Specifications

BMA180
Preliminary data sheet
Bosch Sensortec
Rev. 1.0 Page 51 / - proprietary information - 06 March 2009
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Specifications within this document are preliminary and subject to change without notice. Document is not intended for publication.
Example:
Measured sensitivity is changed by -1% from +25°C to +85°C. This is equivalent to -2% for full
temperature range. Thus a correction of +2% for full temperature range is necessary. This can
be achieved by choosing tcs <3:0> = “12” or 1100b.
7.11 Control registers description
All single control bits are active at 1, a truth table is provided for commands coded on more than
1 bit.
7.11.1 st_damp
When this bit is set at 1, the damping factor is considered for self-test result (turned on by st0
bit, which makes MEMs electrode moving). This bit should be set before starting the self-test
sequence.
This bit can be masked by adv_int (the value of this bit is ignored when adv_int = 0).
7.11.2 reset_int
This is a one-shot control bit. The behaviour of reset_int is as follows:
a) it is accepted if the appropriate interrupt is latched and generated. In this case, reset_int
event resets the interrupt state to not generate.
b) it is ignored if the appropriate interrupt is not latched or if this one is latched but not
generated.
7.11.3 update_image
When this bit is set to 1b, an image update procedure is started: all EEPROM content is copied
to image registers and the bit update_image is turned to 0 when the procedure is finished.
No write or read to image registers and no EEPROM write is allowed during the update from
EEPROM.
An automatic update image procedure also occurs:
a) after Power On reset
b) after soft_reset is issued via the serial interface.
7.11.4 ee_w
This bit must first be written to 1 to be able to write anything into image registers (20h .. 3Bh).
I
2
C acknowledgement procedure for protected/non-protected area:
a) I
2
C slave address: if correct, BMA180 sets acknowledge.
b) I
2
C register address (I
2
C write): BMA180 sets acknowledge for both unprotected and
protected registers.
c) I
2
C write data (I
2
C write): BMA180 sets acknowledge for both unprotected and protected
registers; no write is done for protected register.
d) I
2
C read data (I
2
C read): acknowledge is set by a master; no error detection is possible.
After power on reset or soft reset, ee_w = 0.