Path: utzoo!attcan!uunet!cbmvax!daveh
From: daveh@cbmvax.UUCP (Dave Haynie)
Newsgroups: comp.sys.amiga.tech
Subject: Re: B2000 Rev 4.4 Motherboard
Message-ID: <4331@cbmvax.UUCP>
Date: 26 Jul 88 17:06:28 GMT
References: <826@raven.ukc.ac.uk>
Organization: Commodore Technology, West Chester, PA
Lines: 46

in article <826@raven.ukc.ac.uk>, rpa@raven.ukc.ac.uk (R.P.Almeida) says:
> 
>  Could someone at CATS tell me ehat the changes between 4.3 and 4.4 are ?

How about someone in Systems Design?  The R4.4 board has two resistors on
the board layout that had to be added by hand on the R4.3 board.  It also
has a few traces and things moved around, to make it easier to produce
than a R4.3 board.

> Also could someone tell me which link causes the 0x00C00000 memory to be
> mapped at 0x00080000 ?

That's the link marked J101.  But DON'T move this jumper until you get a
1 meg Fat Agnus installed, or the system will die miserably as soon as
any of that remapped-into-chipram-space-but-not-really-chip-accessable
memory gets touched.

>  I also have the memory expansion board from an A2000 (the original Amiga2000)
> populated to 1Mbyte.

Remove the memory chips and throw it away!

>  I wanted to install it in the B2000, so i disconnected link J500 on the B2000
> , so as to disable the 0x00C00000 memory totally, and installed the board.
> 	It didnt work.

No, it wouldn't.

> This worries me, are the A2000 and B2000 CPU slot timings that different?

There are some slight differences, both in timing (mainly the difference
between Thin and Fat Agnus) and in signals on the CPU slots (due to the
B2000's full CPU slot implementation).  This isn't a problem is you
design things to the published specs.  The A2000's add-on board wasn't
designed to our specifications, it was designed specifically for the
A2000, using unpublished information about the A2000 that doesn't
necessarily apply to any other Amiga.  It should only be used in an
A2000. 

> 	Thank you

> 		Richard Almeida
-- 
Dave Haynie  "The 32 Bit Guy"     Commodore-Amiga  "The Crew That Never Rests"
   {ihnp4|uunet|rutgers}!cbmvax!daveh      PLINK: D-DAVE H     BIX: hazy
		"I can't relax, 'cause I'm a Boinger!"