Freescale Semiconductor FRDM-FXS-MULTI 데이터 시트
MMA8652FC
Sensors
52
Freescale Semiconductor, Inc.
•
Four interrupt sources can WAKE the device: Transient, Orientation, Tap, and the Motion/Freefall. One or more of these
functions can be enabled.
functions can be enabled.
—
To WAKE the device, the desired function(s) must be enabled in CTRL_REG4 register and set to WAKE-to-SLEEP
in CTRL_REG3 register.
in CTRL_REG3 register.
—
All enabled functions still run in SLEEP mode at the SLEEP ODR.
Only the functions that have been selected for WAKE from SLEEP will actually WAKE the device (as configured in
register 0x2C).
Only the functions that have been selected for WAKE from SLEEP will actually WAKE the device (as configured in
register 0x2C).
—
The Auto-WAKE/SLEEP interrupt does not affect the WAKE/SLEEP, nor does the data ready interrupt.
—
Note that the FIFO does not WAKE the device.
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When set to 1, the FIFO gate (bit 7 in Register 0x2C) will hold the last data in the FIFO, before transitioning to a
different ODR. After the buffer is flushed, it will accept new sample data at the current ODR. See Register 0x2C for
the WAKE-from-SLEEP interrupt enable bit definitions.
different ODR. After the buffer is flushed, it will accept new sample data at the current ODR. See Register 0x2C for
the WAKE-from-SLEEP interrupt enable bit definitions.
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MMA8652FC has four functions that can be used to keep the sensor from falling asleep: Transient, Orientation, Tap and
Motion/Freefall.
Motion/Freefall.
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Auto-SLEEP bit:
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If the Auto-SLEEP bit is disabled, then the device can only toggle between STANDBY and WAKE mode.
—
If Auto-SLEEP interrupt is enabled, then transitioning from ACTIVE mode to Auto-SLEEP mode (or vice versa)
generates an interrupt.
generates an interrupt.
6.12
System and 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).
of the fields within CTRL_REG1 (0x2A).
6.12.1
0x2A: CTRL_REG1 System Control 1 register
CTRL_REG1 register configures the Auto-WAKE sample frequency, output data rate selection, and enables the fast-read mode
and STANDBY/ACTIVE mode selection.
and STANDBY/ACTIVE mode selection.
Table 93. 0x2A CTRL_REG1 register (Read/Write)
Back to Register Address Map
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
ASLP_RATE1
ASLP_RATE0
DR2
DR1
DR0
—
F_READ
ACTIVE
Table 94. CTRL_REG1 register
Bit(s)
Field
Description
7–6
ASLP_RATE[1:0]
Configures the Auto-WAKE sample frequency when the device is in SLEEP Mode.
See
See
Table 95
.
00 (default)
5–3
DR[2:0]
Data rate selection
See
See
Table 96
.
000 (default)
2
—
1
F_READ
Fast-read mode: Data format is limited to single byte
0 Normal mode (default)
1 Fast Read Mode
0 Normal mode (default)
1 Fast Read Mode
0
ACTIVE
Full-scale selection
0 STANDBY mode (default)
1 ACTIVE mode
0 STANDBY mode (default)
1 ACTIVE mode