M68HC08 datasheet(95/332 Pages) FREESCALE

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Oscillator (OSC)

MC68HC908JB16 — Rev. 1.1

Technical Data

Freescale Semiconductor

Oscillator (OSC)

7.4 I/O Signals

The following paragraphs describe the oscillator input/output (I/O)

signals.

7.4.1 Crystal Amplifier Input Pin (OSC1)

The OSC1 pin is an input to the crystal oscillator amplifier.

7.4.2 Crystal Amplifier Output Pin (OSC1)

The OSC2 pin is the output of the crystal oscillator inverting amplifier.

7.4.3 Oscillator Enable Signal (SIMOSCEN)

The SIMOSCEN signal comes from the system integration module (SIM)

and enables the oscillator.

7.4.4 Crystal Output Frequency Signal (OSCXCLK)

OSCXCLK is the crystal oscillator output signal. It runs at the full speed

of the crystal (fXCLK) and comes directly from the crystal oscillator circuit.

Figure 7-1 shows only the logical relation of OSCXCLK to OSC1 and

OSC2 and may not represent the actual circuitry. The duty cycle of

OSCXCLK is unknown and may depend on the crystal and other

external factors. Also, the frequency and amplitude of OSCXCLK can be

unstable at startup.

7.4.5 Clock Doubler Out (OSCDCLK)

OSCDCLK is the clock doubler output signal. It runs at twice the speed

of the crystal (fXCLK) and comes from the clock doubler circuit.

M68HC08 데이터시트(PDF) 95 Page - Freescale Semiconductor, Inc