Datasheet

RL78/L12 CHAPTER 10 WATCHDOG TIMER
R01UH0330EJ0200 Rev.2.00 327
Dec 13, 2013
CHAPTER 10 WATCHDOG TIMER
10.1 Functions of Watchdog Timer
The counting operation of the watchdog timer is set by the option byte (000C0H).
The watchdog timer operates on the low-speed on-chip oscillator clock (f
IL).
The watchdog timer is used to detect an inadvertent program loop. If a program loop is detected, an internal reset
signal is generated.
Program loop is detected in the following cases.
• If the watchdog timer counter overflows
• If a 1-bit manipulation instruction is executed on the watchdog timer enable register (WDTE)
• If data other than “ACH” is written to the WDTE register
• If data is written to the WDTE register during a window close period
When a reset occurs due to the watchdog timer, bit 4 (WDTRF) of the reset control flag register (RESF) is set to 1. For
details of the RESF register, see CHAPTER 20 RESET FUNCTION.
When 75% + 1/2f
IL of the overflow time is reached, an interval interrupt can be generated.
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