TLE9461ESV33 datasheet(84/140 Pages) INFINEON

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TLE9461ES V33

Lite CAN SBC Family

Supervision Functions

Datasheet

Rev.1.1

2019-09-27

12.2

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 functions can be selected and programmed in SBC Normal Mode. The configuration

stays unchanged in SBC Stop Mode.

Please refer to Table 24 to match the SBC Modes with the respective watchdog modes.

The watchdog timing is programmed via SPI command in the register WD_CTRL. 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 watchdog trigger

command is executed when the SPI command is interpreted, i.e. 3 clock cycles (typ. 3µs) after the transition

of Chip Select input (CSN) from Low to High.

When coming from SBC Init, SBC Restart Mode or in certain cases from SBC Stop Mode, the watchdog timer is

always started with a long open window. The long open window (tLW = 200ms) allows the microcontroller to

run its initialization sequences and then to trigger the watchdog via 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 10000 ms. This setting is valid for both watchdog types.

The following watchdog timer periods are available:

• WD Setting 1: 10ms

• WD Setting 2: 20ms

• WD Setting 3: 50ms

• WD Setting 4: 100ms

• WD Setting 5: 200ms

• WD Setting 6: 500ms

• WD Setting 7: 1000ms

• WD Setting 8: 10000ms

In case of a watchdog reset, SBC Restart or SBC Fail-Safe Mode is entered according to the configuration and

the SPI bits WD_FAIL are set. Once the RSTN goes High again the watchdog immediately starts with a long

open window the SBC enters automatically SBC Normal Mode.

Table 24

Watchdog Functionality by SBC Modes

SBC Mode

Watchdog Mode

Remarks

INIT Mode

Starts with Long Open

Window

Watchdog starts with Long Open Window after RSTN

is released

Normal Mode

WD Programmable

Window Watchdog, Time-Out watchdog or switched

Off for SBC Stop Mode

Stop Mode

Watchdog is fixed or Off

Sleep Mode

Off

SBC starts with Long Open Window when entering

SBC Normal Mode.

Restart Mode

Off

SBC starts with Long Open Window when entering

SBC Normal Mode.

TLE9461ESV33 Datasheet(PDF) 84 Page - Infineon Technologies AG

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