Now I'm really confused, Joe. Thanks for stirring the coals, though.
I can't find any Intel memory data before '82, and by that time they were on
5-volt-only EPROMs all the way. The brocheure I'm thinking of, with respect
to that 8748 evaluation board, has the "it's a 5-volt world" slogan that Intel
liked to use in promoting the 2716 back then, but I'll find the '78 8748 book
eventually, since I just looked at it yesterday.
't seems like I'll never learn to keep house ...
Dick
----- Original Message -----
From: "Joe" <rigdonj_at_cfl.rr.com>
To: <classiccmp_at_classiccmp.org>
Sent: Monday, May 06, 2002 4:51 PM
Subject: Re: 2708 Programming Algorithm?
> Dick,
>
> No I didn't. It's "Intel 8080 Microcomputer Systems User's Manual",
September 1975. I've got it right here in front of me. FWIW I don't think the
27xxs were even out when this data book was printed. There's no 27xx parts in
here at all. The "Intel MCS-80 User's Manual", October 1977 lists the 2716 and
stresses that it's a 5v only part but it doesn't list the 2708 at all. Both
books state the the 8708 uses standard power supplies; +12v, +/- 5v.
>
> The older manual also list a 8704 that's a 512 x 8 bit part (instead of 1k
x 8), perhaps that's what you're thinking of.
>
> Joe
>
>
> At 12:51 PM 5/6/02 -0600, you wrote:
> >I do believe you've misread part of the spec's, Joe. The 8708, IIRC, is a
> >5-volt-only version of the 2708, otherwise masqueraded as the 2758. I got
one
> >of these back in the mid-late '70's, on an 8748 evaluation board, and as
such,
> >it was my first 5-volt-only EPROM. They were described by the Intel FAE as
> >2716's with a flaw in one half or the other, and they were available in two
> >types, with either a high or low enable where the 2716 had an address line.
> >
> >Dick
> >
> >----- Original Message -----
> >From: "Joe" <rigdonj_at_cfl.rr.com>
> >To: <classiccmp_at_classiccmp.org>
> >Sent: Monday, May 06, 2002 3:29 PM
> >Subject: Re: 2708 Programming Algorithm?
> >
> >
> >> Steve,
> >>
> >> I don't have the programming instructions for the 2708 but I do have
them
> >for the intel 8708 and intels later manuals state that they're the same.
> >Here's what I have in the sept 1975 8080 Microcomputer Systems User's
manual.
> >>
> >> At 08:21 AM 5/6/02 -0700, you wrote:
> >> >I obtained a bunch of 2708 UVEPROM's, and I'd like to
> >> >be able to program them. As you may know, they require
> >> >a different algorithm than the 2716 and on, and three
> >> >voltages, +5, +12, and -5.
> >> >
> >> >I'm building a little board that will program 1/2 (the
> >> >upper or lower) of a 2716 to a 2708 (I can program
> >> >2716's). But I can't find a description of the
> >> >algorithm that is detailed enough. What I think I know
> >> >is:
> >> >
> >> >1. The /OE line must be high
> >>
> >> Intel says to raise the CS*/WE line to +12 volt.
> >>
> >>
> >> >2. select address and data (start at addr 0)
> >>
> >> Correct. A note here says that the logicx levels for the address, data
> >and voltage supply lines are the same as for the read mode.
> >>
> >> >3. bring PGM line from 0 to 27 volts for 1 mSec,
> >>
> >> Correct except you can use 25 (min) to 27 (max) volts according to the
> >manual.
> >>
> >> then
> >> >drop back to 0 (this seems very strange)
> >>
> >> You have to allow for the setup time for the new address and data. The
> >times are 10uS (min) for each but they could be different for the 2708.
> >>
> >> >4. repeat 100 times per address (not all at once,
> >>
> >> NO. This isn't what's in the intel manual. It says one programming
pulse
> >per address per loop. And that a loop is one pass through all the
addresses.
> >You have to repeat the loop until N (passes) x Tpw (programming pulse
width)
> >>= 100mS.
> >>
> >>
> >>
> >>
> >> >increment the address lines and loop to avoid
> >> >"overheating" a byte.
> >> >5. drop /OE and verify.
> >>
> >>
> >> "Note that programming and read loops can be alternated"
> >>
> >>
> >> >
> >> >
> >> >Does anybody have an authoritative description, and a
> >> >current requirement for the +5, +12, -5, and
> >> >programming pulse? Thanks.
> >>
> >> It varies according to the temperature but the max occurs at low temp
and
> >is about 11ma for Icc _at_5.25v, 65ma for Idd @12.6v with CS*/WE high and
about
> >35 ma with CS*/WE low, 41ma for Ibb _at_-5.25v with CS*/WE high and about 17ma
> >with CS*/WE low.
> >>
> >> The programming pulse current is typically 10mA with 20mA max.
> >>
> >> Have fun!
> >>
> >> Joe
> >>
> >>
> >> >
> >> >__________________________________________________
> >> >Do You Yahoo!?
> >> >Yahoo! Health - your guide to health and wellness
> >> >http://health.yahoo.com
> >> >
> >>
> >>
> >
> >
>
>
Received on Mon May 06 2002 - 15:20:10 BST