CHAPTER 9 WATCHDOG TIMER
User’s Manual U16898EJ3V0UD
146
9.2 Configuration of Watchdog Timer
The watchdog timer consists of the following hardware.
Table 9-3. Configuration of Watchdog Timer
Item Configuration
Control registers
Watchdog timer mode register (WDTM)
Watchdog timer enable register (WDTE)
Figure 9-1. Block Diagram of Watchdog Timer
f
RL
/2
2
Clock
input
controller
Output
controller
Internal reset signal
WDCS2
Internal bus
WDCS1 WDCS0
f
X
/2
4
WDCS3
WDCS4
0
1
1
Selector
16-bit
counter
or
2
13
/f
X
to
2
20
/f
X
2
11
/f
RL
to
2
18
/f
RL
Watchdog timer enable
register (WDTE)
Watchdog timer mode
register (WDTM)
3
2
Clear
Option byte
(to set “low-speed
internal oscillator cannot be
stopped” or “low-speed
internal oscillator can be
stopped by software”)
Remarks 1.
f
RL
: Low-speed internal oscillation clock oscillation frequency
2.
f
X
: System clock oscillation frequency