LPS27HHTW datasheet(12/55 Pages) STMICROELECTRONICS

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FIFO

The LPS27HHTW embeds 128 slots of 40-bit data FIFO to store the pressure and temperature 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 (13h) and

each mode is selected by the TRIG_MODES bit and F_MODE[1:0] bits in FIFO_CTRL (13h). 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 pad 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 (14h). If FIFO_WTM (14h)(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.

LPS27HHTW

FIFO

DS13489 - Rev 1

page 12/55

LPS27HHTW Arkusz danych(PDF) 12 Page - STMicroelectronics