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

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MMA8452Q
Sensors
Freescale Semiconductor, Inc.
37
6.7 Control Registers
Note: Except for STANDBY mode selection, the device must be in STANDBY mode to change any of the fields within
CTRL_REG1 (0X2A).
0x2A: CTRL_REG1 System Control 1 Register
It is important to note that when the device is Auto-SLEEP mode, the system ODR and the data rate for all the system
functional blocks are overridden by the data rate set by the ASLP_RATE field.
DR[2:0] bits select the Output Data Rate (ODR) for acceleration samples. The default value is 000 for a data rate of 800 Hz.
ACTIVE bit selects between STANDBY mode and ACTIVE mode. The default value is 0 for STANDBY mode.
LNOISE bit selects between normal full dynamic range mode and a high sensitivity, Low Noise mode. In Low Noise mode, the
maximum signal that can be measured is ±4g. Note: Any thresholds set above 4g will not be reached.
F_READ bit selects between Normal and Fast Read mode. When selected, the auto-increment counter will skip over the LSB
data bytes.
0x2A: CTRL_REG1 Register (Read/Write)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
ASLP_RATE1 ASLP_RATE0 DR2 DR1 DR0 LNOISE F_READ ACTIVE
Table 53. CTRL_REG1 Description
ASLP_RATE[1:0]
Configures the Auto-WAKE sample frequency when the device is in SLEEP Mode. Default value: 00.
See Table 54 for more information.
DR[2:0]
Data rate selection. Default value: 000.
See Table 55 for more information.
LNOISE
Reduced noise reduced Maximum range mode. Default value: 0.
(0: Normal mode; 1: Reduced Noise mode)
F_READ
Fast Read mode: Data format limited to single Byte Default value: 0.
(0: Normal mode 1: Fast Read Mode)
ACTIVE
Full Scale selection. Default value: 00.
(0: STANDBY mode; 1: ACTIVE mode)
Table 54. SLEEP Mode Rate Description
ASLP_RATE1 ASLP_RATE0 Frequency (Hz)
0 0 50
0 1 12.5
1 0 6.25
1 1 1.56
Table 55. System Output Data Rate Selection
DR2 DR1 DR0 ODR Period
0 0 0 800 Hz 1.25 ms
0 0 1 400 Hz 2.5 ms
0 1 0 200 Hz 5 ms
0 1 1 100 Hz 10 ms
1 0 0 50 Hz 20 ms
1 0 1 12.5 Hz 80 ms
1 1 0 6.25 Hz 160 ms
1 1 1 1.56 Hz 640 ms
Table 56. Full Scale Selection
Active Mode
0 STANDBY
1 ACTIVE