mc68hc908jb8 Freescale Semiconductor, Inc, mc68hc908jb8 Datasheet - Page 91

• Manufacturer Part Number: mc68hc908jb8
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

7.4 I/O Signals
7.4.1 Crystal Amplifier Input Pin (OSC1)
7.4.2 Crystal Amplifier Output Pin (OSC2)
7.4.3 Oscillator Enable Signal (SIMOSCEN)
7.4.4 External Clock Source (OSCXCLK)
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
Freescale Semiconductor
The series resistor (R
oscillator guidelines and may not be required for all ranges of operation,
especially with high-frequency crystals. Refer to the crystal
manufacturer’s data for more information.
The following paragraphs describe the oscillator input/output (I/O)
signals.
The OSC1 pin is an input to the crystal oscillator amplifier.
The OSC2 pin is the output of the crystal oscillator inverting amplifier.
The SIMOSCEN signal comes from the system integration module (SIM)
and enables the oscillator.
The crystal oscillator output signal passes through the clock doubler and
OSCXCLK is the output signal of the clock doubler. OSCXCLK runs at
twice the speed of the crystal (f
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.
Oscillator (OSC)
S
) is included in the diagram to follow strict Pierce
XCLK
).
Figure 7-1
shows only the logical
Oscillator (OSC)
Technical Data
I/O Signals
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