23 Mar
2002
23 Mar
'02
12:52 a.m.
There were several makers that sported an xx15 type where the normal 16Kx1
dram was an xx16. What these were, generally but not in all cases, were
products of a die shrink that resulted in a shorter refresh interval. That
was certainly the case with the MOSTEK 4115's. Those worked famously well in
applications like the Apple][ which was a big seller at the time.
more below ...
Dick
----- Original Message -----
From: "Pete Turnbull" <pete(a)dunnington.u-net.com>
To: <classiccmp(a)classiccmp.org>
Sent: Saturday, March 23, 2002 2:21 AM
Subject: Re: ZX81 and 6116
On Mar 22, 22:43, Richard Erlacher wrote:
Yep ... they were an oddity all right. I don't remember using them, but the
number certainly does ring a bell, as an oddity, of course. It wasn't unusual
to look at such oddities as opportunity to save some dough on components,
since they often became "distress" merchandise on the surplus market.
I guess I'm having a "senior
moment" but I don't remember the 4118 at
all,
though I definitely remember that there was such
a thing. Mostek made a
couple of pseudo-static RAM parts that were on a ~2716-compatible pinout.
Was
that one of them? I've got some 1K- and 2K-
byte parts from those days
but I
don't remember the numbers right offhand.
Perhaps someone could refresh my recollection.
4118 is the same pinout as a 2716 except that pin 21 is the /WR line
instead of Vpp, and pin 19 is NC instead of A10. It's a genuine static
part, 1K x 8. A 6116 is similar, but 2K x 8, with A10 on pin 19. There
are also low-power CMOS versions of the 6116. Zilog made a "quasi-static
RAM" 4K x 8, called Z8132, but it's 28-pin. They also, confusingly, made
16-pin dynamic RAMs 8K x 1 and 16K x 1 called Z6115 and Z6116, similar to
the more common 4116 DRAM.
Pete Peter Turnbull
Network Manager
University of York