4.3 Subclock Generator
1.
Connecting a 32.768-kHz/38.4 kHz crystal oscillator
Clock pulses can be supplied to the subclock divider by connecting a 32.768-kHz/38.4 kHz crystal
oscillator, as shown in figure 4-7. Follow the same precautions as noted under 3. notes on board
design for the system clock in 4.2.
Figure 4-7 Typical Connection to 32.768-kHz/38.4 kHz Crystal Oscillator (Subclock)
Figure 4-8 shows the equivalent circuit of the 32.768-kHz/38.4 kHz crystal oscillator.
Figure 4-8 Equivalent Circuit of 32.768-kHz/38.4 kHz Crystal Oscillator
C
S
C
0
L
R
S
X
1
X
2
C = 1.5 pF typ
R = 14 k typ
f = 32.768 kHz/38.4kHz
0
S
W
Ω
S
X
X
C
1
C
2
1
2
C = C = 15 pF (typ.)
1
2
Frequency
32.768 kHz
38.4 kHz
Crystal oscillator
NDK
Seiko Instrument Inc.
Products Name
MX73P
VTC-200
91