TLE8263-2E Datasheet, PDF (57/94 Pages) Infineon Technologies AG – Universal System Basis Chip

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tCWmin
Window Watchdog Timing (SPI)
tWD
tCWmax
closed window
Un-
certainty
TLE8263-2E
Supervision Functions
tOWmin
tOWmax
open window
uncertainty
0.45
0.55
Figure 23 Window Watchdog Definitions
t_CW
t_OW
WD
t_CW
t_OW
t_CW+t_OW
t_LW
Refresh
bit
safe trigger area
t / [tWDPER]
0.9
1.0
1.1
Wd1_per .vsd
t_CW
t_OW
t_LW
t_CW
t_LW
t_CW
t_OW
t_WDR
t
RO
Watchdog
timer reset
normal
operation
Time-out
(too long)
normal
operation
timeout
(too short)
Figure 24 Window Watchdog Timing Diagram for config 1 and config 3
t
normal
operation
Wd2_per.vsd
11.2.3 Changing the Watchdog Settings
The settings of the watchdog can be changed during the operation of the watchdog. The change is done with a
SPI programming into the Watchdog Configuration Register. The new setting is programmed together with a valid
watchdog trigger according to the old settings. The timer with the new settings starts with this SPI command. The
toggling of the “WD Refresh” bit needs to be continued (transition HIGH to LOW or LOW to HIGH) with the new
settings.
If the new settings were not valid, the watchdog will continue with the old settings and generate a “Wrong WD Set”
interrupt.
Data Sheet
57
Rev. 1.0, 2009-03-31