Interaction between /dev/par and /dev/ser
Randell Jesup
jesup at cbmvax.commodore.com
Sat May 11 18:21:43 AEST 1991
In article <1991May07.174216.1325 at digibd.com> rhealey at 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 at 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") ;-)
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