Specifications

BMA180

Preliminary data sheet

Bosch Sensortec

Rev. 1.0 Page 16 / - proprietary information - 06 March 2009

as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.

Specifications within this document are preliminary and subject to change without notice. Document is not intended for publication.

4 Operation modes

BMA180 is able to work in different operation modes:

- Standard modes a) low power mode (current optimized normal mode)

b) 3 low noise modes (noise optimized normal modes)

- Sleep mode device is “sleeping”; power consumption is at minimum

- Wake up mode device is “sleeping” for a certain time, waking up for a

certain time, falling back to sleep, etc. This mode is an

intermediate mode to the standard modes and sleep mode.

All modes mentioned above are shortly described below. A detailed description of the

configuration of these modes is given in 7.8.3.

4.1 Normal operational mode

In normal operational mode the sensor IC can be addressed via digital interface. Data and

status registers can be read out and control registers and EEPROM values can be read and

changed. In parallel to normal operation the user has the option to activate several internal logic

paths and set criteria to trigger the interrupt pin.

BMA180 is providing 4 different sub-modes in normal operation mode (see also 7.8.3).

• low power mode

• low noise mode

• super-low noise mode and

• ultra-low noise mode (similar to super-low noise mode, but reduced bandwidth)

BMA180 is designed to enable low current consumption of 575µA in low power mode, by

providing at the same time a very high resolution of at least 12bit. In the 3 low-noise modes,

current is higher, but resolution is up to 14bit (depending on selected bandwidth).

A self-test procedure can be started in operational mode for testing of the complete signal

evaluation path including the micro-machined sensor IC structure, the evaluation ASIC and the

physical connection to the host system.

4.2 Sleep mode

4.2.1 General information

Sleep mode is activated by setting a special control bit. In sleep mode reduced communication

to the sensor IC is possible – all read and write commands are forbidden

except command

used to wake up the device or soft_reset command. The recommended command to switch to

operational mode is the wake-up call.

Sleep mode could be used,

a) if the sensor is only used part-time. In this case, the µC is deactivating and

reactivating BMA180 according to its usage (duty cycling = switching between sleep

and standard mode).