CHAPTER 10 WATCHDOG TIMER
User’s Manual U14826EJ5V0UD
120
10.3 Watchdog Timer Control Registers
The following two registers are used to control the watchdog timer.
• Timer clock selection register 2 (TCL2)
• Watchdog timer mode register (WDTM)
(1) Timer clock selection register 2 (TCL2)
TCL2 sets the watchdog timer count clock.
This register is set with an 8-bit memory manipulation instruction.
RESET input clears TCL2 to 00H.
Figure 10-2. Format of Timer Clock Selection Register 2
TCL22
0
0
1
1
TCL21
0
1
0
1
f
X
/2
4
f
X
/2
6
f
X
/2
8
f
X
/2
10
(313 kHz)
(78.1 kHz)
(19.5 kHz)
(4.88 kHz)
f
CC
/2
4
f
CC
/2
6
f
CC
/2
8
f
CC
/2
10
(62.5 kHz)
(15.6 kHz)
(3.91 kHz)
(977 Hz)
TCL20
0
0
0
0
Setting prohibited
Other than above
At f
X
= 5.0 MHz operation
At f
CC
= 1.0 MHz operation
0
0
0
0
0
TCL22
TCL21
TCL20
TCL2
7
6
5
4
Symbol
Address
After reset
R/W
FF42H
00H
R/W
3
<2>
<1>
<0>
Count clock selection
Remarks 1.
f
X
: System clock oscillation frequency (ceramic/crystal oscillation)
2.
f
CC
: System clock oscillation frequency (RC oscillation)
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