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From: miner@ulowell.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: Auto-config and timers
Message-ID: <1109@ulowell.cs.ulowell.edu>
Date: Fri, 27-Feb-87 00:20:43 EST
Article-I.D.: ulowell.1109
Posted: Fri Feb 27 00:20:43 1987
Date-Received: Sun, 1-Mar-87 08:12:27 EST
References: <957@petsd.UUCP>
Reply-To: miner@ulowell.cs.ulowell.edu (Richard Miner)
Organization: University of Lowell
Lines: 27

In article <957@petsd.UUCP> fredc@petsd.UUCP (Fred Cassirer) writes:
> He's building a memory board, that will auto-config, and wants to
> throw a timer on board.   The problem is:
> He needs to add a clock/timer chip to the expansion bus but doesn't want
> it to make it auto-config.  Is there an address that the clock.....

The way auto-config works is on a per board basis.  In other words, if you
have a memory board that also has a clock, a 68881, crash recovery logic, 
a corkscrew, whatever, it all boots as a single board.

> It seems like overkill to have to auto-config a timer when you are
> only going to read it once on power up (and at reset).

This is the purpose of auto-config, many devices just need to be initialized
at boot time.  The PAL on your friends board contains information stating 
the amount of memory required by it; n-Meg bytes + clock-register-bytes 
(you might have to make this a multiple of 64K).  You have to tell the 
system that you want the clocked mapped to memory!  If you just stick it at 
the end of your ram the Amiga will not know it is there and may map another 
device at that address.

At boot time when the system says hello to memory board it will check 
for a driver routine.  Have the driver read the clock registers 
and set the time.  Why not take advantage of a great feature supplied by
the system? 
-- 
Rich Miner !ulowell!miner Cntr for Productivity Enhancement 617-452-5000x2693