5.3

Continuous mode

Continuous mode (FIFO_CTRL (2Eh) (FMODE[2:0] = 110) provides a continuous FIFO update: when 32 unread

samples are stored in memory, as new data arrives the oldest data is discarded and overwritten by the newer.

A FIFO threshold flag FIFO_SRC (2Fh)(FTH) is asserted when the number of unread samples in FIFO is greater

than or equal to FIFO_CTRL (2Eh)(FTH4:0).

It is possible to route FIFO_SRC (2Fh)(FTH) to the INT1 pin by writing the INT1_FTH bit to ‘1’ in register

INT1_CTRL (21h) or to the INT2 pin by writing the INT2_FTH bit to ‘1’ in register INT2_CTRL (22h).

A full-flag interrupt can be enabled (INT1_CTRL (21h) (INT_ FSS5)= '1' or INT2_CTRL (22h) (INT_ FSS5) = '1')

when the FIFO becomes saturated and in order to read the contents all at once. If an overrun occurs, the oldest

sample in FIFO is overwritten and the OVRN flag in FIFO_SRC (2Fh) 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_SRC (2Fh) (FSS[5:0]).

IIS3DHHC

Continuous mode

DS12292 - Rev 3

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