4004/8008 (was Re: Forgotten PC History)
ethan.dicks at usap.gov
Mon Aug 11 03:56:39 CDT 2008
On Mon, Aug 11, 2008 at 08:29:28AM +0100, Pete Turnbull wrote:
> On 11/08/2008 07:37, schwepes at moog.netaxs.com wrote:
> >The 8008 was only introduced a year after the 4004 which was
> >introduced in 1971. I can't find a pin out for either of them
> >but I suspect that they might be pin compatable...
> Not even close, I'm afraid. The 4004 is a 16-pin device with Vdd (-10V)
> and Vss (+5V) on the centre pins of the two sides, the 4 data bits on
> pins 1-4, and the two clock phases and SYNC on pins 6-8. The 8008 is an
> 18-pin device with Vcc (+5V) and Vss (-9V) on diagonally opposite
> corners (pins 1 and 10), D0-D7 on pins 2-9, and the clock phases and
> SYNC on the other side (pins 14-16):
> 4004 8008
> __ __ __ __
> D0 | U | CMRAM0 (-9V) Vss | U | INT
> D1 | | CMRAM1 D0 | | READY
> D2 | | CMRAM2 D1 | | phi1
> D3 | | CMRAM3 D2 | | phi2
> (+5V) Vss | | Vdd (-10V) D3 | | SYNC
> phi1 | | CMROM D4 | | S0
> phi2 | | TEST D5 | | S1
> SYNC |_____| RESET D6 | | S2
> D7 |_____| Vcc (+5V)
Hmm... I happen to have a couple of 4004 chips (one pulled from a
non-UPC barcode scanner, the other from a commercial kitchen scale),
and I've long fantasized about building some showcase 4004 circuit,
probably a digital clock.
I don't happen to have the 4004 datasheet handy (and can't get to it
for a number of hours), but the -10V Vdd requirement makes me wonder
if it's possible/feasible to use a pair of ganged ICL7660s (still made
by Dallas/Maxim) to generate it. This chip came up recently as a
possibility for generating -5V Vdd for 4116 DRAMs (and I think the
concensus was that it would probably be adequate for up to 16 chips),
so I do recall that it can only source a few mA (each 4116 needs a
few dozen uA)...
I don't see a GND pin on the 4004, so I'm at a loss to estimate
what it would require for Vdd. Anyone know or can check easily?
Also, does anyone know about any sort of 4004 emulator or simulator?
I wouldn't mind trying my hand at some code *before* trying to build
out the hardware.
Ethan Dicks, A-333-S Current South Pole Weather at 11-Aug-2008 at 08:50 Z
South Pole Station
PSC 468 Box 400 Temp -68.4 F (-55.8 C) Windchill -111.4 F (-79.7 C)
APO AP 96598 Wind 17.0 kts Grid 23 Barometer 671.5 mb (10950 ft)
Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html
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