Examples Of Incorrect Resonator Connection - NEC 78K0 User Manual

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 6-10 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 6-10 shows examples of incorrect resonator connection.
Figure 6-10. Examples of Incorrect Resonator Connection (1/2)
(a) Too long wiring
V
SS
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 6 CLOCK GENERATOR
*
X1 X2
User's Manual U15947EJ2V0UD
(b) Crossed signal line
PORT
V X1 X2
SS
. Do
SS
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