MC68HC08AS20 Datasheet, PDF (71/386 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

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Section 7. Central Processor Unit (CPU)
7.1 Contents
7.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
7.3 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
7.4 CPU Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
7.4.1 Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
7.4.2 Index Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74
7.4.3 Stack Pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
7.4.4 Program Counter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
7.4.5 Condition Code Register . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
7.5 Arithmetic/Logic Unit (ALU) . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
7.6 CPU During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . 79
7.7 Instruction Set Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
7.8 Opcode Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
7.2 Introduction
This section describes the central processor unit (CPU). The M68HC08
CPU is an enhanced and fully object-code-compatible version of the
M68HC05 CPU. The CPU08 Reference Manual (Freescale document
number CPU08RM/AD) contains a description of the CPU instruction
set, addressing modes, and architecture.
MC68HC08AS20 — Rev. 4.1
Freescale Semiconductor
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