CHAPTER 9 WATCH TIMER
User’s Manual U16899EJ2V0UD
227
Figure 9-2. Format of Watch Timer Operation Mode Register (WTM)
Address: FF6FH After reset: 00H R/W
Symbol
7 6 5 4 3 2
<1>
<0>
WTM
WTM7 WTM6 WTM5 WTM4 WTM3 WTM2 WTM1 WTM0
WTM7
Watch timer count clock selection
0
f
X
/2
7
(78.125 kHz)
1
f
XT
(32.768 kHz)
WTM6
WTM5
WTM4
Prescaler interval time selection
0
0
0
2
4
/f
W
0
0
1
2
5
/f
W
0
1
0
2
6
/f
W
0
1
1
2
7
/f
W
1
0
0
2
8
/f
W
1
0
1
2
9
/f
W
1
1
0
2
10
/f
W
1
1
1
2
11
/f
W
WTM3
WTM2
Interrupt time selection
0
0
2
14
/f
W
0
1
2
13
/f
W
1
0
2
5
/f
W
1
1
2
4
/f
W
WTM1
5-bit counter operation control
0
Clear after operation stop
1
Start
WTM0
Watch timer operation enable
0
Operation stop (clear both prescaler and timer)
1
Operation
enable
Caution Do not change the count clock and interval time (by setting bits 4 to 7 (WTM4 to WTM7) of WTM)
during watch timer operation.
Remarks 1. f
W
: Watch timer clock frequency (f
X
/2
7
or f
XT
)
2. f
X
: High-speed system clock oscillation frequency
3. f
XT
: Subsystem clock oscillation frequency
4. Figures in parentheses apply to operation with f
X
= 10 MHz, f
XT
= 32.768 kHz.
Содержание MuPD78F0132H
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