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Section number Title Page
25.3 Features.........................................................................................................................................................................478
25.4 Functional overview......................................................................................................................................................479
25.4.1 Unlocking and updating the watchdog.........................................................................................................481
25.4.2 Watchdog configuration time (WCT)..........................................................................................................482
25.4.3 Refreshing the watchdog..............................................................................................................................483
25.4.4 Windowed mode of operation......................................................................................................................483
25.4.5 Watchdog disabled mode of operation.........................................................................................................483
25.4.6 Debug modes of operation........................................................................................................................... 483
25.5 Testing the watchdog.................................................................................................................................................... 484
25.5.1 Quick test..................................................................................................................................................... 485
25.5.2 Byte test........................................................................................................................................................485
25.6 Backup reset generator..................................................................................................................................................486
25.7 Generated resets and interrupts.....................................................................................................................................487
25.8 Memory map and register definition.............................................................................................................................487
25.8.1 Watchdog Status and Control Register High (WDOG_STCTRLH)........................................................... 488
25.8.2 Watchdog Status and Control Register Low (WDOG_STCTRLL)............................................................ 490
25.8.3 Watchdog Time-out Value Register High (WDOG_TOVALH).................................................................490
25.8.4 Watchdog Time-out Value Register Low (WDOG_TOVALL)..................................................................491
25.8.5 Watchdog Window Register High (WDOG_WINH).................................................................................. 491
25.8.6 Watchdog Window Register Low (WDOG_WINL)................................................................................... 492
25.8.7 Watchdog Refresh register (WDOG_REFRESH)....................................................................................... 492
25.8.8 Watchdog Unlock register (WDOG_UNLOCK).........................................................................................492
25.8.9 Watchdog Timer Output Register High (WDOG_TMROUTH)................................................................. 493
25.8.10 Watchdog Timer Output Register Low (WDOG_TMROUTL).................................................................. 493
25.8.11 Watchdog Reset Count register (WDOG_RSTCNT).................................................................................. 494
25.8.12 Watchdog Prescaler register (WDOG_PRESC).......................................................................................... 494
25.9 Watchdog operation with 8-bit access.......................................................................................................................... 494
25.9.1 General guideline......................................................................................................................................... 494
25.9.2 Refresh and unlock operations with 8-bit access.........................................................................................495
KS22/KS20 Sub-Family Reference Manual , Rev. 3, May 2016
NXP Semiconductors 19