lsm303: add new sensor, 6-Axis Accelerometer/Compass

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

src/lsm303/lsm303.cxx

@@ -0,0 +1,156 @@
+/*
+ * Author: Brendan Le Foll <brendan.le.foll@intel.com>
+ * Copyright (c) 2014 Intel Corporation.
+ *
+ * Code based on LSM303DLH sample by Jim Lindblom SparkFun Electronics
+ * and the CompensatedCompass.ino by Frankie Chu from SeedStudio
+ *
+ * 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 <stdlib.h>
+
+#include "lsm303.h"
+
+using namespace upm;
+
+LSM303::LSM303(int bus, int addrMag, int addrAcc)
+{
+    mraa_result_t ret = MRAA_SUCCESS;
+
+    m_addrMag = addrMag;
+    m_addrAcc = addrAcc;
+
+    m_i2c = mraa_i2c_init(bus);
+
+    buf[0] = CTRL_REG1_A;
+    buf[1] = 0x27;
+    ret = mraa_i2c_address(m_i2c, m_addrAcc);
+    ret = mraa_i2c_write(m_i2c, buf, 2);
+
+    // 0x27 = normal power mode, all accel axes on
+    buf[0] = CTRL_REG1_A;
+    buf[1] = 0x27;
+    ret = mraa_i2c_address(m_i2c, m_addrAcc);
+    ret = mraa_i2c_write(m_i2c, buf, 2);
+
+    // scale == 2, can be 4 or 8
+    buf[0] = CTRL_REG4_A;
+    buf[1] = 0x00;
+    ret = mraa_i2c_address(m_i2c, m_addrAcc);
+    ret = mraa_i2c_write(m_i2c, buf, 2);
+
+    // 0x14 = mag 30Hz output rate
+    buf[0] = CRA_REG_M;
+    buf[1] = 0x14;
+    ret = mraa_i2c_address(m_i2c, m_addrMag);
+    ret = mraa_i2c_write(m_i2c, buf, 2);
+
+    // magnetic scale = +/-1.3Gaussmagnetic scale = +/-1.3Gauss
+    buf[0] = CRB_REG_M;
+    buf[1] = 0x20; // MAG_SCALE_1_3;
+    ret = mraa_i2c_address(m_i2c, m_addrMag);
+    ret = mraa_i2c_write(m_i2c, buf, 2);
+
+    // 0x00 = continouous conversion mode
+    buf[0] = MR_REG_M;
+    buf[1] = 0x00;
+    ret = mraa_i2c_address(m_i2c, m_addrMag);
+    ret = mraa_i2c_write(m_i2c, buf, 2);
+}
+
+LSM303::~LSM303() {
+    mraa_i2c_stop(m_i2c);
+}
+
+float
+LSM303::getHeading()
+{
+    if (getCoordinates() != MRAA_SUCCESS) {
+        return -1;
+    }
+
+    float heading = 180 * atan2(coor[Y], coor[X])/M_PI;
+
+    if (heading < 0)
+        heading += 360;
+
+    return heading;
+}
+
+uint8_t*
+LSM303::getRawAccelData()
+{
+    return &accel[0];
+}
+
+uint8_t*
+LSM303::getRawCoorData()
+{
+    return &coor[0];
+}
+
+mraa_result_t
+LSM303::getCoordinates()
+{
+    mraa_result_t ret = MRAA_SUCCESS;
+
+    memset(&buf[0], 0, sizeof(uint8_t)*6);
+    ret = mraa_i2c_address(m_i2c, m_addrMag);
+    ret = mraa_i2c_write_byte(m_i2c, OUT_X_H_M);
+    ret = mraa_i2c_address(m_i2c, m_addrMag);
+    int num = mraa_i2c_read(m_i2c, buf, 6);
+    if (num != 6) {
+        return ret;
+    }
+    // convert to coordinates
+    for (int i=0; i<3; i++) {
+        coor[i] = (buf[0*i] << 8) | buf[1*i];
+    }
+    // note that coor array is in XZY order
+    //printf("X=%x, Y=%x, Z=%x\n", coor[X], coor[Y], coor[Z]);
+
+    return ret;
+}
+
+// helper function that writes a value to the acc and then reads
+int
+LSM303::readThenWrite(uint8_t reg)
+{
+    mraa_i2c_address(m_i2c, m_addrAcc);
+    mraa_i2c_write_byte(m_i2c, reg);
+    mraa_i2c_address(m_i2c, m_addrAcc);
+    return (int) mraa_i2c_read_byte(m_i2c);
+}
+
+mraa_result_t
+LSM303::getAcceleration()
+{
+    mraa_result_t ret = MRAA_SUCCESS;
+
+    accel[2] = (readThenWrite(OUT_X_L_A) << 8) | (readThenWrite(OUT_X_H_A));
+    accel[0] = (readThenWrite(OUT_Y_L_A) << 8) | (readThenWrite(OUT_Y_H_A));
+    accel[1] = (readThenWrite(OUT_Z_L_A) << 8) | (readThenWrite(OUT_Z_H_A));
+    //printf("X=%x, Y=%x, Z=%x\n", accel[X], accel[Y], accel[Z]);
+
+    return ret;
+}