Datasheet

MMA8652FC
Sensors
48 Freescale Semiconductor, Inc.
6.10.4 0x26: PULSE_TMLT Pulse Time Window 1 register
Bits TMLT7 – TMLT0 define the maximum time interval that can elapse between the start of the acceleration on the selected axis
exceeding the specified threshold, and the end when the acceleration on the selected axis must go below the specified threshold
to be considered a valid pulse.
The minimum time step for the pulse time limit is defined in Ta ble 79 and Table 80.
• Maximum time for a given ODR and Oversampling mode is the time step pulse multiplied by 255.
• The time steps available are dependent on the Oversampling mode and whether the pulse low-pass filter option is enabled
or not.
• The pulse low-pass filter is set in Register 0x0F.
Table 77.
0x26 PULSE_TMLT register (Read/Write)
Back to Register Address Map
Bit
7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
TMLT7 TMLT6 TMLT5 TMLT4 TMLT3 TMLT2 TMLT1 TMLT0
Table 78. PULSE_TMLT register
Bit(s) Field Description
7–0 TMLT[7:0]
Pulse Time Limit
0000_0000 (default)
Table 79. Time Step for PULSE time limit (Reg 0x0F) Pulse_LPF_EN = 1
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
Table 80. Time Step for PULSE Time Limit (Reg 0x0F) Pulse_LPF_EN = 0
ODR (Hz)
Max Time Range (s) Time Step (ms)
Normal LPLN HighRes LP Normal LPLN HighRes LP
800 0.159 0.159 0.159 0.159 0.625 0.625 0.625 0.625
400 0.159 0.159 0.159 0.319 0.625 0.625 0.625 1.25
200 0.319 0.319 0.159 0.638 1.25 1.25 0.625 2.5
100 0.638 0.638 0.159 1.28 2.5 2.5 0.625 5
50 1.28 1.28 0.159 2.55 5 5 0.625 10
12.5 1.28 5.1 0.159 10.2 5 20 0.625 40
6.25 1.28 5.1 0.159 10.2 5 20 0.625 40
1.56 1.28 5.1 0.159 10.2 5 20 0.625 40