BMA253
Data sheet
Page 24
Register (0x36) cal_trigger is a write-only register. Once triggered, the status of the fast
correction process is reflected in the status bit (0x36) cal_rdy. Bit (0x36) cal_rdy is ‘0’ while the
correction is in progress. Otherwise it is ‘1’. Bit (0x36) cal_rdy is ´0´ when (0x36) cal_trigger is
not ´00´.
For the 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 9:
Table 9: Offset target settings
(0x37)
offset_target_x/y/z
Target value
00b
01b
10b
11b
0g
+1g
-1g
0g
Fast compensation should not be used in combination with any of the low-power modes. In low-
power mode the conditions (availability of necessary data) for proper function of fast
compensation are not fulfilled.
4.5.3 Manual compensation
The contents of the public compensation registers (0x38, 0x39, 0x3A) offset_filt_x/y/z can be
set manually via the digital interface. It is recommended to write into these registers directly
after a new data interrupt has occurred in order not to disturb running offset computations.
Writing to the offset compensation registers is not allowed while the fast compensation
procedure is running.
4.5.4 Inline calibration
For certain applications, it is often desirable to calibrate the offset once and to store the
compensation values permanently. This can be achieved by using one of the aforementioned
offset compensation methods to determine the proper compensation values and then storing
these values permanently in the NVM. See section 4.6 Non-volatile memory for details of the
storing procedure.
Each time the device is reset, the compensation values are loaded from the non-volatile
memory into the image registers and used for offset compensation until they are possibly
overwritten using one of the other compensation methods.
BST-BMA253-DS000-01 | Revision 1.0 | August 2015
Bosch Sensortec
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Note: Specifications within this document are subject to change without notice.
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