BMA250 Bosch Sensortec, BMA250 Datasheet - Page 19
Manufacturer Part Number
3-AXIS ACCELEROMETER DIGITAL I/F
Specifications of BMA250
BMA250 - Digital, Triaxial Acceleration Sensor
X, Y, Z
±2g, 4g, 8g, 16g
256LSB/g, 128LSB/g, 64LSB/g, 16LSB/g
Voltage - Supply
1.62 V ~ 3.6 V
8Hz ~ 1kHz
Package / Case
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
For Use With
828-1024 - BMA250 DAUGHTERCARD FOR DEV KIT
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
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.
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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.
Figure 4: Principle of offset compensation
Page 19 / not for publishing
03 March 2011