MC68HC16Z1 Datasheet, PDF (95/500 Pages) Freescale Semiconductor, Inc – M68HC16Z Series

Freescale Semiconductor, Inc.
IPIPE0
IPIPE1
MICROSEQUENCER
DATA
BUS
INSTRUCTION PIPELINE
A
B
C
EXECUTION UNIT
Figure 4-5 Instruction Execution Model
16 EXEC UNIT MODEL
4.10.1 Microsequencer
The microsequencer controls the order in which instructions are fetched, advanced
through the pipeline, and executed. It increments the program counter and generates
multiplexed external tracking signals IPIPE0 and IPIPE1 from internal signals that con-
trol execution sequence.
4.10.2 Instruction Pipeline
The pipeline is a three stage FIFO that holds instructions while they are decoded and
executed. Depending upon instruction size, as many as three instructions can be in
the pipeline at one time (single-word instructions, one held in stage C, one being exe-
cuted in stage B, and one latched in stage A).
4.10.3 Execution Unit
The execution unit evaluates opcodes, interfaces with the microsequencer to advance
instructions through the pipeline, and performs instruction operations.
M68HC16 Z SERIES
USER’S MANUAL
CENTRAL PROCESSING UNIT
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