mc68hc908as60 Freescale Semiconductor, Inc, mc68hc908as60 Datasheet - Page 156

• Manufacturer Part Number: mc68hc908as60
• Description: Mc68hc908as60 Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Clock Generator Module (CGM)
10.2 Introduction
10.3 Features
Technical Data
10.8
10.8.1
10.8.2
10.9
10.10 Acquisition/Lock Time Specifications . . . . . . . . . . . . . . . . . . . 176
10.10.1 Acquisition/Lock Time Definitions. . . . . . . . . . . . . . . . . . . . 176
10.10.2 Parametric Influences on Reaction Time . . . . . . . . . . . . . .177
10.10.3 Choosing a Filter Capacitor . . . . . . . . . . . . . . . . . . . . . . . . 178
The clock generator module (CGM) generates the crystal clock signal,
CGMXCLK, which operates at the frequency of the crystal. The CGM
also generates the base clock signal, CGMOUT, from which the system
clocks are derived. CGMOUT is based on either the crystal clock divided
by two or the phase-locked loop (PLL) clock, CGMVCLK, divided by two.
The PLL is a frequency generator designed for use with 1-MHz to 8-MHz
crystals or ceramic resonators. The PLL can generate an 8-MHz bus
frequency without using a 32-MHz crystal.
Features of the CGM include:
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Freescale Semiconductor, Inc.
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Phase-locked loop with output frequency in integer multiples of the
crystal reference
Programmable hardware voltage-controlled oscillator (VCO) for
low-jitter operation
Automatic bandwidth control mode for low-jitter operation
Automatic frequency lock detector
CPU interrupt on entry or exit from locked condition
Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
CGM During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . 175
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175
Clock Generator Module (CGM)
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MC68HC908AS60 — Rev. 1.0