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From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.unix.amiga
Subject: Re: Interaction between /dev/par and /dev/ser
Message-ID: <21488@cbmvax.commodore.com>
Date: 11 May 91 08:21:43 GMT
References: <1991May07.174216.1325@digibd.com>
Reply-To: jesup@cbmvax.commodore.com (Randell Jesup)
Distribution: na
Organization: Commodore, West Chester, PA
Lines: 18

In article <1991May07.174216.1325@digibd.com> rhealey@digibd.com (Rob Healey) writes:
>	As an aside, WHY do the two devices interact and is this quirk
>	fixed in 2.0 like all the other annoying 1.1 problems?

	Well, they do share some of the CIA resources for handling IO bits.
I don't think DTR should move if the printer is in use, so it may have been
an extra bit mistakenly written to the register.  Let's see... PA7 on cia b
is DTR, PA3-6 are other serial control lines, PA2 is printer SEL, PA1 is
printer POUT, and PA0 is printer BUSY.  cia a has the printer data lines in
PBx, and drdy and ack hooked up to PC and F.

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.commodore.com  BIX: rjesup  
Disclaimer: Nothing I say is anything other than my personal opinion.
Thus spake the Master Ninjei: "To program a million-line operating system
is easy, to change a man's temperament is more difficult."
(From "The Zen of Programming")  ;-)