NEC μCOM-4
Developer	NEC
Manufacturer	NEC
Type	Microcontrollers
Production	October, 1977
Architecture	4-bit
Technology	nMOC "nMOC" is not in the list (BiCMOS, CMOS, Static CMOS, Dynamic CMOS, nMOS, pMOS, Bipolar, ECL, Schottky TTL, Schottky transistor, ...) of allowed values for the "technology" property.
Clock	150 kHz-1 mHz
Package	DIP28, DIP42

The μCOM-4 line is an extended family of 4-bit microcontrollers developed by NEC in the late 1970s. This family was designed to be low-cost, mass-produced, microcontrollers for ECRs, industrial controllers, appliance controllers, games, toys, scientific calculators, and other consumer electronics. The μCOM-4 line is based on the μPD751, the first Japanese single-chip microprocessor.

Introduction Date

1977				1980
Q1	Q2	Q3	Q4	Q1	Q2	Q3	Q4
μCOM-42	μCOM-43	μCOM-44	μCOM-45			μCOM-75

Families

The μCOM-4 was original divided into two separate domains:

μCOM-42

The μCOM-42 was specifically marketed for electronic cash registers (ECRs), Point of Sale (POS), and electronic scale applications. The μCOM-42 chips were specifically designed for controlling 8x4 keyboards, 8-digit displays, and various ECR-type printers. The μCOM-42 had a separate, modified instruction set, compared with the rest of the μCOM-4 families.

μCOM-43/44/45

The μCOM-43/44/45 was marketed as a general-purpose microcontroller suited for a large array of low-cost consumer and industrial applications. These MCUs shared a common instruction set.

Design

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Instruction set

Main article: μCOM-4 ISA

The family was originally split into two sets of ISAs. The μCOM-42 had an instruction set specifically designed to facilitate its use in Electronic Cash Register (ECR) and Scale products. The μCOM-43/4/5 were designed to be general purpose microcontrollers.

See also

• μCOM-8

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