MC68HC908GT16 Datasheet, PDF (111/412 Pages) Motorola, Inc – Microcontrollers

Internal Clock Generator (ICG) Module
Features
7.3 Features
The ICG has these features:
• Selectable external clock generator, either 1-pin external source
or 2-pin crystal, multiplexed with port pins
• Internal clock generator with programmable frequency output in
integer multiples of a nominal frequency (307.2 kHz ± 25 percent)
• Frequency adjust (trim) register to improve variability
to ±4 percent
• Bus clock software selectable from either internal or external clock
(bus frequency range from 76.8 kHz ± 25 percent to 9.75 MHz ±
25 percent in 76.8-kHz increments
NOTE: Do not exceed the maximum bus frequency of 8 MHz at 5.0 V and
4 MHz at 3.0 V.
• Timebase clock automatically selected from external if external
clock is available
• Clock monitor for both internal and external clocks
7.4 Functional Description
The ICG, shown in Figure 7-1, contains these major submodules:
• Clock enable circuit
• Internal clock generator
• External clock generator
• Clock monitor circuit
• Clock selection circuit
MC68HC908GT16 • MC68HC908GT8 — Rev. 2
MOTOROLA
Internal Clock Generator (ICG) Module
Technical Data
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