UPD784218 Datasheet, PDF (64/92 Pages) NEC – 16-/8-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784218, 784218Y
Main System Clock Oscillator Characteristics (TA = –40 to +85°C)
Resonator Recommended Circuit
Parameter
Ceramic
resonator
or crystal
resonator
X2 X1 VSS
Oscillation
frequency (fX)
Test Conditions
4.5 V ≤ VDD ≤ 5.5 V
MIN.
2
TYP.
MAX.
12.5
Unit
MHz
2.7 V ≤ VDD < 4.5 V
2
6.25
2.2 V ≤ VDD < 2.7 V
2
3
External
clock
X1 input frequency 4.5 V ≤ VDD ≤ 5.5 V
2
(fX)
2.7 V ≤ VDD < 4.5 V
2
X2
X1
2.2 V ≤ VDD < 2.7 V
2
X1 input high-/low-
15
level width (tWXH, tWXL)
µ PD74HCU04
X1 input rise/fall
4.5 V ≤ VDD ≤ 5.5 V
0
time (tXR, tXF)
2.7 V ≤ VDD < 4.5 V
0
2.2 V ≤ VDD < 2.7 V
0
25
MHz
12.5
6.25
250
ns
5
ns
10
20
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 VSS.
• 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 required to either evaluate the
oscillation themselves or apply to the resonator manufacturer for evaluation.
64
Data Sheet U12304EJ2V0DS00