Specifications

BMA180

Preliminary data sheet

Bosch Sensortec

Rev. 1.0 Page 53 / - 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.

7.11.8 soft_reset

BMA180 is reset each time the value B6h is written to this byte. The effect is identical to power-

on reset. Control, status and image registers are reset to values stored in the EEPROM. After

soft_reset or power-on reset BMA180 comes up in normal mode or wake-up mode. It is not

possible to boot BMA180 to sleep mode.

No serial transaction should occur within 10µs after soft_reset command.

7.11.9 sleep

This bit turns the sensor IC in sleep mode, no acceleration measurements can be performed

any more, but control and image registers are not cleared.

When BMA180 is in sleep mode no operation can be performed without waking-up the sensor

IC by setting sleep=0 or soft_reset. As a consequence all write and read operations are

forbidden when the sensor IC is in sleep mode except command used to wake up the device or

soft_reset command.

After sleep mode removal, it takes 1ms to obtain stable acceleration values (>99% data

integrity). User must wait for 10ms before first EEPROM write. For the same reason, BMA180

must not be turned in sleep mode when any update_image, self_test or EEPROM write

procedure is on going.

Attention: This bit should not be set to “1”, when wake-up mode is enabled.

7.11.10 dis_wake_up

When dis_wake_up = 1, wake-up mode is disabled in order to avoid the fact that the ASIC may

enter into sleep mode before EEPROM writing is initiated.

7.11.11 unlock_ee

unlock_ee register allows access to the forbidden area of the EEPROM. Do not use it.

7.11.12 en_offset_x, en_offset_y, en_offset_z

These one-shot control bits enable the offset regulation for the corresponding axis. To regulate

all axis, it is necessary to enable the bits sequentially.

7.11.13 sel_t, sel_x, sel_y, sel_z

sel_* are used for internal purposes only. Do not use these bits.