XC908AS60ACFU Motorola Semiconductor Products, XC908AS60ACFU Datasheet - Page 170

• Manufacturer Part Number: XC908AS60ACFU
• Description: MC68HC908AZ60A, MC68HC908AS60A Hcmos Microcontroller Unit Technical Data
• Manufacturer: Motorola Semiconductor Products

Clock Generator Module (CGM)
10.2 Introduction
10.3 Features
Technical Data
170
10.8.1
10.8.2
10.9
10.10 Acquisition/Lock Time Specifications . . . . . . . . . . . . . . . . 190
10.10.1 Acquisition/Lock Time Definitions . . . . . . . . . . . . . . . . . 190
10.10.2 Parametric Influences on Reaction Time . . . . . . . . . . . .192
10.10.3 Choosing a Filter Capacitor . . . . . . . . . . . . . . . . . . . . . . 193
10.10.4 Reaction Time Calculation . . . . . . . . . . . . . . . . . . . . . . . 193
The 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 high frequency crystals.
Features of the CGM include:
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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
CGM During Break Interrupts . . . . . . . . . . . . . . . . . . . . . . . 190
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
Clock Generator Module (CGM)
MC68HC908AZ60A — Rev 2.0
MOTOROLA