BMA250 Bosch Sensortec, BMA250 Datasheet - Page 28

• Manufacturer Part Number: BMA250
• Description: 3-AXIS ACCELEROMETER DIGITAL I/F
• Manufacturer: Bosch Sensortec
• Series: -r

Specifications of BMA250

• Featured Product: BMA250 - Digital, Triaxial Acceleration Sensor
• Axis: X, Y, Z
• Acceleration Range: ±2g, 4g, 8g, 16g
• Sensitivity: 256LSB/g, 128LSB/g, 64LSB/g, 16LSB/g
• Voltage - Supply: 1.62 V ~ 3.6 V
• Output Type: I²C™, SPI™
• Bandwidth: 8Hz ~ 1kHz
• Interface: I²C, SPI
• Mounting Type: Surface Mount
• Package / Case: 12-VQFN
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With: 828-1024 - BMA250 DAUGHTERCARD FOR DEV KIT
• Other names: 828-1023-2

4.8.6.1 Single tap detection
A single tap is detected and the single tap interrupt is generated after the combined durations of
(0x2A) tap_shock and (0x2A) tap_quiet, if the corresponding slope conditions are fulfilled. The
interrupt is cleared after a delay of 12.5 ms.
4.8.6.2 Double tap detection
A double tap is detected and the double tap interrupt is generated if an event fulfilling the
conditions for a single tap occurs within the set duration in (0x2A) tap_dur after the completion
of the first tap event. The interrupt is cleared after a delay of 12.5 ms.
4.8.6.3 Selecting the timing of tap detection
For each of parameters (0x2A) tap_shock and (0x2A) tap_quiet two values are selectable. By
writing ´0´ (´1´) to bit (0x2A) tap_shock the duration of (0x2A) tap_shock is set to 50 ms (75 ms).
By writing ´0´ (´1´) to bit (0x2A) tap_quiet the duration of (0x2A) tap_quiet is set to 30 ms (20
ms).
The length of (0x2A) tap_dur can be selected by setting the (0x2A) tap_dur bits according to
table 15:
4.8.6.4 Axis and sign information of tap sensing
The sign of the slope of the first tap which triggered the interrupt is stored in bit (0x0B) tap_sign
(´0´ means positive sign, ´1´ means negative sign). The value of this bit persists after clearing
the interrupt.
The axis which triggered the interrupt is indicated by bits (0x0B) tap_first_x, (0x0B) tap_first_y,
and (0x0B) tap_first_z.
The bit corresponding to the triggering axis contains a ´1´ while the other bits hold a ´0´. These
bits are cleared together with clearing the interrupt status.
Rev. 1.0
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
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.
tap_dur
(0x2A)
000b
001b
010b
011b
100b
101b
110b
111b
Table 15: Selection of tap_dur
Page 28 / not for publishing
Data sheet
BMA250
length of tap_dur
200 ms
250 ms
100 ms
150 ms
375 ms
500 ms
700 ms
50 ms
Bosch Sensortec
03 March 2011