BMA020 Bosch Sensortec, BMA020 Datasheet - Page 15

• Manufacturer Part Number: BMA020
• Description: 3-AXIS ACCELEROMETER DIGITAL I/F
• Manufacturer: Bosch Sensortec

Specifications of BMA020

• Axis: X, Y, Z
• Acceleration Range: ± 2g, 4g, 8g
• Sensitivity: 256LSB/g, 128LSB/g, 64LSB/g
• Voltage - Supply: 2 V ~ 3.6 V
• Output Type: Digital
• Bandwidth: 3kHz
• Interface: I²C, SPI
• Mounting Type: Surface Mount
• Package / Case: 12-LGA
• For Use With: 828-1014 - BMA020 TRIBOX DEMO BOARD W/USB828-1008 - BMA020 DAUGHTERCARD FOR DEV KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 828-1000-2

3.2.8 HG_thres, HG_hyst, HG_dur, counter_HG
HG_thres (address 0Eh, bits 7-0 / high-g threshold) and HG_hyst (address 11h, bits 5-3 / high-g
threshold hysteresis) define the high-G level and its associated hysteresis. HG_dur (high-g
threshold qualification duration) and counter_HG (address 0Bh, bits 5 and 4 / high-g counter
down register) are used for debouncing the high-g criteria.
Threshold and duration codes define a criterion for interrupt generation when absolute value of
acceleration is high for long enough duration.
The data format is unsigned integer.
HG_threshold criterion_x is true if
HG_threshold interrupt is set if
HG_threshold criterion_x is false if |acc_x | < (HG_thres - 32*HG_hyst) / 255 * range
HG_threshold interrupt is reset if
HG_thres and HG_hyst codes must be chosen to have (HG_thres - 32*HG_hyst) > 0.
When HG_thres criterion becomes active, a counter is incremented by 1 LSB/ms. When the
high-g acceleration interrupt counter value equals (HG_dur+1), an interrupt is generated.
Depending on counter_HG register value, the counter could also be reset or count down when
HG_thres criterion is false.
Table 7: Description of debouncing counter_HG
If latch_INT=0, the interrupt is not a latched interrupt and then it is reset as soon as HG_thres
criterion becomes false. When interrupt occurs, the interrupt counter is reset.
Rev. 1.2
© 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.
counter_HG<1:0> High acceleration interrupt counter status when
00
01
10
11
Digital, triaxial acceleration sensor
HG_thres criterion is false
Count down by 1 LSB/ms
Count down by 2 LSB/ms
Count down by 3 LSB/ms
|acc_x |
(HG_thres
HG_thres criterion_z) AND interrupt counter = (HG_dur+1)
NOT(HG_thres criterion_x OR HG_thres criterion_y OR
HG_thres criterion_z)
reset
Data sheet
BMA020
Page 15
≥
HG_thres / 255 * range
criterion_x
OR
HG_thres
Bosch Sensortec
criterion_y
30 May 2008
OR