14 Feb
2008
14 Feb
'08
11:57 p.m.
On Friday 15 February 2008 01:46, Ethan Dicks wrote:
Hmm. I wasn't thinking PET as much as C64, when I wrote that. The ROMs in
that one were all 24-pin parts, a 4K character rom and the BASIC and Kernal
being 8K, which would need a 2764.
On Fri, Feb 15, 2008 at 01:11:23AM -0500, Roy J.
Tellason wrote:
No, it doesn't. It's just a minor annoyance, which is probably why I only
gripe about it every now and then nad hvaen't really gotten around to doing
anything about it... :-)
I have the 8052-BASIC based one that Steve
Ciarcia had in an article in
Byte, and that uses a serial connection. Only at 1200 baud, though,
for some reason.
4K doesn't take _that_ long to push over 1200 bps... Replacing a
CBM Kernal ROM is going to need an adapter, as the eprom has
more pins. Are you into making those or do you know of a source for
them?
Depending on which model of CBM you have, there's a no-adapter solution:
for PETs that take 2332 ROMs (i.e., *not* the old Static PETs), the 2532
is a drop-in EPROM. Not the 2732... the 2532. I have a few of them, some
from the old days (with PET firmware on them) and a few blanks that I've
picked up over the years when I was already ordering from some place like
B.G. Micro.
I had a $C000 BASIC ROM die in my first PET (the one I got new, when I was
a kid)... there's now a 2532 in its place. If you can't find any 2532s, you could make a
2732->2532 pin swabber in
a couple layers of machined-pin sockets - the bottom socket goes right
into the PET, the top socket holds the 2732. The middle layer is used
to rearrange whatever pins need relocation. I've had good luck with
stuffing a 1Mbit FLASH ROM into a 32kbit socket that way (and brought out
the extra address pins to a connector to an external switch to be able
to select multiple 4K ROM images). If my description is too vague, I
can try to take a picture to illustrate what I mean.
I can see how you'd stack a couple of sockets to connect the pins you wanted
to connect, but am a little less clear about the other ones. Like if you
wanted to interrupt a signal going through -- just bend it out? Maybe I need
to look at the pinouts of those parts...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
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Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin