Amiga A1060 SideCar

From: Doug Spence <ds_spenc_at_alcor.concordia.ca>
Date: Sat Mar 21 03:47:29 1998

I finally got around to archiving what ROMs I could find in my old
SideCar, and I have a few questions. I know the comp.sys.amiga.hardware
would probably be a better place to ask, but I'm going to ask here anyway.
:) [The SideCar, for those that don't know, is basically an XT clone that
attaches to the side of an Amiga 1000, whos display normally appears in a
window or on a separate 'screen' on the Amiga display.]

I didn't completely disassemble the SideCar, I only took the cover off and
poked around a little.

I got my SideCar 'third-hand' and never had the manual for it. I never
played with the dip switches or jumpers in it. Does anyone know what all
the dip switches are for? There's a bank of eight of them, and another of
four. Currently the 8 are: OFF, ON, ON, OFF, ON, OFF, OFF, ON. The set
of 4 are all OFF.

I checked through memory with DEBUG and located the BIOS code as well as
the stuff the Amiga sends to the PC side via the dual-port RAM. I don't
know how big the BIOS is supposed to be. It looks like it's in two
chunks, of about 4K and 8K. The first section of this code lies at F4000
and goes to about F4Cxx, followed by a bunch of FF's, then at F6000 is a
solid 8K chunk of code, including copyright messages from Commodore
Electronics Ltd. and Phoenix Software Associates Ltd.

Would all of this be in a 16K chunk in the EPROM at location U22 on the
motherboard? It's a 48-pin EPROM with a sticker on it that reads
"380619-02" and "Hydra BIOS 2.05".

Under the daughterboard and the hard drive (I replaced the floppy drive
with an ST-296N in 1991 or so) where I couldn't really see very well, were
at least two other 48-pin chips, at U39 and U40. The only number I could
see was "8621" on the one at position U40. I know that's not a lot of
information, but does anyone know what those are? I'm just interested in
how the SideCar performs its magic.

I looked into the RAM area from E0000-F3FFF which is the shared RAM, and I
was surprised to see some stuff in there from the Amiga side that I don't
think should have been there. After the PC.boot file stuff that was
loaded into the PC side by the Amiga at startup, there was the "info"
program from the Amiga shell. Executing something else on the Amiga side
cleared that area out, and executing "info" again (from ARP 1.3, not the
real AmigaDOS) put the info code back in there. Also, some
filenames from directories on the Amiga side showed up in there. What's
going on?

The SideCar controls the hard drive for the Amiga. Does the Amiga get
the data from the HD through this memory area?

I've never been able to get AREAD/AWRITE to function. They always GURU.
I got the files from a BridgeBoard distribution... do I need special ones
for the SideCar?

Now, the main reason I actually opened the SideCar up: I installed a
Seagate SL-02 SCSI controller when I installed the hard drive. It
conflicted with the floppy controller in the SideCar, and in order to have
floppies and hard drive running at the same time, I had to disable the
floppy controller on the SCSI card. I did this by putting masking tape
over each pin on the card in turn, booting up the Amiga and the PC side,
and recording the results. I eventually decided, from these results, to
tape over 7 of the pins on the SCSI controller card, and this has worked
perfectly since.

I don't know how the pins are numbered, but below is an ASCII graphic
representation. :) The 5th, 6th, 10th, 18th, 19th, 22nd, and 26th pins
are taped over, on the left hand side of the card, reading from front to
back.

    xx x xx x x |
===============================|
                               |o

I hadn't recorded this anywhere, and I was a bit worried that the tape
would be drying out and falling off and making my SideCar go crazy, but
everything was OK. And now it's recorded somewhere. :)


Oh, one other thing. The first part of the boot message is as follows:


 Commodore Hydra BIOS Rev. 2.05 - Test Release -

 Copyright (C) 1985 by Commodore Electronics Ltd.
 Copyright (C) 1984,1985 by Phoenix Software Associates Ltd.
                     All Rights Reserved.


The serial number is under 1000. I'm wondering how common the A1060
SideCar is, and if anyone has one that doesn't boot up with the "Test
Release" message.

The motherboard says:

FAB 380517-01 Rev.4
ASSY NO. 380604-01 Rev.7
?1986 COMMODORE
SIDECAR MAINBOARD

Are there earlier or later revisions out there?


Doug Spence
ds_spenc_at_alcor.concordia.ca
Received on Sat Mar 21 1998 - 03:47:29 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:31:09 BST