UPD78P324 Datasheet, PDF (43/80 Pages) NEC – 16-/8-Bit Single-Chip Microcomputers

µPD78P324, 78P324(A)
(3) µPD78P324(A1) Electrical Specifications (3/9)
Oscillator Characteristics (TA = –40 to +110 °C, VDD = +5 V ±10 %, VSS = 0 V)
Oscillator
Recommended Circuit
Parameter
MIN.
MAX.
Unit
Ceramic oscillator or
crystal oscillator
X2
X1
VSS
C2
C1
Oscillation frequency (fXX)
8
12.5
MHz
X1 X2
External clock
HCMOS
X1 input frequency (fX)
8
inverter
or
X1 X2
No connection
required
X1 input rise time, fall time
(tXR, tXF)
0
HCMOS
inverter
X1 input high-/low-level
width (tWXH, tWXL)
46
12.5
MHz
20
ns
100
ns
Caution When using the system clock oscillation circuit, wire the part encircled in the dotted line in the
following manner to avoid the influence of the wiring capacity, etc.
• Make the wiring as short as possible.
• Avoid intersecting other signal conductors. Avoid approaching lines in which very high fluctuating
currents run.
• Make sure that the grounding point of the oscillation circuit capacitor always has the same
electrical potential as VSS. Avoid grounding with a grand pattern in which very high currents run.
• Do not fetch signals from the oscillation circuit.
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