MC68HC908QY2 MOTOROLA [Motorola, Inc], MC68HC908QY2 Datasheet - Page 108

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

Oscillator Module (OSC)
8.5.2 Crystal Amplifier Output Pin (OSC2/PTA4/BUSCLKX4)
8.5.3 Oscillator Enable Signal (SIMOSCEN)
8.5.4 XTAL Oscillator Clock (XTALCLK)
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For the XTAL oscillator device, the OSC2 pin is the crystal oscillator
inverting amplifier output.
For the external clock option, the OSC2 pin is dedicated to the PTA4 I/O
function. The OSC2EN bit has no effect.
For the internal oscillator or RC oscillator options, the OSC2 pin can
assume other functions according to
Shared
The SIMOSCEN signal comes from the system integration module (SIM)
and enables/disables either the XTAL oscillator circuit, the RC oscillator,
or the internal oscillator.
XTALCLK is the XTAL oscillator output signal. It runs at the full speed of
the crystal (f
Figure 8-1
OSC2 and may not represent the actual circuitry. The duty cycle of
XTALCLK is unknown and may depend on the crystal and other external
factors. Also, the frequency and amplitude of XTALCLK can be unstable
at start up.
Internal oscillator
Pins, or the output of the oscillator clock (BUSCLKX4).
XTAL oscillator
External clock
RC oscillator
shows only the logical relation of XTALCLK to OSC1 and
Option
XCLK
Oscillator Module (OSC)
or
) and comes directly from the crystal oscillator circuit.
Table 8-1. OSC2 Pin Function
Controlled by OSC2EN bit in PTAPUE register
OSC2EN = 0: PTA4 I/O
OSC2EN = 1: BUSCLKX4 output
OSC2 Pin Function
Table 1-3. Function Priority in
Inverting OSC1
PTA4 I/O
MOTOROLA