MC68HC908LJ12CPB FREESCALE [Freescale Semiconductor, Inc], MC68HC908LJ12CPB Datasheet - Page 105

• Manufacturer Part Number: MC68HC908LJ12CPB
• Description: 8-bit microcontroller units
• Manufacturer: FREESCALE [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
Technical Data
106
The oscillator module provides two clock outputs CGMXCLK and
CGMRCLK to the CGM module. CGMXCLK or CGMXCLK divide-by-two
can be selected to drive the SIM module to generate the system bus
clocks. CGMRCLK is the reference clock for the phase-lock-loop, to
generate a higher frequency clock. The oscillator module also provides
the reference clock for the real time clock (RTC) module.
See
module. See
description on RTC.
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:
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Section 7. Oscillator (OSC)
Voltage-controlled oscillator (VCO)
Reference divider
Frequency pre-scaler
Modulo VCO frequency divider
Phase detector
Loop filter
Lock detector
Clock Generator Module (CGM)
Section 12. Real Time Clock (RTC)
for detailed description on oscillator
MC68HC908LJ12
Freescale Semiconductor
for detailed
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Rev. 2.1