Diff: MMA7660/MMA7660.cpp

Revision:

0:8b08136c5edd

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MMA7660/MMA7660.cpp	Mon Mar 24 17:48:19 2014 +0000
@@ -0,0 +1,193 @@
+#include "MMA7660.h"
+
+MMA7660::MMA7660(PinName sda, PinName scl, bool active) : _i2c(sda, scl)
+{
+    setActive(active);
+    samplerate = 64;
+
+}
+
+//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);
+}
+
+void MMA7660::readData(int *data)
+{
+    if (!active) {
+        setActive(true);
+        active = true;
+        wait(0.012 + 1/samplerate); //Wait until new sample is ready, my experience is that 1/samplerate isnt needed, but datasheet says so
+    }
+
+    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);
+
+    if (!active)
+        setActive(false);
+}
+
+
+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::x( void )
+{
+    return getSingle(0);
+}
+
+float MMA7660::y( void )
+{
+    return getSingle(1);
+}
+
+float MMA7660::z( void )
+{
+    return getSingle(2);
+}
+
+
+void MMA7660::setSampleRate(int samplerate)
+{
+    setActive(false);                               //Not allowed to be active to change anything
+    int rates[] = {120, 64, 32, 16, 8, 4, 2, 1};    //Alowed samplerates (and their number in array is also number required for MMA)
+    int sampleLoc = 0, sampleError = 10000, temp;
+    for (int i = 0; i<8; i++) {
+        temp = abs( rates[i] - samplerate );
+        if (temp<sampleError) {
+            sampleLoc = i;
+            sampleError=temp;
+        }
+    }
+
+    //Update the samplerate reg
+    temp = read(MMA7660_SR_R);
+    temp &= ~0x07;                                  //Awake sample rate are lowest 3 bit
+    temp |= sampleLoc;
+    write(MMA7660_SR_R, temp);
+    this->samplerate = rates[sampleLoc];
+    setActive(active);                              //Restore previous active state
+}
+
+
+MMA7660::Orientation MMA7660::getSide( void )
+{
+    char tiltreg = read(MMA7660_TILT_R);
+
+    //We care about 2 LSBs
+    tiltreg &= 0x03;
+    if (tiltreg == 0x01)
+        return MMA7660::Front;
+    if (tiltreg == 0x02)
+        return MMA7660::Back;
+    return MMA7660::Unknown;
+}
+
+MMA7660::Orientation MMA7660::getOrientation( void )
+{
+    char tiltreg = read(MMA7660_TILT_R);
+
+    //We care about bit 2, 3 and 4 (counting from zero)
+    tiltreg &= 0x07<<2;
+    tiltreg >>= 2;
+    if (tiltreg == 0x01)
+        return MMA7660::Left;
+    if (tiltreg == 0x02)
+        return MMA7660::Right;
+    if (tiltreg == 0x05)
+        return MMA7660::Down;
+    if (tiltreg == 0x06)
+        return MMA7660::Up;
+    return MMA7660::Unknown;
+}
+
+
+
+//////////////////////////////////////////////
+///////////////PRIVATE////////////////////////
+//////////////////////////////////////////////
+
+
+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);
+        wait(0.012 + 1/samplerate); //Wait until new sample is ready
+    }
+
+    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);
+
+    if (!active)
+        setActive(false);
+
+    return temp / MMA7660_SENSITIVITY;
+}
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