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Section 4 Clock Pulse Generators
Rev. 6.00 Sep 12, 2006 page 85 of 526
REJ09B0326-0600
Figure 4.8 shows the equivalent circuit of the 32.768-kHz crystal resonator.
C
S
C
0
L
R
S
X
1
X
2
C = 1.5 pF (typ.)
R = 14 k (typ.)
f = 32.768 kHz
Crystal resonator:
0
S
W
Ω
S
MX38T
(Nihon Denpa Kogyo)
Figure 4.8 Equivalent Circuit of 32.768-kHz Crystal Resonator
Pin Connection when Not Using Subclock:
When the subclock is not used, connect pin X
1
to
V
CC
and leave pin X
2
open, as shown in figure 4.9.
X
X
1
2
V
CC
Open
Figure 4.9 Pin Connection when not Using Subclock
4.4 Prescalers
The H8/3644 Group is equipped with two on-chip prescalers having different input clocks
(prescaler S and prescaler W). Prescaler S is a 13-bit counter using the system clock (
φ
) as its
input clock. Its prescaled outputs provide internal clock signals for on-chip peripheral modules.
Prescaler W is a 5-bit counter using a 32.768-kHz signal divided by 4 (
φ
W
/4) as its input clock. Its
prescaled outputs are used by timer A as a time base for timekeeping.
Prescaler S (PSS):
Prescaler S is a 13-bit counter using the system clock (
φ
) as its input clock. It
is incremented once per clock period.
Prescaler S is initialized to H'0000 by a reset, and starts counting on exit from the reset state.
Summary of Contents for F-ZTAT H8/3642A Series
Page 6: ...Rev 6 00 Sep 12 2006 page iv of xx ...
Page 8: ...Rev 6 00 Sep 12 2006 page vi of xx ...
Page 22: ...Rev 6 00 Sep 12 2006 page xx of xx ...
Page 124: ...Section 5 Power Down Modes Rev 6 00 Sep 12 2006 page 102 of 526 REJ09B0326 0600 ...
Page 188: ...Section 6 ROM Rev 6 00 Sep 12 2006 page 166 of 526 REJ09B0326 0600 ...
Page 190: ...Section 7 RAM Rev 6 00 Sep 12 2006 page 168 of 526 REJ09B0326 0600 ...
Page 298: ...Section 9 Timers Rev 6 00 Sep 12 2006 page 276 of 526 REJ09B0326 0600 ...
Page 378: ...Section 12 A D Converter Rev 6 00 Sep 12 2006 page 356 of 526 REJ09B0326 0600 ...
Page 446: ...Section 13 Electrical Characteristics Rev 6 00 Sep 12 2006 page 424 of 526 REJ09B0326 0600 ...