
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
302 of 487
NXP Semiconductors
UM10800
Chapter 17: LPC82x Windowed Watchdog Timer (WWDT)
Once the
WDEN
,
WDPROTECT
, or
WDRESET
bits are set they can not be cleared by
software. Both flags are cleared by an external reset or a Watchdog timer reset.
WDTOF
The Watchdog time-out flag is set when the Watchdog times out, when a feed
error occurs, or when PROTECT =1 and an attempt is made to write to the TC register.
This flag is cleared by software writing a 0 to this bit.
WDINT
The Watchdog interrupt flag is set when the Watchdog counter reaches the value
specified by WARNINT. This flag is cleared when any reset occurs, and is cleared by
software by writing a 0 to this bit.
In all power modes except Deep power-down mode, a Watchdog reset or interrupt can
occur when the watchdog is running and has an operating clock source. The watchdog
oscillator can be configured to keep running in Sleep, Deep-sleep modes, and
Power-down modes.
If a watchdog interrupt occurs in Sleep, Deep-sleep mode, or Power-down mode, and the
WWDT interrupt is enabled in the NVIC, the device will wake up. Note that in Deep-sleep
and Power-down modes, the WWDT interrupt must be enabled in the STARTERP1
register in addition to the NVIC.
See the following registers:
3
WDINT
Warning interrupt flag. Set when the timer reaches the
value in WDWARNINT. Cleared by software.
0
4
WDPROTECT
Watchdog update mode. This bit can be set once by
software and is only cleared by a reset.
0
0
The watchdog time-out value (TC) can be changed at
any time.
1
The watchdog time-out value (TC) can be changed only
after the counter is below the value of WDWARNINT
and WDWINDOW.
5
LOCK
A 1 in this bit prevents disabling or powering down the
watchdog oscillator. This bit can be set once by software
and is only cleared by any reset.
0
31:6 -
Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined.
NA
Table 253. Watchdog mode register (MOD, 0x4000 0000) bit description
Bit
Symbol
Value Description
Reset
value