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Rev. 1.0, 07/01, page 66 of 372
5.2.1 Connecting a 32.768-kHz Crystal Oscillator
Clock pulses can be supplied to the subclock divider by connecting a 32.768-kHz crystal
oscillator, as shown in figure 5-8. Figure 5-9 shows the equivalent circuit of the 32.768-kHz
crystal oscillator.
X
X
C
1
C
2
1
2
C = C = 15 pF (typ.)
12
Figure 5-8 Typical Connection to 32.768-kHz Crystal Oscillator
X
1
X
2
L
S
C
S
C
O
C
O
= 1.5 pF (typ.)
R
S
= 14 kΩ (typ.)
f
W
= 32.768 kHz
R
S
Note: Constants are reference values.
Figure 5-9 Equivalent Circuit of 32.768-kHz Crystal Oscillator
5.2.2 Pin Connection when Not Using Subclock
When the subclock is not used, connect pin X
1
to V
CL
or V
SS
and leave pin X
2
open, as shown in
figure 5-10.
X
1
V
CL
or V
SS
X
2
Open
Figure 5-10 Pin Connection when not Using Subclock