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NUC126
Aug. 08, 2018
Page
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Rev 1.03
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6.25 Window Watchdog Timer (WWDT)
6.25.1
Overview
The Window Watchdog Timer (WWDT) is used to perform a system reset while WWDT counter is not
reload within a specified window period when application program run to uncontrollable status by any
unpredictable condition.
6.25.2
Features
Supports 6-bit down counter value CNTDAT (WWDT_CNT[5:0]) and maximum 6-bit
compare value CMPDAT (WWDT_CTL[21:16]) to adjust the WWDT compare time-out
window period flexible
Supports PSCSEL (WWDT_CTL[11:8]) to programmable maximum 11-bit prescale
counter period of WWDT counter
WWDT counter suspends in Idle/Power-down mode
WWDT counter only can be reloaded within in valid window period to prevent system
reset
6.25.3
Block Diagram
6-bit down counter
11-bit
Prescale
6-bit compare value
CMPDAT
(WWDT_CTL[21:16])
WWDT_CLK
0x3F
comparator
CNTDAT = CMPDAT
WWDTIF
(STATUS[0])
CNTDAT > CMPDAT
INTEN
(WWDT_CTL[1])
WWDT Interrupt
WWDT Reset System
CNTDAT = 0 and internal prescale counter = 0
write RLDCNT
= 0x00005AA5
WWDTRF
(STATUS[1])
PSCSEL
(WWDT_CTL[11:8])
CNTDAT
(WWDT_CNT[5:0])
Synchronizer
write RLDCNT
= 0x00005AA5
Figure 6.25-1 WWDT Block Diagram