Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!mcsun!ukc!cam-cl!news
From: nbvs@cl.cam.ac.uk (Nicko van Someren)
Newsgroups: comp.sys.acorn
Subject: Re: RS423 Interrupts/Events under RiscOS
Message-ID: <1991Jun17.090017.19118@cl.cam.ac.uk>
Date: 17 Jun 91 09:00:17 GMT
References: <2692@m1.cs.man.ac.uk>
Reply-To: nbvs@cl.cam.ac.uk (Nicko van Someren)
Organization: U of Cambridge Comp Lab, UK
Lines: 20

In article <2692@m1.cs.man.ac.uk> rogersh%t3a@uk.ac.man.cs (Huw J. Rogers) writes:
>	Does anyone know how to get RiscOS to generate an event/interrupt
>to the application on receipt of a RS423 character? I *have* looked in
>my (Arthur version) PRMs...

Every time a character comes in on the RS423 it gets put into an input buffer,
buffer number 1.  All insertion (and removal) into buffers goes through the
various buffer vectors insv, remv, cnpv.  If you intercept the insert vector
by calling OS_Claim with R0=&14 your code will be called every time a character
is put in a buffer.  R1 will contain the buffer number so check to see if that
is 1 for the RS423 input buffer and you're away.  Remember to make sure that
the vector code is in the module area if you are running in the desktop as it 
could get paged out otherwise.

Nicko


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| Nicko van Someren, nbvs@cl.cam.ac.uk, (44) 223 358707 or (44) 860 498903    |
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