Freescale Semiconductor Energy Efficient Solutions Xtrinsic MMA8452Q, Технические данные: Техническая информация

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MMA8452Q
Sensors
Freescale Semiconductor, Inc.
33
0x23 - 0x25: PULSE_THSX, Y, Z Pulse Threshold for X, Y & Z Registers
The pulse threshold can be set separately for the X, Y and Z axes. The PULSE_THSX, PULSE_THSY and PULSE_THSZ
registers define the threshold which is used by the system to start the pulse detection procedure.
The threshold values range from 1 to 127 with steps of 0.63g/LSB at a fixed 8g acceleration range, thus the minimum
resolution is always fixed at 0.063g/LSB. If the Low-Noise bit in Register 0x2A is set then the maximum threshold will be 4g. The
PULSE_THSX, PULSE_THSY and PULSE_THSZ registers define the threshold which is used by the system to start the pulse
detection procedure. The threshold value is expressed over 7-bits as an unsigned number.
0x26: PULSE_TMLT Pulse Time Window 1 Register
The bits TMLT7 through 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 Table 42 and Table 43 . 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.
0x23: PULSE_THSX Register (Read/Write)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0 THSX6 THSX5 THSX4 THSX3 THSX2 THSX1 THSX0
Table 38. PULSE_THSX Description
THSX[6:0] Pulse Threshold on X-axis. Default value: 000_0000.
0x24: PULSE_THSY Register (Read/Write)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0 THSY6 THSY5 THSY4 THSY3 THSY2 THSY1 THSY0
Table 39. PULSE_THSY Description
THSY[6:0]
Pulse Threshold on Y-axis. Default value: 000_0000.
0x25: PULSE_THSZ Register (Read/Write)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0 THSZ6 THSZ5 THSZ4 THSZ3 THSZ2 THSZ1 THSZ0
Table 40. PULSE_THSZ Description
THSZ[6:0]
Pulse Threshold on Z-axis. Default value: 000_0000.
0x26: PULSE_TMLT Register (Read/Write)
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 41. PULSE_TMLT Description
TMLT[7:0]
Pulse Time Limit. Default value: 0000_0000.
Table 42. 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