Library for the MMA7660 triple axis accelerometer

Dependents:   mbed_Shield_LCD_Accelerometer mbed_Shield_Accelerometer

Fork of MMA7660 by Erik -

MMA7660.cpp

Committer:
Sissors
Date:
2012-10-14
Revision:
0:7bc29a9ea016
Child:
1:8997a1b348dd

File content as of revision 0:7bc29a9ea016:

#include "MMA7660.h"

MMA7660::MMA7660(PinName sda, PinName scl, PinName interrupt) : _i2c(sda, scl)
{
    _interrupt = interrupt;
    active = false;
    samplerate = 120;
}

//Since the MMA lacks a WHO_AM_I register, we can only check if there is a device that answers to the I2C address
bool MMA7660::testConnection( void )
{
    if (_i2c.write(MMA7660_ADDRESS, NULL, 0) == 0 )
        return true;
    else
        return false;
}

void MMA7660::setActive(bool state)
{
    char modereg = read(MMA7660_MODE_R);
    modereg &= ~(1<<0);

    //If it somehow was in testmode, disable that
    if (modereg && (1<<2)) {
        modereg &= ~(1<<2);
        write(MMA7660_MODE_R, modereg);
    }

    modereg += state;
    write(MMA7660_MODE_R, modereg);
}

//Add timeout!
void MMA7660::readData(int *data)
{
    if (!active) {
        setActive(true);
        active = true;
    }

    char temp[3];
    bool alert;

    do {
        alert = false;
        read(MMA7660_XOUT_R, temp, 3);
        for (int i = 0; i<3; i++) {
            if (temp[i] > 63)
                alert = true;
            if (temp[i] > 31)
                temp[i] += 128+64;
            data[i] = (signed char)temp[i];
        }
    } while (alert);
}

void MMA7660::readData(float *data)
{
    int intdata[3];
    readData(intdata);
    for (int i = 0; i<3; i++)
        data[i] = intdata[i]/MMA7660_SENSITIVITY;
}

float MMA7660::getX( void ) {
    return getSingle(0);
    }

float MMA7660::getY( void ) {
    return getSingle(1);
    }
    
float MMA7660::getZ( void ) {
    return getSingle(2);
    }        

void MMA7660::write(char address, char data)
{
    char temp[2];
    temp[0]=address;
    temp[1]=data;

    _i2c.write(MMA7660_ADDRESS, temp, 2);
}

char MMA7660::read(char address)
{
    char retval;
    _i2c.write(MMA7660_ADDRESS, &address, 1, true);
    _i2c.read(MMA7660_ADDRESS, &retval, 1);
    return retval;
}

void MMA7660::read(char address, char *data, int length)
{
    _i2c.write(MMA7660_ADDRESS, &address, 1, true);
    _i2c.read(MMA7660_ADDRESS, data, length);
}

float MMA7660::getSingle( int number )
{
    if (!active) {
        setActive(true);
        active = true;
    }

    signed char temp;
    bool alert;

    do {
        alert = false;
        temp = read(MMA7660_XOUT_R + number);
        if (temp > 63)
            alert = true;
        if (temp > 31)
            temp += 128+64;
    }

    while (alert);

    return temp / MMA7660_SENSITIVITY;
}