L9680 datasheet(196/277 Pages) STMICROELECTRONICS

Teilenummer	L9680

Bauteilbeschribung	Automotive advanced airbag IC for mid/high end applications

PDF	277 Pages

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Hersteller	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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196 / 277 page

Safing logic

L9680

196/277

DocID029257 Rev 1

Safing logic

12.1

Safing logic overview

The integrated safing logic uses data from on-board and remote locations by decoding the

various SPI communications between the interfaces and the main microcontroller. The

safing logic has several programmable features enabling its ability to decode SPI

transmissions and can process data from up to 16 sensors. The operating mode involves

simple symmetrical data threshold comparisons, with the use of symmetrical or

asymmetrical counters. A high level diagram is shown in the figure below. Please note that

this top-level diagram is simplified, and references more detailed flowcharts to show a)

message decoding, b) valid data limits, c) effects of the 'combine' function, d) comparison to

thresholds and arming, and e) the setting of the 'compare complete bit. Four independent

arming outputs, ARM1INT, ARM2INT, ARM3INT and ARM4INT, are also mapped internally

to any of the integrated squib drivers.

Figure 50. Top level safing engine flow chart

L9680 Datenblatt(PDF) 196 Page - STMicroelectronics