247
CHAPTER 11 WATCHDOG TIMER
11.1 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 interval timer cannot be used at the same time).
(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 11-1. Watchdog Timer Runaway Detection Times
Runaway Detection Time
MCS = 1
MCS = 0
2
11
×
1/f
XX
2
11
×
1/f
X
(410
µ
s)
2
12
×
1/f
X
(819
µ
s)
2
12
×
1/f
XX
2
12
×
1/f
X
(819
µ
s)
2
13
×
1/f
X
(1.64 ms)
2
13
×
1/f
XX
2
13
×
1/f
X
(1.64 ms)
2
14
×
1/f
X
(3.28 ms)
2
14
×
1/f
XX
2
14
×
1/f
X
(3.28 ms)
2
15
×
1/f
X
(6.55 ms)
2
15
×
1/f
XX
2
15
×
1/f
X
(6.55 ms)
2
16
×
1/f
X
(13.1 ms)
2
16
×
1/f
XX
2
16
×
1/f
X
(13.1 ms)
2
17
×
1/f
X
(26.2 ms)
2
17
×
1/f
XX
2
17
×
1/f
X
(26.2 ms)
2
18
×
1/f
X
(52.4 ms)
2
19
×
1/f
XX
2
19
×
1/f
X
(104.9 ms)
2
20
×
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.
Summary of Contents for PD78052
Page 2: ...2 MEMO ...
Page 8: ...8 MEMO ...
Page 16: ...16 MEMO ...
Page 36: ...36 MEMO ...
Page 158: ...158 MEMO ...
Page 174: ...174 MEMO ...
Page 240: ...240 MEMO ...
Page 260: ...260 MEMO ...
Page 340: ...340 MEMO ...
Page 392: ...392 MEMO ...
Page 438: ...438 MEMO ...
Page 482: ...482 CHAPTER 20 REAL TIME OUTPUT PORT MEMO ...
Page 510: ...510 MEMO ...
Page 524: ...524 MEMO ...
Page 560: ...560 MEMO ...
Page 576: ...576 MEMO ...
Page 598: ...598 MEMO ...
Page 602: ...602 MEMO ...