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CHAPTER 22 ELECTRICAL SPECIFICATIONS (
Subsystem Clock Oscillator Characteristics (T
Resonator
Recommended Circuit
Crystal
(V
)
XT1
XT2
SS
resonator
R1
C4
C3
External
XT1
XT2
clock
Notes 1. Indicates only oscillator characteristics. Refer to AC Characteristics for instruction execution time.
2. Time required to stabilize oscillation after V
Cautions 1. When using the subsystem 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
• Do not ground the capacitor to a ground pattern through which a high current flows.
• Do not fetch signals from the oscillator.
2. The subsystem clock oscillator is designed as a low-amplitude circuit for reducing current
consumption, and is more prone to malfunction due to noise than the main system clock
oscillator. Particular care is therefore required with the wiring method when the subsystem
clock is used.
Remark
For the resonator selection and oscillator constant, customers are required to either evaluate the
oscillation themselves or apply to the resonator manufacturer for evaluation.
= –40 to +85°C, V
A
Parameter
Oscillation frequency
Note 1
(f
)
XT
Oscillation stabilization
V
Note 2
time
V
XT1 input frequency
Note 1
(f
)
XT
XT1 input high-/low-level
width (t
, t
)
XTH
XTL
reaches oscillation voltage range MIN.
DD
User's Manual U15331EJ4V1UD
µ
PD789488, 78F9488, 789489, 78F9489)
= 1.8 to 5.5 V)
DD
Conditions
MIN.
32
= 4.5 to 5.5 V
DD
= 1.8 to 5.5 V
DD
32
14.3
TYP.
MAX.
Unit
32.768
35
kHz
1.2
2
s
10
35
kHz
µ
15.6
s
.
SS
345
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