Andrew Lindsay / MAG3110

Simple library for MAG3110 magenetometer as built into Avnet Wi-Go module

Dependencies:   MotionSensor

Dependents:   Wi-Go-MagnetometerTest EE202A_HW1_MH serialtoxively mbed_nanosec_timer ... more

MAG3110.cpp@6:f510561f6107, 2013-12-31 (annotated)

Committer:
mmaas
Date:
Tue Dec 31 17:16:37 2013 +0000
Revision:
6:f510561f6107
Parent:
1:5a0e7a58d980
Child:
7:0f45239e157a
Moved calibrate operation into the library

Who changed what in which revision?

UserRevisionLine numberNew contents of line
SomeRandomBloke 0:63a8594a3866 1
SomeRandomBloke 0:63a8594a3866 2 #include "MAG3110.h"
SomeRandomBloke 0:63a8594a3866 3 #include "mbed.h"
SomeRandomBloke 0:63a8594a3866 4
SomeRandomBloke 0:63a8594a3866 5 /******************************************************************************
SomeRandomBloke 0:63a8594a3866 6 * Constructors
SomeRandomBloke 0:63a8594a3866 7 ******************************************************************************/
mmaas 6:f510561f6107 8 MAG3110::MAG3110(PinName sda, PinName scl): _i2c(sda, scl),
SomeRandomBloke 1:5a0e7a58d980 9 _i2c_address(0x1D), _pc(NULL), _debug(false)
SomeRandomBloke 0:63a8594a3866 10 {
SomeRandomBloke 1:5a0e7a58d980 11 begin();
SomeRandomBloke 1:5a0e7a58d980 12 }
SomeRandomBloke 0:63a8594a3866 13
mmaas 6:f510561f6107 14 MAG3110::MAG3110(PinName sda, PinName scl, Serial *pc): _i2c(sda, scl),
mmaas 6:f510561f6107 15 _i2c_address(0x1D), _pc(pc), _debug(true)
SomeRandomBloke 1:5a0e7a58d980 16 {
SomeRandomBloke 1:5a0e7a58d980 17 begin();
SomeRandomBloke 0:63a8594a3866 18 }
SomeRandomBloke 0:63a8594a3866 19
SomeRandomBloke 1:5a0e7a58d980 20 void MAG3110::begin()
SomeRandomBloke 0:63a8594a3866 21 {
SomeRandomBloke 1:5a0e7a58d980 22 char cmd[2];
SomeRandomBloke 0:63a8594a3866 23
SomeRandomBloke 1:5a0e7a58d980 24 cmd[0] = MAG_CTRL_REG2;
SomeRandomBloke 1:5a0e7a58d980 25 cmd[1] = 0x80;
SomeRandomBloke 1:5a0e7a58d980 26 _i2c.write(_i2c_address, cmd, 2);
SomeRandomBloke 1:5a0e7a58d980 27
SomeRandomBloke 1:5a0e7a58d980 28 cmd[0] = MAG_CTRL_REG1;
SomeRandomBloke 1:5a0e7a58d980 29 cmd[1] = MAG_3110_SAMPLE80+MAG_3110_OVERSAMPLE2+MAG_3110_ACTIVE;
SomeRandomBloke 1:5a0e7a58d980 30 _i2c.write(_i2c_address, cmd, 2);
mmaas 6:f510561f6107 31
SomeRandomBloke 1:5a0e7a58d980 32 // No adjustment initially
SomeRandomBloke 1:5a0e7a58d980 33 _avgX = 0;
SomeRandomBloke 1:5a0e7a58d980 34 _avgY = 0;
SomeRandomBloke 0:63a8594a3866 35 }
SomeRandomBloke 0:63a8594a3866 36
SomeRandomBloke 0:63a8594a3866 37 // Read a single byte form 8 bit register, return as int
SomeRandomBloke 0:63a8594a3866 38 int MAG3110::readReg(char regAddr)
SomeRandomBloke 0:63a8594a3866 39 {
SomeRandomBloke 0:63a8594a3866 40 char cmd[1];
SomeRandomBloke 0:63a8594a3866 41
SomeRandomBloke 0:63a8594a3866 42 cmd[0] = regAddr;
SomeRandomBloke 1:5a0e7a58d980 43 _i2c.write(_i2c_address, cmd, 1);
SomeRandomBloke 0:63a8594a3866 44
SomeRandomBloke 0:63a8594a3866 45 cmd[0] = 0x00;
SomeRandomBloke 1:5a0e7a58d980 46 _i2c.read(_i2c_address, cmd, 1);
SomeRandomBloke 0:63a8594a3866 47 return (int)( cmd[0]);
SomeRandomBloke 0:63a8594a3866 48 }
SomeRandomBloke 0:63a8594a3866 49
SomeRandomBloke 0:63a8594a3866 50
SomeRandomBloke 0:63a8594a3866 51 // read a register per, pass first reg value, reading 2 bytes increments register
SomeRandomBloke 0:63a8594a3866 52 // Reads MSB first then LSB
SomeRandomBloke 0:63a8594a3866 53 int MAG3110::readVal(char regAddr)
SomeRandomBloke 0:63a8594a3866 54 {
SomeRandomBloke 0:63a8594a3866 55 char cmd[2];
SomeRandomBloke 0:63a8594a3866 56
SomeRandomBloke 0:63a8594a3866 57 cmd[0] = regAddr;
SomeRandomBloke 1:5a0e7a58d980 58 _i2c.write(_i2c_address, cmd, 1);
SomeRandomBloke 0:63a8594a3866 59
SomeRandomBloke 0:63a8594a3866 60 cmd[0] = 0x00;
SomeRandomBloke 0:63a8594a3866 61 cmd[1] = 0x00;
SomeRandomBloke 1:5a0e7a58d980 62 _i2c.read(_i2c_address, cmd, 2);
SomeRandomBloke 0:63a8594a3866 63 return (int)( (cmd[1]|(cmd[0] << 8))); //concatenate the MSB and LSB
SomeRandomBloke 0:63a8594a3866 64 }
SomeRandomBloke 0:63a8594a3866 65
SomeRandomBloke 0:63a8594a3866 66
SomeRandomBloke 0:63a8594a3866 67 float MAG3110::getHeading()
SomeRandomBloke 0:63a8594a3866 68 {
SomeRandomBloke 0:63a8594a3866 69 int xVal = readVal(MAG_OUT_X_MSB);
SomeRandomBloke 0:63a8594a3866 70 int yVal = readVal(MAG_OUT_Y_MSB);
SomeRandomBloke 0:63a8594a3866 71 return (atan2((double)(yVal - _avgY),(double)(xVal - _avgX)))*180/PI;
SomeRandomBloke 0:63a8594a3866 72 }
SomeRandomBloke 0:63a8594a3866 73
SomeRandomBloke 0:63a8594a3866 74 void MAG3110::getValues(int *xVal, int *yVal, int *zVal)
SomeRandomBloke 0:63a8594a3866 75 {
SomeRandomBloke 0:63a8594a3866 76 *xVal = readVal(MAG_OUT_X_MSB);
SomeRandomBloke 0:63a8594a3866 77 *yVal = readVal(MAG_OUT_Y_MSB);
SomeRandomBloke 0:63a8594a3866 78 *zVal = readVal(MAG_OUT_Z_MSB);
SomeRandomBloke 0:63a8594a3866 79 }
SomeRandomBloke 0:63a8594a3866 80
SomeRandomBloke 0:63a8594a3866 81
SomeRandomBloke 0:63a8594a3866 82 void MAG3110::setCalibration(int minX, int maxX, int minY, int maxY )
SomeRandomBloke 0:63a8594a3866 83 {
SomeRandomBloke 0:63a8594a3866 84 _avgX=(maxX+minX)/2;
SomeRandomBloke 0:63a8594a3866 85 _avgY=(maxY+minY)/2;
SomeRandomBloke 0:63a8594a3866 86 }
SomeRandomBloke 0:63a8594a3866 87
SomeRandomBloke 0:63a8594a3866 88
SomeRandomBloke 0:63a8594a3866 89
mmaas 6:f510561f6107 90 void MAG3110::calXY(PinName pin, int activeValue )
mmaas 6:f510561f6107 91 {
mmaas 6:f510561f6107 92 DigitalIn calPin(pin);
mmaas 6:f510561f6107 93 int tempXmax, tempXmin, tempYmax, tempYmin, newX, newY;
mmaas 6:f510561f6107 94
mmaas 6:f510561f6107 95
mmaas 6:f510561f6107 96 // Wait for Button Press and Release before beginning calibration
mmaas 6:f510561f6107 97 while(calPin != activeValue) {}
mmaas 6:f510561f6107 98 while(calPin == activeValue) {}
SomeRandomBloke 0:63a8594a3866 99
SomeRandomBloke 0:63a8594a3866 100
mmaas 6:f510561f6107 101 // Read initial values of magnetomoter - read it here to create a slight delay for calPin to settle
mmaas 6:f510561f6107 102 tempXmax = tempXmin = readVal(MAG_OUT_X_MSB);
mmaas 6:f510561f6107 103 tempYmax = tempYmin = readVal(MAG_OUT_Y_MSB);
mmaas 6:f510561f6107 104
mmaas 6:f510561f6107 105 // Update min and max values until calPin asserted again
mmaas 6:f510561f6107 106 while(calPin != activeValue) {
mmaas 6:f510561f6107 107 newX = readVal(MAG_OUT_X_MSB);
mmaas 6:f510561f6107 108 newY = readVal(MAG_OUT_Y_MSB);
mmaas 6:f510561f6107 109 if (newX > tempXmax) tempXmax = newX;
mmaas 6:f510561f6107 110 if (newX < tempXmin) tempXmin = newX;
mmaas 6:f510561f6107 111 if (newY > tempYmax) tempYmax = newY;
mmaas 6:f510561f6107 112 if (newY < tempYmin) tempYmin = newY;
mmaas 6:f510561f6107 113 }
mmaas 6:f510561f6107 114
mmaas 6:f510561f6107 115 setCalibration( tempXmin, tempXmax, tempYmin, tempYmax );
mmaas 6:f510561f6107 116
mmaas 6:f510561f6107 117 }
mmaas 6:f510561f6107 118