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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"><title>Procyon AVRlib: pulse.c Source File</title><link href="dox.css" rel="stylesheet" type="text/css"></head><body><!-- Generated by Doxygen 1.4.2 --><div class="qindex"><a class="qindex" href="main.html">Main Page</a> | <a class="qindex" href="modules.html">Modules</a> | <a class="qindex" href="annotated.html">Data Structures</a> | <a class="qindex" href="dirs.html">Directories</a> | <a class="qindex" href="files.html">File List</a> | <a class="qindex" href="functions.html">Data Fields</a> | <a class="qindex" href="globals.html">Globals</a> | <a class="qindex" href="pages.html">Related Pages</a></div><h1>pulse.c</h1><a href="pulse_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment">00001 <span class="comment">/*! \file pulse.c \brief Pulse/frequency generation function library. */</span>00002 <span class="comment">//*****************************************************************************</span>00003 <span class="comment">//</span>00004 <span class="comment">// File Name : 'pulse.c'</span>00005 <span class="comment">// Title : Pulse/frequency generation function library</span>00006 <span class="comment">// Author : Pascal Stang - Copyright (C) 2000-2002</span>00007 <span class="comment">// Created : 2002-08-19</span>00008 <span class="comment">// Revised : 2003-05-29</span>00009 <span class="comment">// Version : 0.7</span>00010 <span class="comment">// Target MCU : Atmel AVR Series</span>00011 <span class="comment">// Editor Tabs : 4</span>00012 <span class="comment">//</span>00013 <span class="comment">// This code is distributed under the GNU Public License</span>00014 <span class="comment">// which can be found at http://www.gnu.org/licenses/gpl.txt</span>00015 <span class="comment">//</span>00016 <span class="comment">//*****************************************************************************</span>00017 00018 <span class="preprocessor">#include <avr/io.h></span>00019 <span class="preprocessor">#include <avr/interrupt.h></span>00020 <span class="preprocessor">#include <avr/pgmspace.h></span>00021 00022 <span class="preprocessor">#include "<a class="code" href="global_8h.html">global.h</a>"</span>00023 <span class="preprocessor">#include "<a class="code" href="timer_8h.html">timer.h</a>"</span>00024 <span class="preprocessor">#include "<a class="code" href="pulse_8h.html">pulse.h</a>"</span>00025 00026 <span class="comment">// Global variables</span>00027 <span class="comment">// pulse generation registers</span>00028 <span class="keyword">volatile</span> <span class="keyword">static</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> PulseT1AMode;00029 <span class="keyword">volatile</span> <span class="keyword">static</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> PulseT1ACount;00030 <span class="keyword">volatile</span> <span class="keyword">static</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> PulseT1APeriodTics;00031 <span class="keyword">volatile</span> <span class="keyword">static</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> PulseT1BMode;00032 <span class="keyword">volatile</span> <span class="keyword">static</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> PulseT1BCount;00033 <span class="keyword">volatile</span> <span class="keyword">static</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> PulseT1BPeriodTics;00034 00035 <span class="comment">// pulse mode bit definitions</span>00036 <span class="comment">// PULSE_MODE_COUNTED</span>00037 <span class="comment">// if true, the requested number of pulses are output, then output is turned off</span>00038 <span class="comment">// if false, pulses are output continuously</span>00039 <span class="preprocessor">#define PULSE_MODE_CONTINUOUS 0x00</span>00040 <span class="preprocessor"></span><span class="preprocessor">#define PULSE_MODE_COUNTED 0x01</span>00041 <span class="preprocessor"></span>00042 <span class="comment">// functions</span>00043 00044 <span class="keywordtype">void</span> pulseInit(<span class="keywordtype">void</span>)00045 {00046 <span class="comment">// initialize timer1 for pulse operation</span>00047 pulseT1Init();00048 }00049 00050 <span class="keywordtype">void</span> pulseT1Init(<span class="keywordtype">void</span>)00051 {00052 <span class="comment">// try to make sure that timer1 is in "normal" mode</span>00053 <span class="comment">// most importantly, turn off PWM mode</span>00054 <a class="code" href="group__timerpwm.html#ga2">timer1PWMOff</a>();00055 00056 <span class="comment">// set some reasonable initial values</span>00057 <span class="comment">// in case the user forgets to</span>00058 PulseT1AMode = 0;00059 PulseT1BMode = 0;00060 PulseT1ACount = 0;00061 PulseT1BCount = 0;00062 PulseT1APeriodTics = 0x8000;00063 PulseT1BPeriodTics = 0x8000;00064 00065 <span class="comment">// attach the pulse service routines to</span>00066 <span class="comment">// the timer 1 output compare A and B interrupts</span>00067 <a class="code" href="group__timer.html#ga8">timerAttach</a>(TIMER1OUTCOMPAREA_INT,pulseT1AService);00068 <a class="code" href="group__timer.html#ga8">timerAttach</a>(TIMER1OUTCOMPAREB_INT,pulseT1BService);00069 }00070 00071 <span class="keywordtype">void</span> pulseT1Off(<span class="keywordtype">void</span>)00072 {00073 <span class="comment">// turns pulse outputs off immediately</span>00074 00075 <span class="comment">// set pulse counters to zero (finished)</span>00076 PulseT1ACount = 0;00077 PulseT1BCount = 0;00078 <span class="comment">// disconnect OutputCompare action from OC1A pin</span>00079 cbi(TCCR1A,COM1A1);00080 cbi(TCCR1A,COM1A0);00081 <span class="comment">// disconnect OutputCompare action from OC1B pin</span>00082 cbi(TCCR1A,COM1B1);00083 cbi(TCCR1A,COM1B0);00084 <span class="comment">// detach the pulse service routines</span>00085 <a class="code" href="group__timer.html#ga9">timerDetach</a>(TIMER1OUTCOMPAREA_INT);00086 <a class="code" href="group__timer.html#ga9">timerDetach</a>(TIMER1OUTCOMPAREB_INT);00087 }00088 00089 <span class="keywordtype">void</span> pulseT1ASetFreq(u16 freqHz)00090 {00091 <span class="comment">// set the frequency of the pulse output</span>00092 <span class="comment">// we need to find the requested period/2 (in timer tics)</span>00093 <span class="comment">// from the frequency (in hertz)</span>00094 00095 <span class="comment">// calculate how many tics in period/2</span>00096 <span class="comment">// this is the (timer tic rate)/(2*requested freq)</span>00097 PulseT1APeriodTics = ((u32)F_CPU/((u32)<a class="code" href="group__timer.html#ga7">timer1GetPrescaler</a>()*2*freqHz));00098 }00099 00100 <span class="keywordtype">void</span> pulseT1BSetFreq(u16 freqHz)00101 {00102 <span class="comment">// set the frequency of the pulse output</span>00103 <span class="comment">// we need to find the requested period/2 (in timer tics)</span>00104 <span class="comment">// from the frequency (in hertz)</span>00105 00106 <span class="comment">// calculate how many tics in period/2</span>00107 <span class="comment">// this is the (timer tic rate)/(2*requested freq)</span>00108 PulseT1BPeriodTics = ((u32)F_CPU/((u32)<a class="code" href="group__timer.html#ga7">timer1GetPrescaler</a>()*2*freqHz));00109 }00110 00111 <span class="keywordtype">void</span> pulseT1ARun(u16 nPulses)00112 {00113 <span class="comment">// set the number of pulses we want and the mode</span>00114 <span class="keywordflow">if</span>(nPulses)00115 {00116 <span class="comment">// if the nPulses is non-zero, use "counted" mode</span>00117 PulseT1AMode |= PULSE_MODE_COUNTED;00118 PulseT1ACount = nPulses<<1;00119 }00120 <span class="keywordflow">else</span>00121 {00122 <span class="comment">// if nPulses is zero, run forever</span>00123 PulseT1AMode &= ~PULSE_MODE_COUNTED;00124 PulseT1ACount = 1<<1;00125 }00126 <span class="comment">// set OutputCompare action to toggle OC1A pin</span>00127 cbi(TCCR1A,COM1A1);00128 sbi(TCCR1A,COM1A0);00129 00130 <span class="comment">// now the "enabling" stuff</span>00131 00132 <span class="comment">// set the output compare one pulse cycle ahead of current timer position </span>00133 <span class="comment">// to make sure we don't have to wait until the timer overflows and comes</span>00134 <span class="comment">// back to the current value</span>00135 <span class="comment">// set future output compare time to TCNT1 + PulseT1APeriodTics</span>00136 <span class="comment">//outw(OCR1A, inw(TCNT1) + PulseT1APeriodTics);</span>00137 OCR1A += PulseT1APeriodTics;00138 00139 <span class="comment">// enable OutputCompare interrupt</span>00140 sbi(TIMSK, OCIE1A);00141 }⌨️ 快捷键说明
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