UPD78F9177 NEC, UPD78F9177 Datasheet - Page 29

• Manufacturer Part Number: UPD78F9177
• Description: 8-BIT SINGLE-CHIP MICROCONTROLLER
• Manufacturer: NEC

Subsystem Clock Oscillator Characteristics (T
Crystal
resonator
External
clock
Resonator
Notes 1. Indicates only oscillator characteristics. Refer AC Characteristics for instruction execution time.
Cautions 1. When using the subsystem clock oscillator, wire as follows in the area enclosed by the
Remark
2. Time required to stabilize oscillation after reset or STOP mode release.
Recommended Circuit
For the resonator selection and oscillator constant, customers are requested to either evaluate the
oscillation themselves or apply to the resonator manufacturer for evaluation.
2. The subsystem clock oscillator is designed as a low-amplitude circuit for reducing current
XT1
V
PP
broken lines in the above figures to avoid an adverse effect from wiring capacitance.
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.
C3
XT1
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.
C4
R
XT2
XT2
Oscillation frequency (f
Oscillation stabilization time
XT1 input frequency (f
XT1 input high-/low-level width
(t
XTH
, t
XTL
)
Parameter
A
Data Sheet U14022EJ1V0DS00
= 40 to +85 C, V
XT
XT
)
)
Note 1
Note 1
Note 2
V
DD
DD
= 4.5 to 5.5 V
Conditions
= 1.8 to 5.5 V)
PD78F9177, 78F9177Y
MIN.
14.3
32
32
32.768
TYP.
1.2
MAX.
15.6
35
10
35
2
SS0
.
Unit
kHz
kHz
s
s
s
29