Rev. 1.0, 02/00, page 182 of 1141
9.7
Subclock Oscillator Circuit
9.7.1
Connecting 32.768 kHz Crystal Resonator
When using a subclock, connect a 32.768 kHz crystal resonator to X1 and X2 pins as shown in
figure 9.8.
For precautions on connecting, see Note on Board Design, in section 9.3.1 Connecting a Crystal
Resonator.
X1
X2
C
2
C
1
C
1
= C
2
= 15 pF (Typ)
Figure 9.8 Connecting a 32.768 kHz Crystal Resonator (Example)
Figure 9.9 shows a crystal resonator equivalent circuit.
X1
C
S
C
0
= 1.5 pF (Typ)
R
S
= 14 k
Ω
(Typ)
f
W
= 32.768 kHz
Type: MX38T (Nihon Denpa Kogyo Co., Ltd.)
Note: Values shown are the reference values.
X2
C
0
L
s
R
s
Figure 9.9 32.768 kHz Crystal Resonator Equivalent Circuit