18 May
2005
18 May
'05
5:17 p.m.
Hi
There is a good chance it is an interface part.
Remember the 8008 bus is not TTL.
Dwight
From: "Brent Hilpert" <hilpert at
cs.ubc.ca>
I (too) can not find a reference for the uA3656 in the Fairchild Full Line
Condensed Catalog (1975).
However, I believe Fairchild's naming convention is that "uA..." would
indicate
analog or interface functionality.
Speculation #1:
If there are some connections from the uA3656 to the 1101s (or 1702s) (but
not
pin-for-pin parallelling) it may be a TTL<->MOS
sense-amplifier/driver/level-converter. Early MOS memory chips used external
drivers/sense amplifiers, and specialised ICs were produced for those functions.
For example, I found Motorola refs for DS3645/75 (hex 3S latch driver for MOS
mem), DS3647/77 (quad 3S MOS mem IO reg), MC3461 (dual NMOS Memory Sense Amp)
(from Motorola Linear 1976).
Perhaps it is from the Motorola DS36.. line, but second-sourced from
Fairchild.
Speculation #2:
An A/D or D/A converter (perhaps connected to the nearby D connector?).
BTW & FWIW:
On your web page about the AMI S6800
(http://www.classiccmp.org/hp/ami/ami.htm),
you wonder what the FCM7002 IC is.
It is a clock/calendar chip, like those used in the
1970s for constructing
digital clocks: the FCM7001 (aka CT7001) was a
clock/calendar chip with
multiplexed 6-digit 7-segment display outputs. If I have it correctly, on the
FCM7002 the 7-segment outputs are replaced with BCD outputs. (... built a clock
using the 7001, and saw the 7002 on a real-time-clock I/O board for the TI-990
in the late 1970s, must have been rather awkward for the board designers to
interface.)
"Joe R." wrote:
Does anyone have any information about this IC? I have two of them. I
found them in the memory section of an Intel 8008 based computer. The other
RAMs are Intel 1101s so I'm guessing that these are equivelent parts but I
want to be sure. The date code on these is 7114 and they're white ceramic
with gold lids and faint grey traces to each leg. Here
<http://www.classiccmp.org/hp/i8008-1/close-up.jpg> is a picture of the
board with the two ICs installed. The ICs in the top row are 1702 EPROMs.
The 1101 RAMs are in the second row. These two parts are the 2nd and 3rd
parts from the RH end. FWIW I have a 1970 and a 1973 Fairchild catalogs but
neigher one lists any uA36xx parts.
Joe