BMA150 datasheet(14/56 Pages) BOSCH

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Data sheet

BMA150

Triaxial, digital acceleration sensor

Bosch Sensortec

Rev. 1.6

Page 14

30 October 2008

as copying and passing on to 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.

3.2 Interrupt settings

Five different types of interrupts can be programmed. When the corresponding criterion

becomes valid, the interrupt pin is triggered to a high level. All interrupt criteria are combined

and drive the interrupt pad with an Boolean <OR> condition.

Interrupt generations may be disturbed by changes of EEPROM, image or other control bits

because some of these bits influence the interrupt calculation. As a consequence, no write

sequence should occur when microprocessor is triggered by interrupt or the interrupt should be

deactivated on the microprocessor side when write sequences are operated.

Interrupt criteria are using digital code coming from digital filter output. As a consequence all

thresholds are scaled with range selection (section 3.1.3.2). Timings used for high acceleration

and low acceleration debouncing are absolute values (1 LSB of HG_dur and LG_dur registers

corresponds to 1 millisecond, timiming accuracy is proportional to oscillator accuracy = +/-10%),

thus it does not depend on selected bandwidth. Timings used for any motion interrupt and alert

detection are proportional to bandwidth settings (section 3.1.3).

3.2.1 Enable_LG:

This bit (address 0Bh, bit 0) enables the LG_thres criteria to generate an interrupt.

3.2.2 Enable_HG:

This bit (address 0Bh, bit 1) enables the HG_thres criteria to generate an interrupt.

3.2.3 Enable_adv_INT:

This bit (address 15h, bit 6) is used to disable advanced interrupt control bits (any_motion,

alert). If enable_adv_INT=0, writing to these bits has no effect on sensor IC function.

3.2.4 Any_motion:

This bit ((address 0Bh, bit 6)enables the any motion criteria to generate directly an interrupt. It

can not be turned on simultaneously with alert. This bit can be masked by enable_ adv_INT, the

value of this bit is ignored when enable_adv_INT=0 (section 3.2.3).

3.2.5 Alert:

If this bit (address 0Bh, bit 7) is at 1, the any_motion criterion will set BMA150 into alert mode

(section 3.2.9). This bit can be masked by enable_adv_INT, the value of this bit is ignored when

enable_adv_INT=0 (section 3.2.3).

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