s908ab32ag0cfue Freescale Semiconductor, Inc, s908ab32ag0cfue Datasheet - Page 133

• Manufacturer Part Number: s908ab32ag0cfue
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

9.4 Functional Description
MC68HC908AB32
Freescale Semiconductor
SIMOSCEN
OSC2
OSC1
CGMRDV
DETECTOR
DETECTOR
—
CGMVDV
PHASE
LOCK
LOCK
Rev. 1.1
CRYSTAL OSCILLATOR
The CGM consists of three major sub-modules:
Figure 9-1
•
•
•
V
DDA
CGMRCLK
Crystal oscillator circuit which generates the constant crystal
frequency clock, CGMXCLK.
Phase-locked loop (PLL) which generates the programmable
VCO frequency clock CGMVCLK.
Base clock selector circuit; this software-controlled circuit selects
either CGMXCLK divided by two or the VCO clock CGMVCLK
divided by two, as the base clock CGMOUT. The SIM derives the
system clocks from CGMOUT.
Figure 9-1. CGM Block Diagram
AUTO
FREQUENCY
BANDWIDTH
CONTROL
CGMXFC
MUL[7:4]
DIVIDER
Clock Generator Module (CGM)
FILTER
shows the structure of the CGM.
LOOP
ACQ
PLL ANALOG
V
SS
CIRCUIT
SELECT
CLOCK
PLLIE
CONTROLLED
BCS
OSCILLATOR
INTERRUPT
CONTROL
CGMVCLK
VOLTAGE
VRS[7:4]
PLLF
÷
2
CGMXCLK
A
B S*
Clock Generator Module (CGM)
*When S = 1, CGMOUT = B
CGMOUT
CGMINT
USER MODE
PTC3
MONITOR MODE
TO SIM, SCI
Technical Data
TO SIM
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