TLE9261-3QX Datasheet, PDF (110/186 Pages) Infineon Technologies AG – Dedicated Data Sheets are available for the different product variants

TLE9261-3QX
Supervision Functions
14.2.4 Watchdog during SBC Stop Mode
The watchdog can be disabled for SBC Stop Mode in SBC Normal Mode. For safety reasons, there is a special
sequence to be followed in order to disable the watchdog as described in Figure 50. Two different SPI bits
(WD_STM_ EN_0, WD_STM_ EN_1) in the registers WK_CTRL_1 and WD_CTRL need to be set.
Correct WD disabling
sequence
Set bit
WD_STM_EN_1 = 1
with next WD Trigger
Set bit
WD_STM_EN_0 = 1
Before subsequent WD Trigger
Change to
SBC Stop Mode
WD is switched off
Sequence Errors
• Missing to set bit
WD_STM_EN_0 with the
next watchdog trigger after
having set WD_STM_EN_1
• Staying in Normal Mode
instead of going to Stop
Mode with the next trigger
Will enable the WD :
• Switching back to SBC
Normal Mode
• Triggering the watchdog
Figure 50 Watchdog disabling sequence in SBC Stop Mode
If a sequence error occurs, then the bit WD_STM_ EN_1 will be cleared and the sequence has to be started again.
The watchdog can be enabled by triggering the watchdog in SBC Stop Mode or by switching back to SBC Normal
Mode via SPI command. In both cases the watchdog will start with a long open window and the bits
WD_STM_EN_1 and WD_STM_ EN_0 are cleared. After the long open window the watchdog has to be served
as configured in the WD_CTRL register.
Note: The bit WD_STM_ EN_0 will be cleared automatically when the sequence is started and it was 1 before.
14.2.5 Watchdog Start in SBC Stop Mode due to Bus Wake
In SBC Stop Mode the Watchdog can be disabled. In addition a feature is available which will start the watchdog
with any BUS wake (CAN) during SBC Stop Mode. The feature is enabled by setting the bit WD_EN_ WK_BUS = 1
(= default value after POR). The bit can only be changed in SBC Normal Mode and needs to be programmed
before starting the watchdog disable sequence.
A wake on CAN will generate an interrupt and the RXD pin for CAN is pulled to low. By these signals the
microcontroller is informed that the watchdog is startedwith a long open window. After the long open window the
watchdog has to be served as configured in the WD_CTRL register.
To disable the watchdog again, the SBC needs to be switched to Normal Mode and the sequence needs to be
sent again.
Data Sheet
110
Rev. 1.1, 2014-09-26