MMA8652.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 
00019 #include "MMA8652.h"
00020 #include "common_define.h"
00021 #define UINT14_MAX        16383
00022   
00023 MMA8652::MMA8652(PinName sda, PinName scl) : _i2c(sda, scl) {
00024  
00025     begin();
00026 }
00027 
00028 
00029 MMA8652::~MMA8652() { }
00030 
00031               
00032 void MMA8652::RegRead( char reg, char * d, int len)
00033 {
00034     // char cmd = reg;
00035     // char i2c_addr = MMA8652_SLAVE_ADDR;
00036     // int status;
00037     // printf("i2c_addr = 0x%x \r\n",i2c_addr);
00038     // status = _i2c.write( i2c_addr, &cmd, 1);
00039     // status = _i2c.read (i2c_addr, d, len);
00040     // if(status == 0)
00041     // {
00042     //     printf("success \r\n");
00043     // }
00044     // else
00045     // {
00046     //     printf("failer \r\n");
00047     // }
00048     i2cReadForFXS_MUTIL(&_i2c,MMA8652_SLAVE_ADDR,(uint8_t*)d,reg,len);
00049 
00050 }
00051 
00052 void MMA8652::begin(void)
00053 {
00054     char data[2];
00055     // write 0000 0000 = 0x00 to accelerometer control register 1 to place MMA8652 into
00056     // standby
00057     // [7-1] = 0000 000
00058     // [0]: active=0
00059     data[0] = MMA8652_CTRL_REG1;
00060     data[1] = 0x00;
00061     _i2c.write( MMA8652_SLAVE_ADDR, data, 2);
00062     
00063     // write 0000 0001= 0x01 to XYZ_DATA_CFG register
00064     // [7]: reserved
00065     // [6]: reserved
00066     // [5]: reserved
00067     // [4]: hpf_out=0
00068     // [3]: reserved
00069     // [2]: reserved
00070     // [1-0]: fs=00 for accelerometer range of +/-2g range with 0.244mg/LSB
00071     data[0] = MMA8652_XYZ_DATA_CFG;
00072     data[1] = 0x00;
00073     _i2c.write( MMA8652_SLAVE_ADDR, data, 2);
00074 
00075     // write 0000 1101 = 0x0D to accelerometer control register 1
00076     // [7-6]: aslp_rate=00
00077     // [5-3]: dr=100 for 50Hz data rate
00078     // [2]: 0
00079     // [1]: 0
00080     // [0]: active=1 to take the part out of standby and enable sampling
00081     data[0] = MMA8652_CTRL_REG1;
00082     data[1] = 0x21;
00083     _i2c.write( MMA8652_SLAVE_ADDR, data, 2);
00084 }
00085 
00086 char  MMA8652::getWhoAmI(void)
00087 {
00088     char Id = 0x00;
00089     RegRead(MMA8652_WHOAMI, &Id, 1);
00090     return Id;
00091 }
00092 
00093 void MMA8652::ReadXYZ(float * a)
00094 {
00095     char d[7];
00096     int16_t t[6];
00097 
00098     RegRead( MMA8652_STATUS, d, 7);
00099     t[0] = ((d[1] * 256) + ((unsigned short) d[2]));
00100     t[1] = ((d[3] * 256) + ((unsigned short) d[4]));
00101     t[2] = ((d[5] * 256) + ((unsigned short) d[6]));
00102 
00103     a[0] = (float) t[0] / 16384.0;
00104     a[1] = (float) t[1] / 16384.0;
00105     a[2] = (float) t[2] / 16384.0;
00106   
00107 }
00108 
00109 
00110 void MMA8652::ReadXYZraw(int16_t * d)
00111 {
00112     char res[6];
00113     int16_t acc;
00114     RegRead( MMA8652_OUT_X_MSB, res, 6);
00115 
00116     acc = (res[0] << 6) | (res[1] >> 2);
00117     if (acc > UINT14_MAX/2)
00118         acc -= UINT14_MAX;
00119     d[0] = acc;
00120     acc = (res[2] << 6) | (res[3] >> 2);
00121     if (acc > UINT14_MAX/2)
00122         acc -= UINT14_MAX;
00123     d[1] = acc;
00124     acc = (res[4] << 6) | (res[5] >> 2);
00125     if (acc > UINT14_MAX/2)
00126         acc -= UINT14_MAX;
00127     d[2] = acc;
00128 }
00129   
00130