LPS25HB Datasheet, PDF (15/40 Pages) STMicroelectronics – MEMS pressure sensor: 260-1260 hPa absolute digital output barometer

LPS25HB
FIFO
bits of FIFO_CTRL (2Eh).The FIFO continues filling until it's full (32 slots of data for
pressure output). When full, the FIFO discards the older data as the new arrive. Once a
trigger event occurs, the FIFO starts operating in FIFO mode. A trigger event can be
configured in INTERRUPT_CFG (24h).
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 and the FIFO starts operating in Stream mode. A
trigger event can be configured in INTERRUPT_CFG (24h).
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 watermark defined by the
WTM_POINT[4:0] bits of FIFO_CTRL (2Eh) (refer to Table 8).
WTM_POINT[4:0]
00001
00011
00111
01111
11111
Table 8. Running average sample size
FIFO_MEAN_MODE sample size
2-sample moving average
4-sample moving average
8-sample moving average
16-sample moving average
32-sample moving average
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.
4.7
Bypass-to-FIFO mode
In Bypass-to-FIFO (F_MODE[2:0] in FIFO_CTRL (2Eh) set to '111'), the FIFO is in Bypass
mode until a trigger event occurs and the FIFO starts operating in FIFO mode. A trigger
event can be configured in INTERRUPT_CFG (24h).
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