Path: utzoo!attcan!uunet!wuarchive!zaphod.mps.ohio-state.edu!samsung!munnari.oz.au!metro!ipso!runxtsa!applix
From: applix@runxtsa.runx.oz.au (Andrew Morton)
Newsgroups: comp.sys.m68k
Subject: Re: autovector on the '010
Summary: How to get 010 to autovector
Message-ID: <893@runxtsa.runx.oz.au>
Date: 10 Apr 90 06:10:35 GMT
References: <1990Apr07.090036.26347@csuchico.edu>
Organization: RUNX Unix Timeshare.  Sydney, Australia.
Lines: 15

In article <1990Apr07.090036.26347@csuchico.edu>, garlick@csuchico.edu (Jim Garlick) writes:
> In my 68010 manual, I'm having a hard time finding where it says
> how to use interrupt autovectoring.  On the 030 and 040, you pull
> the AVEC* line, right?  What do you do on the 010 and 020?  I'd 
> like to avoid handling an interrupt acknowledge cycle at all, 
> if possible.

	When the 68000/010 recognises a pending interrupt it
puts the level of the interrupt out on a1-a3 and puts FC0, FC1 and FC2
high and asserts /AS. Under these circumstances external hardware
must assert (lower) the CPU's /VPA signal. This will cause autovectoring.

	If the system does not have a mix of vectored & non-vectored
interrupt sources you can simply decode FC0-2 high and /AS asserted
to drive /VPA low.