HD6413007F20 Datasheet, PDF (443/798 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

12. Watchdog Timer
Section 12 Watchdog Timer
12.1 Overview
The H8/3006 and H8/3007 have an on-chip watchdog timer (WDT). The WDT has two selectable
functions: it can operate as a watchdog timer to supervise system operation, or it can operate as an
interval timer. As a watchdog timer, it generates a reset signal for the H8/3006 and H8/3007 chip
if a system crash allows the timer counter (TCNT) to overflow before being rewritten. In interval
timer operation, an interval timer interrupt is requested at each TCNT overflow.
12.1.1 Features
WDT features are listed below.
• Selection of eight counter clock sources
φ/2, φ /32, φ /64, φ /128, φ /256, φ /512, φ /2048, or φ /4096
• Interval timer option
• Timer counter overflow generates a reset signal or interrupt.
The reset signal is generated in watchdog timer operation. An interval timer interrupt is
generated in interval timer operation.
• Watchdog timer reset signal resets the entire H8/3006 and H8/3007 internally, and can also be
output externally.
The reset signal generated by timer counter overflow during watchdog timer operation resets
the entire H8/3006 and H8/3007 internally. An external reset signal can be output from the
RESO pin to reset other system devices simultaneously.
Rev.5.00 Sep. 12, 2007 Page 413 of 764
REJ09B0396-0500