Subclock Generator - Renesas H8 Series Hardware Manual

4.3

Subclock Generator

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 4.8. Follow the same precautions as noted under 3. notes on board
design for the system clock in section 4.2.
Note that only operation at 32.768 kHz is guaranteed on the H8/38124 Group.
X
1
X
2
Figure 4.8 Typical Connection to 32.768 kHz/38.4 kHz Crystal Oscillator (Subclock)
Figure 4.9 shows the equivalent circuit of the 32.768 kHz/38.4 kHz crystal oscillator.
X
1
Figure 4.9 Equivalent Circuit of 32.768 kHz/38.4 kHz Crystal Oscillator
Pin Connection when Not Using Subclock
When the subclock is not used, connect pin X
4.10.
C
1
C = C
1 2
Frequency
38.4 kHz
C
2
32.768 kHz
C
S
L
S
to GND and leave pin X
1
Section 4 Clock Pulse Generators
= 15 pF (typ.)
Crystal oscillator
Seiko Instruments Inc.
Nihon Denpa Kogyo
R
S
C
C = 1.5 pF typ
0
0
Ω
R = 14 k typ
S
f = 32.768 kHz/38.4 kHz
W
2
Rev. 7.00 Mar 10, 2005 page 111 of 652
Products Name
VTC-200
MX73P
X
2
open, as shown in figure
REJ09B0042-0700