LSM6DS33 Datasheet, PDF (25/77 Pages) STMicroelectronics – iNEMO inertial module: always-on 3D accelerometer and 3D gyroscope

LSM6DS33
Functionality
5.4.4
5.4.5
5.4.6
A FIFO threshold flag FIFO_STATUS2 (3Bh)(FTH) is asserted when the number of unread
samples in FIFO is greater than or equal to FIFO_CTRL1 (06h) and FIFO_CTRL2
(07h)(FTH [11:0]).
It is possible to route FIFO_STATUS2 (3Bh) (FTH) to the INT1 pin by writing in register
INT1_CTRL (0Dh) (INT1_FTH) = ‘1’ or to the INT2 pin by writing in register INT2_CTRL
(0Eh) (INT2_FTH) = ‘1’.
A full-flag interrupt can be enabled, INT1_CTRL (0Dh) (INT_ FULL_FLAG) = '1', in order to
indicate FIFO saturation and eventually read its content all at once.
If an overrun occurs, at least one of the oldest samples in FIFO has been overwritten and
the OVER_RUN flag in FIFO_STATUS2 (3Bh) is asserted.
In order to empty the FIFO before it is full, it is also possible to pull from FIFO the number of
unread samples available in FIFO_STATUS1 (3Ah) and FIFO_STATUS2 (3Bh)
(DIFF_FIFO[11:0]).
Continuous-to-FIFO mode
In Continuous-to-FIFO mode (FIFO_CTRL5 (0Ah) (FIFO_MODE_[2:0] = 011), FIFO
behavior changes according to the trigger event detected in one of the following interrupt
registers FUNC_SRC (53h), TAP_SRC (1Ch), WAKE_UP_SRC (1Bh) and D6D_SRC
(1Dh).
When the selected trigger bit is equal to '1', FIFO operates in FIFO mode.
When the selected trigger bit is equal to '0', FIFO operates in Continuous mode.
Bypass-to-Continuous mode
In Bypass-to-Continuous mode (FIFO_CTRL5 (0Ah) (FIFO_MODE_[2:0] = '100'), data
measurement storage inside FIFO operates in Continuous mode when selected triggers in
one of the following interrupt registers FUNC_SRC (53h), TAP_SRC (1Ch),
WAKE_UP_SRC (1Bh) and D6D_SRC (1Dh) are equal to '1', otherwise FIFO content is
reset (Bypass mode).
FIFO reading procedure
The data stored in FIFO are accessible from dedicated registers (FIFO_DATA_OUT_L
(3Eh) and FIFO_DATA_OUT_H (3Fh)) and each FIFO sample is composed of 16 bits.
All FIFO status registers (FIFO_STATUS1 (3Ah), FIFO_STATUS2 (3Bh), FIFO_STATUS3
(3Ch), FIFO_STATUS4 (3Dh)) can be read at the start of a reading operation, minimizing
the intervention of the application processor.
Saving data in the FIFO buffer is organized in four FIFO data sets consisting of 6 bytes
each:
The 1^st FIFO data set is reserved for gyroscope data;
The 2^nd FIFO data set is reserved for accelerometer data;
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