MH_Z19.cpp

00001 /* mbed MH-Z19 Library
00002  * Copyright (c) 2016, zeus3110
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00020  * THE SOFTWARE.
00021  */
00022 
00023 #include "MH_Z19.h"
00024 
00025 MH_Z19::MH_Z19(PinName p) : Port(p) {
00026     Port.rise(this, &MH_Z19::rise);
00027     Port.fall(this, &MH_Z19::fall);
00028     OnWidth=2;
00029     T.start();
00030 }
00031 
00032 int MH_Z19::ReadCO2PPM() {
00033     
00034     return ((CO2_MAX_PPM)*(OnWidth-2)/(PWM_CYCLE_MS-4));
00035 
00036 }
00037     
00038 
00039 void MH_Z19::rise() {
00040     T.reset();
00041 }
00042 
00043 void MH_Z19::fall() {
00044     OnWidth=T.read_ms();
00045 }
00046 
00047