HD64F7144F50V Datasheet, PDF (425/932 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

12. Watchdog Timer
Section 12 Watchdog Timer
The watchdog timer (WDT) is an 8-bit timer that can reset this LSI internally if the counter
overflows without rewriting the counter value due to a system crash or the like.
When this watchdog function is not needed, the WDT can be used as an interval timer. In interval
timer operation, an interval timer interrupt is generated each time the counter overflows.
The block diagram of the WDT is shown in figure 12.1.
12.1 Features
• Switchable between watchdog timer mode and interval timer mode
In watchdog timer mode
• Output WDTOVF signal
If the counter overflows, it is possible to select whether this LSI is internally reset or not. A
power-on reset or manual reset can be selected as an in internal reset.
In interval timer mode
• If the counter overflows, the WDT generates an interval timer interrupt (ITI).
• Clears software standby mode
• Selectable from eight counter input clocks.
WDT0400A_030020030800
Rev.4.00 Mar. 27, 2008 Page 379 of 882
REJ09B0108-0400