Not to be confused with μPD550 (previous version, also called "μCOM-45").

NEC μCOM-45
Manufacturer	NEC
Model Number	μCOM-45
Part Number	μPD550
Introduction	1978 (launch)
General information
Family	μCOM-45
Clock	150 kHz-440 kHz
Microarchitecture
Microarchitecture	μCOM-4
Technology	pMOS
Word size	4 bit 0.5 octets 1 nibbles
Electrical
Op. Temp	-10 °C – 70 °C
Supply VDD	-35 V
Supply VSS	0 V
Memory
RAM	16 B 1.6e-5 MB 0.016 kB 128 b 1.6e-8 GB (32x4 bit)
ROM	1 kB 0.001 MB 1,000 B 8,000 b 1.0e-6 GB (1000x8 bit)
Stack	1 levels
Pins
Pins	28
I/O ports	21
Packaging
Package	DIP28 (DIP)

The μPD554 or μCOM-45 is a 4-bit microcontroller introduced in 1978 by NEC as part of their μCOM-45 family. This particular model was capable of directly driving fluorescent indicator panels at -35 volts. This model replaces the older μPD550 which had a reduced amount of ROM.

Design

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Instruction Set

Main article: μCOM-4 ISA

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Documents

• NEC μPD554 datasheet

See also

• μCOM-45
• μCOM-4
• μCOM-8

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