CHAPTER 1 INTRODUCTION
User’s Manual U14272EJ3V0UM
48
Figure 1-8 shows the external circuits of the clock oscillator.
Figure 1-8. External Circuits of Clock Oscillator
(a) Crystal oscillation
(b) External clock
V
R
4181
Open
External
clock
GND_OSC
Note 1
Note 2
Note 1
Note 2
V
R
4181
Notes 1. CLKX1, RTCX1
2. CLKX2, RTCX2
Cautions 1.
When using the clock oscillator, wire as follows in the area enclosed by the broken line in
the above figures 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.
2.
Ensure that no load such as wiring capacity is applied to the CLKX2 or RTCX2 pin when
inputting an external clock.
Figure 1-9 shows examples of the incorrect connection circuit of the resonator.
Содержание VR4181 mPD30181
Страница 2: ...User s Manual U14272EJ3V0UM 2 MEMO ...