MC68HC705P9 Datasheet, PDF (44/160 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Central Processor Unit (CPU)
4.2 Features
Features include:
• 2.1-MHz bus frequency
• 8-bit accumulator
• 8-bit index register
• 13-bit program counter
• 6-bit stack pointer
• Condition code register with five status flags
• 62 instructions
• Eight addressing modes
• Power-saving stop, wait, and data-retention modes
4.3 Introduction
The central processor unit (CPU) consists of a CPU control unit, an
arithmetic/logic unit (ALU), and five CPU registers. The CPU control unit
fetches and decodes instructions. The ALU executes the instructions.
The CPU registers contain data, addresses, and status bits that reflect
the results of CPU operations.
4.4 CPU Control Unit
The CPU control unit fetches and decodes instructions during program
operation. The control unit selects the memory locations to read and
write and coordinates the timing of all CPU operations.
Technical Data
44
Central Processor Unit (CPU)
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Go to: www.freescale.com
MC68HC705P9 — Rev. 4.0
MOTOROLA