MMA7660FC.cpp

00001 /*
00002  * MMA7760.h
00003  * Library for accelerometer_MMA7760
00004  *
00005  * Copyright (c) 2013 seeed technology inc.
00006  * Author        :   FrankieChu
00007  * Create Time   :   Jan 2013
00008  * Change Log    :
00009  *
00010  * The MIT License (MIT)
00011  *
00012  * Permission is hereby granted, free of charge, to any person obtaining a copy
00013  * of this software and associated documentation files (the "Software"), to deal
00014  * in the Software without restriction, including without limitation the rights
00015  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00016  * copies of the Software, and to permit persons to whom the Software is
00017  * furnished to do so, subject to the following conditions:
00018  *
00019  * The above copyright notice and this permission notice shall be included in
00020  * all copies or substantial portions of the Software.
00021  *
00022  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00023  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00024  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00025  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00026  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00027  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00028  * THE SOFTWARE.
00029  */
00030 
00031 #include "MMA7660.h"
00032 
00033 I2C i2c(I2C_SDA,I2C_SCL);
00034 
00035 /*Function: Write a byte to the register of the MMA7660*/
00036 void MMA7660::write(uint8_t _register, uint8_t _data)
00037 {
00038     char data[2] = {_register,_data};
00039     int check;
00040     //Wire.begin();
00041     //Wire.beginTransmission(MMA7660_ADDR);
00042     //Wire.write(_register);
00043     //Wire.write(_data);
00044     //Wire.endTransmission();
00045     check = i2c.write(MMA7660_ADDR<<1,data,2);
00046     if(check != 0)
00047         printf("I2C Write Failure\n\r");
00048 }
00049 /*Function: Read a byte from the regitster of the MMA7660*/
00050 uint8_t MMA7660::read(uint8_t _register)
00051 {
00052     char data_read[2] = {_register,0};
00053     int check;
00054     check = i2c.write(MMA7660_ADDR<<1,data_read,1); // write _register to set up read
00055     check = i2c.read(MMA7660_ADDR<<1,data_read,2); // execute read
00056     if(check != 0)
00057         printf("I2C Read failure\n\r");
00058     printf("read back data 0x%x, 0x%x from register 0x%x",data_read[0],data_read[1],_register);
00059     //uint8_t data_read;
00060     //Wire.begin();
00061     //Wire.beginTransmission(MMA7660_ADDR);
00062     //Wire.write(_register);
00063     //Wire.endTransmission();
00064     //Wire.beginTransmission(MMA7660_ADDR);
00065     //Wire.requestFrom(MMA7660_ADDR,1);
00066     //while(Wire.available())
00067     //{
00068     //  data_read = Wire.read();
00069     //}
00070     //Wire.endTransmission();
00071     return data_read[1];
00072 }
00073 
00074 void MMA7660::init()
00075 {
00076     i2c.frequency(400000);
00077     setMode(MMA7660_STAND_BY);
00078     setSampleRate(AUTO_SLEEP_32);
00079     setMode(MMA7660_ACTIVE);
00080 }
00081 void MMA7660::setMode(uint8_t mode)
00082 {
00083     write(MMA7660_MODE,mode);
00084 }
00085 void MMA7660::setSampleRate(uint8_t rate)
00086 {
00087     write(MMA7660_SR,rate);
00088 }
00089 /*Function: Get the contents of the registers in the MMA7660*/
00090 /*          so as to calculate the acceleration.            */
00091 void MMA7660::getXYZ(int8_t *x,int8_t *y,int8_t *z)
00092 {
00093     char val[3];
00094     int count = 0;
00095     bool done = false;
00096     val[0] = val[1] = val[2] = 64;
00097 //    while(Wire.available() > 0)
00098 //        Wire.read();
00099 //    Wire.requestFrom(MMA7660_ADDR,3);
00100 //    while(Wire.available())
00101 //    {
00102 //        if(count < 3)
00103 //        {
00104 //            while ( val[count] > 63 )  // reload the damn thing it is bad
00105 //            {
00106 //              val[count] = Wire.read();
00107 //            }
00108 //        }
00109 //        count++;
00110 //    }
00111     for(count = 0; count < 3 && done == false; count ++){
00112         i2c.read(MMA7660_ADDR<<1, val,3);
00113         if(val[0] < 63 && val[1]<63 && val[2]<63)
00114             done = true;
00115     }
00116     
00117     *x = ((char)(val[0]<<2))/4;
00118     *y = ((char)(val[1]<<2))/4;
00119     *z = ((char)(val[2]<<2))/4;
00120 }
00121 
00122 void MMA7660::getSignedXYZ(int8_t *x,int8_t *y,int8_t *z)
00123 {
00124     int8_t val[3];
00125     getXYZ(val + 0, val + 1, val + 2);
00126     
00127     for (size_t i = 0; i < sizeof(val); i++) {
00128         val[i] = val[i] >= 32 ? val[i] - 64 : val[i];
00129     }
00130     *x = val[0];
00131     *y = val[1];
00132     *z = val[2];
00133 }
00134 
00135 void MMA7660::getAcceleration(float *ax,float *ay,float *az)
00136 {
00137     int8_t x,y,z;
00138     getSignedXYZ(&x,&y,&z);
00139     *ax = x/21.33;
00140     *ay = y/21.33;
00141     *az = z/21.33;
00142 }