RL78/G1A CHAPTER 10 WATCHDOG TIMER
CHAPTER 10 WATCHDOG TIMER
10.1 Functions of Watchdog Timer
<R>
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 19 RESET FUNCTION.
When 75% + 1/2/f
IL of the overflow time is reached, an interval interrupt can be generated.
R01UH0305EJ0200 Rev.2.00 333
Jul 04, 2013
