UPD784915B Datasheet, PDF (66/86 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784915B, 784916B
Oscillator Characteristics (main clock) (TA = –10 to +70°C, VDD = AVDD = 4.0 to 5.5 V, VSS = AVSS = 0 V)
Oscillator
Crystal oscillator
Recommended Circuit
Parameter
Oscillation frequency (fXX)
MIN. MAX. Unit
4
16 MHz
X1
X2 VSS
C1 C2
Oscillator Characteristics (subclock) (TA = –10 to +70°C, VDD = AVDD = 2.7 to 5.5 V, VSS = AVSS = 0 V)
Oscillator
Crystal oscillator
Recommended Circuit
XT1 XT2 VSS
Parameter
Oscillation frequency (fXT)
MIN. MAX. Unit
32
35 kHz
C1 C2
Caution
When using the main system clock and subsystem clock oscillation circuits, wire the portion
enclosed by the broken line in the above figures as follows to avoid the adverse influence of
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 in the
neighborhood of a signal line through which a high alternating current flows.
• Always keep the ground point of the capacitor of the oscillator circuit to the same potential
as VSS. Do not ground the capacitor to a ground pattern to which a high current flows.
• Do not extract signals from the oscillation circuit.
Exercise particular care in using the subsystem clock oscillation circuit because the amplifica-
tion factor of this circuit is kept low to reduce the power dissipation.
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