UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
924 of 1269
NXP Semiconductors
UM10503
Chapter 34: LPC43xx Windowed Watchdog timer (WWDT)
34.8 Block diagram
The block diagram of the Watchdog is shown below in the
. The
synchronization logic (PCLK - WDCLK) is not shown in the block diagram.
34.9 Watchdog timing examples
The following figures illustrate several aspects of Watchdog Timer operation is shown
below in
Table 779. Watchdog Timer Window register (WINDOW - 0x4008 0018) bit description
Bit
Symbol
Description
Reset value
23:0
WDWINDOW Watchdog window value.
0xFF FFFF
31:24
-
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
NA
Fig 108. Watchdog block diagram
watchdog
interrupt
WDRESET
(WDMOD[1])
WDTOF
(WDMOD[2])
WDINT
(WDMOD[3])
WDEN
(WDMOD[0])
chip reset
÷4
feed error
feed ok
wd_clk
enable count
WDMOD
register
compare
WDTV
compare
in
range
underflow
feed sequence
detect and
protection
WDFEED
feed ok
fe
ed
o
k
compare
0
interrupt
compare
WDCLKSEL
clock
select
24-bit down counter
WDINTVAL
WDWIND
WDTC
shadow bit
WDPROTECT
(WDMOD[4])
WDT
C
writ
e