PD17012_15 Datasheet, PDF (315/320 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLERS WITH DIGITAL TUNING SYSTEM HARDWARE

µPD17012, 17P012
APPENDIX A. NOTES ON CONNECTING CRYSTAL RESONATOR
When using the system clock oscillator, wire as follows in the area enclosed by the broken lines in the figure
below to avoid an adverse effect from wiring capacitance.
• Keep the wiring length as short as possible.
• Do not cross the wiring with the other signal lines. Do not route the wiring near a signal line through which a high
fluctuating current flows.
• Always make the ground point of the oscillator capacitor the same potential as GND. Do not ground the capacitor
to a ground pattern through which a high current flows.
• Do not fetch signals from the oscillator.
Also caution is required for the following three points when connecting the capacitor and adjusting the
operating frequency.
<1> If capacitances C1 and C2 are too high, the oscillation startup characteristic may be degraded or the current
consumption may rise.
<2> The trimmer capacitor for adjusting the oscillation frequency is generally connected to the XIN pin. However,
depending on the crystal resonator used, the oscillation stabilization may be affected (in this case, connect
the trimmer capacitor to the XOUT pin). Therefore, oscillation should be evaluated by the crystal resonator
that is actually being used.
<3> Adjust the oscillation frequency while measuring the LCD drive waveform (83.3 Hz) or VCO oscillation
frequency. If the probe is connected to the XOUT or XIN pin, the oscillation frequency cannot be measured
correctly due to the probe capacitance.
µPD17012, 17P012
XOUT
XIN
4.5 MHz crystal resonator
C1
C2
Data Sheet U10101EJ4V0DS
313