UPD78F9177 Datasheet, PDF (28/56 Pages) NEC – 8-BIT SINGLE-CHIP MICROCONTROLLER

µPD78F9177, 78F9177Y
Main System Clock Oscillator Characteristics (TA = −40 to +85 °C, VDD = 1.8 to 5.5 V)
Resonator Recommended Circuit
Parameter
Ceramic
resonator
VPP X1 X2
Note 1
Oscillation frequency (fX)
C1 C2
Note 2
Oscillation stabilization time
Crystal
resonator
VPP X1 X2
Note 1
Oscillation frequency (fX)
C1 C2
Note 2
Oscillation stabilization time
Conditions
VDD = oscillation
voltage range
After VDD reaches
oscillation voltage
range MIN.
VDD = 4.5 to 5.5 V
External
clock
Note 1
X1
X2
X1 input frequency (fX)
X1 input high-/low-level width
(tXH, tXL)
Note 1
X1 input frequency (fX)
X1
X2
VDD = 2.7 to 5.5 V
MIN. TYP. MAX. Unit
1.0
5.0 MHz
4 ms
1.0
5.0 MHz
10 ms
30
1.0
5.0 MHz
85
500 ns
1.0
5.0 MHz
X1 input high-/low-level width
VDD = 2.7 to 5.5 V
85
OPEN
(tXH, tXL)
500 ns
Notes 1. Indicates only oscillator characteristics. Refer to AC Characteristics for instruction execution time.
2. Time required to stabilize oscillation after reset or STOP mode release. Use a resonator that stabilizes
oscillation within the oscillation wait time.
Cautions 1. When using the main system clock oscillator, wire as follows in the area enclosed by the
broken lines 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 VSS0.
• Do not ground the capacitor to a ground pattern through which a high current flows.
• Do not fetch signals from the oscillator.
2. When the main system clock is stopped and the device is operating on the subsystem clock,
wait until the oscillation stabilization time has been secured by the program before
switching back to the main system clock.
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.
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Data Sheet U14022EJ1V0DS00