text: /**
   * @file adcDCpropab.c
   *
   * @author Andy Lindsay
   *
   * @copyright
   * Copyright (C) Parallax, Inc. 2013. All Rights MIT Licensed.
   *
   * @brief Initialize ADC124S021 and measure voltage as a raw, 12-bit5 adc value.
   * @n @n <b><i>CONSTRUCTION ZONE:</i></b> This library is preliminary, revisions 
   * pending.
   */
  
  #include "simpletools.h"
  #include "adcDCpropab.h"
  
  static int dout, din, scl, cs;
  
  int adc124S021dc(int channel);
  
  void adc_init(int csPin, int sclPin, int doPin, int diPin)
  {
    dout = doPin;
    din = diPin;
    scl = sclPin;
    cs = csPin;  
  }
  
  int adc_in(int channel)
  {
    adc124S021dc(channel);
    int val = adc124S021dc(channel);
    return val;
  }
  
  int adc124S021dc(int channel)
  {
    channel = (channel & 3) << 12;
    high(cs);
    high(scl);
    low(din);
    input(dout);
    low(cs);
    int val = 0;
    for(int i = 15; i >= 0; i--)
    {
      val = val << 1;
      low(scl);
      high(scl);
      set_output(din, (channel >> i) & 1);
      val = val + (get_state(dout) & 1);
    }
    high(cs);
    return val;
  }  
  
  
  /**
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   *
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   * copy of this software and associated documentation files (the "Software"),
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   *
   * The above copyright notice and this permission notice shall be included in
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