4004/8008 (was Re: Forgotten PC History)

Pete Turnbull pete at dunnington.plus.com
Mon Aug 11 07:36:45 CDT 2008


On 11/08/2008 09:56, Ethan Dicks wrote:
> On Mon, Aug 11, 2008 at 08:29:28AM +0100, Pete Turnbull wrote:

>> 	       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)
>>

> 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.

It takes about 30mA to run a 4004.

> 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?

Some data sheets list Vdd = -15V and Vss = 0V, so the -10/+5 is just a 
convenience.  Logic levels are relative to Vss.

> 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.

The whole manual is available at 
http://www.intel.com/museum/archives/4004ip.htm

I came across this while looking for something else: 
http://tams-www.informatik.uni-hamburg.de/applets/hades/webdemos/80-mcs4/intro/mcs4.html

Never tried it, but it might be a place to start.

-- 

Pete						Peter Turnbull
						Network Manager
						University of York



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