MMA7660FC.cpp

00001 // Author: Edoardo De Marchi
00002 /* Copyright (C) 2012 mbed.org, MIT License
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
00005  * and associated documentation files (the "Software"), to deal in the Software without restriction,
00006  * including without limitation the rights to use, copy, modify, merge, publish, distribute,
00007  * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
00008  * furnished to do so, subject to the following conditions:
00009  *
00010  * The above copyright notice and this permission notice shall be included in all copies or
00011  * substantial portions of the Software.
00012  *
00013  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
00014  * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00015  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
00016  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00017  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00018  */
00019  
00020  
00021 #include "MMA7660FC.h"
00022 
00023 float TILT_XY[64] = {0, 2.69, 5.38, 8.08, 10.81, 13.55, 16.33, 19.16, 22.02, 24.95, 27.95, 31.04, 34.23, 37.54, 41.01, 44.68, 48.59, 52.83, 57.54, 62.95, 69.64, 79.86, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -79.86, -69.64, -62.95, -57.54, -52.83, -48.59, -44.68, -41.01, -37.54, -34.23, -31.04, -27.95, -24.95, -22.02, -19.16, -16.33, -13.55, -10.81, -8.08, -5.38, -2.69}; 
00024 float TILT_Z[64] = {90.00, 87.31, 84.62, 81.92, 79.19, 76.45, 73.67, 70.84, 67.98, 65.05, 62.05, 58.96, 55.77, 52.46, 48.99, 45.32, 41.41, 37.17, 32.46, 27.05, 20.36, 10.14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10.14, -20.36, -27.05, -32.46, -37.17, -41.41, -45.32, -48.99, -52.46, -55.77, -58.96, -62.05, -65.05, -67.98, -70.84, -73.67, -76.45, -79.19, -81.92, -84.62, -87.31};
00025 
00026 
00027 
00028         // Connect module at I2C address addr using I2C port pins sda and scl
00029 MMA7660FC::MMA7660FC(PinName sda, PinName scl, int addr) : m_i2c(sda, scl)
00030 {
00031     SPI_W_Address = addr;                   // Write address
00032     SPI_R_Address = SPI_W_Address | 1;      // Read address                
00033 }
00034 
00035 
00036         // Destroys instance
00037 MMA7660FC::~MMA7660FC()
00038 {
00039 }
00040 
00041 
00042         // Device initialization
00043 void MMA7660FC::init()
00044 { 
00045     write_reg(INTSU_STATUS, 0x00);      // interrupt disable
00046     write_reg(SR_STATUS, 0x07);         // 1 Samples/Second   
00047 }
00048 
00049 
00050         // Reads the tilt angle
00051 void MMA7660FC::read_Tilt(float *x, float *y, float *z)
00052 {
00053     const char Addr_X = OUT_X;
00054     char buf[3] = {0,0,0};
00055     
00056     m_i2c.write(SPI_W_Address, &Addr_X, 1);         // Pointer to the OUT_X register
00057     m_i2c.read(SPI_W_Address, buf, 3);              // Read register content into buffer with 6bit
00058     
00059     // returns the x, y, z coordinates transformed into full degrees
00060     *x = TILT_XY[(int)buf[0]];
00061     *y = TILT_XY[(int)buf[1]];
00062     *z = TILT_Z[(int)buf[2]];       
00063 }
00064 
00065 
00066       // Reads x data
00067 int MMA7660FC::read_x()
00068 {
00069     m_i2c.start();                  // Start
00070     m_i2c.write(SPI_W_Address);     // A write to device
00071     m_i2c.write(OUT_X);             // Register to read
00072     m_i2c.start();                  
00073     m_i2c.write(SPI_R_Address);     // Read from device
00074     char x = m_i2c.read(0);         // Read the data
00075     m_i2c.stop();
00076     
00077     return (int)x;  
00078 }
00079 
00080 
00081       // Reads y data
00082 int MMA7660FC::read_y()
00083 {
00084     m_i2c.start();                  // Start
00085     m_i2c.write(SPI_W_Address);     // A write to device
00086     m_i2c.write(OUT_Y);             // Register to read
00087     m_i2c.start();                  
00088     m_i2c.write(SPI_R_Address);     // Read from device
00089     char y = m_i2c.read(0);         // Read the data
00090     m_i2c.stop();
00091     
00092     return (int)y; 
00093 }
00094 
00095 
00096       // Reads z data
00097 int MMA7660FC::read_z()
00098 {
00099     m_i2c.start();                  // Start
00100     m_i2c.write(SPI_W_Address);     // A write to device
00101     m_i2c.write(OUT_Z);             // Register to read
00102     m_i2c.start();                  
00103     m_i2c.write(SPI_R_Address);     // Read from device
00104     char z = m_i2c.read(0);         // Read the data
00105     m_i2c.stop();
00106     
00107     return (int)z;
00108 }
00109 
00110     // Reads MMA7660FC Orientation
00111 char const* MMA7660FC::read_Side()
00112 {
00113     char tiltStatus = read_reg(TILT_STATUS);
00114 
00115     if((tiltStatus & 0x03) == 0x01)
00116         return "Front";
00117     if((tiltStatus & 0x03) == 0x02)
00118         return "Back";
00119     
00120     return "Unknown"; 
00121 }
00122 
00123 
00124     // Reads MMA7660FC Orientation
00125 char const* MMA7660FC::read_Orientation()
00126 {
00127     char tiltStatus = read_reg(TILT_STATUS);
00128 
00129     if((tiltStatus & 0x1c) == 0x04)
00130         return "Left";
00131     if((tiltStatus & 0x1c) == 0x08)
00132         return "Right";
00133     if((tiltStatus & 0x1c) == 0x14)
00134         return "Down";
00135     if((tiltStatus & 0x1c) == 0x18)
00136         return "Up";
00137  
00138     return "Unknown";    
00139 }
00140 
00141 
00142 
00143         // Read from specified MMA7660FC register
00144 char MMA7660FC::read_reg(char addr)
00145 {   
00146     m_i2c.start();                  // Start
00147     m_i2c.write(SPI_W_Address);     // A write to device
00148     m_i2c.write(addr);              // Register to read
00149     m_i2c.start();                  
00150     m_i2c.write(SPI_R_Address);     // Read from device
00151     char c = m_i2c.read(0);         // Read the data
00152     m_i2c.stop();                   
00153  
00154     return c;   
00155 }
00156 
00157 
00158         // Write register (The device must be placed in Standby Mode to change the value of the registers) 
00159 void MMA7660FC::write_reg(char addr, char data)
00160 {
00161     char cmd[2] = {0, 0};
00162     
00163     cmd[0] = MODE_STATUS;
00164     cmd[1] = 0x00;                          // Standby Mode on
00165     m_i2c.write(SPI_W_Address, cmd, 2);
00166   
00167     cmd[0] = addr;
00168     cmd[1] = data;                          // New value of the register
00169     m_i2c.write(SPI_W_Address, cmd, 2); 
00170       
00171     cmd[0] = MODE_STATUS;
00172     cmd[1] = 0x01;                          // Active Mode on
00173     m_i2c.write(SPI_W_Address, cmd, 2);               
00174 }
00175 
00176 
00177         //  check if the address exist on an I2C bus 
00178 int MMA7660FC::check()
00179 { 
00180     return m_i2c.write(SPI_W_Address, NULL, 0); 
00181 }