The Hitachi HMCS40 is a family of 4-bit microcontrollers developed by Hitachi. Two types of each component were manufactured, one using PMOS logic for low cost and another using CMOS where lower power was more desired than cost.

The chips contained 4-bit ALU performing BCD arithmetic. 512 to 2,048 Words (10-bit ea) of program ROM. Additional 128 Words (10-bit ea) of pattern ROM. 32 to 160 digits (4-bit ea) of data RAM. Chips also contained Event/Timer-Counter and 22-44 I/O lines. Output was aimed for driving dot matrix Liquid Crystal displays. The HMCS40 was used in a very large array of games, toys, controllers, and office equipment.

Devices

Part	Program (bits)	Data (bits)	Registers	Stack Registers	I/O Lines
HMCS42	512x10 ROM	32x4 RAM	?	?	22 I/O lines
HMCS43	1024x10 ROM	80x4 RAM	?	?	32 I/O lines
HMCS44	2048x10 ROM	160x4 RAM	8	4	32 I/O lines
HMCS45	2048x10 ROM	160x4 RAM	6	4	44 I/O lines
HMCS46	4096x10 ROM	256x4 RAM	8	4	32 I/O lines
HMCS47	4096x10 ROM	256x4 RAM	6	4	44 I/O lines

Design

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