Chapter 10 Watchdog Timer; Outline Of Watchdog Timer; Watchdog Timer Functions - NEC mPD780344 Series User Manual

10.1 Outline of Watchdog Timer

The watchdog timer can also be used to generate a non-maskable interrupt request, maskable interrupt request,
or RESET signal at the preset time intervals.

10.2 Watchdog Timer Functions

The watchdog timer has the following functions.
• Watchdog timer
• Interval timer
• Oscillation stabilization time selection
Caution Select the watchdog timer mode or the interval timer mode with the watchdog timer mode register
(WDTM). (The watchdog timer and the interval timer cannot be used simultaneously.)
Figure 10-1 shows a block diagram of the watchdog timer.
f
X
8
f /2
X
Oscillation stabilization
time select register
(OSTS)
210

CHAPTER 10 WATCHDOG TIMER

Figure 10-1. Watchdog Timer Block Diagram
Clock
input
Divider
controller
RUN Division
mode selector
OSTS2 OSTS1 OSTS0 WDCS2 WDCS1 WDCS0
Watchdog timer
clock select
register (WDCS)
Internal bus
User's Manual U15798EJ2V0UD
Divided
clock
Output
selector
controller
3
WDTM3
RUN WDTM4
Watchdog timer
mode register
(WDTM)
INTWDT
RESET
WDT mode signal