Revision 0:7bc29a9ea016, committed 2012-10-14

Comitter:

Sissors

Date:

Sun Oct 14 08:02:53 2012 +0000

Child:

1:8997a1b348dd

Commit message:

v0.1

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MMA7660.cpp	Sun Oct 14 08:02:53 2012 +0000
@@ -0,0 +1,123 @@
+#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;
+}
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MMA7660.h	Sun Oct 14 08:02:53 2012 +0000
@@ -0,0 +1,115 @@
+#include "mbed.h"
+
+
+#ifndef MMA7660_H
+#define MMA7660_H
+
+#define MMA7660_ADDRESS     0x98
+#define MMA7660_SENSITIVITY 21.33
+
+#define MMA7660_XOUT_R      0x00
+#define MMA7660_YOUT_R      0x01
+#define MMA7660_ZOUT_R      0x02
+#define MMA7660_MODE_R      0x07
+
+class MMA7660
+{
+public:
+    /**
+    * Creates a new MMA7660 object
+    *
+    * @param sda - I2C data pin
+    * @param scl - I2C clock pin
+    * @param interrupt - Interrupt pin (default = NC)
+    */
+    MMA7660(PinName sda, PinName scl, PinName interrupt = NC);
+
+    /**
+    * Tests if communication is possible with the MMA7660
+    *
+    * Because the MMA7660 lacks a WHO_AM_I register, this function can only check
+    * if there is an I2C device that responds to the MMA7660 address
+    *
+    * @param return - true for successfull connection, false for no connection
+    */
+    bool testConnection( void );
+    
+    /**
+    * Sets the active state of the MMA7660
+    *
+    * Note: This is unrelated to awake/sleep mode
+    *
+    * @param state - true for active, false for standby
+    */
+    void setActive( bool state);
+    
+    /**
+    * Reads acceleration data from the sensor
+    *
+    * When the parameter is a pointer to an integer array it will be the raw data. 
+    * When it is a pointer to a float array it will be the acceleration in g's
+    * 
+    * @param data - pointer to array with length 3 where the acceleration data will be stores, X-Y-Z
+    */
+    void readData( int *data);
+    void readData( float *data);
+    
+    /** Get X-data
+    *
+    * @param return - X-acceleration in g's
+    */
+    float getX( void );
+    
+    /** Get Y-data
+    *
+    * @param return - Y-acceleration in g's
+    */
+    float getY( void );
+    
+    /** Get Z-data
+    *
+    * @param return - Z-acceleration in g's
+    */
+    float getZ( void );        
+
+
+private:
+
+    /**
+    * Writes data to the device, could be private, but public is handy so you can transmit directly to the MPU.
+    *
+    * @param adress - register address to write to
+    * @param data - data to write
+    */
+    void write( char address, char data);
+
+    /**
+    * Read data from the device, could be private, but public is handy so you can transmit directly to the MPU.
+    *
+    * @param adress - register address to write to
+    * @return - data from the register specified by RA
+    */
+    char read( char adress);
+    
+    /**
+     * Read multiple regigsters from the device, more efficient than using multiple normal reads. 
+     *
+     * @param adress - register address to write to
+     * @param length - number of bytes to read
+     * @param data - pointer where the data needs to be written to 
+     */
+     void read( char adress, char *data, int length);
+     
+     /**
+     * Reads single axis
+     */
+     float getSingle(int number);
+
+    I2C _i2c;
+    bool active;
+    PinName _interrupt;
+    float samplerate;
+};
+
+
+#endif