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| 3 | <title>Procyon AVRlib: a2d.c Source File</title> |
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| 8 | <h1>a2d.c</h1><a href="a2d_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment">00001 <span class="comment">/*! \file a2d.c \brief Analog-to-Digital converter function library. */</span> |
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| 9 | 00002 <span class="comment">//*****************************************************************************</span> |
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| 10 | 00003 <span class="comment">//</span> |
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| 11 | 00004 <span class="comment">// File Name : 'a2d.c'</span> |
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| 12 | 00005 <span class="comment">// Title : Analog-to-digital converter functions</span> |
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| 13 | 00006 <span class="comment">// Author : Pascal Stang - Copyright (C) 2002</span> |
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| 14 | 00007 <span class="comment">// Created : 2002-04-08</span> |
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| 15 | 00008 <span class="comment">// Revised : 2002-09-30</span> |
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| 16 | 00009 <span class="comment">// Version : 1.1</span> |
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| 17 | 00010 <span class="comment">// Target MCU : Atmel AVR series</span> |
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| 18 | 00011 <span class="comment">// Editor Tabs : 4</span> |
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| 19 | 00012 <span class="comment">//</span> |
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| 20 | 00013 <span class="comment">// This code is distributed under the GNU Public License</span> |
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| 21 | 00014 <span class="comment">// which can be found at http://www.gnu.org/licenses/gpl.txt</span> |
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| 22 | 00015 <span class="comment">//</span> |
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| 23 | 00016 <span class="comment">//*****************************************************************************</span> |
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| 24 | 00017 |
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| 25 | 00018 <span class="preprocessor">#include <avr/io.h></span> |
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| 26 | 00019 <span class="preprocessor">#include <avr/interrupt.h></span> |
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| 27 | 00020 |
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| 28 | 00021 <span class="preprocessor">#include "<a class="code" href="global_8h.html">global.h</a>"</span> |
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| 29 | 00022 <span class="preprocessor">#include "<a class="code" href="a2d_8h.html">a2d.h</a>"</span> |
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| 30 | 00023 |
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| 31 | 00024 <span class="comment">// global variables</span> |
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| 32 | 00025 <span class="comment"></span> |
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| 33 | 00026 <span class="comment">//! Software flag used to indicate when</span> |
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| 34 | 00027 <span class="comment">/// the a2d conversion is complete.</span> |
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| 35 | <a name="l00028"></a><a class="code" href="a2d_8c.html#a0">00028</a> <span class="comment"></span><span class="keyword">volatile</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> <a class="code" href="a2d_8c.html#a0">a2dCompleteFlag</a>; |
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| 36 | 00029 |
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| 37 | 00030 <span class="comment">// functions</span> |
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| 38 | 00031 |
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| 39 | 00032 <span class="comment">// initialize a2d converter</span> |
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| 40 | <a name="l00033"></a><a class="code" href="group__a2d.html#ga0">00033</a> <span class="keywordtype">void</span> <a class="code" href="group__a2d.html#ga0">a2dInit</a>(<span class="keywordtype">void</span>) |
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| 41 | 00034 { |
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| 42 | 00035 sbi(ADCSR, ADEN); <span class="comment">// enable ADC (turn on ADC power)</span> |
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| 43 | 00036 cbi(ADCSR, ADFR); <span class="comment">// default to single sample convert mode</span> |
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| 44 | 00037 <a class="code" href="group__a2d.html#ga2">a2dSetPrescaler</a>(ADC_PRESCALE); <span class="comment">// set default prescaler</span> |
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| 45 | 00038 <a class="code" href="group__a2d.html#ga3">a2dSetReference</a>(ADC_REFERENCE); <span class="comment">// set default reference</span> |
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| 46 | 00039 cbi(ADMUX, ADLAR); <span class="comment">// set to right-adjusted result</span> |
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| 47 | 00040 |
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| 48 | 00041 sbi(ADCSR, ADIE); <span class="comment">// enable ADC interrupts</span> |
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| 49 | 00042 |
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| 50 | 00043 <a class="code" href="a2d_8c.html#a0">a2dCompleteFlag</a> = FALSE; <span class="comment">// clear conversion complete flag</span> |
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| 51 | 00044 sei(); <span class="comment">// turn on interrupts (if not already on)</span> |
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| 52 | 00045 } |
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| 53 | 00046 |
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| 54 | 00047 <span class="comment">// turn off a2d converter</span> |
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| 55 | <a name="l00048"></a><a class="code" href="group__a2d.html#ga1">00048</a> <span class="keywordtype">void</span> <a class="code" href="group__a2d.html#ga1">a2dOff</a>(<span class="keywordtype">void</span>) |
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| 56 | 00049 { |
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| 57 | 00050 cbi(ADCSR, ADIE); <span class="comment">// disable ADC interrupts</span> |
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| 58 | 00051 cbi(ADCSR, ADEN); <span class="comment">// disable ADC (turn off ADC power)</span> |
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| 59 | 00052 } |
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| 60 | 00053 |
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| 61 | 00054 <span class="comment">// configure A2D converter clock division (prescaling)</span> |
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| 62 | <a name="l00055"></a><a class="code" href="group__a2d.html#ga2">00055</a> <span class="keywordtype">void</span> <a class="code" href="group__a2d.html#ga2">a2dSetPrescaler</a>(<span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> prescale) |
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| 63 | 00056 { |
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| 64 | 00057 outb(ADCSR, ((inb(ADCSR) & ~ADC_PRESCALE_MASK) | prescale)); |
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| 65 | 00058 } |
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| 66 | 00059 |
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| 67 | 00060 <span class="comment">// configure A2D converter voltage reference</span> |
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| 68 | <a name="l00061"></a><a class="code" href="group__a2d.html#ga3">00061</a> <span class="keywordtype">void</span> <a class="code" href="group__a2d.html#ga3">a2dSetReference</a>(<span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> ref) |
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| 69 | 00062 { |
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| 70 | 00063 outb(ADMUX, ((inb(ADMUX) & ~ADC_REFERENCE_MASK) | (ref<<6))); |
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| 71 | 00064 } |
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| 72 | 00065 |
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| 73 | 00066 <span class="comment">// sets the a2d input channel</span> |
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| 74 | <a name="l00067"></a><a class="code" href="group__a2d.html#ga4">00067</a> <span class="keywordtype">void</span> <a class="code" href="group__a2d.html#ga4">a2dSetChannel</a>(<span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> ch) |
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| 75 | 00068 { |
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| 76 | 00069 outb(ADMUX, (inb(ADMUX) & ~ADC_MUX_MASK) | (ch & ADC_MUX_MASK)); <span class="comment">// set channel</span> |
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| 77 | 00070 } |
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| 78 | 00071 |
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| 79 | 00072 <span class="comment">// start a conversion on the current a2d input channel</span> |
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| 80 | <a name="l00073"></a><a class="code" href="group__a2d.html#ga5">00073</a> <span class="keywordtype">void</span> <a class="code" href="group__a2d.html#ga5">a2dStartConvert</a>(<span class="keywordtype">void</span>) |
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| 81 | 00074 { |
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| 82 | 00075 sbi(ADCSR, ADIF); <span class="comment">// clear hardware "conversion complete" flag </span> |
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| 83 | 00076 sbi(ADCSR, ADSC); <span class="comment">// start conversion</span> |
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| 84 | 00077 } |
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| 85 | 00078 |
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| 86 | 00079 <span class="comment">// return TRUE if conversion is complete</span> |
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| 87 | <a name="l00080"></a><a class="code" href="group__a2d.html#ga6">00080</a> u08 <a class="code" href="group__a2d.html#ga6">a2dIsComplete</a>(<span class="keywordtype">void</span>) |
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| 88 | 00081 { |
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| 89 | 00082 <span class="keywordflow">return</span> bit_is_set(ADCSR, ADSC); |
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| 90 | 00083 } |
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| 91 | 00084 |
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| 92 | 00085 <span class="comment">// Perform a 10-bit conversion</span> |
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| 93 | 00086 <span class="comment">// starts conversion, waits until conversion is done, and returns result</span> |
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| 94 | <a name="l00087"></a><a class="code" href="group__a2d.html#ga7">00087</a> <span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> <a class="code" href="group__a2d.html#ga7">a2dConvert10bit</a>(<span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> ch) |
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| 95 | 00088 { |
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| 96 | 00089 <a class="code" href="a2d_8c.html#a0">a2dCompleteFlag</a> = FALSE; <span class="comment">// clear conversion complete flag</span> |
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| 97 | 00090 outb(ADMUX, (inb(ADMUX) & ~ADC_MUX_MASK) | (ch & ADC_MUX_MASK)); <span class="comment">// set channel</span> |
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| 98 | 00091 sbi(ADCSR, ADIF); <span class="comment">// clear hardware "conversion complete" flag </span> |
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| 99 | 00092 sbi(ADCSR, ADSC); <span class="comment">// start conversion</span> |
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| 100 | 00093 <span class="comment">//while(!a2dCompleteFlag); // wait until conversion complete</span> |
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| 101 | 00094 <span class="comment">//while( bit_is_clear(ADCSR, ADIF) ); // wait until conversion complete</span> |
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| 102 | 00095 <span class="keywordflow">while</span>( bit_is_set(ADCSR, ADSC) ); <span class="comment">// wait until conversion complete</span> |
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| 103 | 00096 |
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| 104 | 00097 <span class="comment">// CAUTION: MUST READ ADCL BEFORE ADCH!!!</span> |
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| 105 | 00098 <span class="keywordflow">return</span> (inb(ADCL) | (inb(ADCH)<<8)); <span class="comment">// read ADC (full 10 bits);</span> |
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| 106 | 00099 } |
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| 107 | 00100 |
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| 108 | 00101 <span class="comment">// Perform a 8-bit conversion.</span> |
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| 109 | 00102 <span class="comment">// starts conversion, waits until conversion is done, and returns result</span> |
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| 110 | <a name="l00103"></a><a class="code" href="group__a2d.html#ga8">00103</a> <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> <a class="code" href="group__a2d.html#ga8">a2dConvert8bit</a>(<span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> ch) |
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| 111 | 00104 { |
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| 112 | 00105 <span class="comment">// do 10-bit conversion and return highest 8 bits</span> |
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| 113 | 00106 <span class="keywordflow">return</span> <a class="code" href="group__a2d.html#ga7">a2dConvert10bit</a>(ch)>>2; <span class="comment">// return ADC MSB byte</span> |
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| 114 | 00107 } |
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| 115 | 00108 <span class="comment"></span> |
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| 116 | 00109 <span class="comment">//! Interrupt handler for ADC complete interrupt.</span> |
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| 117 | <a name="l00110"></a><a class="code" href="a2d_8c.html#a10">00110</a> <span class="comment"></span><a class="code" href="a2d_8c.html#a10">SIGNAL</a>(SIG_ADC) |
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| 118 | 00111 { |
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| 119 | 00112 <span class="comment">// set the a2d conversion flag to indicate "complete"</span> |
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| 120 | 00113 <a class="code" href="a2d_8c.html#a0">a2dCompleteFlag</a> = TRUE; |
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| 121 | 00114 } |
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| 122 | 00115 |
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| 123 | </pre></div><hr size="1"><address style="align: right;"><small>Generated on Sun Oct 29 03:41:06 2006 for Procyon AVRlib by |
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| 124 | <a href="http://www.doxygen.org/index.html"> |
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| 125 | <img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.4.2 </small></address> |
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| 126 | </body> |
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| 127 | </html> |
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