mc68hc908sr12 Freescale Semiconductor, Inc, mc68hc908sr12 Datasheet - Page 112

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

Clock Generator Module (CGM)
8.2 Introduction
Data Sheet
112
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 clock, CGMVCLK (an integer
multiple of CGMPCLK) provides clock reference for the PWM and
analog modules.
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .135
Special Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Acquisition/Lock Time Specifications . . . . . . . . . . . . . . . . . . . 137
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .135
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .136
CGM During Break Interrupts. . . . . . . . . . . . . . . . . . . . . . . 136
Acquisition/Lock Time Definitions. . . . . . . . . . . . . . . . . . . .137
Parametric Influences on Reaction Time . . . . . . . . . . . . . . 137
Choosing a Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Clock Generator Module (CGM)
MC68HC908SR12•MC68HC08SR12 — Rev. 5.0
Freescale Semiconductor