I have both a 4004 and a 8008 - but I would not let them go for - well let's
say it would take a lot to make me give them up! )-:  One of them is in an
Intel development board, the other in a product - I do not remember which is
which.  Unfortunately, I do not have any documentation on either chip.

Good luck on your quest.

David V. Fansler
Network Administrator
AutoCyte, Inc.
336-222-9707 Ext. 261
dfansler@autocyte.com
Now Showing! www.mindspring.com\~dfansler\  Updated July 13, 1999


                -----Original Message-----
                From:   Keelan Lightfoot [mailto:keelan@MAIL.BZZZZZZ.COM]
                Sent:   Monday, September 20, 1999 12:46 PM
                To:     PICLIST@mitvma.mit.edu
                Subject:        4004 on PIC?

                Does anyone know if there exists an Intel 4004 emulator for
a PIC MCU?
                (Preferably 16F84). If not, where could I get a databook on
the 4004? I am
                interested in building a pin compatible emulated 4004, using
the PIC (Using
                a 16 pin socket and a small PCB with an SMD PIC, clock
components and
                voltage conversion circuitry). I don't have any practical
application in
                mind, I just think it would be an interesting project to
emulate the first
                Microprocessor with a PIC, then builda working computer
around it.

                Also, where could I get a 4004? If I am to build an
emulator, I would need
                to know that once it is built, it behaves exactly like the
real thing.

                I think that the 74f184 would have enough pins to emulate
all the signals
                used and created by a 4004 -- The pinout of the 4004 is as
follows:

                             _______    _______
                           _|       \__/       |_
                  <--> D0 |_|1               16|_| RAM0 -->
                           _|                  |_
                  <--> D1 |_|2               15|_| RAM1 -->
                           _|                  |_
                  <--> D2 |_|3               14|_| RAM2 -->
                           _|                  |_
                  <--> D3 |_|4               13|_| RAM3 -->
                           _|       4004       |_
                (+5v) Vss |_|5               12|_| Vdd (-10v)
                           _|                  |_
                 --> CLK1 |_|6               11|_| ROM  -->
                           _|                  |_
                 --> CLK2 |_|7               10|_| TST <--
                           _|                  |_
                 <-- SYNC |_|8                9|_| RST <--
                            |__________________|

                Meaning that if I ignore the Vss and Vdd lines, I have to
deal with 14 I/0
                lines., which I'd have to fit into PIC's 13. I could maybe
lose 1 of the
                clock lines, but I have no idea what they do (Why is there
2? Is this like
                the PICs where only a few external components are required
to create an
                oscillator?) I couldn't use the clock lines to directly
drive the PIC,
                because some of the CISC instructions might need a few RISC
instructions to
                execute.

                I have a 4004 instruction list, and it looks like it would
be an easy thing
                to emulate. The tough part would be to have emulate all the
output signals
                with proper timing.

                At what speed did the 4004 run? I imagine a 16F84 at 10 MHz
would be
                adequate enough to emulate any Microprocessor created in
1971.

                If anyone could provide me with information as to what all
the pins mean or
                where I could get a databook, It would be greatly
appreciated :)

                - Keelan Lightfoot