Motorola 68000-16 and 68450 chips...

From: Julian Richardson <JRichardson_at_softwright.co.uk>
Date: Fri Apr 27 05:31:19 2001

>> also, does anyone know of anything that used 68450 chips?
(they're 4-channel
>> DMA controllers for the 68k apparently). I found a couple of
these amongst
>> the piles of junk I have and am curious as to where I might have
got them -
>
> In a 64 pin DIL package or a 68 pin (?) PGA package?

64-pin DIL.

> I've seen the former in sevaral machines, including the Torch XXX.
The
> latter was used in the PERQ3a. Although if you stripped either of
those
> machines for parts, I would feel justified in stripping _you_ for
parts :-)

hmm, strip away :-)
It's possible... I never had a complete XXX system, but Torch used to be my
local source of PC bits (around 1990 or so) and I knew the guys there via a
friend of mine. I remember piles of XXX machines on the shelves gathering
dust, not sure what happened to those (are Torch still around? Unlikely).
Occasionally I used to get other odds and ends from there (I have a set of
XXX floppies someplace) so may have had a dead XXX system board or something
from them which I pulled the 68450's from.

I used to work for a place up in Cambridge that was primarily a PC repair
shop, but they used to sell anything computer-related so long as it was
mainstream-ish (ie. lots of Amstrads etc. too). Occasionally we'd get
oddities in, which is where a couple of my bigger systems have come from.
The boss always wanted such machines stripped for useful parts (typically
just memory and disks, workstation monitors if they were there) and then the
rest was scrapped :-(

Unfortunately he always wanted a ridiculous amount of money for any of these
systems complete, otherwise I would have saved whatever I could (anything
with SCSI disks seemed to automatically command a tenfold price increase!).
I have a vague memory of at least one XXX system which passed through there,
an IMP system, several big Apricot towers, and some Acorn Unix system of
some sort. It's possible I scavenged the 68450's from the bin awaiting
disposal, although I have no idea what I thought I was going to do with them
:)

I seem to remember a big white cabinet on wheels (3' high, 18" wide by maybe
4' deep) which we used to ride around the warehouse on :-) No idea what the
innards of it were though! Oh, for some reason video memory was never saved
- if we had a dead PC SVGA card it just got thrown out as-is. I had a nice
little scam going pulling memory off these dead boards and selling it to
people wanting to upgrade their PC video cards from 512KB to 1MB.... the
video memory was usually intact even if the boards were toast.

cheers

Jules
Received on Fri Apr 27 2001 - 05:31:19 BST