Section 1. Cpu - Renesas H8/300 Series Programming Manual

Section 1. CPU

This document is a reference manual for programming the H8/300, a high-speed central
processing unit with a Hitachi-original RISC-like architecture that is employed as a CPU core
in a series of low-cost single-chip microcomputers intended for applications ranging from
smart cards to office and factory automation.
The H8/300 features a concise instruction set in which most frequently-used instructions are
two bytes long and execute in just two states (0.2µs with a 10MHz system clock). Its general
registers can be accessed as 16-bit word registers or 8-bit byte registers. The instruction set
includes both 8-bit and 16-bit instructions.
Section 1 of this manual summarizes the CPU architecture and instruction set. Section 2 gives
detailed descriptions of the instructions. Appendices give an operation code map, a complete
list of the instruction set, and tables for calculating instruction execution time. Programmers
should also refer to the User's Manual of the chip being programmed for information on bus
cycles, interrupt service, I/O ports, power-down modes, and on-chip facilities such as memory
and timers, and for a memory map.
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