UM11029
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© NXP Semiconductors N.V. 2017. All rights reserved.
User manual
Rev. 1.0 — 16 June 2017
422 of 515
NXP Semiconductors
UM11029
Chapter 22: LPC84x Windowed Watchdog Timer (WWDT)
22.7 Functional description
The following figures illustrate several aspects of Watchdog Timer operation.
Table 422. Watchdog Timer Window register (WINDOW, 0x4000 0018) bit description
Bit
Symbol
Description
Reset
Value
23:0
WINDOW 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 53. Early watchdog feed with windowed mode enabled
125A
1258
1259
1257
WDCLK / 4
Watchdog
Counter
Early Feed
Event
Watchdog
Reset
Conditions :
WINDOW
= 0x1200
WARNINT
= 0x3FF
TC
= 0x2000
Fig 54. Correct watchdog feed with windowed mode enabled
Correct Feed
Event
1201
11FF
1200
WDCLK / 4
Watchdog
Counter
Watchdog
Reset
11FC
11FD
2000
1FFE
1FFF
11FE
1FFD 1FFC
Conditions :
WDWINDOW = 0x1200
WDWARNINT = 0x3FF
WDTC
= 0x2000
Fig 55. Watchdog warning interrupt
Watchdog
Interrupt
0403
0401
0402
WDCLK / 4
Watchdog
Counter
03FE
03FF
03FD
03FB
03FC
0400
03FA 03F9
Conditions :
WINDOW
= 0x1200
WARNINT
= 0x3FF
TC
= 0x2000