LPS22DF datasheet(12/54 Pages) STMICROELECTRONICS

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FIFO

The LPS22DF embeds 128 slots of 24-bit data FIFO to store the pressure output values. This allows consistent

power saving for the system, since the host processor does not need to continuously poll data from the sensor,

but it can wake up only when needed and burst the significant data out from the FIFO. This buffer can work

according to six different modes:

•

Bypass mode

•

FIFO mode

•

Continuous (Dynamic-Stream) mode

•

Continuous (Dynamic-Stream)-to-FIFO mode

•

Bypass-to-Continuous (Dynamic-Stream)

•

Bypass-to-FIFO mode

The FIFO buffer is enabled when a configuration different from all bits '0' are written in FIFO_CTRL (14h) and

each mode is selected by the TRIG_MODES bit and F_MODE[1:0] bits in FIFO_CTRL (14h). Programmable

FIFO threshold status, FIFO overrun events and the number of unread samples stored are available in the

FIFO_STATUS1 (25h) and FIFO_STATUS2 (26h) registers and can be set to generate dedicated interrupts on the

INT_DRDY pin using the CTRL_REG3 (12h) register.

FIFO_STATUS2 (26h)(FIFO_WTM_IA) goes to '1' when the number of unread samples (FIFO_STATUS1 (25h)

(FSS[7:0]) is greater than or equal to WTM[6:0] in FIFO_WTM (15h). If FIFO_WTM (15h)(WTM[6:0]) is equal to 0,

FIFO_STATUS2 (26h)(FIFO_WTM_IA) stays at '0'.

FIFO_STATUS2 (26h)(FIFO_OVR_IA) is equal to '1' if a FIFO slot is overwritten.

FIFO_STATUS1 (25h)(FSS[7:0]) contains stored data levels of unread samples; when FSS[7:0] is equal to

‘00000000’, FIFO is empty; when FSS[7:0] is equal to ‘10000000’, FIFO is full and the unread samples are 128.

LPS22DF

FIFO

DS13316 - Rev 1

page 12/54

LPS22DF Datenblatt(PDF) 12 Page - STMicroelectronics