mc68hc11k4 Freescale Semiconductor, Inc, mc68hc11k4 Datasheet - Page 37

• Manufacturer Part Number: mc68hc11k4
• Description: Mc68hc11k1 Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

2.5 Crystal Driver and External Clock Input (XTAL and EXTAL)
M68HC11K Family
MOTOROLA
CAUTION:
RESET SWITCH
OPTIONAL POWER-ON DELAY AND MANUAL RESET SWITCH
MANUAL
4.7 k
It is important to protect the MCU against corruption of RAM and
EEPROM during power transitions. This can be done with a low-voltage
interrupt (LVI) circuit which holds the RESET pin low when V
below the minimum operating level.
circuit that incorporates two LVI devices and an external switch.
These two pins provide the interface for either a crystal or a
CMOS-compatible clock to control the internal clock generator circuitry.
The frequency applied to these pins is four times higher than the desired
E-clock rate.
When an external CMOS-compatible clock input is connected to the
EXTAL pin, the XTAL pin must be left unterminated.
In all cases, use caution around the oscillator pins.
Load capacitances shown in
manufacturer and should include all stray layout capacitances.
Freescale Semiconductor, Inc.
For More Information On This Product,
Figure 2-5. External Reset Circuit
V
DD
1.0
4.7 k
Go to: www.freescale.com
MC34164
Pin Description
GND
IN
Crystal Driver and External Clock Input (XTAL and EXTAL)
RESET
Figure 2-6
MC34064
Figure 2-5
GND
V
IN
DD
RESET
are specified by the crystal
shows a suggested reset
V
DD
4.7 k
TO RESET
OF M68HC11
Pin Description
Technical Data
DD
drops
37