Datasheet

MMA8451Q
Sensors
26 Freescale Semiconductor, Inc.
0x0D: WHO_AM_I Device ID Register
The device identification register identifies the part. The default value is 0x1A. This value is factory programmed. Consult the
factory for custom alternate values.
0x0E: XYZ_DATA_CFG Register
The XYZ_DATA_CFG register sets the dynamic range and sets the high-pass filter for the output data. When the HPF_OUT
bit is set, both the FIFO and DATA registers will contain high-pass filtered data.
The default full scale value range is 2g and the high-pass filter is disabled.
0x0F: HP_FILTER_CUTOFF High-Pass Filter Register
This register sets the high-pass filter cutoff frequency for removal of the offset and slower changing acceleration data. The
output of this filter is indicated by the data registers (0x01-0x06) when bit 4 (HPF_OUT) of Register 0x0E is set. The filter cutoff
options change based on the data rate selected as shown in Ta bl e 23. For details of implementation on the high-pass filter, refer to
Freescale application note, AN4071.
0x0D: WHO_AM_I Device ID Register (Read Only)
Bit
7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
00011 0 1 0
0x0E: XYZ_DATA_CFG (Read/Write)
Bit
7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
000HPF_OUT0 0 FS1FS0
Table 20. XYZ Data Configuration Descriptions
HPF_OUT Enable High-pass output data 1 = output data High-pass filtered. Default value: 0.
FS[1:0] Output buffer data format full scale. Default value: 00 (2g).
Table 21. Full Scale Range
FS1 FS0 Full Scale Range
00 2
01 4
10 8
11 Reserved
0x0F: HP_FILTER_CUTOFF: High-Pass Filter Register (Read/Write)
Bit
7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0 0 Pulse_HPF_BYP Pulse_LPF_EN 0 0 SEL1 SEL0
Table 22. High-Pass Filter Cutoff Register Descriptions
Pulse_HPF_BYP
Bypass High-Pass Filter (HPF) for Pulse Processing Function.
0: HPF enabled for Pulse Processing, 1: HPF Bypassed for Pulse Processing
Default value: 0.
Pulse_LPF_EN
Enable Low-Pass Filter (LPF) for Pulse Processing Function.
0: LPF disabled for Pulse Processing, 1: LPF Enabled for Pulse Processing
Default value: 0.
SEL[1:0]
HPF Cutoff frequency selection.
Default value: 00 (see Table 23
).