UM10462
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2016. All rights reserved.
User manual
Rev. 5.5 — 21 December 2016
373 of 523
NXP Semiconductors
UM10462
Chapter 17: LPC11U3x/2x/1x Windowed Watchdog Timer (WWDT)
17.8 Register description
The Watchdog Timer contains the registers shown in
[1]
Reset Value reflects the data stored in used bits only. It does not include reserved bits content.
17.8.1 Watchdog mode register
The WDMOD register controls the operation of the Watchdog. Note that a watchdog feed
must be performed before any changes to the WDMOD register take effect.
Table 336. Register overview: Watchdog timer (base address 0x4000 4000)
Name
Access Address
offset
Description
Reset
Value
Reference
MOD
R/W
0x000
Watchdog mode register. This
register contains the basic mode and
status of the Watchdog Timer.
0
TC
R/W
0x004
Watchdog timer constant register.
This 24-bit register determines the
time-out value.
0xFF
FEED
WO
0x008
Watchdog feed sequence register.
Writing 0xAA followed by 0x55 to this
register reloads the Watchdog timer
with the value contained in WDTC.
NA
TV
RO
0x00C
Watchdog timer value register. This
24-bit register reads out the current
value of the Watchdog timer.
0xFF
CLKSEL
R/W
0x010
Watchdog clock select register.
0
WARNINT
R/W
0x014
Watchdog Warning Interrupt compare
value.
0
WINDOW
R/W
0x018
Watchdog Window compare value.
0xFF FFFF
Table 337. Watchdog mode register (MOD - 0x4000 4000) bit description
Bit
Symbol
Value Description
Reset
value
0
WDEN
Watchdog enable bit. Once this bit has been written with
a 1, it cannot be rewritten with a 0.
0
0
The watchdog timer is stopped.
1
The watchdog timer is running.
1
WDRESET
Watchdog reset enable bit. Once this bit has been
written with a 1 it cannot be rewritten with a 0.
0
0
A watchdog timeout will not cause a chip reset.
1
A watchdog timeout will cause a chip reset.
2
WDTOF
Watchdog time-out flag. Set when the watchdog timer
times out, by a feed error, or by events associated with
WDPROTECT. Cleared by software. Causes a chip
reset if WDRESET = 1.
0 (only
after
external
reset)
3
WDINT
Warning interrupt flag. Set when the timer reaches the
value in WDWARNINT. Cleared by software.
0