Identify this card?
exe...@nunya.biz
lead from the upper left corner that ends in a female RCA plug. There
are four chips labeled mpdz114lc-3, the "m" is actually the greek letter
mu. One large (40 pin) IC has a label on it that says Q.C. OK. There is
a ROM chip with a label that has AZ as part of a logo. Most of the other
chips seem to be logic chips (74LSXXX)
Well, I pulled the "Q.C. OK" sticker off, and the large IC has "IC" in a
box followed by CIC8645BE and then below that 8443. I'm clueless as to
this chip.
There are no other identifying marks on chips or card.
Any ideas?
Roy
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Michael Black
(exe...@nunya.biz) writes:
> I'll try to get a scan done soon, but for now, the card has a two wire
> lead from the upper left corner that ends in a female RCA plug. There
> are four chips labeled mpdz114lc-3, the "m" is actually the greek letter
> mu. One large (40 pin) IC has a label on it that says Q.C. OK. There is
> a ROM chip with a label that has AZ as part of a logo. Most of the other
> chips seem to be logic chips (74LSXXX)
>
> Well, I pulled the "Q.C. OK" sticker off, and the large IC has "IC" in a
> box followed by CIC8645BE and then below that 8443. I'm clueless as to
> this chip.
>
> There are no other identifying marks on chips or card.
>
> Any ideas?
>
> Roy
>
Check the 40pin, and make sure it doesn't say 6845.
Then the mpdz114lc to make sure it doesn't say 2114.
The first would be the video controller used in all the standard
80 column cards. The mpdz114lc would then be the RAM to go with it.
The phono connector would be the video out.
Michael
Mark C. Spaeth
: It sounds like an 80 column card, with some misread numbers.
:
: Check the 40pin, and make sure it doesn't say 6845.
: Then the mpdz114lc to make sure it doesn't say 2114.
Good read... 6845's are used in all kinds of wacky early 80's
PCBs (including arcade games), and 2114s are everyone's favorite
1kx4 srams :)
--
Mark Spaeth msp...@mtl.mit.edu
50 Vassar St., #38.265 msp...@mit.edu
Cambridge, MA 02139
(617) 452-2354 http://rgvac.978.org/~mspaeth
exe...@nunya.biz
Mark C. Spaeth wrote:
> Michael Black <et...@freenet.carleton.ca> wrote:
> : It sounds like an 80 column card, with some misread numbers.
> :
> : Check the 40pin, and make sure it doesn't say 6845.
> : Then the mpdz114lc to make sure it doesn't say 2114.
>
> Good read... 6845's are used in all kinds of wacky early 80's
> PCBs (including arcade games), and 2114s are everyone's favorite
> 1kx4 srams :)
>
Except that I didn't misread the chip.
Perhaps they miswrote it?
Peter de Vroomen
>
> Check the 40pin, and make sure it doesn't say 6845.
> Then the mpdz114lc to make sure it doesn't say 2114.
I second everything said here.
Funny though, that they'd use 2114's together with a 6845. I believe DRAM's
were cheaper than SRAM's then, as it is now. The 6845 handles the refresh of
dynamic RAM's, so they could as well have used cheaper DRAM's. The only
thing I can think of are that you'd need at least 8 DRAM's, and only 4
2114's.
Does anyone have schematics for an 80 column card for the Apple 2? I have
lots of old Hercules compatible cards, I could make my own 80 column card
:).
PeterV
Mark C. Spaeth
:
:
:> Michael Black <et...@freenet.carleton.ca> wrote:
:> : It sounds like an 80 column card, with some misread numbers.
:> :
:> : Check the 40pin, and make sure it doesn't say 6845.
:> : Then the mpdz114lc to make sure it doesn't say 2114.
:>
:> Good read... 6845's are used in all kinds of wacky early 80's
:> PCBs (including arcade games), and 2114s are everyone's favorite
:> 1kx4 srams :)
6845 is one mfg's part number for it, so it's possible (probable)
it's just from another company.
Eric Smith
> Funny though, that they'd use 2114's together with a 6845. I believe DRAM's
> were cheaper than SRAM's then, as it is now. The 6845 handles the refresh of
> dynamic RAM's, so they could as well have used cheaper DRAM's. The only
> thing I can think of are that you'd need at least 8 DRAM's, and only 4
> 2114's.
You'd need 8 DRAMs, two multiplexers for the address, and a delay line
and some logic to generate the RAS and CAS strobes.
2114 chips were cheap during the early Apple II era. Later the 6116
2K*8 SRAM was even more cost effective.
DRAMs did eventually appear in four-bit-wide configurations, but those
were not available when 80 column cards were being developed.
> Does anyone have schematics for an 80 column card for the Apple 2? I have
> lots of old Hercules compatible cards, I could make my own 80 column card
Videx provided excellent documentation on their Videoterm and Ultraterm
cards, including schematics and firmware source code.
Leon Howell
> PCBs (including arcade games),
Huh? Arcade games? I don't remember any B&W arcade games. Are you
implying that this chip is capable of color? If so, *Thousands* of
Apple & non-Apple users might be interested in a hardware hack! :)
Michael Black
You just parallel some more bits of memory, to add some bits to control
color. The same way that there was an option on the OSI Superboard II.
What you miss is that the 6845 is a fairly generic device. It required
quite a bit of extra circuitry in order to work (witness the comment
about using it with dynamic ram), but that means it was very flexible
in its applications. One might really look at it as a RAM controller
for video applications. You needed an external character generator ROM,
you needed the rest of the video circuitry after that, and it was fairly
programmable, and hence there was no problem doing other things with it.
Had it been one of the later 80-column ICs, there would have been severe
limitations. Those provided for much more compact operation, but there
wasn't much you could do but build it up as the manufacturer showed in
the application note, feed in your characters at one end and get video out
the other.
There were plenty of applications that used the 6845 for color, back
when the Apple II was current. And maybe a lot more after that, when
it was used in the IBM CGA card, and later iterations of IBM video (unless
by that time it was integrated into other circuitry, and the 6845 core
was a subset of what was there).
Michael
Eric Smith
> PCBs (including arcade games),
purita...@yahoo.com (Leon Howell) writes:
> Huh? Arcade games? I don't remember any B&W arcade games. Are you
> implying that this chip is capable of color? If so, *Thousands* of
> Apple & non-Apple users might be interested in a hardware hack! :)
The 6845 doesn't know anything about either monochrome or color. It's
perfectly happy to let you do either, since you have to supply the video
encoding circuitry yourself either way.
For example, the IBM's first color display card for the PC, the CGA,
used the 6845 for both text and graphics.
Paul R. Santa-Maria
> I don't remember any B&W arcade games.
Asteroids. Space invaders. Space War. Battlezone.
--
Paul
Monroe, Michigan USA
Mike Spurgeon
> Leon Howell wrote:
>
>>I don't remember any B&W arcade games.
>
>
> Asteroids. Space invaders. Space War. Battlezone.
pong...
Simon Williams
> > Good read... 6845's are used in all kinds of wacky early 80's
> > PCBs (including arcade games),
>
> Huh? Arcade games? I don't remember any B&W arcade games.
A bit long in the tooth by the eighties, but there were quite a few b/w
games in the 70's... Space Invaders, Gunfight, Night Driver... and of
course, Pong!
--
._____. SIMON WILLIAMS *email*at*luddite*dot*ca*
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Liam Busey
"Paul R. Santa-Maria" <pau...@buckeye-express.com> wrote in message
news:411C25ED...@buckeye-express.com...
> Leon Howell wrote:
> > I don't remember any B&W arcade games.
>
> Asteroids. Space invaders. Space War. Battlezone.
I think space invaders had an overlay. ;)
Liam