I would never, Never, NEVER, in today's world, use an 8080 because of the
multiple supplies. It wouldn't do much good to use an 8085 in an 8080
application, since the timing's different and the two are quite different. The
8085, at least, doesn't require three supplies. I don't know why they wasted
all those pins on things like the pseudo-serial I/O and all those interrupts.
Hardly anyone ever figured out how to use them well. It would have been more
sensible to put the 8 address lines there and save the external latch and the
strobe for it.
see below, plz.
Dick
----- Original Message -----
From: "ajp166" <ajp166_at_bellatlantic.net>
To: <classiccmp_at_classiccmp.org>
Sent: Sunday, September 30, 2001 7:15 PM
Subject: Re: 8080 vs. 8080A
> Track the clock through the logic... there is a divide by 2 in there.
>
You could be right about that. I'm just not motivated to trace it out.
>
> Also the 9080 250ns part was late in the game and hard to find.
>
Yeah, but it's what came on some of the boards I used.
>
> If you want an 8080 that was really fast use a 8085-5 (5mhz)
> or the later 80c85-6(6mhz). the latter was a nice part as it
> was CMOS.
>
I still have half a dozen or so of the iSBC 8024 boards. They used that puppy
(8085-5). Like all Intel iSBC's, they do some things better than others, and
they're not nearly as flexible as I'd like.
>
> I still have a potload of 8080s and 8085s and my design favorite
> for small systems is the 8085 over the Z80.
>
Why? It's slower and requires more parts to support it. The only exception I
can think of, and that's for really small applications, is the
8085+8755+8155/56+8185's for RAM. Nowadays, it makes more sense to sell those
parts on eBay and hire a team to build your app with the proceeds.
For what the small circuit with the 8085 will do, it's easier to use a
68HC705C9. That's the size of a quarter and has 16K ROM, + I/O +async I/O,
timers, etc. and costs less than the stuff I mentioned before, in fact, less
than any one of those IC's. An ATMEL flash version of the 875x supersets they
offer is faster, cheaper, and easier to use as well. Almost any single chipper
would be easier. The only reason to have any interest in those old CPU chips is
for historical purposes.
>
> Allison
>
> -----Original Message-----
> From: Richard Erlacher <edick_at_idcomm.com>
> To: classiccmp_at_classiccmp.org <classiccmp_at_classiccmp.org>
> Date: Sunday, September 30, 2001 8:23 PM
> Subject: Re: 8080 vs. 8080A
>
>
> >Well, Allison, it appears you're right. The AMD 9080 was the one with
> the 250ns
> >clock (4 MHz) period, now that I've looked a couple of references.
> Thanks for
> >clearing that up.
> >
> >However, that doesn't explain what's going on in my iSBC8020-4's. I'll
> have to
> >figure that one out.
> >
> >Dick
> >----- Original Message -----
> >From: "ajp166" <ajp166_at_bellatlantic.net>
> >To: <classiccmp_at_classiccmp.org>
> >Sent: Sunday, September 30, 2001 5:12 PM
> >Subject: Re: 8080 vs. 8080A
> >
> >
> >> no, it was 2mhz.
> >>
> >> using 8224 the usual crystal was 18.435 (2.0483333*9).
> >> there was a -1. -2 and -3 version of the part but the fastest was
> 3mhz.
> >>
> >> I used to sell upD8080AF for NEC and I had to know my competition.
> >>
> >> Allison
> >>
> >> -----Original Message-----
> >> From: Richard Erlacher <edick_at_idcomm.com>
> >> To: classiccmp_at_classiccmp.org <classiccmp_at_classiccmp.org>
> >> Date: Sunday, September 30, 2001 6:23 PM
> >> Subject: Re: 8080 vs. 8080A
> >>
> >>
> >> >BTW, the 8080 was a 2.5 MHz part, wasn't it? I've got a couple Intel
> >> app-notes
> >> >where they generate a baud-rate clock from 24.576 MHz and generate
> the
> >> CPU clock
> >> >from that, at 2.4576 MHz for the CPU. That's on an i8080-2.
> >> >
> >> >Dick
> >> >
> >> >----- Original Message -----
> >> >From: "ajp166" <ajp166_at_bellatlantic.net>
> >> >To: <classiccmp_at_classiccmp.org>
> >> >Sent: Sunday, September 30, 2001 2:31 PM
> >> >Subject: Re: 8080 vs. 8080A
> >> >
> >> >
> >> >> Wrong!
> >> >>
> >> >> The I8080A is AS fast as the i8080. the i8080A-1 is faster but not
> >> twice
> >> >> as the fastest 8080[A] was only 3mhz and hte standard part was
> 2mhz.
> >> >>
> >> >> Allison
> >> >>
> >> >> -----Original Message-----
> >> >> From: John Galt <gmphillips_at_earthlink.net>
> >> >> To: classiccmp_at_classiccmp.org <classiccmp_at_classiccmp.org>
> >> >> Date: Sunday, September 30, 2001 3:57 PM
> >> >> Subject: Re: 8080 vs. 8080A
> >> >>
> >> >>
> >> >> >"The i8080A is essentially twice as fast as the
> >> >> > standard i8080 and COULD be used more easily with low-power logic
> >> since
> >> >> its
> >> >> >demands aren't as stringent".
> >> >> >
> >> >> >Ok, that's a good start.
> >> >> >
> >> >> >But, I don't think "low power" TTL (transistor transistor logic)
> had
> >> >> >anything to do with the complexity of the code being executed on
> the
> >> >> chip.
> >> >> >True? I had assumed
> >> >> >that the references to the 8080 only being compatible
> >> >> >with "low-power TTL" and the 8080A being compatible
> >> >> >with "standard TTL" had something to do with the support chips
> (Ram,
> >> >> clock,
> >> >> >etc) that could be used with the 8080 vs. the 8080A.
> >> >> >
> >> >> >Since I'm new to this mail list, let me explain why I would
> >> >> >show up here and ask such a question to begin with.
> >> >> >
> >> >> >I'm a chip collector. I am trying to document the differences
> >> between
> >> >> the
> >> >> >different early Intel microprocessors. Not worried about massive
> >> >> detail,
> >> >> >just the major differences (PMOS, vs. NMOS, vs.
> >> >> >HMOS, clock speed, transistor count, etc).
> >> >> >
> >> >> >The only microprocessor that I don't have a good handle
> >> >> >on is the 8080 and the difference between the 8080 and 8080A.
> >> >> >
> >> >> >I also know that the 8080 was introduced sometime
> >> >> >around April 1974. I have not been able to find an
> >> >> >introduction date for the 8080A. Was it introduced at
> >> >> >the same time? Does anyone know?
> >> >> >
> >> >> >I also need an Intel C8080 or C8080-8 for my
> >> >> >collection. If you have one, I want it. I have been looking
> >> >> >for one for months and have not been able to find one.
> >> >> >If you have either of these chips in good condition
> >> >> >(no desoldered parts wanted), I'm offering 400.00
> >> >> >for the C8080-8 and 500.00 for a C8080.
> >> >> >
> >> >> >If you need a replacement for the C8080 or C8080-8 you sell me,
> I'll
> >> >> GIVE
> >> >> >you a D8080A free as part of the
> >> >> >deal.
> >> >> >
> >> >> >----- Original Message -----
> >> >> >From: "Richard Erlacher" <edick_at_idcomm.com>
> >> >> >To: <classiccmp_at_classiccmp.org>
> >> >> >Sent: Sunday, September 30, 2001 1:21 PM
> >> >> >Subject: Re: 8080 vs. 8080A
> >> >> >
> >> >> >
> >> >> >> This makes no sense at all, though it may be because I'm
> >> >> misinterpreting
> >> >> >the way
> >> >> >> in which you've put it.
> >> >> >>
> >> >> >> I have Intel boards that come in versions with the i8080 and
> also,
> >> >> >> optionally,with the i8080A, and, aside from the clock frequency
> and
> >> >> memory
> >> >> >> access times, they're identical. The i8080A is essentially
> twice
> >> as
> >> >> fast
> >> >> >as the
> >> >> >> standard i8080 and COULD be used more easily with low-power
> logic
> >> >> since
> >> >> >its
> >> >> >> demands aren't as stringent.
> >> >> >>
> >> >> >> The i8080A will, AFAIK, replace the i8080 in all applications
> >> without
> >> >> ill
> >> >> >> effects.
> >> >> >>
> >> >> >> BTW, please turn off "rich-text" mode in your email editor when
> you
> >> >> >compose
> >> >> >> messages for this group, as some folks' mail readers can't
> >> interpret
> >> >> the
> >> >> >> rich-text/HTML format.
> >> >> >>
> >> >> >> Dick
> >> >> >> ++++++++++++++++++++++++++++++++++++++
> >> >> >> ----- Original Message -----
> >> >> >> From: John Galt
> >> >> >> To: classiccmp_at_classiccmp.org
> >> >> >> Sent: Sunday, September 30, 2001 10:17 AM
> >> >> >> Subject: 8080 vs. 8080A
> >> >> >>
> >> >> >>
> >> >> >> Can anyone here describe the technical differences between
> >> >> >> an Intel 8080 and Intel 8080A CPU?
> >> >> >>
> >> >> >> The ONLY ref. I have been able to find seems to indicate that
> there
> >> >> was a
> >> >> >bug in
> >> >> >> the 8080 and as a result it would only work with low power TTL?
> >> >> >>
> >> >> >> The problem was fixed in the 8080A and it would work with
> standard
> >> >> TTL?
> >> >> >>
> >> >> >> Does this make sense to anyone?
> >> >> >>
> >> >> >> Could anyone put this into laymans terms for me?
> >> >> >>
> >> >> >> Thanks,
> >> >> >>
> >> >> >> George Phillips - gmphillips_at_earthlink.net
> >> >> >>
> >> >> >
> >> >>
> >> >>
> >> >
> >>
> >>
> >
> >
>
>
Received on Mon Oct 01 2001 - 00:07:42 BST