L3G4200D.cpp

00001 /**
00002  * Copyright (c) 2011 Pololu Corporation.  For more information, see
00003  * 
00004  * http://www.pololu.com/
00005  * http://forum.pololu.com/
00006  * 
00007  * Permission is hereby granted, free of charge, to any person
00008  * obtaining a copy of this software and associated documentation
00009  * files (the "Software"), to deal in the Software without
00010  * restriction, including without limitation the rights to use,
00011  * copy, modify, merge, publish, distribute, sublicense, and/or sell
00012  * copies of the Software, and to permit persons to whom the
00013  * Software is furnished to do so, subject to the following
00014  * conditions:
00015  * 
00016  * The above copyright notice and this permission notice shall be
00017  * included in all copies or substantial portions of the Software.
00018  * 
00019  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00020  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
00021  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00022  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
00023  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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00025  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
00026  * OTHER DEALINGS IN THE SOFTWARE.
00027  */
00028  
00029 #include "mbed.h"
00030 #include <L3G4200D.h>
00031 #include <math.h>
00032 
00033 // Defines ////////////////////////////////////////////////////////////////
00034 
00035 // The Arduino two-wire interface uses a 7-bit number for the address, 
00036 // and sets the last bit correctly based on reads and writes
00037 // mbed I2C libraries take the 7-bit address shifted left 1 bit
00038 // #define GYR_ADDRESS (0xD2 >> 1)
00039 #define GYR_ADDRESS 0xD2
00040 
00041 // Public Methods //////////////////////////////////////////////////////////////
00042 
00043 // Constructor
00044 L3G4200D::L3G4200D(PinName sda, PinName scl):
00045     _device(sda, scl)
00046 {
00047     _device.frequency(400000);
00048     // Turns on the L3G4200D's gyro and places it in normal mode.
00049     // 0x0F = 0b00001111
00050     // Normal power mode, all axes enabled
00051     writeReg(L3G4200D_CTRL_REG1, 0x0F);
00052     writeReg(L3G4200D_CTRL_REG4, 0x20); // 2000 dps full scale
00053 
00054 }
00055 
00056 // Writes a gyro register
00057 void L3G4200D::writeReg(byte reg, byte value)
00058 {
00059     data[0] = reg;
00060     data[1] = value;
00061     
00062     _device.write(GYR_ADDRESS, data, 2);
00063 }
00064 
00065 // Reads a gyro register
00066 byte L3G4200D::readReg(byte reg)
00067 {
00068     byte value = 0;
00069     
00070     _device.write(GYR_ADDRESS, &reg, 1);
00071     _device.read(GYR_ADDRESS, &value, 1);
00072 
00073     return value;
00074 }
00075 
00076 // Reads the 3 gyro channels and stores them in vector g
00077 void L3G4200D::read(float g[3])
00078 {
00079     // assert the MSB of the address to get the gyro 
00080     // to do slave-transmit subaddress updating.
00081     data[0] = L3G4200D_OUT_X_L | (1 << 7);
00082     _device.write(GYR_ADDRESS, data, 1); 
00083 
00084 //    Wire.requestFrom(GYR_ADDRESS, 6);
00085 //    while (Wire.available() < 6);
00086     
00087     _device.read(GYR_ADDRESS, data, 6); 
00088 
00089     uint8_t xla = data[0];
00090     uint8_t xha = data[1];
00091     uint8_t yla = data[2];
00092     uint8_t yha = data[3];
00093     uint8_t zla = data[4];
00094     uint8_t zha = data[5];
00095 
00096     g[0] = (short) (xha << 8 | xla);
00097     g[1] = (short) (yha << 8 | yla);
00098     g[2] = (short) (zha << 8 | zla);
00099 }