MC908AZ32ACFUE Datasheet, PDF (92/324 Pages) Freescale Semiconductor, Inc – Microcontrollers

Clock Generator Module (CGM)
CGMXCLK can be used by other modules which require precise timing for operation. The duty cycle of
CGMXCLK is not guaranteed to be 50% and depends on external factors, including the crystal and related
external components.
An externally generated clock also can feed the OSC1 pin of the crystal oscillator circuit. Connect the
external clock to the OSC1 pin and let the OSC2 pin float.
OSC1
CGMRDV
CGMRCLK
V_DDA CGMXFC
CLOCK
SELECT
÷2
CIRCUIT
BCS
V_SS
VRS7–VRS4
PHASE
DETECTOR
LOCK
DETECTOR
LOOP
FILTER
VOLTAGE
CONTROLLED
OSCILLATOR
PLL ANALOG
BANDWIDTH
CONTROL
INTERRUPT
CONTROL
CGMXCLK
A
CGMOUT
B _S*
*When S = 1,
CGMOUT = B
PTC3
MONITOR MODE
USER MODE
CGMINT
LOCK
CGMVDV
AUTO ACQ
MUL7–MUL4
PLLIE PLLF
FREQUENCY
DIVIDER
CGMVCLK
Figure 8-1. CGM Block Diagram
MC68HC908AZ32A Data Sheet, Rev. 2
92
Freescale Semiconductor