: U of Wisconsin CS Dept
Lines: 30

In article <1206@wpi.wpi.edu> dseah@wpi.wpi.edu (David I Seah) writes:
> [...]
>says something like "Cards that use /INH will work properly if the system is
>running at 1.024 MHz".  On Page 166, The Book says that "Pulling this line
>[/INH] low during 01 inhibits (disables) the memory on the main circuit
>board."
>What would a peripheral card use /INH for functionally?
                             ___
	I dunno exactly what INH does (being a software person), but I
remember from reading the manuals (a loooong time ago) that the CP/M card
disabled the 6502 so that it could do its business. It did it in cycles,
so that the 6502 would be disabled while the Z80 would use the busses, then
it would reenable the 6502 (so that it's dynamic registers didn't die a
horrible death), etc.
>Is there some kludge availiable for bringing a Microsoft CP/M board up to
>speed?                                     ___
	I doubt it, given that it relies on INH, and the hardware ref. said
that that won't work in fast mode. So, unless you want to play with the gs'
motherboard... Why would you want to anyways? Wouldn't it only affect the
native 6502 code that gets called from the Z80 stuff? What I would do to
take care of the problem is write a small program which just set the gs to
slow speed & ran the CP/M startup program - not too hard.

>| <<<<<(((((( DAVE SEAH ))))))>>>>> |	Internet:  dseah@wpi.wpi.edu
>| Worcester  Polytechnic  Institute |	Bitnet:	   dseah@wpi.bitnet
>| Computer Engineering Class of '90 |	AppleLink: Omnitreant
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		Jason Blochowiak (blochowi@garfield.cs.wisc.edu)
			"Not your average iconoclast..."
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