adxl345: Grove 3-Axis Accelerometer

Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>

src/adxl345/CMakeLists.txt

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+set (libname "adxl345")
+set (libdescription "libupm Digital Accelerometer")
+set (module_src ${libname}.cxx)
+set (module_h ${libname}.h)
+upm_module_init()

src/adxl345/adxl345.cxx

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+/*
+ * Author: Mihai Tudor Panu <mihai.tudor.panu@intel.com>
+ * Copyright (c) 2014 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <iostream>
+#include <unistd.h>
+#include "math.h"
+#include "adxl345.h"
+
+#define READ_BUFFER_LENGTH 6
+
+//address and id
+#define ADXL345_I2C_ADDR 0x53
+#define ADXL345_ID 0x00
+
+//control registers
+#define ADXL345_OFSX 0x1E
+#define ADXL345_OFSY 0x1F
+#define ADXL345_OFSZ 0x20
+#define ADXL345_TAP_THRESH 0x1D
+#define ADXL345_TAP_DUR 0x21
+#define ADXL345_TAP_LATENCY 0x22
+#define ADXL345_ACT_THRESH 0x24
+#define ADXL345_INACT_THRESH 0x25
+#define ADXL345_INACT_TIME 0x26
+#define ADXL345_INACT_ACT_CTL 0x27
+#define ADXL345_FALL_THRESH 0x28
+#define ADXL345_FALL_TIME 0x29
+#define ADXL345_TAP_AXES 0x2A
+#define ADXL345_ACT_TAP_STATUS 0x2B
+
+//interrupt registers
+#define ADXL345_INT_ENABLE 0x2E
+#define ADXL345_INT_MAP 0x2F
+#define ADXL345_INT_SOURCE 0x30
+
+//data registers (read only)
+#define ADXL345_XOUT_L 0x32
+#define ADXL345_XOUT_H 0x33
+#define ADXL345_YOUT_L 0x34
+#define ADXL345_YOUT_H 0x35
+#define ADXL345_ZOUT_L 0x36
+#define ADXL345_ZOUT_H 0x37
+#define DATA_REG_SIZE 6
+
+//data and power management
+#define ADXL345_BW_RATE 0x2C
+#define ADXL345_POWER_CTL 0x2D
+#define ADXL345_DATA_FORMAT 0x31
+#define ADXL345_FIFO_CTL 0x38
+#define ADXL345_FIFO_STATUS 0x39
+
+//useful values
+#define ADXL345_POWER_ON 0x08
+#define ADXL345_AUTO_SLP 0x30
+#define ADXL345_STANDBY 0x00
+
+//scales and resolution
+#define ADXL345_FULL_RES 0x08
+#define ADXL345_10BIT 0x00
+#define ADXL345_2G 0x00
+#define ADXL345_4G 0x01
+#define ADXL345_8G 0x02
+#define ADXL345_16G 0x03
+
+using namespace upm;
+
+Adxl345::Adxl345(int bus)
+{
+    //init bus and reset chip
+    m_i2c = mraa_i2c_init(bus);
+
+    mraa_i2c_address(m_i2c, ADXL345_I2C_ADDR);
+    m_buffer[0] = ADXL345_POWER_CTL;
+    m_buffer[1] = ADXL345_POWER_ON;
+    mraa_i2c_write(m_i2c, m_buffer, 2);
+
+    mraa_i2c_address(m_i2c, ADXL345_I2C_ADDR);
+    m_buffer[0] = ADXL345_DATA_FORMAT;
+    m_buffer[1] = ADXL345_16G | ADXL345_FULL_RES;
+    mraa_i2c_write(m_i2c, m_buffer, 2);
+
+    //2.5V sensitivity is 256 LSB/g = 0.00390625 g/bit
+    //3.3V x and y sensitivity is 265 LSB/g = 0.003773584 g/bit, z is the same
+
+    m_offsets[0] = 0.003773584;
+    m_offsets[1] = 0.003773584;
+    m_offsets[2] = 0.00390625;
+
+    Adxl345::update();
+}
+
+Adxl345::~Adxl345()
+{
+    mraa_i2c_stop(m_i2c);
+}
+
+float*
+Adxl345::getAcceleration()
+{
+    for(int i = 0; i < 3; i++){
+        m_accel[i] = m_rawaccel[i] * m_offsets[i];
+    }
+    return &m_accel[0];
+}
+
+int16_t*
+Adxl345::getRawValues()
+{
+    return &m_rawaccel[0];
+}
+
+uint8_t
+Adxl345::getScale(){
+
+    uint8_t result;
+
+    mraa_i2c_address(m_i2c, ADXL345_I2C_ADDR);
+    mraa_i2c_write_byte(m_i2c, ADXL345_DATA_FORMAT);
+
+    mraa_i2c_address(m_i2c, ADXL345_I2C_ADDR);
+    result = mraa_i2c_read_byte(m_i2c);
+
+    return pow(2, (result & 0x03) + 1);
+}
+
+mraa_result_t
+Adxl345::update(void)
+{
+    mraa_i2c_address(m_i2c, ADXL345_I2C_ADDR);
+    mraa_i2c_write_byte(m_i2c, ADXL345_XOUT_L);
+
+    mraa_i2c_address(m_i2c, ADXL345_I2C_ADDR);
+    mraa_i2c_read(m_i2c, m_buffer, DATA_REG_SIZE);
+
+    // x
+    m_rawaccel[0] = ((m_buffer[1] << 8 ) | m_buffer[0]);
+    // y
+    m_rawaccel[1] = ((m_buffer[3] << 8 ) | m_buffer[2]);
+    // z
+    m_rawaccel[2] = ((m_buffer[5] << 8 ) | m_buffer[4]);
+
+    return MRAA_SUCCESS;
+}

src/adxl345/adxl345.h

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+/*
+ * Author: Mihai Tudor Panu <mihai.tudor.panu@intel.com>
+ * Copyright (c) 2014 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#pragma once
+
+#include <mraa/i2c.h>
+
+#define READ_BUFFER_LENGTH 6
+
+namespace upm {
+
+/**
+ * @brief Adxl345 accelerometer library
+ * @defgroup adxl345 libupm-adxl345
+ */
+
+/**
+ * @brief C++ API for Adxl345 (3-axis digital accelerometer)
+ *
+ * The Adxl345 is a 3-axis digital accelerometer.
+ * (http://www.seeedstudio.com/wiki/images/2/2c/ADXL345_datasheet.pdf)
+ * The sensor has configurable resolutions for measuring ±2g, ±4g, ±8g or ±16g.
+ * Note that the sensor it is incompatible and will not be detected on the I2C bus
+ * by the Intel Edison using the Arduino breakout board at 5V (3V3 will work fine).
+ *
+ * @ingroup adxl345 i2c
+ * @snippet adxl345.cxx Interesting
+ * @image html adxl345.jpeg
+ */
+class Adxl345 {
+public:
+    /**
+     * Creates an Adxl345 object
+     *
+     * @param bus number of used i2c bus
+     */
+    Adxl345(int bus);
+
+    /**
+     * Adxl345 object destructor
+     */
+    ~Adxl345();
+
+    /**
+     * Returns a pointer to a float[3] that contains acceleration (g) forces
+     *
+     * @return float* to a float[3]
+     */
+    float* getAcceleration();
+
+    /**
+     * Returns a pointer to an int[3] that contains the raw register values for X, Y and Z
+     *
+     * @return int* to an int[3]
+     */
+    int16_t* getRawValues();
+
+    /**
+     * Returns the scale the accelerometer is currently set up to: 2, 4, 8 or 16
+     *
+     * @return uint with current scale value
+     */
+    uint8_t getScale();
+
+    /**
+     * Updates the acceleration values from i2c bus
+     *
+     * @return 0 for success
+     */
+    mraa_result_t update();
+private:
+    float m_accel[3];
+    float m_offsets[3];
+    int16_t m_rawaccel[3];
+    uint8_t m_buffer[READ_BUFFER_LENGTH];
+    mraa_i2c_context m_i2c;
+};
+
+}

src/adxl345/jsupm_adxl345.i

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+%module jsupm_adxl345
+%include "../upm.i"
+%include "../carrays_int16_t.i"
+%include "../carrays_float.i"
+
+%{
+    #include "adxl345.h"
+%}
+
+%typemap(out) int16_t * {
+    $result = SWIG_NewPointerObj(SWIG_as_voidptr(result), SWIGTYPE_p_int16Array, 0 | 0 );
+}
+
+%typemap(out) float * {
+    $result = SWIG_NewPointerObj(SWIG_as_voidptr(result), SWIGTYPE_p_floatArray, 0 | 0 );
+}
+
+%include "adxl345.h"
+
+%include <carrays.i>

src/adxl345/pyupm_adxl345.i

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+%module pyupm_adxl345
+%include "../upm.i"
+%include "../carrays_int16_t.i"
+%include "../carrays_float.i"
+
+%typemap(out) int16_t * {
+    $result = SWIG_NewPointerObj(SWIG_as_voidptr(result), SWIGTYPE_p_int16Array, 0 | 0 );
+}
+
+%typemap(out) float * {
+    $result = SWIG_NewPointerObj(SWIG_as_voidptr(result), SWIGTYPE_p_floatArray, 0 | 0 );
+}
+
+%feature("autodoc", "3");
+
+#ifdef DOXYGEN
+%include "adxl345_doc.i"
+#endif
+
+%include "adxl345.h"
+%{
+    #include "adxl345.h"
+%}