Erik - / AK8975

Basic library for interfacing the AK8975 using I2C. It does not include more advanced functions. The datasheet does not include what the self-test should return for example, so this library does not include the self-test function.

AK8975.h@1:76f65416ae1b, 2012-05-07 (annotated)

Committer:
Sissors
Date:
Mon May 07 12:01:10 2012 +0000
Revision:
1:76f65416ae1b
Parent:
0:bceb91239894 
v1.1

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 0:bceb91239894 1 /* Library for AK8975 digital compass IC, for use with I2C
Sissors 0:bceb91239894 2
Sissors 0:bceb91239894 3 This library contains basic functionality, if you want more, make it ;)
Sissors 0:bceb91239894 4
Sissors 0:bceb91239894 5 */
Sissors 0:bceb91239894 6
Sissors 0:bceb91239894 7 #ifndef AK8975_H
Sissors 0:bceb91239894 8 #define AK8975_H
Sissors 0:bceb91239894 9
Sissors 0:bceb91239894 10 /**
Sissors 0:bceb91239894 11 * Includes
Sissors 0:bceb91239894 12 */
Sissors 0:bceb91239894 13 #include "mbed.h"
Sissors 0:bceb91239894 14
Sissors 0:bceb91239894 15 /**
Sissors 0:bceb91239894 16 * Registers
Sissors 0:bceb91239894 17 */
Sissors 0:bceb91239894 18 #define AK8975_ID_REG 0x00
Sissors 0:bceb91239894 19 #define AK8975_ST1_REG 0x02
Sissors 0:bceb91239894 20 #define AK8975_X_REG 0x03
Sissors 0:bceb91239894 21 #define AK8975_Y_REG 0x05
Sissors 0:bceb91239894 22 #define AK8975_Z_REG 0x07
Sissors 0:bceb91239894 23 #define AK8975_ST2_REG 0x09
Sissors 0:bceb91239894 24 #define AK8975_CONTROL_REG 0x0A
Sissors 0:bceb91239894 25 #define AK8975_SELFTEST_REG 0x0C
Sissors 0:bceb91239894 26
Sissors 0:bceb91239894 27 /**
Sissors 0:bceb91239894 28 * Bits
Sissors 0:bceb91239894 29 */
Sissors 0:bceb91239894 30 #define AK8975_DRDY_BIT 0
Sissors 0:bceb91239894 31 #define AK8975_DERROR_BIT 2
Sissors 0:bceb91239894 32 #define AK8975_OFLOW_BIT 3
Sissors 0:bceb91239894 33
Sissors 0:bceb91239894 34 #define AK8975_SINGLE_MEASUREMENT 1
Sissors 0:bceb91239894 35
Sissors 0:bceb91239894 36 #define AK8975_SENSITIVITY 0.3
Sissors 0:bceb91239894 37
Sissors 1:76f65416ae1b 38 /** AK8975 magnetometer/digital compass simple library.
Sissors 1:76f65416ae1b 39 *
Sissors 1:76f65416ae1b 40 * Example:
Sissors 1:76f65416ae1b 41 * @code
Sissors 1:76f65416ae1b 42 * #include "mbed.h"
Sissors 1:76f65416ae1b 43 * #include "AK8975.h"
Sissors 1:76f65416ae1b 44 *
Sissors 1:76f65416ae1b 45 * DigitalOut led1(LED1);
Sissors 1:76f65416ae1b 46 * Serial pc(USBTX, USBRX); // tx, rx
Sissors 1:76f65416ae1b 47 * AK8975 mag(p9,p10,0x0E);
Sissors 1:76f65416ae1b 48 *
Sissors 1:76f65416ae1b 49 *
Sissors 1:76f65416ae1b 50 * int main() {
Sissors 1:76f65416ae1b 51 * int data[3];
Sissors 1:76f65416ae1b 52 * if (mag.testConnection())
Sissors 1:76f65416ae1b 53 * pc.printf("Connection succeeded. \n");
Sissors 1:76f65416ae1b 54 * else
Sissors 1:76f65416ae1b 55 * pc.printf("Connection failed. \n");
Sissors 1:76f65416ae1b 56 *
Sissors 1:76f65416ae1b 57 * while(1) {
Sissors 1:76f65416ae1b 58 * led1=!led1;
Sissors 1:76f65416ae1b 59 * mag.startMeasurement();
Sissors 1:76f65416ae1b 60 * wait(0.5); //(or use the isReady() function)
Sissors 1:76f65416ae1b 61 * mag.getAll(data);
Sissors 1:76f65416ae1b 62 * pc.printf("X: %d", data[0]);
Sissors 1:76f65416ae1b 63 * pc.putc('\n');
Sissors 1:76f65416ae1b 64 * pc.printf("Y: %d", data[1]);
Sissors 1:76f65416ae1b 65 * pc.putc('\n');
Sissors 1:76f65416ae1b 66 * pc.printf("Z: %d", data[2]);
Sissors 1:76f65416ae1b 67 * pc.putc('\n');
Sissors 1:76f65416ae1b 68 * }
Sissors 1:76f65416ae1b 69 * }
Sissors 1:76f65416ae1b 70 * @endcode
Sissors 1:76f65416ae1b 71 */
Sissors 0:bceb91239894 72 class AK8975 {
Sissors 0:bceb91239894 73 public:
Sissors 0:bceb91239894 74 /**
Sissors 0:bceb91239894 75 * Constructor.
Sissors 0:bceb91239894 76 *
Sissors 0:bceb91239894 77 * @param sda - mbed pin to use for the SDA I2C line.
Sissors 0:bceb91239894 78 * @param scl - mbed pin to use for the SCL I2C line.
Sissors 0:bceb91239894 79 * @param I2Caddress - the I2C address of the device (0x0C - 0x0F)
Sissors 0:bceb91239894 80 */
Sissors 0:bceb91239894 81 AK8975(PinName sda, PinName scl, char address);
Sissors 0:bceb91239894 82
Sissors 0:bceb91239894 83 /**
Sissors 0:bceb91239894 84 * Checks connection with the device.
Sissors 0:bceb91239894 85 *
Sissors 0:bceb91239894 86 * @return - true if working connection, otherwise false
Sissors 0:bceb91239894 87 */
Sissors 0:bceb91239894 88 bool testConnection( void );
Sissors 0:bceb91239894 89
Sissors 0:bceb91239894 90 /**
Sissors 0:bceb91239894 91 * Checks if measurement is ready
Sissors 0:bceb91239894 92 *
Sissors 0:bceb91239894 93 * @return - true if available measurement, otherwise false
Sissors 0:bceb91239894 94 */
Sissors 0:bceb91239894 95 bool isReady( void );
Sissors 0:bceb91239894 96
Sissors 0:bceb91239894 97 /**
Sissors 0:bceb91239894 98 * Gets the X data
Sissors 0:bceb91239894 99 *
Sissors 0:bceb91239894 100 * @return - signed integer containing the raw data
Sissors 0:bceb91239894 101 */
Sissors 0:bceb91239894 102 int getX( void );
Sissors 0:bceb91239894 103
Sissors 0:bceb91239894 104 /**
Sissors 0:bceb91239894 105 * Gets the Y data
Sissors 0:bceb91239894 106 *
Sissors 0:bceb91239894 107 * @return - signed integer containing the raw data
Sissors 0:bceb91239894 108 */
Sissors 0:bceb91239894 109 int getY( void );
Sissors 0:bceb91239894 110
Sissors 0:bceb91239894 111 /**
Sissors 0:bceb91239894 112 * Gets the Z data
Sissors 0:bceb91239894 113 *
Sissors 0:bceb91239894 114 * @return - signed integer containing the raw data
Sissors 0:bceb91239894 115 */
Sissors 0:bceb91239894 116 int getZ( void );
Sissors 0:bceb91239894 117
Sissors 0:bceb91239894 118 /**
Sissors 0:bceb91239894 119 * Gets all the data, this is more efficient than calling the functions individually
Sissors 0:bceb91239894 120 *
Sissors 0:bceb91239894 121 * @param data - pointer to integer array with length 3 where data is stored (data[0]=X - data[1]=Y - data[2]=Z)
Sissors 0:bceb91239894 122 */
Sissors 0:bceb91239894 123 void getAll( int *data );
Sissors 0:bceb91239894 124
Sissors 0:bceb91239894 125
Sissors 0:bceb91239894 126
Sissors 0:bceb91239894 127 /**
Sissors 0:bceb91239894 128 * Checks if there is a data error due to reading at wrong moment
Sissors 0:bceb91239894 129 *
Sissors 0:bceb91239894 130 * @return - true for error, false for no error
Sissors 0:bceb91239894 131 */
Sissors 0:bceb91239894 132 bool getDataError( void );
Sissors 0:bceb91239894 133
Sissors 0:bceb91239894 134 /**
Sissors 0:bceb91239894 135 * Checks if a magnetic overflow happened (sensor saturation)
Sissors 0:bceb91239894 136 *
Sissors 0:bceb91239894 137 * @return - true for error, false for no error
Sissors 0:bceb91239894 138 */
Sissors 0:bceb91239894 139 bool getOverflow( void );
Sissors 0:bceb91239894 140
Sissors 0:bceb91239894 141 /**
Sissors 0:bceb91239894 142 * Starts a measurement cycle
Sissors 0:bceb91239894 143 */
Sissors 0:bceb91239894 144 void startMeasurement( void );
Sissors 0:bceb91239894 145
Sissors 0:bceb91239894 146
Sissors 0:bceb91239894 147
Sissors 0:bceb91239894 148 private:
Sissors 0:bceb91239894 149 I2C connection;
Sissors 0:bceb91239894 150 char deviceAddress;
Sissors 0:bceb91239894 151
Sissors 0:bceb91239894 152 /**
Sissors 0:bceb91239894 153 * Writes data to the device
Sissors 0:bceb91239894 154 *
Sissors 0:bceb91239894 155 * @param adress - register address to write to
Sissors 0:bceb91239894 156 * @param data - data to write
Sissors 0:bceb91239894 157 */
Sissors 0:bceb91239894 158 void write( char address, char data);
Sissors 0:bceb91239894 159
Sissors 0:bceb91239894 160 /**
Sissors 0:bceb91239894 161 * Read data from the device
Sissors 0:bceb91239894 162 *
Sissors 0:bceb91239894 163 * @param adress - register address to write to
Sissors 0:bceb91239894 164 * @return - data from the register specified by RA
Sissors 0:bceb91239894 165 */
Sissors 0:bceb91239894 166 char read( char adress);
Sissors 0:bceb91239894 167
Sissors 0:bceb91239894 168 /**
Sissors 0:bceb91239894 169 * Read multtiple regigsters from the device, more efficient than using multiple normal reads.
Sissors 0:bceb91239894 170 *
Sissors 0:bceb91239894 171 * @param adress - register address to write to
Sissors 0:bceb91239894 172 * @param length - number of bytes to read
Sissors 0:bceb91239894 173 * @param data - pointer where the data needs to be written to
Sissors 0:bceb91239894 174 */
Sissors 0:bceb91239894 175 void read( char adress, char *data, int length);
Sissors 0:bceb91239894 176 };
Sissors 0:bceb91239894 177 #endif