HD6437101 RENESAS [Renesas Technology Corp], HD6437101 Datasheet - Page 316

• Manufacturer Part Number: HD6437101
• Description: 32-Bit RISC Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 9 Watchdog Timer
9.6.5
If a WDTOVF output signal is input to the RES pin, the chip cannot initialize correctly.
Avoid logical input of the WDTOVF signal to the RES input pin. To reset the entire system with
the WDTOVF signal, use the circuit shown in figure 9.9.
9.6.6
If the RSTE bit is cleared to 0 in watchdog timer mode, the chip will not be reset internally when a
TCNT overflow occurs, but TCNT and TCSR in the WDT will be reset.
9.6.7
When an internal reset is effected by TCNT overflow in watchdog timer mode, the processor waits
until the end of the bus cycle at the time of manual reset generation before making the transition to
manual reset exception processing.
9.6.8
The WDTOVF pin should not be pulled down. However, if it is necessary to pull this pin down, a
resistance of 1 MΩ or higher should be used.
Rev.1.00 Sep. 18, 2008 Page 282 of 522
REJ09B0069-0100
Reset signal to entire system
System Reset by WDTOVF Signal
Internal Reset in Watchdog Timer Mode
Manual Reset in Watchdog Timer Mode
Notes on Using WDTOVF Pin
Figure 9.9 Example of System Reset Circuit Using WDTOVF Signal
Reset input
This LSI