mc68hc908qb4 Freescale Semiconductor, Inc, mc68hc908qb4 Datasheet - Page 98

• Manufacturer Part Number: mc68hc908qb4
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Oscillator Module (OSC)
11.3.5 RC Oscillator
The RC oscillator circuit is designed for use with an external resistor (R
a tolerance within 25% of the expected frequency. See
The capacitor (C) for the RC oscillator is internal to the MCU. The R
1% or less to minimize its effect on the frequency.
In this configuration, the OSC2 pin can be used as general-purpose input/output (I/O) port pins or other
alternative pin function. The OSC2EN bit can be set to enable the OSC2 output function on the pin.
Enabling the OSC2 output can affect the external RC oscillator frequency, f
11.4 Interrupts
There are no interrupts associated with the OSC module.
11.5 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power-consumption standby modes.
11.5.1 Wait Mode
The OSC module remains active in wait mode.
11.5.2 Stop Mode
The OSC module can be configured to remain active in stop mode by setting OSCENINSTOP located in
a configuration register.
98
SIMOSCEN (INTERNAL SIGNAL) OR
MCU
OSCENINSTOP (BIT LOCATED IN
CONFIGURATION REGISTER)
V
DD
Figure 11-3. RC Oscillator External Connections
EN
R
EXT
OSC1
EXTERNAL RC
OSCILLATOR
MC68HC908QB8 Data Sheet, Rev. 2
INTCLK
RCCLK
OSC2 — AVAILABLE FOR ALTERNATIVE PIN FUNCTION
See the electricals section for component value.
0
Figure
1
1
0
11-3.
OSCOPT = EXTERNAL RC SELECTED
BUSCLKX4
ALTERNATIVE
PIN FUNTION
EXT
EXT
÷ 2
value must have a tolerance of
) to provide a clock source with
BUSCLKX2
RCCLK
.
OSC2EN
Freescale Semiconductor