File content as of revision 2:66db0f91b215:

// Author: Nicholas Herriot
/* Copyright (c) 2013 Vodafone, MIT License
 *
 * 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 "MMA8452.h"



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}; 
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};



// Connect module at I2C address using I2C port pins sda and scl
Accelerometer_MMA8452::Accelerometer_MMA8452(PinName sda, PinName scl,int frequency) : m_i2c(sda, scl) , m_frequency(frequency)
{
    //m_i2c.frequency(m_frequency);
}


// Destroys instance
Accelerometer_MMA8452::~Accelerometer_MMA8452()
{

}

// Setting the control register bit 1 to true to activate the MMA8452
int Accelerometer_MMA8452::activate()
{
    char mcu_address = (MMA8452_ADDRESS<<1);
    char init[2];
    init[0] = CTRL_REG_1;                 // control register 1
    init[1] = 0x01;                       // set to active
    //while(m_i2c.write(mcu_address,init,2));
    
    if(m_i2c.write(mcu_address,init,2) == 0)
    {
         // pc.printf("The initialisation worked");
         return 0;  // return 0 to indicate success
    }
    else
    {
        // pc.printf("The initialisation failed");
        return 1;   // crumbs it failed!!!
    }
         
}


// Device initialization
void Accelerometer_MMA8452::init()
{
    
    write_reg(INTSU_STATUS, 0x10);      // automatic interrupt after every measurement
    write_reg(SR_STATUS, 0x00);         // 120 Samples/Second
    write_reg(MODE_STATUS, 0x01);       // Active Mode
    
}


// Get device ID 
int Accelerometer_MMA8452::get_DeviceID(int& deviceID)
{
    char mcu_address = (MMA8452_ADDRESS<<1);
    int z = 0;
    m_i2c.start();
    wait( 0.1);
    if( m_i2c.write( mcu_address) == 0) 
    {
        //printf( "GetDeviceId NAK on writing address");
        return 1;
    }
    wait( 0.1);
    if( m_i2c.write( WHO_AM_I) == 0) 
    {
        //printf( "GetDeviceId NAK on writing register address");

        return 1;
    }
    wait( 0.1);
    m_i2c.start();
    wait( 0.1);
    if( m_i2c.write( mcu_address | 0x01) == 0)          // this is asking to read the slave address - even though it's a 'write' method!!! Crap API...
    {
        //printf( "GetDeviceId NAK on writing address");

        return 1;
    }
    wait( 0.1);
    deviceID  = m_i2c.read(0);
    z = m_i2c.read(0);
    wait( 0.1);
    m_i2c.stop();
    return 0;

}


// Reads the tilt angle
void Accelerometer_MMA8452::read_Tilt(float *x, float *y, float *z)
{

    const char Addr_X = OUT_X_MSB;
    char buf[3] = {0,0,0};
    
    m_i2c.write(MMA8452_ADDRESS, &Addr_X, 1);         // Pointer to the OUT_X_MSB register
    m_i2c.read(MMA8452_ADDRESS, buf, 3);              // Read register content into buffer with 6bit
    
    // returns the x, y, z coordinates transformed into full degrees
    *x = TILT_XY[(int)buf[0]];
    *y = TILT_XY[(int)buf[1]];
    *z = TILT_Z[(int)buf[2]];      
  
}


// Reads x data
int Accelerometer_MMA8452::read_x()
{
    char mcu_address = (MMA8452_ADDRESS <<1);

    m_i2c.start();                      // Start
    m_i2c.write(mcu_address);           // A write to devic
    m_i2c.write(OUT_X_LSB);             // Register to read
    m_i2c.start();                  
    m_i2c.write(mcu_address);           // Read from device
    int x = m_i2c.read(0);             // Read the data
    m_i2c.stop();
    
    return x;  

}


// Reads y data
int Accelerometer_MMA8452::read_y()
{
    char mcu_address = (MMA8452_ADDRESS <<1);

    m_i2c.start();                  // Start
    m_i2c.write(mcu_address);              // A write to device 0x98
    m_i2c.write(OUT_Y_MSB);             // Register to read
    m_i2c.start();                  
    m_i2c.write(mcu_address);              // Read from device 0x99
    int y = m_i2c.read(0);         // Read the data
    m_i2c.stop();
    
    return y; 

}


// Reads z data
int Accelerometer_MMA8452::read_z()
{
    char mcu_address = (MMA8452_ADDRESS <<1);
    
    m_i2c.start();                  // Start
    m_i2c.write(mcu_address);              // A write to device 0x98
    m_i2c.write(OUT_Z_MSB);             // Register to read
    m_i2c.start();                  
    m_i2c.write(mcu_address);              // Read from device 0x99
    int z = m_i2c.read(0);         // Read the data
    m_i2c.stop();
    
    return z;

}


// Reads xyz
int Accelerometer_MMA8452::read_xyz(char *x, char *y, char *z) 
{
    
    
    char mcu_address = (MMA8452_ADDRESS <<1);
    char register_buffer[6] ={0,0,0,0,0,0};
    const char Addr_X = OUT_X_MSB;
    m_i2c.write(mcu_address);              // A write to device 0x98
    m_i2c.write(MMA8452_ADDRESS, &Addr_X, 1);         // Pointer to the OUT_X_MSB register
    
    if(m_i2c.write(mcu_address,&Addr_X,1) == 0)
    {
        if(m_i2c.read(mcu_address,register_buffer,6) == 0)
        {
            *x = register_buffer[1];
            *y = register_buffer[3];
            *z = register_buffer[5];
            return 0;           // yahoooooo
        }
        else
        {
            return 1;           // failed oh nooo!
        }    
    }
    else
    {
        return 1;               // failed oh nooo!
    }

}

        // Write register (The device must be placed in Standby Mode to change the value of the registers) 
void Accelerometer_MMA8452::write_reg(char addr, char data)
{

    char cmd[2] = {0, 0};
    
    cmd[0] = MODE_STATUS;
    cmd[1] = 0x00;                      // Standby Mode on
    m_i2c.write(MMA8452_ADDRESS, cmd, 2);
  
    cmd[0] = addr;
    cmd[1] = data;                      // New value of the register
    m_i2c.write(MMA8452_ADDRESS, cmd, 2); 
      
    cmd[0] = MODE_STATUS;
    cmd[1] = 0x01;                      // Active Mode on
    m_i2c.write(MMA8452_ADDRESS, cmd, 2);
                  
}



        // Read from specified MMA7660FC register
char Accelerometer_MMA8452::read_reg(char addr)
{
    
    m_i2c.start();                  // Start
    m_i2c.write(0x98);              // A write to device 0x98
    m_i2c.write(addr);              // Register to read
    m_i2c.start();                  
    m_i2c.write(0x99);              // Read from device 0x99
    char c = m_i2c.read(0);         // Read the data
    m_i2c.stop();                   
 
    return c;
    
}