UPD784938 Datasheet, PDF (387/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 13 WATCHDOG TIMER
The watchdog timer is a timer that detects inadvertent program loops.
Watchdog timer interrupts are used to detect system or program errors. For this purpose, instructions that clear the
watchdog timer (start the count) within a given period are inserted at various places in a program.
If an instruction that clears the watchdog timer is not executed within the set time and the watchdog timer overflows,
a watchdog timer interrupt (INTWDT) is generated and a program error is reported.
13.1 Configuration
The watchdog timer block diagram is shown in Figure 13-1.
Figure 13-1. Watchdog Timer Block Diagram
fCLK
Watchdog timer
fCLK/2²¹
fCLK/2²⁰
fCLK/2¹⁹
fCLK/2¹⁷
Selector
INTWDT
Clear signal
Preliminary User’s Manual U13987EJ1V0UM00
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