MC68HC705P9 Datasheet, PDF (28/160 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Pin Descriptions
Freescale Semiconductor, Inc.
2.3.2.2 Ceramic Resonator Connections
To reduce cost, use a ceramic
resonator in place of the crystal.
Figure 2-4 shows a ceramic
resonator circuit. For the values
of any external components,
follow the recommendations of
the resonator manufacturer. The
load capacitance values used in
the oscillator circuit design
should include all stray layout
capacitances. To minimize
output distortion, mount the
resonator and capacitors as
close as possible to the pins.
MCU
CERAMIC
RESONATOR
Figure 2-4. Ceramic Resonator
Connections
NOTE:
Because the frequency stability of ceramic resonators is not as high as
that of crystal oscillators, using a ceramic resonator may degrade the
performance of the ADC.
2.3.2.3 External Clock Connections
An external clock from another
CMOS-compatible device can
drive the OSC1 input, with the
OSC2 pin unconnected, as
Figure 2-5 shows.
2.3.3 RESET
A logic zero on the RESET pin
forces the MCU to a known
startup state. The RESET pin
input circuit contains an internal
Schmitt trigger to improve noise
immunity.
MCU
EXTERNAL
CMOS CLOCK
UNCONNECTED
Figure 2-5. External Clock
Connections
Technical Data
28
Pin Descriptions
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Go to: www.freescale.com
MC68HC705P9 — Rev. 4.0
MOTOROLA