NEC 78K0/KD1 Series User Manual page 113

Cautions 1. When using the X1 oscillator and subsystem clock oscillator, wire as follows in the area
enclosed by the broken lines in the Figure 5-11 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 V
not ground the capacitor to a ground pattern through which a high current flows.
• Do not fetch signals from the oscillator.
Note that the subsystem clock oscillator is designed as a low-amplitude circuit for reducing
power consumption.
Figure 5-11 shows examples of incorrect resonator connection.
Figure 5-11. Examples of Incorrect Resonator Connection (1/2)
(a) Too long wiring
IC
V
Remark When using the subsystem clock, replace X1 and X2 with XT1 and XT2, respectively. Also, insert
resistors in series on the XT2 side.
CHAPTER 5 CLOCK GENERATOR
X2 X1
SS
Preliminary User's Manual U16315EJ1V0UD
(b) Crossed signal line
PORT
IC X2 X1
V
SS
. Do
SS
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