L9779WD-SPI datasheet(107/141 Pages) STMICROELECTRONICS

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L9779WD-SPI

Functional description

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to 0ms, then the ERROR COUNTER is incremented by one even if a correct response is

received within the time window. The maximum error reaction time is given by: maximum

response-time, response at the end of a time-window and ERROR COUNTER 0 ' 5 *

(100ms + 12.6ms) = 563ms.

Note that clock-tolerances have to be taken into account additionally.

Watchdog influence on power up/down management unit

The watchdog AB1 counter is increased every time the watchdog error counter is EC > 7,

which means it has an overflow. If the AB1 counter reaches the value of 7 and a further error

occurs, the system will be switched off same as it would happen in case of the already

existing PWL_EN_TIMEOUTN signal.

Watchdog influence on smart power reset

WDA has influence on the RST pin only if the WDA error counter is EC > 7 and the resulting

reset signal "WD_RST" is enabled by SPI configuration bit "INIT_WDR" in WR_RESPTIME

command.

Watchdog influence on Lsa functions (Section 6.8.1)

For LSa functions OUT1, OUT2, OUT3, OUT4 (not OUT5).

In case of an internal WDA event (e.g. the WDA error counter is EC > 4 which results in the

signal WDA_INT being set) or in case of the WDA pin being pulled low externally, the output

stages OUT1, OUT2, OUT3, OUT4 go to inactive state.

Watchdog influence on LSd functions OUT13, OUT14 (starter relay drivers)

Section 6.8.4

In case of an internal WDA event (e.g. the WDA error counter is EC > 4 which results in the

signal WDA_INT being set) or in case of the WDA pin being pulled low externally, the

OUT13 and OUT14 stages go to inactive state after the time delay THOLD if the WDA event

is still active.

Watchdog influence on Ignition drivers IGN1, IGN2, IGN3, IGN4

In case of an internal WDA event (e.g. the WDA error counter is EC > 4 which results in the

signal WDA_INT being set) or in case of the WDA pin is pulled low externally, the output

stages go to inactive state.

Watchdog influence on CAN transceiver

The WDA has influence on the CAN if the SPI configuration bit CAN_TDI is set.

Once the CAN_TDI bit is set, in case of an internal WDA event (e.g. the WDA error counter

is EC > 4 which results in the signal WDA_INT being set) or in case of the WDA pin is pulled

low externally, the CAN goes to receive-only mode (RxOnly).

L9779WD-SPI Datasheet(PDF) 107 Page - STMicroelectronics