MMA8452QR1 Freescale Semiconductor, MMA8452QR1 Datasheet - Page 37

• Manufacturer Part Number: MMA8452QR1
• Description: Board Mount Accelerometers LOW G 3-AXIS 12BT EX VLT
• Manufacturer: Freescale Semiconductor

Specifications of MMA8452QR1

• Sensing Axis: X, Y, Z
• Acceleration: 2 g, 4 g, 8 g
• Digital Output - Number Of Bits: 8 bit, 12 bit
• Supply Voltage (max): 3.6 V
• Supply Voltage (min): 1.95 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Digital Output - Bus Interface: I2C
• Shutdown: Yes
• Sensitivity: 256 count/g, 512 count/g, 1024 count/g
• Package / Case: QFN-16
• Output Type: Digital
• Rohs Compliant: Yes
• Peak Reflow Compatible (260 C): Yes
• Acceleration Range: ± 2g, ± 4g, ± 8g
• No. Of Axes: 3
• Ic Interface Type: I2C
• Sensor Case Style: QFN
• No. Of Pins: 16
• Supply Voltage Range: 1.95V To 3.6V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table 38. PULSE_THSX Description
0x23 - 0x25: PULSE_THSX, Y, Z Pulse Threshold for X, Y & Z Registers
registers define the threshold which is used by the system to start the pulse detection procedure.
0x24 PULSE_THSY Register (Read/Write)
Table 40. PULSE_THSZ Description
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
0x26 PULSE_TMLT Register (Read/Write)
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.
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 39. PULSE_THSY Description
Table 41. PULSE_TMLT Description
Sensors
Freescale Semiconductor
0x23 PULSE_THSX Register (Read/Write)
0x25 PULSE_THSZ Register (Read/Write)
The pulse threshold can be set separately for the X, Y and Z axes. The PULSE_THSX, PULSE_THSY and PULSE_THSZ
The threshold values range from 1 to 127 with steps of 0.63g/LSB at a fixed 8g acceleration range, thus the minimum
The bits TMLT7 through TMLT0 define the maximum time interval that can elapse between the start of the acceleration on the
The minimum time step for the pulse time limit is defined in
TMLT7
Bit 7
Bit 7
Bit 7
Bit 7
THSX[6:0]
0
THSY[6:0]
TMLT[7:0]
0
0
THSZ[6:0]
Table 42. Time Step for PULSE Time Limit (Reg 0x0F) Pulse_LPF_EN = 1
ODR (Hz)
12.5
6.25
1.56
800
400
200
100
50
THSY6
TMLT6
THSX6
THSZ6
Bit 6
Bit 6
Bit 6
Bit 6
Normal
Pulse Threshold on X-axis. Default value: 000_0000.
Pulse Threshold on Y-axis. Default value: 000_0000.
Pulse Time Limit. Default value: 0000_0000.
0.319
0.638
Pulse Threshold on Z-axis. Default value: 000_0000.
1.28
2.55
5.1
5.1
5.1
5.1
Max Time Range (s)
THSY5
THSX5
TMLT5
THSZ5
LPLN
0.319
0.638
Bit 5
Bit 5
1.28
2.55
20.4
20.4
20.4
Bit 5
Bit 5
5.1
HighRes
0.319
0.638
0.638
0.638
0.638
0.638
0.638
0.638
THSX4
THSY4
THSZ4
TMLT4
Bit 4
Bit 4
Bit 4
Bit 4
Table 42
0.319
0.638
1.28
2.55
20.4
40.8
40.8
5.1
LP
THSX3
THSY3
THSZ3
TMLT3
Bit 3
Bit 3
Bit 3
Bit 3
and
Normal
1.25
2.5
Table
10
20
20
20
20
5
43. Maximum time for a given ODR and
THSX2
THSZ2
THSY2
TMLT2
Bit 2
Bit 2
LPLN
Bit 2
Bit 2
1.25
2.5
Time Step (ms)
10
20
80
80
80
5
HighRes
1.25
2.5
2.5
2.5
2.5
2.5
2.5
2.5
THSX1
THSZ1
THSY1
TMLT1
Bit 1
Bit 1
Bit 1
Bit 1
1.25
160
160
2.5
LP
10
20
80
5
MMA8452Q
THSX0
THSZ0
THSY0
TMLT0
Bit 0
Bit 0
Bit 0
Bit 0
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