Information

BMA280

Data sheet

Page 32

BST-BMA280-DS000-11 | Revision 1.8 | August 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.

The parameters (0x2A) tap_shock and (0x2A) tap_quiet apply to both single tap and double tap

detection, while (0x2A) tap_dur applies to double tap detection only. Within the duration of

(0x2A) tap_shock any slope exceeding (0x2B) tap_th after the first event is ignored. Contrary to

this, within the duration of (0x2A) tap_quiet no slope exceeding (0x2B) tap_th must occur,

otherwise the first event will be cancelled.

4.7.6.1 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.

Do not map single-tap to any INT pin if you do not want to use it.

4.7.6.2 Double tap detection

A 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 automatically cleared after a delay of 12.5 ms.

4.7.6.3 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 11:

Table 11: Selection of tap_dur

(0x2A)

tap_dur

length of tap_dur

000b

50 ms

001b

100 ms

010b

150 ms

011b

200 ms

100b

250 ms

101b

375 ms

110b

500 ms

111b

700 ms