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From: israel@mitisft.Convergent.COM (Paul Israel)
Newsgroups: comp.misc
Subject: Re: Help Hapless Hardware Hacker
Keywords: PC/XT hardware homebrew
Message-ID: <1565@mitisft.Convergent.COM>
Date: 10 Aug 90 20:17:31 GMT
References: <2930@sodium.ATT.COM>
Reply-To: israel@mitisft.UUCP (Renegade of Berkeley)
Organization: Unisys Network Computing Group, San Jose
Lines: 22


	Are you pulling any wait states? Maybe you're generating a
conflict with the floppy controller. Also, if you've got any bus
signals that your board is loading past two LS-equivalent inputs,
that can also cause problems. Maybe the board isn't seated properly
in the backplane slot, or the slot itself has problems - try moving the
board to another one. Also, make sure your output connector is properly
grounded.

	As to the register address, I'm not sure if it conflicts with
anything else or not, as I don't currently have access to a PC Technical
Reference manual, but certain IO addresses are reserved for dedicated
PC functions. If your decode is stepping on someone elses toes, it might
look as if your board functions ok, but at the same time may end up
screwing over another PC port. Try examining what your port outputs
while you attempt a disk write - if something comes out, then you've
definitely committed a decoding no-no.
-- 
Paul Israel
Renegade Systems, 434 South Bernardo Ave, #2 Sunnyvale, CA 94086
Disclaimer: "Who, me? I wasn't even there!"
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