CHAPTER 11 WATCHDOG TIMER FUNCTIONS
User’s Manual U16896EJ2V0UD
352
(2) Operation as interval timer
Watchdog timer 1 can be made to operate as an interval timer that repeatedly generates interrupts using the
count value set in advance as the interval, by clearing the WDTM1.WDTM14 bit to 0.
When watchdog timer 1 operates as an interval timer, the interrupt mask flag (WDTMK) and priority
specification flags (WDTPR0 to WDTPR2) of the WDTIC register are valid and maskable interrupt request
signals (INTWDTM1) can be generated. The default priority of the INTWDTM1 signal is set to the highest
level among the maskable interrupt request signals.
The interval timer continues to operate in the HALT mode, but it stops operating in the STOP mode and the
IDLE mode.
Cautions 1. Once the WDTM14 bit is set to 1 (thereby selecting the watchdog timer 1 mode), the
interval timer mode is not entered as long as reset is not performed.
2. When the subclock is selected for the CPU clock, the count operation of the watchdog
timer 1 stops (the value of the watchdog timer is maintained).
Table 11-3. Interval Time of Interval Timer
Interval Time
Clock
f
XW
= 4 MHz
f
XW
= 5 MHz
f
XW
= 10 MHz
2
13
/f
XW
2.048 ms
1.638 ms
0.819 ms
2
14
/f
XW
4.096 ms
3.277 ms
1.638 ms
2
15
/f
XW
8.192 ms
6.554 ms
3.277 ms
2
16
/f
XW
16.38 ms
13.11 ms
6.554 ms
2
17
/f
XW
32.77 ms
26.21 ms
13.11 ms
2
18
/f
XW
65.54 ms
52.43 ms
26.21 ms
2
19
/f
XW
131.1 ms
104.9 ms
52.43 ms
2
21
/f
XW
524.3 ms
419.4 ms
209.7 ms
Remark
f
XW
= f
X
: Watchdog timer 1 clock frequency
Содержание ?PD703302
Страница 2: ...User s Manual U16896EJ2V0UD 2 MEMO ...