Datasheet

Sensors
30 NXP Semiconductors
MMA8452Q
0x18: FF_MT_COUNT debounce register
This register sets the number of debounce sample counts for the event trigger.
This register sets the minimum number of debounce sample counts of continuously matching the detection condition user
selected for the freefall, motion event.
When the internal debounce counter reaches the FF_MT_COUNT value a freefall/motion event flag is set. The debounce counter
will never increase beyond the FF_MT_COUNT value. Time step used for the debounce sample count depends on the ODR
chosen and the oversampling mode as shown in Table 30.
0x18: FF_MT_COUNT register (read/write)
Bit
7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
D7 D6 D5 D4 D3 D2 D1 D0
Table 29. FF_MT_COUNT description
Field Description
D[7:0]
Count value. Default value: 0000_0000
Table 30. FF_MT_COUNT relationship with the ODR
ODR (Hz)
Max time range (s) Time step (ms)
Normal LPLN HighRes LP Normal LPLN HighRes LP
800 0.319 0.319 0.319 0.319 1.25 1.25 1.25 1.25
400 0.638 0.638 0.638 0.638 2.5 2.5 2.5 2.5
200 1.28 1.28 0.638 1.28 5 5 2.5 5
100 2.55 2.55 0.638 2.55 10 10 2.5 10
50 5.1 5.1 0.638 5.1 20 20 2.5 20
12.5 5.1 20.4 0.638 20.4 20 80 2.5 80
6.25 5.1 20.4 0.638 40.8 20 80 2.5 160
1.56 5.1 20.4 0.638 40.8 20 80 2.5 160