mc908jl16 Freescale Semiconductor, Inc, mc908jl16 Datasheet - Page 66

• Manufacturer Part Number: mc908jl16
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Oscillator (OSC)
5.3 Internal Oscillator
The internal oscillator clock (ICLK) is a free running 50-kHz clock that requires no external components.
It is used as the reference clock input to the computer operating properly (COP) module and the SIM.
The internal oscillator by default is always available and is free running after POR or reset. It can be
stopped in stop mode by setting the STOP_ICLKDIS bit before executing the STOP instruction.
Figure 5-4
5.4 I/O Signals
The following paragraphs describe the oscillator I/O signals.
5.4.1 Crystal Amplifier Input Pin (OSC1)
OSC1 pin is an input to the crystal oscillator amplifier or the input to the RC oscillator circuit.
5.4.2 Crystal Amplifier Output Pin (OSC2/RCCLK/PTA6/KBI6)
For the XTAL oscillator, OSC2 pin is the output of the crystal oscillator inverting amplifier.
For the RC oscillator, OSC2 pin can be configured as a general purpose I/O pin PTA6, or the output of
the RC oscillator, RCCLK.
5.4.3 Oscillator Enable Signal (SIMOSCEN)
The SIMOSCEN signal comes from the system integration module (SIM) and enables/disables the XTAL
oscillator circuit or the RC-oscillator.
66
shows the logical representation of components of the internal oscillator circuitry.
The internal oscillator is a free running oscillator and is available after each
POR or reset. It is turned-off in stop mode by setting the STOP_ICLKDIS
bit in CONFIG2 (see
Oscillator
XTAL
RC
STOP_ICLKDIS
CONFIG2
MC68HC908JL16 Data Sheet, Rev. 1.1
3.4 Configuration Register 2
FROM SIM
Figure 5-4. Internal Oscillator
SIMOSCEN
Controlled by PTA6EN bit in PTAPUE ($000D)
NOTE
PTA6EN = 0: RCCLK output
PTA6EN = 1: PTA6/KBI6
OSC2 Pin Function
Inverting OSC1
EN
TO SIM AND COP
ICLK
(CONFIG2)).
OSCILLATOR
INTERNAL
Freescale Semiconductor