UPD789304 Datasheet, PDF (38/64 Pages) NEC – 8-BIT SINGLE-CHIP MICROCONTROLLER

µPD789304, 789306, 789314, 789316
Main System Clock Oscillator Characteristics
Ceramic/crystal oscillation (µPD789304, 789306)
(TA = –40 to +85°C, VDD = 1.8 to 5.5 V)
Resonator Recommended Circuit
Parameter
Ceramic
resonator
IC X2 X1
Oscillation frequency (fX)^Note
1
Conditions
MIN.
1.0
TYP.
MAX.
5.0
Unit
MHz
Crystal
resonator
C2 C1
Oscillation stabilization
time^{Note 2}
After VDD reaches
oscillation voltage
range MIN.
IC X2 X1
Oscillation frequency^{Note 1}
1.0
C2 C1
Oscillation stabilization
time^{Note 2}
VDD = 4.5 to 5.5 V
4
ms
5.0
MHz
10
ms
30
ms
External
clock
X2
X1
X1 input frequency (fX)^{Note 1}
X1 input high-/low-level
width (tXH, tXL)
1.0
5.0
MHz
85
500
ns
X2
X1
X1 input frequency (fX)^{Note 1} VDD = 2.7 to 5.5 V
1.0
X1 input high-/low-level
VDD = 2.7 to 5.5 V
85
width (tXH, tXL)
OPEN
5.0
MHz
500
ns
Notes 1.
2.
Indicates only oscillator characteristics. Refer to AC Characteristics for instruction execution time.
Time required to stabilize oscillation after reset or STOP mode release. Use a resonator whose
oscillation stabilizes within the oscillation stabilization 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 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 requested to either evaluate the
oscillation themselves or apply to the resonator manufacturer for evaluation.
38
Data Sheet U14384EJ1V0DS