BMC150 datasheet(59/142 Pages) BOSCH

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Datasheet

eCompass BMC150

Page 59

BST-BMC150-DS000-04 | Revision 1.0 | July 2014

Bosch Sensortec

third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

Note: Specifications within this document are subject to change without notice. Not intended for publication.

4.9.4 Low-threshold interrupt

When the data registers’ (DATAX, DATAY and DATAZ) values drop below the threshold level

defined by the “Low Threshold register (0x4F), the corresponding interrupt status bits for those

axes are set (“Low Int X”, “Low Int Y” and “Low Int Z” in register 0x4A). This is done for each

axis independently. Please note that the X and Y axis value for overflow is -4096. However, no

interrupt is generated on these values. See chapter 4.9.6 for more information on overflow.

Hereby, one bit in “Low Threshold” corresponds to roughly 6µT (not exactly, as the raw

magnetic field values DATAX, DATAY and DATAZ are not temperature compensated).

The Low-threshold interrupt is issued on INT3 pin when one or more values of the data registers

DATAX, DATAY and DATAZ drop below the threshold level defined by the “Low Threshold”

generation:

Result =

(DATAX < “Low Threshold” x 16) AND “Low Int X en” is “0” OR

(DATAY < “Low Threshold” x 16) AND “Low Int Y en” is “0” OR

(DATAZ < “Low Threshold” x 16) AND “Low Int Z en” is “0”

Note: Threshold interrupt enable bits (“Low INT [XYZ] en”) are active low and “1” (disabled) by

default.

Figure 16: Low-threshold interrupt function

Low threshold

measurements

INT3 pin (non-latched)

INT3 pin (latched)

Read interrupt status

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