HD6412350 Hitachi, HD6412350 Datasheet - Page 548

• Manufacturer Part Number: HD6412350
• Description: (HD6412350 / HD6432351) 16-BIT MICROCONTROLLER
• Manufacturer: Hitachi

12.5.3
If the mode is switched from watchdog timer to interval timer, or vice versa, while the WDT is
operating, errors could occur in the incrementation. Software must stop the watchdog timer (by
clearing the TME bit to 0) before switching the mode.
12.5.4
If the WDTOVF output signal is input to the RES pin of the H8S/2350 Series, the H8S/2350
Series will not be initialized correctly. Make sure that the WDTOVF signal is not input logically
to the RES pin. To reset the entire system by means of the WDTOVF signal, use the circuit shown
in figure 12-9.
12.5.5
The H8S/2350 Series is not reset internally if TCNT overflows while the RSTE bit is cleared to 0
during watchdog timer operation, but TCNT and TSCR of the WDT are reset.
TCNT, TCSR, and RSTCR cannot be written to while the WDTOVF signal is low. Also note that
a read of the WOVF flag is not recognized during this period. To clear the WOVF falg, therefore,
read TCSR after the WDTOVF signal goes high, then write 0 to the WOVF flag.
528
Reset signal to entire system
Switching between Watchdog Timer Mode and Interval Timer Mode
System Reset by WDTOVF Signal
Internal Reset in Watchdog Timer Mode
Figure 12-9 Circuit for System Reset by WDTOVF Signal (Example)
Reset input
H8S/2350 Series
WDTOVF
RES