upd78f0103hmca1-5a4-a Renesas Electronics Corporation., upd78f0103hmca1-5a4-a Datasheet - Page 171

• Manufacturer Part Number: upd78f0103hmca1-5a4-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

9.1 Functions of Watchdog Timer
signal is generated.
For details of RESF, see CHAPTER 16 RESET FUNCTION.
oscillator as shown in Table 9-2.
The watchdog timer is used to detect an inadvertent program loop. If a program loop is detected, an internal reset
When a reset occurs due to the watchdog timer, bit 4 (WDTRF) of the reset control flag register (RESF) is set to 1.
The operation mode of the watchdog timer (WDT) is switched according to the option byte setting of the internal
Remarks 1. f
2
2
2
2
2
2
2
2
During Internal Oscillation Clock Operation
11
12
13
14
15
16
17
18
/f
/f
/f
/f
/f
/f
/f
/f
R
R
R
R
R
R
R
R
(4.27 ms)
(8.53 ms)
(17.07 ms)
(34.13 ms)
(68.27 ms)
(136.53 ms)
(273.07 ms)
(546.13 ms)
2. f
3. Figures in parentheses apply to operation at f
Table 9-1. Loop Detection Time of Watchdog Timer
R
XP
: Internal oscillation clock frequency
: High-speed system clock oscillation frequency
CHAPTER 9 WATCHDOG TIMER
User’s Manual U16846EJ3V0UD
Loop Detection Time
2
2
2
2
2
2
2
2
During High-Speed System Clock Operation
13
14
15
16
17
18
19
20
/f
/f
/f
/f
/f
/f
/f
/f
XP
XP
XP
XP
XP
XP
XP
XP
(819.2
(1.64 ms)
(3.28 ms)
(6.55 ms)
(13.11 ms)
(26.21 ms)
(52.43 ms)
(104.86 ms)
µ
s)
R
= 480 kHz (MAX.), f
XP
= 10 MHz
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