TxIR.cpp

00001 
00002 /******************************************************************************
00003  * Low level infrared transmission
00004  * This library provides a low level interface to send IR commands. in principle
00005  * other higher level IR type remotes could be build on top of this. I wrote
00006  * this code to send IR commands to a Nikon camera, which it works rather well
00007  * for. 
00008  *
00009  * Copyright (C) 2010 Ali Saidi
00010  * 
00011  * Permission is hereby granted, free of charge, to any person obtaining a copy
00012  * of this software and associated documentation files (the "Software"), to deal
00013  * in the Software without restriction, including without limitation the rights
00014  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00015  * copies of the Software, and to permit persons to whom the Software is
00016  * furnished to do so, subject to the following conditions:
00017  * 
00018  * The above copyright notice and this permission notice shall be included in
00019  * all copies or substantial portions of the Software.
00020  * 
00021  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00022  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00023  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00024  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00025  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00026  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00027  * THE SOFTWARE.
00028  */
00029  
00030  #include "TxIR.hpp"
00031  
00032 
00033 void
00034 TxIR::doAction()
00035 {
00036     if (pos >= len) {
00037         delete [] data;
00038         _inUse = false;
00039         txPin.write(0);
00040         return;
00041     }
00042         
00043     delay.attach_us(this, &TxIR::doAction, data[pos++]);
00044     if (high)
00045         txPin.write(0);
00046     else
00047         txPin.write(0.5);
00048    high = !high;
00049 }
00050 
00051 bool
00052 TxIR::txSeq(unsigned freq, unsigned _len, const unsigned *_data) 
00053 {
00054     // @todo a lock or semaphore should be used here
00055     if (inUse())
00056         return false;
00057     _inUse = true;
00058     
00059     // keep a copy of the data, so it can't change
00060     len = _len;
00061     data = new unsigned[len];
00062     memcpy(data, _data, len * sizeof(unsigned));
00063     pos = 0;
00064     
00065     // setup the PWM
00066     txPin.write(0.0);
00067     txPin.period_us(freq);
00068     
00069     // Get the interrupt ready
00070     delay.detach();
00071     high = true;
00072     delay.attach_us(this, &TxIR::doAction, data[pos++]);
00073     
00074     // Begin
00075     txPin.write(0.5);
00076     
00077     return true;
00078 }