UPD75218 NEC, UPD75218 Datasheet - Page 45

• Manufacturer Part Number: UPD75218
• Description: 4-BIT SINGLE-CHIP MICROCOMPUTER
• Manufacturer: NEC

CHARACTERISTICS OF THE SUBSYSTEM CLOCK OSCILLATOR (T
Notes 1. The oscillator frequency and input frequency indicate only the oscillator characteristics. See the item
Caution When the subsystem clock oscillator is used, conform to the following guidelines when wiring at the
Resonator
Crystal
resonator
Note 3
External
clock
2. The oscillation settling time means the time required for the oscillation to settle after V
3. Recommended resonators are listed on the next page.
portions surrounded by dotted lines in the figures above to eliminate the influence of the wiring capacity.
• The wiring must be as short as possible.
• Other signal lines must not run in these areas. Any line carrying a high fluctuating current must be
• The grounding point of the capacitor of the oscillator must have the same potential as that of V
• No signal must be taken from the oscillator.
When the subsystem clock is used, pay special attention to its wiring; the subsystem clock oscillator
has low amplification to minimize current consumption and is more likely to malfunction due to noise
than the main system clock oscillator.
of AC characteristics for the instruction execution time.
of the oscillation voltage range.
kept away as far as possible.
It must not be grounded to ground patterns carrying a large current.
C3
XT1
Recommended
constants
XT1
Leave open
XT2
XT2
V
DD
330 k
C4
Oscillator
frequency
(f
Oscillation
settling time
Note 2
XT1 input
frequency
(f
XT1 input
high/low
level width
(t
Parameter
XT
XT
XTH
)
)
, t
Note 1
XTL
)
V
DD
= 4.5 to 6.0 V
Conditions
a
= -40 to +85 C, V
Min.
32
32
10
32.768
Typ.
1.0
DD
= 2.7 to 6.0 V)
Max.
100
35
10
32
2
DD
reaches Min.
PD75218
Unit
kHz
kHz
s
s
s
DD
45
.