Information

The watchdog can also generate an interrupt. If IRQ_RST_EN is set, then on the above
mentioned events WDOG_ST_CTRL_L[INT_FLG] is set, generating an interrupt. A
watchdog reset is also generated WCT time later to ensure the watchdog is fault tolerant.
The interrupt can be cleared by writing 1 to INT_FLG.
The gap of WCT between interrupt and reset means that the WDOG time-out value must
be greater than WCT. Otherwise, if the interrupt was generated due to a time-out, a
second consecutive time-out will occur in that WCT gap. This will trigger the backup
reset generator to generate a reset to the system, prematurely ending the interrupt service
routine execution. Also, jobs such as counting the number of watchdog resets would not
be done.
23.7 Memory map and register definition
This section consists of the memory map and register descriptions.
WDOG memory map
Absolute
address
(hex)
Register name
Width
(in bits)
Access Reset value
Section/
page
4005_2000
Watchdog Status and Control Register High
(WDOG_STCTRLH)
16 R/W 01D3h 23.7.1/418
4005_2002
Watchdog Status and Control Register Low
(WDOG_STCTRLL)
16 R/W 0001h 23.7.2/420
4005_2004 Watchdog Time-out Value Register High (WDOG_TOVALH) 16 R/W 004Ch 23.7.3/420
4005_2006 Watchdog Time-out Value Register Low (WDOG_TOVALL) 16 R/W 4B4Ch 23.7.4/421
4005_2008 Watchdog Window Register High (WDOG_WINH) 16 R/W 0000h 23.7.5/421
4005_200A Watchdog Window Register Low (WDOG_WINL) 16 R/W 0010h 23.7.6/422
4005_200C Watchdog Refresh register (WDOG_REFRESH) 16 R/W B480h 23.7.7/422
4005_200E Watchdog Unlock register (WDOG_UNLOCK) 16 R/W D928h 23.7.8/423
4005_2010 Watchdog Timer Output Register High (WDOG_TMROUTH) 16 R/W 0000h 23.7.9/423
4005_2012 Watchdog Timer Output Register Low (WDOG_TMROUTL) 16 R/W 0000h
23.7.10/
423
4005_2014 Watchdog Reset Count register (WDOG_RSTCNT) 16 R/W 0000h
23.7.11/
424
4005_2016 Watchdog Prescaler register (WDOG_PRESC) 16 R/W 0400h
23.7.12/
424
Chapter 23 Watchdog Timer (WDOG)
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
Freescale Semiconductor, Inc. 417