NEC 78K0 Series User Manual page 596

Internal Oscillator Characteristics
= −40 to +85°C, 1.8 V ≤ V
(T
A
Resonator
8 MHz internal oscillator
240 kHz internal oscillator
Notes 1. Indicates only oscillator characteristics. Refer to AC Characteristics for instruction execution time.
2. This is the frequency when RSTS (bit 7 of the internal oscillation mode register (RCM)) = 1. It is 5.6 MHz
(TYP.) when RSTS = 0.
XT1 Oscillator Characteristics
= −40 to +85°C, 1.8 V ≤ V
(T
A
Resonator Recommended Circuit
V XT2
Crystal SS
resonator
Rd
C4
Note Indicates only oscillator characteristics. Refer to AC Characteristics for instruction execution time.
Cautions 1. When using the XT1 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
• Do not ground the capacitor to a ground pattern through which a high current flows.
• Do not fetch signals from the oscillator.
2. The XT1 oscillator is designed as a low-amplitude circuit for reducing power consumption, and
is more prone to malfunction due to noise than the X1 oscillator. Particular care is therefore
required with the wiring method when the XT1 clock is used.
Remark For the resonator selection and oscillator constant, customers are requested to either evaluate the
oscillation themselves or apply to the resonator manufacturer for evaluation.
596
CHAPTER 29 ELECTRICAL SPECIFICATIONS (TARGET)
≤ 5.5 V, V
= EV = EV
DD DD SS
Parameter
Internal high-speed oscillation
Note 1
clock frequency (f )
RH
Internal low-speed oscillation
clock frequency (f )
RL
≤ 5.5 V, V
= EV = EV
DD DD SS
Parameter
XT1
XT1 clock oscillation
Note
frequency (f )
XT
C3
Preliminary User's Manual U17260EJ3V1UD
= AV = 0 V)
SS SS
Conditions
2.7 V ≤ V ≤ 5.5 V
DD
1.8 V ≤ V
< 2.7 V
DD
2.7 V ≤ V ≤ 5.5 V
DD
1.8 V ≤ V
< 2.7 V
DD
= AV = 0 V)
SS SS
Conditions
MIN. TYP. MAX. Unit
Note 2 Note 2 Note 2
7.6 8.0 8.4 MHz
Note 2 Note 2 Note 2
7.6 8.0 10.4 MHz
216 240 264 kHz
120 240 264 kHz
MIN. TYP. MAX. Unit
32 32.768 35 kHz
.
SS