BMA150 datasheet(19/56 Pages) BOSCH

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Data sheet

BMA150

Triaxial, digital acceleration sensor

Bosch Sensortec

Rev. 1.6

Page 19

30 October 2008

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.

3.2.10 New_data_int

If this bit (address 15h, bit 5) is set to 1, an interrupt will be generated when all three axes

acceleration values are new, i.e. BMA150 updated all acceleration values after latest serial

read-out. Interrupt generated from new data detection is a latched one; microcontroller has to

write reset_INT at 1 after interrupt has been detected high (section 3.3.1). This interrupt is also

reset by any acceleration byte read procedure (read access to address 02h to 07h).

New data interrupt always occurs at the end of the Z-axis value update in the output register

(3kHz rate). Following figure shows two examples of X-axis read out and the corresponding

interrupt generation.

Figure 3: Explanation of new data interrupt.

left side - read out command of x-axis prior to next x-axis conversion

→ new data interrupt after completion of current conversion cycle after z-axis

conversion

right side - read out of x-axis send after x-axis conversion

→ new data interrupt at the end of next period when x axis has been updated

Please refer to chapter 8.1 for more details.

Note: When using the I2C interface for data transfer, the data read out phase can be longer than

330µs (depending on I2C clock frequency and the amount of data transmitted). Starting a new

data read out sequence may lead to the situation that the new_data_int may not be cleared right

in time. This must be considered and taken care of properly.

X-axis value read out

New data interrupt

X-axis value read out

New data interrupt

X-axis value read out

New data interrupt

X-axis value read out

New data interrupt

…

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