Code listings for the I4004 or I4040

dwight dkelvey at
Sat Mar 19 18:03:25 CDT 2016

There is a 4201 by national semi on ebay.
I bought a 4201 recently for around $10.
I'm mostly looking for a 4040. I have a 4289,
three 4002-1s and two 4002-2s. I'd like to setup
the 4289 such that I have a boot ROM and then shadow
it into RAM. I'd then disable the ROM and run on
RAM only. The 4040 is a lot easier to setup for
both write and read from the RAM.
I also have an extra 4004 but it is an early zebra.
I'd like to hang on to it.

From: cctalk <cctalk-bounces at> on behalf of Paul Birkel <pbirkel at>
Sent: Saturday, March 19, 2016 11:40 AM
To: 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: Code listings for the I4004 or I4040

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at] On Behalf Of Brent
Sent: Friday, March 18, 2016 5:41 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Code listings for the I4004 or I4040

I had a failed 4201 chip (clock gen), it would be nice to come across a
replacement, but solved the problem with a substitute made from 3 CMOS


Brent:  Could you share your CMOS circuit design for a 4201 substitute?

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