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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: timer.c Source File</title><link href="dox.css" rel="stylesheet" type="text/css"></head><body><!-- Generated by Doxygen 1.3.6 --><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="files.html">File List</a> | <a class="qindex" href="functions.html">Data Fields</a> | <a class="qindex" href="globals.html">Globals</a></div><h1>timer.c</h1><a href="timer_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre>00001 <span class="comment">/*! \file timer.c \brief System Timer function library. */</span>00002 <span class="comment">//*****************************************************************************</span>00003 <span class="comment">//</span>00004 <span class="comment">// File Name : 'timer.c'</span>00005 <span class="comment">// Title : System Timer function library</span>00006 <span class="comment">// Author : Pascal Stang - Copyright (C) 2000-2002</span>00007 <span class="comment">// Created : 11/22/2000</span>00008 <span class="comment">// Revised : 07/09/2003</span>00009 <span class="comment">// Version : 1.1</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">#ifndef WIN32</span>00019 <span class="preprocessor"></span><span class="preprocessor"> #include <avr/io.h></span>00020 <span class="preprocessor"> #include <avr/signal.h></span>00021 <span class="preprocessor"> #include <avr/interrupt.h></span>00022 <span class="preprocessor"> #include <avr/pgmspace.h></span>00023 <span class="preprocessor"> #include <avr/sleep.h></span>00024 <span class="preprocessor">#endif</span>00025 <span class="preprocessor"></span>00026 <span class="preprocessor">#include "<a class="code" href="global_8h.html">global.h</a>"</span>00027 <span class="preprocessor">#include "<a class="code" href="timer_8h.html">timer.h</a>"</span>00028 00029 <span class="preprocessor">#include "<a class="code" href="rprintf_8h.html">rprintf.h</a>"</span>00030 00031 <span class="comment">// Program ROM constants</span>00032 <span class="comment">// the prescale division values stored in order of timer control register index</span>00033 <span class="comment">// STOP, CLK, CLK/8, CLK/64, CLK/256, CLK/1024</span>00034 <span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> __attribute__ ((progmem)) TimerPrescaleFactor[] = {0,1,8,64,256,1024};00035 <span class="comment">// the prescale division values stored in order of timer control register index</span>00036 <span class="comment">// STOP, CLK, CLK/8, CLK/32, CLK/64, CLK/128, CLK/256, CLK/1024</span>00037 <span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> __attribute__ ((progmem)) TimerRTCPrescaleFactor[] = {0,1,8,32,64,128,256,1024};00038 00039 <span class="comment">// Global variables</span>00040 <span class="comment">// time registers</span>00041 <span class="keyword">volatile</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> TimerPauseReg;00042 <span class="keyword">volatile</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> Timer0Reg0;00043 <span class="keyword">volatile</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> Timer2Reg0;00044 00045 <span class="keyword">typedef</span> void (*voidFuncPtr)(<span class="keywordtype">void</span>);00046 <span class="keyword">volatile</span> <span class="keyword">static</span> voidFuncPtr TimerIntFunc[TIMER_NUM_INTERRUPTS];00047 00048 <span class="comment">// delay for a minimum of <us> microseconds </span>00049 <span class="comment">// the time resolution is dependent on the time the loop takes </span>00050 <span class="comment">// e.g. with 4Mhz and 5 cycles per loop, the resolution is 1.25 us </span>00051 <span class="keywordtype">void</span> delay(<span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> us) 00052 {00053 <span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> delay_loops;00054 <span class="keyword">register</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> i;00055 00056 delay_loops = (us+3)/5*CYCLES_PER_US; <span class="comment">// +3 for rounding up (dirty) </span>00057 00058 <span class="comment">// one loop takes 5 cpu cycles </span>00059 <span class="keywordflow">for</span> (i=0; i < delay_loops; i++) {};00060 } 00061 <a name="l00062"></a><a class="code" href="timer128_8h.html#a39">00062</a> <span class="keywordtype">void</span> <a class="code" href="timer_8c.html#a7">timerInit</a>(<span class="keywordtype">void</span>)00063 {00064 u08 intNum;00065 <span class="comment">// detach all user functions from interrupts</span>00066 <span class="keywordflow">for</span>(intNum=0; intNum<TIMER_NUM_INTERRUPTS; intNum++)00067 <a class="code" href="timer128_8h.html#a53">timerDetach</a>(intNum);00068 00069 <span class="comment">// initialize all timers</span>00070 <a class="code" href="timer_8c.html#a8">timer0Init</a>();00071 <a class="code" href="timer_8c.html#a9">timer1Init</a>();00072 <span class="preprocessor"> #ifdef TCNT2 // support timer2 only if it exists</span>00073 <span class="preprocessor"></span> timer2Init();00074 <span class="preprocessor"> #endif</span>00075 <span class="preprocessor"></span> <span class="comment">// enable interrupts</span>00076 sei();00077 }00078 <a name="l00079"></a><a class="code" href="timer128_8h.html#a40">00079</a> <span class="keywordtype">void</span> <a class="code" href="timer_8c.html#a8">timer0Init</a>()00080 {00081 <span class="comment">// initialize timer 0</span>00082 <a class="code" href="timer128_8h.html#a44">timer0SetPrescaler</a>( <a class="code" href="timer_8h.html#a20">TIMER0PRESCALE</a> ); <span class="comment">// set prescaler</span>00083 outb(TCNT0, 0); <span class="comment">// reset TCNT0</span>00084 sbi(TIMSK, TOIE0); <span class="comment">// enable TCNT0 overflow interrupt</span>00085 00086 <a class="code" href="timer_8c.html#a17">timer0ClearOverflowCount</a>(); <span class="comment">// initialize time registers</span>00087 }00088 <a name="l00089"></a><a class="code" href="timer128_8h.html#a41">00089</a> <span class="keywordtype">void</span> <a class="code" href="timer_8c.html#a9">timer1Init</a>(<span class="keywordtype">void</span>)00090 {00091 <span class="comment">// initialize timer 1</span>00092 <a class="code" href="timer128_8h.html#a45">timer1SetPrescaler</a>( <a class="code" href="timer_8h.html#a21">TIMER1PRESCALE</a> ); <span class="comment">// set prescaler</span>00093 outb(TCNT1H, 0); <span class="comment">// reset TCNT1</span>00094 outb(TCNT1L, 0);00095 sbi(TIMSK, TOIE1); <span class="comment">// enable TCNT1 overflow</span>00096 }00097 00098 <span class="preprocessor">#ifdef TCNT2 // support timer2 only if it exists</span>00099 <span class="preprocessor"></span><span class="keywordtype">void</span> timer2Init(<span class="keywordtype">void</span>)00100 {00101 <span class="comment">// initialize timer 2</span>00102 <a class="code" href="timer128_8h.html#a46">timer2SetPrescaler</a>( TIMER2PRESCALE ); <span class="comment">// set prescaler</span>00103 outb(TCNT2, 0); <span class="comment">// reset TCNT2</span>00104 sbi(TIMSK, TOIE2); <span class="comment">// enable TCNT2 overflow</span>00105 00106 timer2ClearOverflowCount(); <span class="comment">// initialize time registers</span>00107 }00108 <span class="preprocessor">#endif</span>00109 <span class="preprocessor"></span><a name="l00110"></a><a class="code" href="timer128_8h.html#a44">00110</a> <span class="keywordtype">void</span> <a class="code" href="timer128_8h.html#a44">timer0SetPrescaler</a>(u08 prescale)00111 {00112 <span class="comment">// set prescaler on timer 0</span>00113 outp( (inb(TCCR0) & ~<a class="code" href="timer_8h.html#a10">TIMER_PRESCALE_MASK</a>) | prescale, TCCR0);00114 }00115 <a name="l00116"></a><a class="code" href="timer128_8h.html#a45">00116</a> <span class="keywordtype">void</span> <a class="code" href="timer128_8h.html#a45">timer1SetPrescaler</a>(u08 prescale)00117 {00118 <span class="comment">// set prescaler on timer 1</span>00119 outp( (inb(TCCR1B) & ~<a class="code" href="timer_8h.html#a10">TIMER_PRESCALE_MASK</a>) | prescale, TCCR1B);00120 }00121 00122 <span class="preprocessor">#ifdef TCNT2 // support timer2 only if it exists</span>00123 <span class="preprocessor"></span><span class="keywordtype">void</span> <a class="code" href="timer128_8h.html#a46">timer2SetPrescaler</a>(u08 prescale)00124 {00125 <span class="comment">// set prescaler on timer 2</span>00126 outp( (inb(TCCR2) & ~TIMER_PRESCALE_MASK) | prescale, TCCR2);00127 }00128 <span class="preprocessor">#endif</span>00129 <span class="preprocessor"></span><a name="l00130"></a><a class="code" href="timer128_8h.html#a48">00130</a> u16 <a class="code" href="timer_8c.html#a12">timer0GetPrescaler</a>(<span class="keywordtype">void</span>)00131 {00132 <span class="comment">// get the current prescaler setting</span>00133 <span class="keywordflow">return</span> (pgm_read_word(TimerPrescaleFactor+(inb(TCCR0) & <a class="code" href="timer_8h.html#a10">TIMER_PRESCALE_MASK</a>)));00134 }00135 <a name="l00136"></a><a class="code" href="timer128_8h.html#a49">00136</a> u16 <a class="code" href="timer_8c.html#a13">timer1GetPrescaler</a>(<span class="keywordtype">void</span>)00137 {00138 <span class="comment">// get the current prescaler setting</span>00139 <span class="keywordflow">return</span> (pgm_read_word(TimerPrescaleFactor+(inb(TCCR1B) & <a class="code" href="timer_8h.html#a10">TIMER_PRESCALE_MASK</a>)));00140 }00141 00142 <span class="preprocessor">#ifdef TCNT2 // support timer2 only if it exists</span>00143 <span class="preprocessor"></span>u16 <a class="code" href="timer128_8c.html#a20">timer2GetPrescaler</a>(<span class="keywordtype">void</span>)00144 {00145 <span class="comment">//TODO: can we assume for all 3-timer AVR processors,</span>00146 <span class="comment">// that timer2 is the RTC timer?</span>00147 00148 <span class="comment">// get the current prescaler setting</span>00149 <span class="keywordflow">return</span> (pgm_read_word(TimerRTCPrescaleFactor+(inb(TCCR2) & TIMER_PRESCALE_MASK)));00150 }00151 <span class="preprocessor">#endif</span>00152 <span class="preprocessor"></span><a name="l00153"></a><a class="code" href="timer128_8h.html#a52">00153</a> <span class="keywordtype">void</span> <a class="code" href="timer128_8h.html#a52">timerAttach</a>(u08 interruptNum, <span class="keywordtype">void</span> (*userFunc)(<span class="keywordtype">void</span>) )00154 {00155 <span class="comment">// make sure the interrupt number is within bounds</span>00156 <span class="keywordflow">if</span>(interruptNum < TIMER_NUM_INTERRUPTS)00157 {00158 <span class="comment">// set the interrupt function to run</span>00159 <span class="comment">// the supplied user's function</span>00160 TimerIntFunc[interruptNum] = userFunc;00161 }00162 }00163 <a name="l00164"></a><a class="code" href="timer128_8h.html#a53">00164</a> <span class="keywordtype">void</span> <a class="code" href="timer128_8h.html#a53">timerDetach</a>(u08 interruptNum)00165 {00166 <span class="comment">// make sure the interrupt number is within bounds</span>00167 <span class="keywordflow">if</span>(interruptNum < TIMER_NUM_INTERRUPTS)00168 {00169 <span class="comment">// set the interrupt function to run nothing</span>00170 TimerIntFunc[interruptNum] = 0;00171 }00172 }00173 <span class="comment">/*</span>00174 <span class="comment">u32 timerMsToTics(u16 ms)</span>00175 <span class="comment">{</span>00176 <span class="comment"> // calculate the prescaler division rate</span>00177 <span class="comment"> u16 prescaleDiv = 1<<(PRG_RDB(TimerPrescaleFactor+inp(TCCR0)));</span>00178 <span class="comment"> // calculate the number of timer tics in x milliseconds</span>00179 <span class="comment"> return (ms*(F_CPU/(prescaleDiv*256)))/1000;</span>00180 <span class="comment">}</span>00181 <span class="comment"></span>00182 <span class="comment">u16 timerTicsToMs(u32 tics)</span>00183 <span class="comment">{</span>00184 <span class="comment"> // calculate the prescaler division rate</span>00185 <span class="comment"> u16 prescaleDiv = 1<<(PRG_RDB(TimerPrescaleFactor+inp(TCCR0)));</span>00186 <span class="comment"> // calculate the number of milliseconds in x timer tics</span>00187 <span class="comment"> return (tics*1000*(prescaleDiv*256))/F_CPU;</span>00188 <span class="comment">}</span>00189 <span class="comment">*/</span><a name="l00190"></a><a class="code" href="timer128_8h.html#a54">00190</a> <span class="keywordtype">void</span> <a class="code" href="timer128_8h.html#a54">timerPause</a>(<span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> pause_ms)00191 {00192 <span class="comment">// pauses for exactly <pause_ms> number of milliseconds</span>00193 u08 timerThres;00194 u32 ticRateHz;00195 u32 pause;00196 00197 <span class="comment">// capture current pause timer value</span>00198 timerThres = inb(TCNT0);00199 <span class="comment">// reset pause timer overflow count</span>00200 TimerPauseReg = 0;00201 <span class="comment">// calculate delay for [pause_ms] milliseconds</span>00202 <span class="comment">// prescaler division = 1<<(PRG_RDB(TimerPrescaleFactor+inp(TCCR0)))</span>00203 ticRateHz = F_CPU/<a class="code" href="timer_8c.html#a12">timer0GetPrescaler</a>();00204 <span class="comment">// precision management</span>00205 <span class="comment">// prevent overflow and precision underflow</span>00206 <span class="comment">// -could add more conditions to improve accuracy</span>00207 <span class="keywordflow">if</span>( ((ticRateHz < 429497) && (pause_ms <= 10000)) )00208 pause = (pause_ms*ticRateHz)/1000;00209 <span class="keywordflow">else</span>00210 pause = pause_ms*(ticRateHz/1000);00211 00212 <span class="comment">// loop until time expires</span>00213 <span class="keywordflow">while</span>( ((TimerPauseReg<<8) | inb(TCNT0)) < (pause+timerThres) )00214 {00215 <span class="keywordflow">if</span>( TimerPauseReg < (pause>>8));00216 {00217 <span class="comment">// save power by idling the processor</span>00218 set_sleep_mode(SLEEP_MODE_IDLE);00219 sleep_mode();00220 }00221 }00222 00223 <span class="comment">/* old inaccurate code, for reference</span>00224 <span class="comment"> </span>00225 <span class="comment"> // calculate delay for [pause_ms] milliseconds</span>00226 <span class="comment"> u16 prescaleDiv = 1<<(PRG_RDB(TimerPrescaleFactor+inp(TCCR0)));</span>00227 <span class="comment"> u32 pause = (pause_ms*(F_CPU/(prescaleDiv*256)))/1000;</span>00228 <span class="comment"> </span>⌨️ 快捷键说明
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