MC9S08GT16 MOTOROLA [Motorola, Inc], MC9S08GT16 Datasheet - Page 114

• Manufacturer Part Number: MC9S08GT16
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

Internal Clock Generator (ICG) Module
ICGC2 = $30 (%00110000)
ICGS1 = $xx
ICGS2 = $xx
ICGFLTLU/L = $xx
ICGTRM
7.4.4
In this example, the FLL will be used (in FEI mode) to multiply the internal 243 kHz (approximate)
reference clock up to 10.8 MHz to achieve 5.4 MHz bus frequency. This system will also use the trim
function to fine tune the frequency based on an external reference signal.
After the MCU is released from reset, the ICG is in self-clocked mode (SCM) and supplies approximately
8 MHz on ICGOUT which corresponds to a 4 MHz bus frequency (f
114
Bit 7
Bit 6:4 MFD
Bit 3
Bit 2:0 RFD
This is read only except for clearing interrupt flag
This is read only. Should read DCOS before performing any time critical tasks
Not used in this example
Not used in this example
Example #3: No External Crystal Connection, 5.4 MHz Bus
Frequency
LOLRE
LOCRE
Figure 7-9. ICG Initialization and Stop Recovery for Example #2
0
011 Sets the MFD multiplication factor to 10
0
000 Sets the RFD division factor to ÷1
RESET, STOP1, OR STOP2
FLL LOCK STATUS
RECOVERY FROM
INITIALIZE ICG
ICG1 = $7A
Generates an interrupt request on loss of lock
Generates an interrupt request on loss of clock
ICG2 = $30
CONTINUE
LOCK = 1?
CHECK
MC9S08GB/GT Data Sheet, Rev. 2.3
YES
NO
SOURCE (f
SERVICE INTERRUPT
FLL LOCK STATUS
FROM STOP3
RECOVERY
CONTINUE
LOCK = 1?
CHECK
Bus
YES
= 4 MHz)
Bus
).
NO
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