6 May
2002
6 May
'02
9:07 a.m.
From: "Richard Erlacher"
<edick(a)idcomm.com>
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
Hi
I believe the half bad 2716 of Intel's were call either
2758 or 2508, not 8708. I'm almost sure that the 8708
was the one that could handle the negative bus levels on
the input, as I said earlier. You are correct that they
sold the H and the L version for the level to put on
the A10.
Dwight
6 May
6 May
9:29 a.m.
It's been a long time, but since I just recently handled the old 8748 doc that
has the reference I thought I saw, it'll be cleared up soon.
I just remember that all the 87xx parts, 8741, 8755, 8748/49, etc, were all
5-volt parts. further, I'm not at all sure that the 8080 had below-ground
signal levels, since they were intended to be attached to bipolar parts, e.g.
8212, etc, which would have been intolerant of that. What I've got in my lap
is the 8080A data, which may, actually be different, but IIRC, the 8080 needed
the negative bias supply so it could swing to ground and the +12 so it could
swing to a reasonable high level. My only contact with the 8080 was on boards
made by Intel, and, while I poked around with a 'scope and other gear from
time to time, I don't recall ever finding an address, data, or control signal
that wasn't TTL compatible.
Dick
----- Original Message -----
From: "Dwight K. Elvey" <dwightk.elvey(a)amd.com>
To: <classiccmp(a)classiccmp.org>
Sent: Monday, May 06, 2002 3:07 PM
Subject: Re: 2708 Programming Algorithm?
>From: "Richard Erlacher"
<edick(a)idcomm.com>
>
>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
Hi
I believe the half bad 2716 of Intel's were call either
2758 or 2508, not 8708. I'm almost sure that the 8708
was the one that could handle the negative bus levels on
the input, as I said earlier. You are correct that they
sold the H and the L version for the level to put on
the A10.
Dwight
10:28 a.m.
Richard Erlacher wrote:
It's been a long time, but since I just recently handled the old 8748 doc that
has the reference I thought I saw, it'll be cleared up soon.
I just remember that all the 87xx parts, 8741, 8755, 8748/49, etc, were all
5-volt parts. further, I'm not at all sure that the 8080 had below-ground
signal levels, since they were intended to be attached to bipolar parts, e.g.
8212, etc, which would have been intolerant of that. What I've got in my lap
is the 8080A data, which may, actually be different, but IIRC, the 8080 needed
the negative bias supply so it could swing to ground and the +12 so it could
swing to a reasonable high level. My only contact with the 8080 was on boards
made by Intel, and, while I poked around with a 'scope and other gear from
time to time, I don't recall ever finding an address, data, or control signal
that wasn't TTL compatible.
But check the specs TTL compatible often is for 1
TTL S load for output
lines
max.
--
Ben Franchuk - Dawn * 12/24 bit cpu *
www.jetnet.ab.ca/users/bfranchuk/index.html
10:51 a.m.
Yes, but doesn't have major effect on the levels while you're within spec.
Dick
----- Original Message -----
From: "Ben Franchuk" <bfranchuk(a)jetnet.ab.ca>
To: <classiccmp(a)classiccmp.org>
Sent: Monday, May 06, 2002 4:28 PM
Subject: Re: 2708 Programming Algorithm?
Richard Erlacher wrote:
>
> It's been a long time, but since I just recently handled the old 8748 doc
that
> has the reference I thought I saw, it'll be
cleared up soon.
>
> I just remember that all the 87xx parts, 8741, 8755, 8748/49, etc, were
all
> 5-volt parts. further, I'm not at all sure
that the 8080 had below-ground
> signal levels, since they were intended to be attached to bipolar parts,
e.g.
> 8212, etc, which would have been intolerant of
that. What I've got in my
lap
> is the 8080A data, which may, actually be
different, but IIRC, the 8080
needed
> the negative bias supply so it could swing to
ground and the +12 so it
could
> swing to a reasonable high level. My only
contact with the 8080 was on
boards
> made by Intel, and, while I poked around with a
'scope and other gear from
> time to time, I don't recall ever finding an address, data, or control
signal
that
wasn't TTL compatible.
But check the specs TTL compatible often is for 1 TTL S
load for output
lines
max.
--
Ben Franchuk - Dawn * 12/24 bit cpu *
www.jetnet.ab.ca/users/bfranchuk/index.html
1:06 p.m.
At 04:28 PM 5/6/02 -0600, Ben wrote:
Richard Erlacher wrote:
>
> It's been a long time, but since I just recently handled the old 8748 doc that
> has the reference I thought I saw, it'll be cleared up soon.
>
> I just remember that all the 87xx parts, 8741, 8755, 8748/49, etc, were all
> 5-volt parts. further, I'm not at all sure that the 8080 had below-ground
> signal levels, since they were intended to be attached to bipolar parts, e.g.
> 8212, etc, which would have been intolerant of that. What I've got in my lap
> is the 8080A data, which may, actually be different, but IIRC, the 8080 needed
> the negative bias supply so it could swing to ground and the +12 so it could
> swing to a reasonable high level. My only contact with the 8080 was on boards
> made by Intel, and, while I poked around with a 'scope and other gear from
> time to time, I don't recall ever finding an address, data, or control signal
> that wasn't TTL compatible.
But check the specs TTL compatible often is for 1 TTL
S load for output
lines max.
That's not the point. The point is that the inputs and outputs are TTL (0V/5V)
level and not a negative voltage. FWIW IIRC even the 8008 had a fan out of more than one.
I have the manual and can look if it matters.
Joe
8312
days inactive
8312
days old
4 comments
4 participants
participants (4)
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bfranchuk＠jetnet.ab.ca -
dwightk.elvey＠amd.com -
edick＠idcomm.com -
rigdonj＠cfl.rr.com