mc68hc908lj24 Freescale Semiconductor, Inc, mc68hc908lj24 Datasheet - Page 110

• Manufacturer Part Number: mc68hc908lj24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Clock Generator Module (CGM)
8.2 Introduction
Data Sheet
110
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133
Special Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Acquisition/Lock Time Specifications . . . . . . . . . . . . . . . . . . . 135
Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133
Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134
CGM During Break Interrupts. . . . . . . . . . . . . . . . . . . . . . . 134
Acquisition/Lock Time Definitions. . . . . . . . . . . . . . . . . . . .135
Parametric Influences on Reaction Time . . . . . . . . . . . . . . 135
Choosing a Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Clock Generator Module (CGM)
MC68HC908LJ24/LK24 — Rev. 2.1
Freescale Semiconductor