Data Sheet

FIFO LPS25HB
20/50 DocID027112 Rev 4
4.5 Bypass-to-Stream mode
In Bypass-to-Stream mode (F_MODE[2:0] in FIFO_CTRL (2Eh) set to '100'), the FIFO is in
Bypass mode until a trigger event occurs which is based on the IA bit in INT_SOURCE
(25h) and the FIFO starts operating in Stream mode. A trigger event can be configured in
INTERRUPT_CFG (24h).
Figure 10. Bypass-to-Stream mode
4.6 FIFO Mean mode
In FIFO Mean mode (F_MODE[2:0] in FIFO_CTRL (2Eh) set to '110'), the pressure data are
not directly sent to the output register but are first stored in the FIFO to calculate the
average. In this mode the FIFO is used to implement a moving average of the pressure data
with a 2, 4, 8, 16 or 32 sample set by changing the FIFO Mean mode sample size defined by
the WTM_POINT[4:0] bits of FIFO_CTRL (2Eh) (refer to Table 9).
There are two possible ways of providing the output pressure data averaged by FIFO:
1. If the FIFO_MEAN_DEC bit in CTRL_REG2 (21h) is set to '0', the output is at the same
ODR of the data coming from the sensor;
2. If the FIFO_MEAN_DEC bit in CTRL_REG2 (21h) is set to '1', the output is decimated
(@1 Hz when ODR = 4 or 2; @1.04 Hz when ODR=3).
Please note that when using the FIFO Mean mode it is not possible to access the FIFO
content.
Table 9.
Running average sample size
WTM_POINT[4:0] FIFO Mean mode sample size
00001 2-sample moving average
00011 4-sample moving average
00111 8-sample moving average
01111 16-sample moving average
11111 3 2 - s a m p l e m o v i n g a v e r a g e