cma3000_d0x.rst

  1CMA3000-D0x Accelerometer
  2=========================
  3
  4Supported chips:
  5* VTI CMA3000-D0x
  6
  7Datasheet:
  8  CMA3000-D0X Product Family Specification 8281000A.02.pdf
  9  <http://www.vti.fi/en/>
 10
 11:Author: Hemanth V <hemanthv@ti.com>
 12
 13
 14Description
 15-----------
 16
 17CMA3000 Tri-axis accelerometer supports Motion detect, Measurement and
 18Free fall modes.
 19
 20Motion Detect Mode:
 21    Its the low power mode where interrupts are generated only
 22    when motion exceeds the defined thresholds.
 23
 24Measurement Mode:
 25    This mode is used to read the acceleration data on X,Y,Z
 26    axis and supports 400, 100, 40 Hz sample frequency.
 27
 28Free fall Mode:
 29    This mode is intended to save system resources.
 30
 31Threshold values:
 32    Chip supports defining threshold values for above modes
 33    which includes time and g value. Refer product specifications for
 34    more details.
 35
 36CMA3000 chip supports mutually exclusive I2C and SPI interfaces for
 37communication, currently the driver supports I2C based communication only.
 38Initial configuration for bus mode is set in non volatile memory and can later
 39be modified through bus interface command.
 40
 41Driver reports acceleration data through input subsystem. It generates ABS_MISC
 42event with value 1 when free fall is detected.
 43
 44Platform data need to be configured for initial default values.
 45
 46Platform Data
 47-------------
 48
 49fuzz_x:
 50    Noise on X Axis
 51
 52fuzz_y:
 53    Noise on Y Axis
 54
 55fuzz_z:
 56    Noise on Z Axis
 57
 58g_range:
 59    G range in milli g i.e 2000 or 8000
 60
 61mode:
 62    Default Operating mode
 63
 64mdthr:
 65    Motion detect g range threshold value
 66
 67mdfftmr:
 68    Motion detect and free fall time threshold value
 69
 70ffthr:
 71    Free fall g range threshold value
 72
 73Input Interface
 74---------------
 75
 76Input driver version is 1.0.0
 77Input device ID: bus 0x18 vendor 0x0 product 0x0 version 0x0
 78Input device name: "cma3000-accelerometer"
 79
 80Supported events::
 81
 82  Event type 0 (Sync)
 83  Event type 3 (Absolute)
 84    Event code 0 (X)
 85      Value     47
 86      Min    -8000
 87      Max     8000
 88      Fuzz     200
 89    Event code 1 (Y)
 90      Value    -28
 91      Min    -8000
 92      Max     8000
 93      Fuzz     200
 94    Event code 2 (Z)
 95      Value    905
 96      Min    -8000
 97      Max     8000
 98      Fuzz     200
 99    Event code 40 (Misc)
100      Value      0
101      Min        0
102      Max        1
103  Event type 4 (Misc)
104
105
106Register/Platform parameters Description
107----------------------------------------
108
109mode::
110
111	0: power down mode
112	1: 100 Hz Measurement mode
113	2: 400 Hz Measurement mode
114	3: 40 Hz Measurement mode
115	4: Motion Detect mode (default)
116	5: 100 Hz Free fall mode
117	6: 40 Hz Free fall mode
118	7: Power off mode
119
120grange::
121
122	2000: 2000 mg or 2G Range
123	8000: 8000 mg or 8G Range
124
125mdthr::
126
127	X: X * 71mg (8G Range)
128	X: X * 18mg (2G Range)
129
130mdfftmr::
131
132	X: (X & 0x70) * 100 ms (MDTMR)
133	   (X & 0x0F) * 2.5 ms (FFTMR 400 Hz)
134	   (X & 0x0F) * 10 ms  (FFTMR 100 Hz)
135
136ffthr::
137
138       X: (X >> 2) * 18mg (2G Range)
139       X: (X & 0x0F) * 71 mg (8G Range)