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      1 /*
      2  * Author: Jon Trulson <jtrulson (at) ics.com>
      3  * Copyright (c) 2015 Intel Corporation.
      4  *
      5  * Permission is hereby granted, free of charge, to any person obtaining
      6  * a copy of this software and associated documentation files (the
      7  * "Software"), to deal in the Software without restriction, including
      8  * without limitation the rights to use, copy, modify, merge, publish,
      9  * distribute, sublicense, and/or sell copies of the Software, and to
     10  * permit persons to whom the Software is furnished to do so, subject to
     11  * the following conditions:
     12  *
     13  * The above copyright notice and this permission notice shall be
     14  * included in all copies or substantial portions of the Software.
     15  *
     16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     17  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     18  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     19  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     20  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
     21  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
     22  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     23  */
     24 
     25 #include <iostream>
     26 #include <string>
     27 #include <stdexcept>
     28 
     29 #include "maxsonarez.h"
     30 
     31 using namespace std;
     32 using namespace upm;
     33 
     34 MAXSONAREZ::MAXSONAREZ(int pin, float aref)
     35 {
     36   if (!(m_aio = mraa_aio_init(pin)))
     37     {
     38       throw std::invalid_argument(std::string(__FUNCTION__) +
     39                                   ": mraa_aio_init() failed, invalid pin?");
     40       return;
     41     }
     42 
     43   m_aRes = (1 << mraa_aio_get_bit(m_aio));
     44   m_aref = aref;
     45 
     46   // volt's per inch of this sensor
     47   m_vI = (m_aref / MAXSONAREZ_RES);
     48 }
     49 
     50 MAXSONAREZ::~MAXSONAREZ()
     51 {
     52   mraa_aio_close(m_aio);
     53 }
     54 
     55 int MAXSONAREZ::inches()
     56 {
     57   int val = mraa_aio_read(m_aio);
     58   float volts = float(val) * (m_aref / m_aRes);
     59 
     60   return int(volts / m_vI);
     61 }
     62