The MC14500B Industrial Control Unit (ICU) is a CMOS one-bit microprocessor designed by Motorola for simple control applications in 1977. It is well-suited to the implementation of ladder logic, and thus could be used to replace relay systems and programmable logic controllers, also intended for serial data manipulation. The processor supports 16 commands, operating at a frequency of 1 MHz. The MC14500B unit does not include a program counter (PC); instead, a clock signal drives a separate PC chip; therefore the size of supported memory is dependent on the implementation of that chip. It was still in production in 1995.
The ICU was conceived by Vern Gregory in the mid-1970s while working as an engineer in a Marketing / Applications group of Motorola Semiconductor Products Sector in Phoenix, AZ; Brian Dellande originated circuit and sub-routine designs, and co-wrote the Manual; Ray DiSilvestro was the bench technician; Terry Malarkey provided management support.
In the CMOS Logic Division in Austin, TX (where it was made) Phil Smith was the chip designer; Mike Hadley provided Product Applications support.
The ICU was a steady seller for 20+ years. As of 2018, it is still available on the aftermarket.
A form of the design served as an embedded controller in a custom automotive chip made for NipponDenso by Motorola—Japan.
- Gregory, Vernon C.; Dellande, Brian; DiSilvestro, Ray; Malarkey, Terry; Smith, Phil; Hadley, Mike (1977). Motorola MC14500B Industrial Control Unit Handbook - Theory and Operation of a CMOS one-bit processor compatible with B series CMOS devices (PDF). Motorola Semiconductor Products Inc. 33-B78/8.0. Retrieved 2017-05-20. (NB. Also available in German language under the title "Motorola MC14500B Industrial Control Unit Handbuch - Theorie und Anwendung eines Ein-Bit-CMOS-Prozessors".)
- Industrial Control Unit MC14500B (PDF). Motorola CMOS Logic Data. Semiconductor Technical Data (revision 3 ed.). Motorola. 1995. pp. 306–313. Archived (PDF) from the original on 2017-05-20. Retrieved 2012-08-01.
- Ludwig, Volker; Paschenda, Klaus; Schepers, Heinz; Terglane, Hermann-Josef; Grannemann, Klaus; John, Burkhard; Komar, Hermann; Meinersen, Ludwig (1986). Written at Neuss & Recklinghausen, Germany. Fast alles über den WDR-1-Bit-Computer (PDF) (in German). Neuss, Germany: DATANorf. Archived (PDF) from the original on 2017-05-20. Retrieved 2017-05-20.
- US patent 4153942A, Vernon C. Gregory, "Industrial control processor", published 1979-05-08, assigned to Motorola, Inc. (also: US 05/761,738; DE2801853A1)
- Ludwig, Volker; Paschenda, Klaus, Remmelmann, Alexander, ed., Bit und Byte - Wir bauen einen Computer [Bit and Byte - We build a computer] (TV series (6 parts)) (in German), WDR-Schulfernsehen
- Mueller, Dieter (2005) . "The famous/infamous MC14500". Archived from the original on 2017-08-03. Retrieved 2018-07-18.
- Mueller, Dieter (2008). "MC14500 and arithmetic". Archived from the original on 2017-05-20. Retrieved 2018-07-18.
- Mueller, Dieter (2008). "A MC14500 modification". Archived from the original on 2017-03-20. Retrieved 2018-07-18.
- Schembri, Thierry; Bizoirre, Sylvain; Boisseau, Olivier; Chauvaud, Pierre-Emmanuel. "WDR-1-Bit Computer". OLD-COMPUTERS.COM. Archived from the original on 2017-05-20. Retrieved 2017-05-20.
- "MC14500 - Motorola". Wikichip. Archived from the original on 2017-05-20. Retrieved 2017-05-20.
- "MC14500B - Motorola". Wikichip. Archived from the original on 2017-05-20. Retrieved 2017-05-20.
- "MC14500 ISA - Motorola". Wikichip. Archived from the original on 2017-05-20. Retrieved 2017-05-20.