MC68HC705C Motorola, MC68HC705C Datasheet - Page 28

• Manufacturer Part Number: MC68HC705C
• Description: HCMOS Microcontroller Unit
• Manufacturer: Motorola

General Description
1.7.2.1 Crystal Resonator
1.7.2.2 Ceramic Resonator
Technical Data
28
NOTE:
The circuit in
crystal oscillator circuit for an AT-cut,
parallel resonant crystal. Follow the
crystal supplier’s recommendations,
because the crystal parameters
determine the external component
values required to provide reliable
startup and maximum stability. The
load capacitance values used in the
oscillator circuit design should
account for all stray layout
capacitances. To minimize output
distortion, mount the crystal and
capacitors as close as possible to the
pins.
Use an AT-cut crystal and not a strip or tuning fork crystal. The MCU
might overdrive or have the incorrect characteristic impedance for a strip
or tuning fork crystal.
To reduce cost, use a ceramic
resonator instead of a crystal. Use the
circuit shown in
ceramic resonator or the circuit shown
in
resonator, and follow the resonator
manufacturer’s recommendations.
The external component values
required for maximum stability and
reliable starting depend upon the
resonator parameters. 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.
Figure 1-10
Figure 1-8
for a 3-pin ceramic
General Description
Figure 1-9
shows a
for a 2-pin
Starting value only. Follow crystal supplier’s
recommendations regarding component
values that will provide reliable startup and
maximum stability.
22 pF
Figure 1-9. 2-Pin Ceramic
Resonator Connections
OSC1
.
OSC1
Figure 1-8. Crystal
C
Connections
MC68HC705C8A — Rev. 2.0
10 M
RESONATOR
2 MHz
XTAL
CERAMIC
MCU
MCU
R
MOTOROLA
OSC2
OSC2
22 pF
C