MMA8451Q8b.cpp

00001 /* Copyright (c) 2010-2011 mbed.org, MIT License
00002 *
00003 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
00004 * and associated documentation files (the "Software"), to deal in the Software without
00005 * restriction, including without limitation the rights to use, copy, modify, merge, publish,
00006 * distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
00007 * Software is furnished to do so, subject to the following conditions:
00008 *
00009 * The above copyright notice and this permission notice shall be included in all copies or
00010 * substantial portions of the Software.
00011 *
00012 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
00013 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00014 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
00015 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00016 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00017 */
00018 // Modify to change full scale gravity range 141207 sc
00019 /*
00020 * Update getGLimit to map to application note AN4076
00021 * http://cache.freescale.com/files/sensors/doc/app_note/AN4076.pdf
00022 * 02/05/2016 sc
00023 */ 
00024 
00025 #include "MMA8451Q8b.h"
00026 
00027 #define REG_WHO_AM_I      0x0D
00028 #define REG_CTRL_REG_1    0x2A
00029 #define REG_OUT_X_MSB     0x01
00030 #define REG_OUT_Y_MSB     0x03
00031 #define REG_OUT_Z_MSB     0x05
00032 #define XYZ_DATA_CFG      0x0E
00033 
00034 #define UINT14_MAX        16383
00035 
00036 #define MAX_2G            0x00
00037 #define MAX_4G            0x01
00038 #define MAX_8G            0x02
00039 
00040 #define NUM_DATA            2
00041 #define GSCALING          1024.0
00042 #define ADDRESS_INDEX       0
00043 #define DATA_INDEX          1
00044 
00045 float gScaling[3] = {4095.0,2048.0,1024.0}; //scaling for acceleration of gravity values
00046 
00047 MMA8451Q::MMA8451Q(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr) {
00048     // activate the peripheral
00049     uint8_t data[2] = {REG_CTRL_REG_1, 0x01};
00050     writeRegs(data, 2);
00051 }
00052 
00053 MMA8451Q::~MMA8451Q() { }
00054 
00055 uint8_t MMA8451Q::getWhoAmI() {
00056     uint8_t who_am_i = 0;
00057     readRegs(REG_WHO_AM_I, &who_am_i, 1);
00058     return who_am_i;
00059 }
00060 
00061 void MMA8451Q::setStandbyMode(){
00062 #define ACTIVEMASK 0x01
00063     uint8_t registerData[1];
00064     uint8_t data[NUM_DATA] = {REG_CTRL_REG_1, 0x00};
00065     
00066     readRegs(REG_CTRL_REG_1, registerData, 1);
00067     data[1] = registerData[0] & ~ACTIVEMASK;
00068     writeRegs(data, NUM_DATA); // put in standby
00069 }
00070 void MMA8451Q::setActiveMode(){
00071 #define ACTIVEMASK 0x01
00072     uint8_t registerData[1];
00073     uint8_t data[NUM_DATA] = {REG_CTRL_REG_1, 0x00};
00074     
00075     readRegs(REG_CTRL_REG_1, registerData, 1);
00076     data[1] = registerData[0] | ACTIVEMASK;
00077     writeRegs(data, NUM_DATA); // put in standby
00078 }
00079 
00080 void MMA8451Q::setGLimit(int gSelect) {   
00081     uint8_t data[NUM_DATA] = {REG_CTRL_REG_1, 0x00};
00082     gChosen = gSelect;
00083     setStandbyMode();
00084     data[ADDRESS_INDEX ] = XYZ_DATA_CFG;
00085     data[DATA_INDEX] = gChosen;
00086     writeRegs(data, 2);// change g limit
00087     setActiveMode(); // make active
00088 }
00089 
00090 float MMA8451Q::getAccX() {
00091     return (float(getAccAxis(REG_OUT_X_MSB))/gScaling[gChosen]);
00092 }
00093 
00094 
00095 float MMA8451Q::getAccY() {
00096     return (float(getAccAxis(REG_OUT_Y_MSB))/gScaling[gChosen]);
00097 }
00098 
00099 float MMA8451Q::getAccZ() {
00100     return (float(getAccAxis(REG_OUT_Z_MSB))/gScaling[gChosen]);
00101 }
00102 
00103 void MMA8451Q::getAccAllAxis(float * res) {
00104     res[0] = getAccX();
00105     res[1] = getAccY();
00106     res[2] = getAccZ();
00107 }
00108 
00109 int16_t MMA8451Q::getAccAxis(uint8_t addr) {
00110     int16_t acc;
00111     uint8_t res[2];
00112     readRegs(addr, res, 2);
00113 
00114     acc = (res[0] << 6) | (res[1] >> 2);
00115     if (acc > UINT14_MAX/2)
00116         acc -= UINT14_MAX;
00117 
00118     return acc;
00119 }
00120 
00121 void MMA8451Q::readRegs(int addr, uint8_t * data, int len) {
00122     char t[1] = {addr};
00123     m_i2c.write(m_addr, t, 1, true);
00124     m_i2c.read(m_addr, (char *)data, len);
00125 }
00126 
00127 void MMA8451Q::writeRegs(uint8_t * data, int len) {
00128     m_i2c.write(m_addr, (char *)data, len);
00129 }