Maor Tanami / Mbed 2 deprecated Final_Project

Example of reading and magnetometer sensor (HMC5883L)

Dependencies:   MODSERIAL mbed-rtos mbed

Fork of ReadingMag_HMC5883L by José Claudio

HMC5883L.cpp@1:aea254b39529, 2016-05-24 (annotated)

Committer:
Maor_T
Date:
Tue May 24 12:08:14 2016 +0000
Revision:
1:aea254b39529
Parent:
0:6bc5f85ca6fa 
amir

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jose_claudiojr 0:6bc5f85ca6fa 1 #include "HMC5883L.h"
jose_claudiojr 0:6bc5f85ca6fa 2
jose_claudiojr 0:6bc5f85ca6fa 3 HMC5883L::HMC5883L(PinName sda, PinName scl): i2c(sda, scl)
jose_claudiojr 0:6bc5f85ca6fa 4 {
jose_claudiojr 0:6bc5f85ca6fa 5 //100KHz, as specified by the datasheet.
jose_claudiojr 0:6bc5f85ca6fa 6 char rx;
jose_claudiojr 0:6bc5f85ca6fa 7
jose_claudiojr 0:6bc5f85ca6fa 8
jose_claudiojr 0:6bc5f85ca6fa 9 i2c.frequency(100000);
jose_claudiojr 0:6bc5f85ca6fa 10 //Testar depois com 400KHz
jose_claudiojr 0:6bc5f85ca6fa 11 //==========================================================================================================
jose_claudiojr 0:6bc5f85ca6fa 12 // Read chip_id
jose_claudiojr 0:6bc5f85ca6fa 13 //==========================================================================================================
jose_claudiojr 0:6bc5f85ca6fa 14 rx = Read(HMC5883L_IDENT_A);
jose_claudiojr 0:6bc5f85ca6fa 15 if (rx != 0x48)//ID do chip
jose_claudiojr 0:6bc5f85ca6fa 16 printf("\ninvalid chip id %d\r\n", rx);
jose_claudiojr 0:6bc5f85ca6fa 17
jose_claudiojr 0:6bc5f85ca6fa 18 //==========================================================================================================
jose_claudiojr 0:6bc5f85ca6fa 19 // Let's set the Configuration Register A
jose_claudiojr 0:6bc5f85ca6fa 20 //==========================================================================================================
jose_claudiojr 0:6bc5f85ca6fa 21 // This register set's the number of samples averaged per measurement output, the rate at which data is written
jose_claudiojr 0:6bc5f85ca6fa 22 // to all three data output registers and the measurement flow of the device.
jose_claudiojr 0:6bc5f85ca6fa 23 // -------------------------------------------------------
jose_claudiojr 0:6bc5f85ca6fa 24 // |CRA7 CRA6 CRA5 CRA4 CRA3 CRA2 CRA1 CRA0 |
jose_claudiojr 0:6bc5f85ca6fa 25 // |(1) MA1(1) MA0(1) DO2(1) DO1(0) DO0(0) MS1(0) MS0(0)| -> This is the default value
jose_claudiojr 0:6bc5f85ca6fa 26 // -------------------------------------------------------
jose_claudiojr 0:6bc5f85ca6fa 27 // CRA7 -> we have to clear this bit for correct operation (0)
jose_claudiojr 0:6bc5f85ca6fa 28 // CRA6 to CRA5 -> Let's select the maximum number of samples averaged per measurement output (11)
jose_claudiojr 0:6bc5f85ca6fa 29 // CRA4 to CRA2 -> Also let's select the maximum data output rate (110)
jose_claudiojr 0:6bc5f85ca6fa 30 // CRA1 to CRA0 -> The measurement flow is defined to normal (00)
jose_claudiojr 0:6bc5f85ca6fa 31 // -------------------------------------------------------
jose_claudiojr 0:6bc5f85ca6fa 32 // |CRA7 CRA6 CRA5 CRA4 CRA3 CRA2 CRA1 CRA0 |
jose_claudiojr 0:6bc5f85ca6fa 33 // |(0) MA1(1) MA0(1) DO2(1) DO1(1) DO0(0) MS1(0) MS0(0)| -> This is the new value, 0x78 in hex
jose_claudiojr 0:6bc5f85ca6fa 34 // -------------------------------------------------------
jose_claudiojr 0:6bc5f85ca6fa 35 //Write(HMC5883L_CONFIG_A,0x78);
jose_claudiojr 0:6bc5f85ca6fa 36 //Write(HMC5883L_CONFIG_A,0x70);
jose_claudiojr 0:6bc5f85ca6fa 37
jose_claudiojr 0:6bc5f85ca6fa 38 //==========================================================================================================
jose_claudiojr 0:6bc5f85ca6fa 39 // The Configuration Register B is set to 0010 0000 by default, this is a +/- 1.3 Ga sensor field range and
jose_claudiojr 0:6bc5f85ca6fa 40 // the gain of LSB/gauss is 1090. This is the maximum value, so let's leave it like that.
jose_claudiojr 0:6bc5f85ca6fa 41 //==========================================================================================================
jose_claudiojr 0:6bc5f85ca6fa 42 //Datasheet page 13. I will explain later
jose_claudiojr 0:6bc5f85ca6fa 43 //Write(HMC5883L_CONFIG_B,0x20);
jose_claudiojr 0:6bc5f85ca6fa 44 //Write(HMC5883L_CONFIG_B,0xA0);
jose_claudiojr 0:6bc5f85ca6fa 45
jose_claudiojr 0:6bc5f85ca6fa 46 //==========================================================================================================
jose_claudiojr 0:6bc5f85ca6fa 47 // Let's set the Mode Register
jose_claudiojr 0:6bc5f85ca6fa 48 //==========================================================================================================
jose_claudiojr 0:6bc5f85ca6fa 49 // This register set's the operation mode, from continuous-measurements mode, single-measurement mode and idle mode.
jose_claudiojr 0:6bc5f85ca6fa 50 // We will set to Continuouse-measurement mode, so the device continuously performs measurements and places the
jose_claudiojr 0:6bc5f85ca6fa 51 // result in the data register
jose_claudiojr 0:6bc5f85ca6fa 52 // ---------------------------------------------
jose_claudiojr 0:6bc5f85ca6fa 53 // |MR7 MR6 MR5 MR4 MR3 MR2 MR1 MR0 | -> This is the new value, 0x78 in hex, we are going to change
jose_claudiojr 0:6bc5f85ca6fa 54 // |(1) (0) (0) (0) (0) (0) MD1(0) MD0(1)| the MD1 and MD0 to 00 and clear the MR7 for correct operation.
jose_claudiojr 0:6bc5f85ca6fa 55 // --------------------------------------------- The final value is 0000 0000 (0x00).
jose_claudiojr 0:6bc5f85ca6fa 56 Write(HMC5883L_MODE,0x00);
jose_claudiojr 0:6bc5f85ca6fa 57 }
jose_claudiojr 0:6bc5f85ca6fa 58
jose_claudiojr 0:6bc5f85ca6fa 59
jose_claudiojr 0:6bc5f85ca6fa 60 void HMC5883L::Write(char reg_address, char data)
jose_claudiojr 0:6bc5f85ca6fa 61 {
jose_claudiojr 0:6bc5f85ca6fa 62 char tx[2];
jose_claudiojr 0:6bc5f85ca6fa 63 tx[0]=reg_address;
jose_claudiojr 0:6bc5f85ca6fa 64 tx[1]=data;
jose_claudiojr 0:6bc5f85ca6fa 65
jose_claudiojr 0:6bc5f85ca6fa 66 i2c.write(HMC5883L_I2C_WRITE,tx,2);
jose_claudiojr 0:6bc5f85ca6fa 67 }
jose_claudiojr 0:6bc5f85ca6fa 68
jose_claudiojr 0:6bc5f85ca6fa 69 char HMC5883L::Read(char data)
jose_claudiojr 0:6bc5f85ca6fa 70 {
jose_claudiojr 0:6bc5f85ca6fa 71 char tx = data;
jose_claudiojr 0:6bc5f85ca6fa 72 char rx;
jose_claudiojr 0:6bc5f85ca6fa 73
jose_claudiojr 0:6bc5f85ca6fa 74 i2c.write(HMC5883L_I2C_WRITE, &tx, 1);
jose_claudiojr 0:6bc5f85ca6fa 75 i2c.read(HMC5883L_I2C_READ, &rx, 1);
jose_claudiojr 0:6bc5f85ca6fa 76 return rx;
jose_claudiojr 0:6bc5f85ca6fa 77 }
jose_claudiojr 0:6bc5f85ca6fa 78
jose_claudiojr 0:6bc5f85ca6fa 79 void HMC5883L::MultiByteRead(char address, char* output, int size)
jose_claudiojr 0:6bc5f85ca6fa 80 {
jose_claudiojr 0:6bc5f85ca6fa 81 i2c.write(HMC5883L_I2C_WRITE, &address, 1); //tell it where to read from
jose_claudiojr 0:6bc5f85ca6fa 82 i2c.read(HMC5883L_I2C_READ, output, size); //tell it where to store the data read
jose_claudiojr 0:6bc5f85ca6fa 83 }
jose_claudiojr 0:6bc5f85ca6fa 84
jose_claudiojr 0:6bc5f85ca6fa 85 float HMC5883L::getMx()
jose_claudiojr 0:6bc5f85ca6fa 86 {
jose_claudiojr 0:6bc5f85ca6fa 87 //return (x * m_Scale);
jose_claudiojr 0:6bc5f85ca6fa 88 char lsb_byte = 0;
jose_claudiojr 0:6bc5f85ca6fa 89 signed short msb_byte;
jose_claudiojr 0:6bc5f85ca6fa 90
jose_claudiojr 0:6bc5f85ca6fa 91 lsb_byte = Read(HMC5883L_X_MSB);
jose_claudiojr 0:6bc5f85ca6fa 92 msb_byte = lsb_byte << 8;
jose_claudiojr 0:6bc5f85ca6fa 93 msb_byte |= Read(HMC5883L_X_LSB);
jose_claudiojr 0:6bc5f85ca6fa 94 return (float)msb_byte;
jose_claudiojr 0:6bc5f85ca6fa 95 /*
jose_claudiojr 0:6bc5f85ca6fa 96 char tx[1];
jose_claudiojr 0:6bc5f85ca6fa 97 char rx[2];
jose_claudiojr 0:6bc5f85ca6fa 98
jose_claudiojr 0:6bc5f85ca6fa 99
jose_claudiojr 0:6bc5f85ca6fa 100 tx[0]=HMC5883L_X_MSB;
jose_claudiojr 0:6bc5f85ca6fa 101 i2c.write(HMC5883L_I2C_READ,tx,1);
jose_claudiojr 0:6bc5f85ca6fa 102 i2c.read(HMC5883L_I2C_READ,rx,2);
jose_claudiojr 0:6bc5f85ca6fa 103 return ((int)rx[0]<<8|(int)rx[1]);
jose_claudiojr 0:6bc5f85ca6fa 104 */
jose_claudiojr 0:6bc5f85ca6fa 105
jose_claudiojr 0:6bc5f85ca6fa 106 }
jose_claudiojr 0:6bc5f85ca6fa 107
jose_claudiojr 0:6bc5f85ca6fa 108 float HMC5883L::getMy()
jose_claudiojr 0:6bc5f85ca6fa 109 {
jose_claudiojr 0:6bc5f85ca6fa 110 //return (y * m_Scale);
jose_claudiojr 0:6bc5f85ca6fa 111
jose_claudiojr 0:6bc5f85ca6fa 112 char lsb_byte = 0;
jose_claudiojr 0:6bc5f85ca6fa 113 signed short msb_byte;
jose_claudiojr 0:6bc5f85ca6fa 114
jose_claudiojr 0:6bc5f85ca6fa 115 lsb_byte = Read(HMC5883L_Y_MSB);
jose_claudiojr 0:6bc5f85ca6fa 116 msb_byte = lsb_byte << 8;
jose_claudiojr 0:6bc5f85ca6fa 117 msb_byte |= Read(HMC5883L_Y_LSB);
jose_claudiojr 0:6bc5f85ca6fa 118 return (float)msb_byte;
jose_claudiojr 0:6bc5f85ca6fa 119 }
jose_claudiojr 0:6bc5f85ca6fa 120
jose_claudiojr 0:6bc5f85ca6fa 121
jose_claudiojr 0:6bc5f85ca6fa 122 float HMC5883L::getMz()
jose_claudiojr 0:6bc5f85ca6fa 123 {
jose_claudiojr 0:6bc5f85ca6fa 124 //return (z * m_Scale);
jose_claudiojr 0:6bc5f85ca6fa 125
jose_claudiojr 0:6bc5f85ca6fa 126 char lsb_byte = 0;
jose_claudiojr 0:6bc5f85ca6fa 127 signed short msb_byte;
jose_claudiojr 0:6bc5f85ca6fa 128
jose_claudiojr 0:6bc5f85ca6fa 129 lsb_byte = Read(HMC5883L_Z_MSB);
jose_claudiojr 0:6bc5f85ca6fa 130 msb_byte = lsb_byte << 8;
jose_claudiojr 0:6bc5f85ca6fa 131 msb_byte |= Read(HMC5883L_Z_LSB);
jose_claudiojr 0:6bc5f85ca6fa 132 return (float)msb_byte;
jose_claudiojr 0:6bc5f85ca6fa 133 }