![background image](http://html.mh-extra.com/html/nec/pd78076/pd78076_user-manual_248169275.webp)
275
CHAPTER 12 WATCHDOG TIMER
12.1 Watchdog Timer Functions
The watchdog timer has the following functions.
• Watchdog timer
• Interval timer
Caution Select the watchdog timer mode or the interval timer mode with the watchdog timer mode
register (WDTM) (the watchdog timer and the interval timer cannot be used simultaneously).
(1) Watchdog timer mode
An inadvertent program loop (runaway) is detected. Upon detection of the runaway, a non-maskable
interrupt request or RESET can be generated.
Table 12-1. Watchdog Timer Runaway Times
Runaway Detection Time
MCS = 1
MCS = 0
2
11
x 1/f
XX
2
11
x 1/f
X
(410
µ
s)
2
12
x 1/f
X
(819
µ
s)
2
12
x 1/f
XX
2
12
x 1/f
X
(819
µ
s)
2
13
x 1/f
X
(1.64 ms)
2
13
x 1/f
XX
2
13
x 1/f
X
(1.64 ms)
2
14
x 1/f
X
(3.28 ms)
2
14
x 1/f
XX
2
14
x 1/f
X
(3.28 ms)
2
15
x 1/f
X
(6.55 ms)
2
15
x 1/f
XX
2
15
x 1/f
X
(6.55 ms)
2
16
x 1/f
X
(13.1 ms)
2
16
x 1/f
XX
2
16
x 1/f
X
(13.1 ms)
2
17
x 1/f
X
(26.2 ms)
2
17
x 1/f
XX
2
17
x 1/f
X
(26.2 ms)
2
18
x 1/f
X
(52.4 ms)
2
19
x 1/f
XX
2
19
x 1/f
X
(104.9 ms)
2
20
x 1/f
X
(209.7 ms)
Remarks 1. f
XX
: Main system clock frequency (f
X
or f
X
/2)
2. f
X
: Main system clock oscillation frequency
3. MCS : Bit 0 of oscillation mode selection register (OSMS)
4. Figures in parentheses apply to operation with f
X
= 5.0 MHz.
Содержание PD78076
Страница 2: ...2 MEMO ...
Страница 12: ...12 MEMO ...
Страница 48: ...48 MEMO ...
Страница 64: ...64 MEMO ...
Страница 82: ...82 MEMO ...
Страница 100: ...100 MEMO ...
Страница 130: ...130 MEMO ...
Страница 180: ...180 MEMO ...
Страница 222: ...222 MEMO ...
Страница 248: ...248 MEMO ...
Страница 288: ...288 MEMO ...
Страница 308: ...308 MEMO ...
Страница 364: ...364 MEMO ...
Страница 494: ...494 MEMO ...
Страница 526: ...526 MEMO ...
Страница 544: ...544 MEMO ...
Страница 558: ...558 MEMO ...
Страница 580: ...580 MEMO ...
Страница 596: ...596 MEMO ...
Страница 598: ...598 MEMO ...
Страница 626: ...626 MEMO ...