EPROM programmer

M H Stein dm561 at torfree.net
Fri Feb 15 03:15:42 CST 2008

Date: Fri, 15 Feb 2008 02:57:08 -0500
From: "Roy J. Tellason" <rtellason at verizon.net>
Subject: Re: EPROM programmer

On Friday 15 February 2008 01:46, Ethan Dicks wrote:
> On Fri, Feb 15, 2008 at 01:11:23AM -0500, Roy J. Tellason wrote:
> > 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...

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...   :-)

The manual has pretty clear instructions for changing the baud rate, up to 19.2
(pp. 8&9); you'll need 2x27128 unless you have a second programmer.

> > 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.

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.

See MCM68764 & MCM68766 (24 pin 8Kx8)


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