13 Apr
2001
13 Apr
'01
7:13 a.m.
I've been working with someone who has an old 8080-based single board
computer he's trying to get to work. We're investigating several
possible problems but it's starting to look like there's a problem with
the EPROM. I have the ROM code he needs and will be checking out the
EPROMS, but we may be faced with a need to reprogram one or both of
these. They're the old 256 byte 1702A Intel chips (ceramic). I've only
programmed the 27xx series but have read that the 1702's are "really
difficult" to program. Was wondering if folks in this group could
comment on how to proceed if/when we decide we need to reprogram one of
these. Are there more modern plug compatible alternatives? We may also
need to replace one or both - any sources known other than eBay?
thanks.
p.s. FYI, the computer here is the "MMD-1", an old 8080
trainer/breadboarding box. here's a picture i found on the web:
http://online.sfsu.edu/~hl/c.E&L-MMD1.html
- glenn
13 Apr
13 Apr
10:31 a.m.
If you have to replace them, you might try www.stocknsource.com. Go to
"Search Our Inventory", and enter the part number.
on 4/13/01 6:13 AM, Glenn Roberts at groberts(a)mitre.org wrote:
I've been working with someone who has an old
8080-based single board
computer he's trying to get to work. We're investigating several
possible problems but it's starting to look like there's a problem with
the EPROM. I have the ROM code he needs and will be checking out the
EPROMS, but we may be faced with a need to reprogram one or both of
these. They're the old 256 byte 1702A Intel chips (ceramic). I've only
programmed the 27xx series but have read that the 1702's are "really
difficult" to program. Was wondering if folks in this group could
comment on how to proceed if/when we decide we need to reprogram one of
these. Are there more modern plug compatible alternatives? We may also
need to replace one or both - any sources known other than eBay?
thanks.
p.s. FYI, the computer here is the "MMD-1", an old 8080
trainer/breadboarding box. here's a picture i found on the web:
http://online.sfsu.edu/~hl/c.E&L-MMD1.html
- glenn
11:11 a.m.
For a number of reasons, it's worth the effort to modify the board to accept,
say, a 2716, which is a single-voltage part 8x as large in capacity, though the
same physical size. First of all, it makes it easier to write meaningful code,
as 256 bytes is a pretty cramped space in which to store a control program.
Second, as you've already discovered, it's difficult to get the 1702's
programmed, and, third, you've probably checked the prices of these parts. I'd
not expend the effort in favor of 2708's or other multi-supply parts, since
these are more difficult to program than the single-voltage parts.
If there exist more than one 24-pin socket, it would be worth the effort to
modify the board to accept a 6116 SRAM as well. The extra RAM will not hurt
either.
If you're into saving the authentic configuration, however, you have a
completely different set of problems. Not only do you have to deal with the
cost of the devices, but you have to figure out how to program them. I'm not at
all sure, but I may have an old (1976 or so) Intel databook that describes how
to program the parts. It may take a few days to find it, though.
Dick
----- Original Message -----
From: "Glenn Roberts" <groberts(a)mitre.org>
To: <classiccmp(a)classiccmp.org>
Sent: Friday, April 13, 2001 5:13 AM
Subject: 1702A EPROM Programming
I've been working with someone who has an old
8080-based single board
computer he's trying to get to work. We're investigating several
possible problems but it's starting to look like there's a problem with
the EPROM. I have the ROM code he needs and will be checking out the
EPROMS, but we may be faced with a need to reprogram one or both of
these. They're the old 256 byte 1702A Intel chips (ceramic). I've only
programmed the 27xx series but have read that the 1702's are "really
difficult" to program. Was wondering if folks in this group could
comment on how to proceed if/when we decide we need to reprogram one of
these. Are there more modern plug compatible alternatives? We may also
need to replace one or both - any sources known other than eBay?
thanks.
p.s. FYI, the computer here is the "MMD-1", an old 8080
trainer/breadboarding box. here's a picture i found on the web:
http://online.sfsu.edu/~hl/c.E&L-MMD1.html
- glenn
2:12 p.m.
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2:53 p.m.
Glenn Roberts <groberts(a)mitre.org> wrote:
I've been working with someone who has an old
8080-based single board
computer he's trying to get to work. We're investigating several
possible problems but it's starting to look like there's a problem with
the EPROM. I have the ROM code he needs and will be checking out the
EPROMS, but we may be faced with a need to reprogram one or both of
these. They're the old 256 byte 1702A Intel chips (ceramic). I've only
programmed the 27xx series but have read that the 1702's are "really
difficult" to program. Was wondering if folks in this group could
comment on how to proceed if/when we decide we need to reprogram one of
these. Are there more modern plug compatible alternatives? We may also
need to replace one or both - any sources known other than eBay?
thanks.
Hi Glenn
I can program 1702A's and with some notice, on time, I
can reconfigure to do 1702's but these are so rare I
haven't dealt with them. For small quantities, if you
send PROMs with return postage, I'll program them for
free ( not more than 10 PROMs ). I can also get schematics
for a programmer that can be put together with a number
of parts ( mostly discrete transistors ) that can be run
from most any uP with a number of I/O ports ( from an
original Intel App note ).
The files should be on DOS format files and can be
S, HEX or BPNF formats. Other formats will take me
some effort to make a converter.
Don't send known blown parts. I don't want to be your
test for parts. I can't be responsible
for parts that may fail while programming but they
will be programmed on an Intel build programming card,
that is know to work.
Let me know.
Dwight
14 Apr
14 Apr
3:35 a.m.
Glenn,
I have a stash of 1702As. I can probably let you have a couple.
Joe
At 07:13 AM 4/13/01 -0400, you wrote:
I've been working with someone who has an old
8080-based single board
computer he's trying to get to work. We're investigating several
possible problems but it's starting to look like there's a problem with
the EPROM. I have the ROM code he needs and will be checking out the
EPROMS, but we may be faced with a need to reprogram one or both of
these. They're the old 256 byte 1702A Intel chips (ceramic). I've only
programmed the 27xx series but have read that the 1702's are "really
difficult" to program. Was wondering if folks in this group could
comment on how to proceed if/when we decide we need to reprogram one of
these. Are there more modern plug compatible alternatives? We may also
need to replace one or both - any sources known other than eBay?
thanks.
p.s. FYI, the computer here is the "MMD-1", an old 8080
trainer/breadboarding box. here's a picture i found on the web:
http://online.sfsu.edu/~hl/c.E&L-MMD1.html
- glenn
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