26 Oct
2015
26 Oct
'15
10:41 a.m.
PET ROMs archive here:
http://www.zimmers.net/anonftp/pub/cbm/firmware/computers/pet/index.html
----- Original Message -----
From: "John Robertson" <jrr at flippers.com>
To: "General Discussion: On-Topic and Off-Topic
Posts" <cctalk at classiccmp.org>
Sent: Monday, October 26, 2015 1:09 PM
Subject: Re: PROMs and EPROMs, specifically
2332/2532/2732
On 10/25/2015 4:37 PM, Adrian Graham wrote:
On 25/10/2015 17:19, "John Robertson"
<jrr at flippers.com> wrote:
It's an MQP Pinmaster48, a 90s-era programmer.
As it happens tonight I got
round to dumping some other EPROMs I had for
someone else and one of them
was an SGS2532 which read fine as an MCM2532 so
I know the machine works
with that age of chip. All my CBM ones give the
same results so I'm assuming
they're dead. Thinking about it there may be
some 2532s at work so I can try
burning a PET tester.
I saw the madrigaldesign adapter on Friday but
after re-re-remaking the one
I was working on yesterday it was beginning to
look a bit rough around the
edges :)
Cheers,
Hi Adrian,
Perhaps one final test for your 2332s is to do a
Diode Test on the pins relative to the ground
pin (pin 12) and Vcc pin (24). These should sow
either open or something like 0.6 or higher
voltage drop across the pins - exchange the
probes to check both directions.
If your gates all read OK (check between Vcc and
GND as well!), then it might be that the brand
of 2332 you have simply draws more current than
your programmer likes. What brand is the PROM?
Perhaps it is in one of our reference book
libraries...
If your 2332s are bad, then have you put out a
call to see if anyone else has archived them
already?
John :-#)#
--
John's Jukes Ltd. 2343 Main St., Vancouver, BC,
Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs,
Jukes, VideoGames)
www.flippers.com
"Old pinballers never die, they just flip out"
Hi John
and others,
Thanks for that. I removed the diodes and
wired 2332 (21) to 2372 (24)
leaving the A11 swap in place, the programmer
complained about pin 18
missing. The adapter in front of me is now
wired like this:
2332 (18) to 2372 (21)
2332 (20) 2x diodes to 2372 18 (band) and 20
(band)
2332 (20) 2k2 resistor to 2332 (24)
2332 (21) to 2372 (24)
Now I get "reverse insertion" hinting I've
wired something upside-down which
isn't the case. I can read 27256 and 2764's
no problem so I'm mounting
things the correct way.
Further digging into available eproms that
the programmer can read reveals
it CAN read 2532s, specifically the MCM2532
which the datasheet tells me has
the same pinout as the 2332. I still get
"reverse insertion error" so I'm
guessing my PROMs are toast.
Cheers,
Reverse insertion may just mean you are
drawing more current on the /OE
and /CS than expected.
How about this - go back to my original
suggestion (no diodes) and this
time add a small resistor to the 2732 pin 18
and Vcc to act as a load.
Try larger resistors if the reader still
complains - and try reading
with NO 2332 in the reader (all FFs). Once you
can trick the reader into
reading air as highs then try your 2332 again
with the working resistor
values for the unused select.
Oh, and what reader are you using? Did you
check with the manufacturer
(or archives somewhere - archive.org?) to see
if they have a trick for
reading 2532/2332s?