MC68HC908QY2 MOTOROLA [Motorola, Inc], MC68HC908QY2 Datasheet - Page 102

• Manufacturer Part Number: MC68HC908QY2
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

Oscillator Module (OSC)
8.2 Introduction
8.3 Features
8.4 Functional Description
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The oscillator module is used to provide a stable clock source for the
microcontroller system and bus. The oscillator module generates two
output clocks, BUSCLKX2 and BUSCLKX4. The BUSCLKX4 clock is
used by the system integration module (SIM) and the computer
operating properly module (COP). The BUSCLKX2 clock is divided by
two in the SIM to be used as the bus clock for the microcontroller.
Therefore the bus frequency will be one forth of the BUSCLKX4
frequency.
The oscillator has these four clock source options available:
The oscillator contains these major subsystems:
1. Internal oscillator: An internally generated, fixed frequency clock,
2. External oscillator: An external clock that can be driven directly
3. External RC: A built-in oscillator module (RC oscillator) that
4. External crystal: A built-in oscillator module (XTAL oscillator) that
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trimmable to
into OSC1.
requires an external R connection only. The capacitor is internal to
the chip.
requires an external crystal or ceramic-resonator.
Internal oscillator circuit
Internal or external clock switch control
External clock circuit
External crystal circuit
External RC clock circuit
Oscillator Module (OSC)
. This is the default option out of reset.
MOTOROLA