NEC μCOM-42 Family
Developer	NEC
Manufacturer	NEC
Type	Microcontrollers
Production	February, 1977
Architecture	4-bit word, 10-bit instructions
ISA	μCOM-42
Word size	4 bit 0.5 octets 1 nibbles
Technology	pMOS
Clock	100 kHz-200 kHz
Package	DIP42

The μCOM-42 (or uCOM-42) was family of 4-bit microcontrollers, part of the μCOM-4 extended family, specifically marketed for electronic cash registers (ECRs), Point of Sale (POS), and electronic scale applications. These 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.

Microcontrollers

μCOM-42 Microcontrollers
Model	Part	Introduction	ROM	RAM	Pins
μCOM-42	μPD548	1977	1920x10 bit	96x4 bit	42
μCOM-42 EVACHIP	μPD555	1977		96x4 bit	64

Design

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μCOM-42 Instruction Set

Main article: μCOM-42 ISA

The μCOM-42 ISA had a set of 72 instructions. Every instruction is a single 10-bit word

See Also

• μCOM-4
• μCOM-8

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