
Section 3   CPU
3.1  Overview
The H8/532 chip has the H8/500 Family CPU:  a high-speed central processing unit designed for
realtime control of a wide range of medium-scale office and industrial equipment.  Its Hitachi-
original architecture features eight 16-bit general registers, internal 16-bit data paths, and an
optimized instruction set.
Section 3 summarizes the CPU architecture and instruction set.
3.1.1  Features
The main features of the H8/500 CPU are listed below.
 General-register machine
— Eight 16-bit general registers
— Seven control registers (two 16-bit registers, five 8-bit registers)
 High speed:  maximum 10MHz
At 10MHz a register-register add operation takes only 200ns.
 Address space managed in 64k-byte pages, expandable to 1M byte*
Page registers make four pages available simultaneously:  a code page, stack page, data page, 
and extended page.
 Two CPU operating modes:
— Minimum mode:  Maximum 64k-byte address space
— Maximum mode:  Maximum 1M-byte address space*
 Highly orthogonal instruction set
Addressing modes and data sizes can be specified independently within each instruction.
 1.5 Addressing modes
Register-register and register-memory operations are supported.
 Optimized for efficient programming in C language
In addition to the general registers and orthogonal instruction set, the CPU has special short 
formats for frequently-used instructions and addressing modes.
*  The CPU architecture supports up to 16M bytes of external memory, but the H8/532 chip has 
only enough address pins to address 1M byte.
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