L3GD20.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,
00024  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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 "L3GD20.h"
00031 
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 0xD6
00040 
00041 
00042 // Public Methods //////////////////////////////////////////////////////////////
00043 
00044 // Constructor
00045 L3GD20::L3GD20(PinName sda, PinName scl):
00046     _L3GD20(sda, scl)
00047 {
00048     char reg_v;
00049     _L3GD20.frequency(200000);
00050     
00051     reg_v = 0;          
00052     write_reg(GYR_ADDRESS,L3GD20_LOW_ODR,reg_v);
00053     
00054   // 0x6F
00055   // DR = 01 (200 Hz ODR); BW = 10 (50 Hz bandwidth); PD = 1 (normal mode); Zen = Yen = Xen = 1 (all axes enabled)
00056     reg_v = 0;    
00057     reg_v |= 0x6F;       
00058     write_reg(GYR_ADDRESS,L3GD20_CTRL_REG1,reg_v);
00059     
00060 
00061 
00062 }
00063 
00064 
00065 
00066 bool L3GD20::read(float *gx, float *gy, float *gz) {
00067     char gyr[6];
00068  
00069     if (recv(GYR_ADDRESS, L3GD20_OUT_X_L, gyr, 6)) {
00070     //scale is 8.75 mdps/digit
00071         *gx = float(short(gyr[1] << 8 | gyr[0]))*0.00875;  
00072         *gy =  float(short(gyr[3] << 8 | gyr[2]))*0.00875;
00073         *gz =  float(short(gyr[5] << 8 | gyr[4]))*0.00875;
00074 
00075  
00076         return true;
00077     }
00078  
00079     return false;
00080 }
00081 
00082 
00083 
00084 
00085 bool L3GD20::write_reg(int addr_i2c,int addr_reg, char v)
00086 {
00087     char data[2] = {addr_reg, v}; 
00088     return L3GD20::_L3GD20.write(addr_i2c, data, 2) == 0;
00089 }
00090 
00091 bool L3GD20::read_reg(int addr_i2c,int addr_reg, char *v)
00092 {
00093     char data = addr_reg; 
00094     bool result = false;
00095     
00096     __disable_irq();
00097     if ((_L3GD20.write(addr_i2c, &data, 1) == 0) && (_L3GD20.read(addr_i2c, &data, 1) == 0)){
00098         *v = data;
00099         result = true;
00100     }
00101     __enable_irq();
00102     return result;
00103 }
00104 
00105 
00106 bool L3GD20::recv(char sad, char sub, char *buf, int length) {
00107     if (length > 1) sub |= 0x80;
00108  
00109     return _L3GD20.write(sad, &sub, 1, true) == 0 && _L3GD20.read(sad, buf, length) == 0;
00110 }