L9177ATR datasheet(35/55 Pages) STMICROELECTRONICS

Part #	L9177ATR

Description	Automotive engine management control IC for small engines

PDF	55 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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35 / 55 page

3.5.8

VRS diagnosis

VRS block enters diagnosis phase on request via SPI and then generates a Fault bit. If the fault exceeds the Tdgc

filter time of 30 µs ±20 %, it is latched. The latched fault is cleared on request via SPI. The VRS diagnostic can

only be activated when the phonic wheel is in stop condition.

Figure 27. VRS diagnosis I-V relationship

GAPGPS00611

3.6

VRS interface

3.6.1

Function characteristic

The flying wheel interface is an interface between the µP and the flying wheel sensor: it conditions signal coming

from magnetic pick-up sensor or hall effect sensor and feeds the digital signal to microcontroller that extracts

flying wheel rotational position, angular speed and acceleration.

Figure 28. VRS typical characteristics

GAPGPS00571

IN +

VRS

IN -

L9177A

VRS interface

DS12175 - Rev 5

page 35/55

L9177ATR Datasheet(PDF) 35 Page - STMicroelectronics