SH7262/SH7264 Group
Hardware Design Guide
REJ06B0999-0100 Rev. 1.00
Page 11 of 36
Jun. 30, 2010
3.3
Connecting a Crystal resonator
Figure 7 shows an example of connecting a crystal resonator to the SH7264.
Place the crystal resonator and capacitors (CL1 and CL2) as close to pins Xin and Xout as possible. To avoid
inductance and to allow the crystal resonator to oscillate accurately, use the points when the capacitors area connected
to the crystal resonator in common and do not place wiring patters close to these components.
Since all the characteristics of the crystal resonator affect the board design, refer to the example shown in Figure 7 and
evaluate the entire system before using. As the circuit ratings of the crystal resonator vary with the resonator and the
floating capacitance, it is recommended to consult the crystal resonator manufacturer on the constants. Make sure that
the applied voltage to the clock pin does not exceed the maximum rating.
The SH7264 includes the feedback resistor, however, an external feedback resistor may be required, according to the
characteristics of the crystal resonator. Evaluate the resistor and capacitor thoroughly to set the parameters.
When not using pins Xin and Xout, fix the level on the Xin pin such as pull-up, pull-down, connect to the power supply
or ground, and leave the Xout pin as open.
Xin
Xout
R
IF
R
ID
R
OF
R
OD
SH7264
CL1
CL2
To internal
sections
Crystal
resonator
Figure 7 Connecting a Crystal Resonator
