3-AXIS ACCELEROMETER DIGITAL I/F

BMA250

Manufacturer Part NumberBMA250
Description3-AXIS ACCELEROMETER DIGITAL I/F
ManufacturerBosch Sensortec
Series-
BMA250 datasheets
 


Specifications of BMA250

Featured ProductBMA250 - Digital, Triaxial Acceleration SensorAxisX, Y, Z
Acceleration Range±2g, 4g, 8g, 16gSensitivity256LSB/g, 128LSB/g, 64LSB/g, 16LSB/g
Voltage - Supply1.62 V ~ 3.6 VOutput TypeI²C™, SPI™
Bandwidth8Hz ~ 1kHzInterfaceI²C, SPI
Mounting TypeSurface MountPackage / Case12-VQFN
Lead Free Status / Rohs StatusLead free / RoHS CompliantFor Use With828-1024 - BMA250 DAUGHTERCARD FOR DEV KIT
Other names828-1023-2  
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Page 19/74

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The meaning of both public and internal registers is the same for all acceleration measurement
ranges. Therefore, with measurement ranges other than ±2g, one or more lower significant bits
of the internal registers are lost when added to an acceleration value, or are set to zero when
the internal compensation value is computed. If a compensation value is too small or too big to
fit into the corresponding internal register, it is saturated to prevent an overflow error.
In a similar way the conversion of the internal register value to the public register value (10bit to
8bit) uses saturation.
Summarized, in dependence to the measurement range which has been set, the compensation
value, which has been written into the public register will correct the data output according to
figure 4.
e.g. ±2g range:
public register = 00000001b  add to acceleration data = ±7.8mg
public register = 00000010b  add to acceleration data = +15.6mg
public register = 00000101b  add to acceleration data = +39.1mg
The public registers are image registers of EEPROM registers. With each image update (see
section 4.7 Non-volatile memory for details) the contents of the non-volatile EEPROM registers
are written to the public registers. At any time the public register can be over-written by the user.
After changing the contents of the public registers by either an image update or manually, all
8bit values are widened to 10bit values and stored in the corresponding internal registers. In the
opposite direction, if the value of an internal register changes due to the computation performed
by a compensation algorithm, it is converted to an 8bit value and stored in the public register.
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.
BMA250
Data sheet
Figure 4: Principle of offset compensation
Page 19 / not for publishing
Bosch Sensortec
= +2LSB
= +4LSB
= +10LSB
03 March 2011