OPTIREG™ SBC TLE9274QXV33
Supervision functions
13.2
Watchdog function
The watchdog is used to monitor the software execution of the microcontroller and to trigger a reset if the
microcontroller stops serving the watchdog due to a lock up in the software.
Two different types of watchdog functions are implemented and can be selected via the bit WD_WIN:
•
•
Time-out watchdog (default value)
Window watchdog
The respective watchdog function can be selected and programmed in SBC Normal mode. The configuration
remains unchanged in SBC Stop mode.
Refer to Table 20 to match the SBC modes with the respective watchdog modes.
Table 20 Watchdog functionality by SBC modes
SBC mode
Watchdog mode
Remarks
INIT mode
Start with long open window Watchdog starts with long open window after RO is
released
Normal mode
Stop mode
WD programmable
Window watchdog, time-out watchdog
Watchdog is fixed or OFF
Watchdog OFF must be performed in SBC Normal
mode
Sleep mode
Restart mode
Fail-Safe mode
OFF
OFF
OFF
SBC will start with long open window when entering
SBC Normal mode
SBC will start with long open window when entering
Normal mode
SBC will start with long open window when entering
SBC Normal mode
The watchdog timing is programmed using an SPI command. As soon as the watchdog is programmed, the
timer starts with the new setting and the watchdog must be served.The watchdog is triggered by sending a
valid SPI-write command to the watchdog configuration register. The trigger SPI command is executed when
the chip select input (CSN) becomes HIGH.
When coming from SBC Init or Restart mode the watchdog timer is always started with a long open window.
The long open window (tLW) allows the microcontroller to run its initialization sequences and then to trigger
the watchdog via the SPI.
The watchdog timer period can be selected via the watchdog timing bit field (WD_TIMER) and is in the range of
10 ms to 1000 ms. This setting is valid for both watchdog types.
The following watchdog timer periods are available:
•
•
•
•
•
•
•
WD setting 1: 10 ms
WD setting 2: 20 ms
WD setting 3: 50 ms
WD setting 4: 100 ms
WD setting 5: 200 ms (reset value)
WD setting 6: 500 ms
WD setting 7: 1000 ms
Datasheet
85
Rev.2.0
2022-05-06
INFINEON [ Infineon ]
