Datasheet

Data Sheet
BMA456
Page 30
BST-BMA456-DS000-01 | Version 1.1 | October 2017 Bosch Sensortec
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Note: Specifications within this document are subject to change without notice.
FIFO synchronization with external interrupts
External interrupts may be synchronized into the FIFO data. For this operation mode the
FIFO_CONFIG_1.fifo_tag_int1_en and FIFO_CONFIG_1.fifo_tag_int2_en need to be enabled, as well
as INT1_IO_CTRL.input_en and INT2_IO_CTRL.input_en. The fh_ext field in FIFO header will then
be set according to the signal at the INT1/INT2 inputs.
FIFO Interrupts
The FIFO supports two interrupts, a FIFO full interrupt and a watermark interrupt:
 The FIFO full interrupt is issued when the FIFO fill level is above the full threshold. The full
threshold is reached just before the last two frames are stored in the FIFO.
 The FIFO watermark is issued when the FIFO fill level is equal or above a watermark defined
in Register FIFO_WTM_0 and FIFO_WTM_1.
In order to enable/use the FIFO full or watermark interrupts map them on the desired interrupt pin via
INT_MAP_DATA.
Both interrupts are suppressed when a read operation on the Register FIFO_DATA is ongoing.
Latched FIFO interrupts will only get cleared, if the status register gets read and the fill level is below
the corresponding FIFO interrupt (full or watermark).
FIFO Reset
The user can trigger a FIFO reset by writing the command fifo_flash (0xB0) in CMD.
Automatic resets are only performed in the following cases:
 A sensor is enabled or disabled in headerless mode
 A transition between headerless and headermode or vice versa has occurred.
 Size of auxiliary sensor data in a frame changed in header or headerless mode