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
Received on Mon May 06 2002 - 17:28:04 BST