MC68HC908LJ12CPB FREESCALE [Freescale Semiconductor, Inc], MC68HC908LJ12CPB Datasheet - Page 101

• Manufacturer Part Number: MC68HC908LJ12CPB
• Description: 8-bit microcontroller units
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Clock Generator Module (CGM)
8.2 Introduction
Technical Data
102
8.7
8.8
8.8.1
8.8.2
8.8.3
8.9
8.9.1
8.9.2
8.9.3
This section describes the clock generator module (CGM). The CGM
generates the base clock signal, CGMOUT, which is based on either the
oscillator clock divided by two or the divided phase-locked loop (PLL)
clock, CGMPCLK, divided by two. CGMOUT is the clock from which the
SIM derives the system clocks, including the bus clock, which is at a
frequency of CGMOUT÷2.
The PLL is a frequency generator designed for use with a low frequency
crystal (typically 32.768kHz) to generate a base frequency and dividing
to a maximum bus frequency of 8MHz.
Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125
Special Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Acquisition/Lock Time Specifications . . . . . . . . . . . . . . . . . . . 127
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .126
CGM During Break Interrupts. . . . . . . . . . . . . . . . . . . . . . . 126
Acquisition/Lock Time Definitions. . . . . . . . . . . . . . . . . . . .127
Parametric Influences on Reaction Time . . . . . . . . . . . . . . 127
Choosing a Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Clock Generator Module (CGM)
MC68HC908LJ12
Freescale Semiconductor
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Rev. 2.1