MMA8452QR1 Freescale Semiconductor, MMA8452QR1 Datasheet - Page 34

• 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

6.4
the motion detection except that high pass filtered data is compared. There is an option to disable the high pass filter through the
function. In this case the behavior is the same as the motion detection. This allows for the device to have 2 motion detection
functions.
0x1D: Transient_CFG Register
acceleration threshold is exceeded. The TRANSIENT_CFG register is used to enable the transient interrupt generation
mechanism for the 3 axes (X, Y, Z) of acceleration. There is also an option to bypass the high pass filter. When the high pass
filter is bypassed, the function behaves similar to the motion detection.
0x1E TRANSIENT_SRC Register
register is read it clears the interrupt for the transient detection. When new events arrive while EA = 1, additional *TRANSE bits
may get set, and the corresponding *_Trans_Pol flag become updated. However no *TRANSE bit may get cleared before the
TRANSIENT_SRC register is read.
Table 32. TRANSIENT_SRC Description
register, all bits get cleared.
Table 31. TRANSIENT_CFG Description
34
0x1E TRANSIENT_SRC Register (Read Only)
MMA8452Q
0x1D TRANSIENT_CFG Register (Read/Write)
HPF_BYP
For more information on the uses of the transient function please review application note AN4071. This function is similar to
The transient detection mechanism can be configured to raise an interrupt when the magnitude of the high pass filtered
The Transient Source register provides the status of the enabled axes and the polarity (directional) information. When this
When the EA bit gets set while ELE = 1, all other status bits get frozen at their current state. By reading the TRANSIENT_SRC
ZTEFE
YTEFE
XTEFE
Y_Trans_Pol
X_Trans_Pol
Z_Trans_Pol
ELE
YTRANSE
XTRANSE
ZTRANSE
Bit 7
Bit 7
0
0
EA
Transient (HPF) Acceleration Detection
Transient event flags are latched into the TRANSIENT_SRC register. Reading of the TRANSIENT_SRC register clears the event
flag. Default value: 0.
0: Event flag latch disabled; 1: Event flag latch enabled
Event flag enable on Z transient acceleration greater than transient threshold event. Default value: 0.
0: Event detection disabled; 1: Raise event flag on measured acceleration delta value greater than transient threshold.
Event flag enable on Y transient acceleration greater than transient threshold event. Default value: 0.
0: Event detection disabled; 1: Raise event flag on measured acceleration delta value greater than transient threshold.
Event flag enable on X transient acceleration greater than transient threshold event. Default value: 0.
0: Event detection disabled; 1: Raise event flag on measured acceleration delta value greater than transient threshold.
Bypass High Pass filter Default value: 0.
0: Data to transient acceleration detection block is through HPF 1: Data to transient acceleration detection block is NOT through
HPF (similar to motion detection function)
Event Active Flag. Default value: 0.
0: no event flag has been asserted; 1: one or more event flag has been asserted.
Z transient event. Default value: 0.
0: no interrupt, 1: Z Transient acceleration greater than the value of TRANSIENT_THS event has occurred
Polarity of Z Transient Event that triggered interrupt. Default value: 0.
0: Z event was Positive g, 1: Z event was Negative g
Y transient event. Default value: 0.
0: no interrupt, 1: Y Transient acceleration greater than the value of TRANSIENT_THS event has occurred
Polarity of Y Transient Event that triggered interrupt. Default value: 0.
0: Y event was Positive g, 1: Y event was Negative g
X transient event. Default value: 0.
0: no interrupt, 1: X Transient acceleration greater than the value of TRANSIENT_THS event has occurred
Polarity of X Transient Event that triggered interrupt. Default value: 0.
0: X event was Positive g, 1: X event was Negative g
Bit 6
Bit 6
EA
0
ZTRANSE
Bit 5
Bit 5
0
Z_Trans_Pol
Bit 4
Bit 4
ELE
YTRANSE
ZTEFE
Bit 3
Bit 3
Y_Trans_Pol
YTEFE
Bit 2
Bit 2
XTRANSE
XTEFE
Bit 1
Bit 1
Freescale Semiconductor
X_Trans_Pol
HPF_BYP
Bit 0
Bit 0
Sensors