HD6417021 Hitachi Semiconductor, HD6417021 Datasheet - Page 341

• Manufacturer Part Number: HD6417021
• Description: SuperH RISC engine
• Manufacturer: Hitachi Semiconductor

12.1
The SuperH microcomputer has a one-channel watchdog timer (WDT) for monitoring system
operations. If a system becomes uncontrolled and the timer counter overflows without being
rewritten correctly by the CPU, an overflow signal (WDTOVF) is output externally . The WDT
can simultaneously generate an internal reset signal for the entire chip.
When this watchdog function is not needed, the WDT can be used as an interval timer. In the
interval timer operation, an interval timer interrupt is generated at each counter overflow. The
WDT is also used in recovering from the standby mode.
12.1.1
• Watchdog timer mode and interval timer mode can be selected.
• Outputs WDTOVF in the watchdog timer mode. When the counter overflows in the watchdog
• Generates interrupts in the interval timer mode. When the counter overflows, it generates an
• Used to clear the standby mode.
• Selection of eight counter clock sources
timer mode, overflow signal WDTOVF is output externally. You can select whether or not to
reset the chip internally when this happens. Either the power-on reset or manual reset signal
can be selected as the internal reset signal.
interval timer interrupt.
Overview
Features
Section 12 Watchdog Timer (WDT)
HITACHI 327