HD6417021 Hitachi Semiconductor, HD6417021 Datasheet - Page 353

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

12.4.4
If a WDTOVF signal is input to the RES pin, the LSI cannot initialize correctly. Avoid logical
input of the WDTOVF output signal to the RES input pin. To reset the entire system with the
WDTOVF signal, use the circuit shown in figure 12.9.
12.4.5
If the RSTE bit is cleared to 0 in the watchdog timer mode, the LSI will not reset internally when a
TCNT overflow occurs, but the TCNT and TCSR in WDT will reset.
System Reset With WDTOVF
Internal Reset With the Watchdog Timer
Figure 12.9 Example of a System Reset Circuit with a WDTOVF Signal
Reset signal to
entire system
Reset input
SuperH
microprocessor
RES
WDTOVF
HITACHI 339