mc68hc908sr12 Freescale Semiconductor, Inc, mc68hc908sr12 Datasheet - Page 116

• Manufacturer Part Number: mc68hc908sr12
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Clock Generator Module (CGM)
8.4.1 Oscillator Module
8.4.2 Phase-Locked Loop Circuit (PLL)
8.4.3 PLL Circuits
Data Sheet
116
The oscillator module provides two clock outputs CGMXCLK and
CGMRCLK to the CGM module. CGMXCLK when selected, is driven to
SIM module to generate the system bus clock. CGMRCLK is used by the
phase-lock-loop to provide a higher frequency system bus clock and the
reference clock for the PWM and analog modules. The oscillator module
also provides the reference clock for the timebase module (TBM). See
Section 7. Oscillator (OSC)
See
TBM. See
description on PWM module.
The PLL is a frequency generator that can operate in either acquisition
mode or tracking mode, depending on the accuracy of the output
frequency. The PLL can change between acquisition and tracking
modes either automatically or manually.
The PLL consists of these circuits:
•
•
•
•
•
•
•
Section 12. Timebase Module (TBM)
Voltage-controlled oscillator (VCO)
Reference divider
Frequency pre-scaler
Modulo VCO frequency divider
Phase detector
Loop filter
Lock detector
Clock Generator Module (CGM)
Section 13. Pulse Width Modulator (PWM)
for detailed oscillator circuit description.
MC68HC908SR12•MC68HC08SR12 — Rev. 5.0
for detailed description on
Freescale Semiconductor
for detailed