Project group 3 / CMPS03

CMPS03 digital compass library.

Fork of CMPS03 by Aaron Berk

CMPS03.cpp@0:c6bcc390612a, 2010-11-27 (annotated)

Committer:
aberk
Date:
Sat Nov 27 12:09:27 2010 +0000
Revision:
0:c6bcc390612a
Child:
1:1585ed4179f0
Version 1.0

Who changed what in which revision?

UserRevisionLine numberNew contents of line
aberk 0:c6bcc390612a 1 /**
aberk 0:c6bcc390612a 2 * @author Aaron Berk
aberk 0:c6bcc390612a 3 *
aberk 0:c6bcc390612a 4 * @section LICENSE
aberk 0:c6bcc390612a 5 *
aberk 0:c6bcc390612a 6 * Copyright (c) 2010 ARM Limited
aberk 0:c6bcc390612a 7 *
aberk 0:c6bcc390612a 8 * Permission is hereby granted, free of charge, to any person obtaining a copy
aberk 0:c6bcc390612a 9 * of this software and associated documentation files (the "Software"), to deal
aberk 0:c6bcc390612a 10 * in the Software without restriction, including without limitation the rights
aberk 0:c6bcc390612a 11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
aberk 0:c6bcc390612a 12 * copies of the Software, and to permit persons to whom the Software is
aberk 0:c6bcc390612a 13 * furnished to do so, subject to the following conditions:
aberk 0:c6bcc390612a 14 *
aberk 0:c6bcc390612a 15 * The above copyright notice and this permission notice shall be included in
aberk 0:c6bcc390612a 16 * all copies or substantial portions of the Software.
aberk 0:c6bcc390612a 17 *
aberk 0:c6bcc390612a 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
aberk 0:c6bcc390612a 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
aberk 0:c6bcc390612a 20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
aberk 0:c6bcc390612a 21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
aberk 0:c6bcc390612a 22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
aberk 0:c6bcc390612a 23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
aberk 0:c6bcc390612a 24 * THE SOFTWARE.
aberk 0:c6bcc390612a 25 *
aberk 0:c6bcc390612a 26 * @section DESCRIPTION
aberk 0:c6bcc390612a 27 *
aberk 0:c6bcc390612a 28 * CMPS03 digital compass module.
aberk 0:c6bcc390612a 29 *
aberk 0:c6bcc390612a 30 * Datasheet:
aberk 0:c6bcc390612a 31 *
aberk 0:c6bcc390612a 32 * http://www.robot-electronics.co.uk/htm/cmps3tech.htm
aberk 0:c6bcc390612a 33 */
aberk 0:c6bcc390612a 34
aberk 0:c6bcc390612a 35 /**
aberk 0:c6bcc390612a 36 * Includes
aberk 0:c6bcc390612a 37 */
aberk 0:c6bcc390612a 38 #include "CMPS03.h"
aberk 0:c6bcc390612a 39
aberk 0:c6bcc390612a 40 CMPS03::CMPS03(PinName sda, PinName scl, int address) {
aberk 0:c6bcc390612a 41
aberk 0:c6bcc390612a 42 i2c = new I2C(sda, scl);
aberk 0:c6bcc390612a 43 //Compass designed to work at 100KHz. See datasheet for details.
aberk 0:c6bcc390612a 44 i2c->frequency(100000);
aberk 0:c6bcc390612a 45 i2cAddress = address;
aberk 0:c6bcc390612a 46
aberk 0:c6bcc390612a 47 }
aberk 0:c6bcc390612a 48
aberk 0:c6bcc390612a 49 char CMPS03::readSoftwareRevision(void){
aberk 0:c6bcc390612a 50
aberk 0:c6bcc390612a 51 char registerNumber = SOFTWARE_REVISION_REG;
aberk 0:c6bcc390612a 52 char registerContents = 0;
aberk 0:c6bcc390612a 53
aberk 0:c6bcc390612a 54 //First, send the number of register we wish to read,
aberk 0:c6bcc390612a 55 //in this case, command register, number 0.
aberk 0:c6bcc390612a 56 i2c->write(i2cAddress, &registerNumber, 1);
aberk 0:c6bcc390612a 57
aberk 0:c6bcc390612a 58 //Now, read one byte, which will be the contents of the command register.
aberk 0:c6bcc390612a 59 i2c->read(i2cAddress, &registerContents, 1);
aberk 0:c6bcc390612a 60
aberk 0:c6bcc390612a 61 return registerContents;
aberk 0:c6bcc390612a 62
aberk 0:c6bcc390612a 63 }
aberk 0:c6bcc390612a 64
aberk 0:c6bcc390612a 65 int CMPS03::readBearing(void){
aberk 0:c6bcc390612a 66
aberk 0:c6bcc390612a 67 char registerNumber = COMPASS_BEARING_WORD_REG;
aberk 0:c6bcc390612a 68 char registerContents[2] = {0x00, 0x00};
aberk 0:c6bcc390612a 69
aberk 0:c6bcc390612a 70 //First, send the number of register we wish to read,
aberk 0:c6bcc390612a 71 //in this case, register numbers 2, 3, which hold the
aberk 0:c6bcc390612a 72 //compass bearing as a 16-bit word.
aberk 0:c6bcc390612a 73 i2c->write(i2cAddress, &registerNumber, 1);
aberk 0:c6bcc390612a 74
aberk 0:c6bcc390612a 75 //Now read two bytes which will be the contents of
aberk 0:c6bcc390612a 76 //these registers.
aberk 0:c6bcc390612a 77 i2c->read(i2cAddress, registerContents, 2);
aberk 0:c6bcc390612a 78
aberk 0:c6bcc390612a 79 //Register 2 [read first], was the high byte, followed by
aberk 0:c6bcc390612a 80 //register 3 [read second], which was the low byte.
aberk 0:c6bcc390612a 81 int bearing = ((int)registerContents[0] << 8) | ((int)registerContents[1]);
aberk 0:c6bcc390612a 82
aberk 0:c6bcc390612a 83 return bearing;
aberk 0:c6bcc390612a 84
aberk 0:c6bcc390612a 85 }