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CHAPTER 20 ELECTRICAL SPECIFICATIONS
686
User’s Manual U15109EJ3V0UD
Recommended Oscillator
(1) Main clock oscillator (T
A
= –40 to +85°C)
(a) Connection of ceramic resonator or crystal resonator
X1
X2
Parameter
Symbol
Conditions
MIN.
TYP.
MAX.
Unit
Oscillation frequency
f
XX
4
20
MHz
–
When reset is released
2
18
/f
XX
s
Oscillation stabilization time
–
When STOP mode is released
Note
s
Note
The TYP. value differs depending on the setting of the oscillation stabilization time select register (OSTS).
Cautions 1. Main clock oscillator operates on the output voltage of the on-chip regulator.
External clock input is prohibited.
2. When using the main clock oscillator, wire as follows in the area enclosed by the broken
lines in the above figure 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
SS
.
••••
Do not ground the capacitor to a ground pattern through which a high current flows.
••••
Do not fetch signals from the oscillator.
3. For the resonator selection and oscillator constant, customers are requested to either
evaluate the oscillation themselves or apply to the resonator manufacturer for evaluation.