NEC μCOM-43 EVACHIP
Manufacturer	NEC
Model Number	EVACHIP-43
Part Number	μPD556, μPD556B
Introduction	1977 (launch)
General information
Family	μCOM-43
Clock	150 kHz-440 kHz
Microarchitecture
Microarchitecture	μCOM-43
Technology	pMOS
Word size	4 bit 0.5 octets 1 nibbles
Electrical
Op. Temp	-10 °C – 70 °C
Supply VDD	-10 V
Supply VSS	0 V
Memory
RAM	48 B 4.8e-5 MB 0.048 kB 384 b 4.8e-8 GB (96x4 bit)
Max Addressable Memory	2 kB
Stack	3 levels
Pins
Pins	64
IRQ lines	2
I/O ports	35
Packaging
Package	QIL64 (QIL), CerQIL64 (CerQIL)

The μPD556 or EVACHIP-43 is a 4-bit evaluation/development microcontroller used for both software and hardware debugging of the μPD546 microcontroller. Since the μCOM-43 is a strict superset of the μCOM-44 and μCOM-45, this evaluation chip was also used for debugging those two those chip families as well.

The 556 is functionally identical to the μPD546 without the internal memory, which instead is needed to be supplied externally and connected via the additional pins. This chip also has a HOLD operation that allows step-by-step inspection of operations.

Design

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Instruction Set

Main article: μCOM-4 ISA

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Documents

• NEC μPD556 datasheet

References

• NEC Microcomputers, Inc., 1980 Catalog, "μCOM-43/44/45 4-Bit Single Chip Microcomputers, μPD556 EVACHIP-43", 153-156 pp.
• NEC Electronics (Europe) GmbH, 1982 Catalog, "μPD556B μCOM-4 4-Bit Single Chip ROM-less Evaluation Chip", 173-176 pp.

See also

• μCOM-43
• μCOM-4
• μCOM-8