BMA222 Datasheet, PDF (19/74 Pages) List of Unclassifed Manufacturers – Digital, triaxial acceleration sensor

BMA222
Data sheet
Bosch Sensortec
bit_11
bit_10
bit_9
bit_8
bit_7
bit_6
bit_5
bit_4
bit_3
bit_2
bit_1
bit_0
public register
add to
acceleration data
offset_filt_x/y/z
or
offset_unfilt_x/y/z
in range
±2g
±4g
±8g
±16g
sign (msb)
500mg
250mg
125mg
range
62.5mg ^conversion
31.3mg
15.6mg
7.8mg (lsb)
sign (msb)
500mg
250mg
125mg
62.5mg
31.3mg
15.6mg
sign (msb)
500mg
250mg
125mg
62.5mg
31.3mg
sign (msb)
500mg
250mg
125mg
62.5mg
sign (msb)
500mg
250mg
125mg
Figure 4: Principle of offset compensation
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 = ±0mg
public register = 00000010b  add to acceleration data = +15.6mg
public register = 00000101b  add to acceleration data = +31.3mg
= ±0LSB
= +1LSB
= +2LSB
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
is 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
values are 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 stored in the public register.
For slow and fast offset compensation, the compensation target can be chosen by setting the
bits (0x37) offset_target_x, (0x37) offset_target_y, and (0x37) offset_target_z according to table
11:
Rev. 1.15
Page 19 / not for publishing
31 - May - 2012
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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.