Diff: CMPS03.cpp

Revision:

0:c6bcc390612a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/CMPS03.cpp	Sat Nov 27 12:09:27 2010 +0000
@@ -0,0 +1,85 @@
+/**
+ * @author Aaron Berk
+ * 
+ * @section LICENSE
+ *
+ * Copyright (c) 2010 ARM Limited
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @section DESCRIPTION
+ *
+ * CMPS03 digital compass module.
+ *
+ * Datasheet:
+ *
+ * http://www.robot-electronics.co.uk/htm/cmps3tech.htm
+ */
+
+/**
+ * Includes
+ */
+#include "CMPS03.h"
+
+CMPS03::CMPS03(PinName sda, PinName scl, int address) {
+
+    i2c = new I2C(sda, scl);
+    //Compass designed to work at 100KHz. See datasheet for details.
+    i2c->frequency(100000);
+    i2cAddress = address;
+
+}
+
+char CMPS03::readSoftwareRevision(void){
+
+    char registerNumber   = SOFTWARE_REVISION_REG;
+    char registerContents = 0;
+
+    //First, send the number of register we wish to read,
+    //in this case, command register, number 0.
+    i2c->write(i2cAddress, &registerNumber, 1);
+    
+    //Now, read one byte, which will be the contents of the command register.
+    i2c->read(i2cAddress, &registerContents, 1);
+    
+    return registerContents;
+    
+}
+
+int CMPS03::readBearing(void){
+
+    char registerNumber = COMPASS_BEARING_WORD_REG;
+    char registerContents[2] = {0x00, 0x00};
+    
+    //First, send the number of register we wish to read,
+    //in this case, register numbers 2, 3, which hold the
+    //compass bearing as a 16-bit word.
+    i2c->write(i2cAddress, &registerNumber, 1);
+    
+    //Now read two bytes which will be the contents of
+    //these registers.
+    i2c->read(i2cAddress, registerContents, 2);
+    
+    //Register 2 [read first], was the high byte, followed by
+    //register 3 [read second], which was the low byte.
+    int bearing = ((int)registerContents[0] << 8) | ((int)registerContents[1]);
+    
+    return bearing;
+    
+}