TLE8263-2E Datasheet, PDF (58/94 Pages) Infineon Technologies AG – Universal System Basis Chip

TLE8263-2E
Confidential
Supervision Functions
11.2.4 Inhibition of the watchdog
During SBC Stop Mode and SBC SW Flash Mode, it is possible to deactivate the watchdog. To avoid unwished
deactivation of the watchdog, a special protocol has to be followed, prior deactivating the watchdog. Please refer
to Figure 25. In the case the exact process below is not respected, the SBC remains in the previous state, and an
interrupt is generated (if not inhibited), and the Wrong WD set bit in the SPI is set.
When the microcontroller requests the SBC to go back to SBC Normal Mode, the Watchdog is reactivated. The
watchdog settings that were valid before entering Stop Mode with watchdog off are valid. The watchdog timer
starts with entering Normal Mode. In case window watchdog was selected the watchdog starts with a closed
window. When setting the WD Refresh bit to 0 for the command that sends the device to Normal Mode the first
watchdog trigger is a change to 1. As in Stop Mode the watchdog settings can not be changed, it is also not
possible to change the watchdog settings with the command that sets the SBC from Stop Mode into Normal Mode.
First battery connection
(POR)
AND
config0 not active
SBC Init mode
(256ms max after reset relaxation)
WD conf
WD not active
SPI cmd
SPI cmd =
SBC SW Flash mode
&,WD OFF
SBC Normal mode
WD trig
Cyclic WK
ON / OFF
WD conf
WD active
SPI cmd =
SBC Normal mode
& WD OFF
& WD Trigger
SPI cmd =
SBC SW Flash mode
&,WD OFF
& WD Trigger
SBC SW Flash mode
WD OFF
SBC Normal mode
WD active
SPI cmd =
SBC Stop mode
& WD OFF
& WD Trigger
SBC Stop mode
Cyclic WK
ON / OFF
WD OFF
inhibition of the WD .vsd
Figure 25 Inhibition of the watchdog
During SBC Stop Mode, when the cyclic wake feature is used and the watchdog is not disabled, it is necessary
that the microcontroller acknowledges the interrupt by reading the SPI Wake register before the next Cyclic Wake
occures. Otherwise, a reset is performed by setting the SBC to SBC Restart Mode.
Data Sheet
58
Rev. 1.0, 2009-03-31