Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!decwrl!labrea!polya!kaufman
From: kaufman@polya.Stanford.EDU (Marc T. Kaufman)
Newsgroups: comp.sys.mac.programmer
Subject: Re: NuBus Interrupts
Message-ID: <7111@polya.Stanford.EDU>
Date: 23 Feb 89 16:44:42 GMT
References: <17495@srcsip.UUCP>
Reply-To: kaufman@polya.Stanford.EDU (Marc T. Kaufman)
Distribution: na
Organization: Stanford University
Lines: 17

In article <17495@srcsip.UUCP> lowry@srcsip.UUCP () writes:
>Does anyone know how long the interrupt line for a slot on the Mac II
>must be asserted?  

>I have a logic pulser that produces a 10 usec pulse.
>When I use it to request an interrupt, it doesn't seem to be recognized.
>If, however, I assert the interrupt line for a second or so, I get lots
>of interrupts.  Do I have to continue to assert the line while the
>OS goes through the slot interrupt queue looking for a service routine?

You have to hold the interrupt line until your software services the interrupt.
The software should clear the interrupt when it is serviced.  The interrupt
line state is used by the OS dispatcher to know which interrupt service
routine to call.  If it is still there when you exit, the OS assumes you want
another one.

Marc Kaufman (kaufman@polya.stanford.edu)