Chapter 8 Watchdog Timer; Functions Of Watchdog Timer - NEC mPD178054 Series User Manual

8.1 Functions of Watchdog Timer

The watchdog timer has the following functions.
• Watchdog timer
• Interval timer
• Selecting oscillation stabilization time
Caution Select the watchdog timer mode or the interval timer mode using the watchdog timer mode
register (WDTM). (The watchdog timer and interval timer cannot be used simultaneously.)
Figure 8-1 shows a block diagram.
Clock
8
f /2 input
X
controller
RUN
OSTS2 OSTS1 OSTS0
Oscillation stabilization
time select register (OSTS)

CHAPTER 8 WATCHDOG TIMER

Figure 8-1. Block Diagram of Watchdog Timer
Divided
Divider clock
selector
Division mode
selector
3
WDCS2 WDCS1 WDCS0
Watchdog timer clock Watchdog timer mode
select register (WDCS) register (WDTM)
Internal bus
User's Manual U15104EJ2V0UD
INTWDT
Output
controller
RESET
WDT mode signal
RUN WDTM4 WDTM3
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