140 lines
2.9 KiB
ReStructuredText
140 lines
2.9 KiB
ReStructuredText
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CMA3000-D0x Accelerometer
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=========================
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Supported chips:
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* VTI CMA3000-D0x
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Datasheet:
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CMA3000-D0X Product Family Specification 8281000A.02.pdf
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<http://www.vti.fi/en/>
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:Author: Hemanth V <hemanthv@ti.com>
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Description
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-----------
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CMA3000 Tri-axis accelerometer supports Motion detect, Measurement and
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Free fall modes.
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Motion Detect Mode:
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Its the low power mode where interrupts are generated only
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when motion exceeds the defined thresholds.
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Measurement Mode:
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This mode is used to read the acceleration data on X,Y,Z
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axis and supports 400, 100, 40 Hz sample frequency.
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Free fall Mode:
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This mode is intended to save system resources.
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Threshold values:
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Chip supports defining threshold values for above modes
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which includes time and g value. Refer product specifications for
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more details.
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CMA3000 chip supports mutually exclusive I2C and SPI interfaces for
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communication, currently the driver supports I2C based communication only.
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Initial configuration for bus mode is set in non volatile memory and can later
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be modified through bus interface command.
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Driver reports acceleration data through input subsystem. It generates ABS_MISC
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event with value 1 when free fall is detected.
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Platform data need to be configured for initial default values.
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Platform Data
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-------------
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fuzz_x:
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Noise on X Axis
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fuzz_y:
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Noise on Y Axis
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fuzz_z:
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Noise on Z Axis
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g_range:
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G range in milli g i.e 2000 or 8000
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mode:
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Default Operating mode
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mdthr:
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Motion detect g range threshold value
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mdfftmr:
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Motion detect and free fall time threshold value
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ffthr:
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Free fall g range threshold value
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Input Interface
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---------------
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Input driver version is 1.0.0
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Input device ID: bus 0x18 vendor 0x0 product 0x0 version 0x0
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Input device name: "cma3000-accelerometer"
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Supported events::
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Event type 0 (Sync)
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Event type 3 (Absolute)
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Event code 0 (X)
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Value 47
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Min -8000
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Max 8000
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Fuzz 200
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Event code 1 (Y)
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Value -28
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Min -8000
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Max 8000
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Fuzz 200
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Event code 2 (Z)
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Value 905
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Min -8000
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Max 8000
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Fuzz 200
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Event code 40 (Misc)
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Value 0
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Min 0
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Max 1
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Event type 4 (Misc)
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Register/Platform parameters Description
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----------------------------------------
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mode::
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0: power down mode
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1: 100 Hz Measurement mode
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2: 400 Hz Measurement mode
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3: 40 Hz Measurement mode
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4: Motion Detect mode (default)
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5: 100 Hz Free fall mode
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6: 40 Hz Free fall mode
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7: Power off mode
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grange::
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2000: 2000 mg or 2G Range
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8000: 8000 mg or 8G Range
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mdthr::
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X: X * 71mg (8G Range)
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X: X * 18mg (2G Range)
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mdfftmr::
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X: (X & 0x70) * 100 ms (MDTMR)
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(X & 0x0F) * 2.5 ms (FFTMR 400 Hz)
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(X & 0x0F) * 10 ms (FFTMR 100 Hz)
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ffthr::
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X: (X >> 2) * 18mg (2G Range)
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X: (X & 0x0F) * 71 mg (8G Range)
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