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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: servo.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>servo.c</h1><a href="servo_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment">00001 <span class="comment">/*! \file servo.c \brief Interrupt-driven RC Servo function library. */</span>00002 <span class="comment">//*****************************************************************************</span>00003 <span class="comment">//</span>00004 <span class="comment">// File Name : 'servo.c'</span>00005 <span class="comment">// Title : Interrupt-driven RC Servo function library</span>00006 <span class="comment">// Author : Pascal Stang - Copyright (C) 2002</span>00007 <span class="comment">// Created : 7/31/2002</span>00008 <span class="comment">// Revised : 8/02/2002</span>00009 <span class="comment">// Version : 1.0</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">#endif</span>00021 <span class="preprocessor"></span>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="servo_8h.html">servo.h</a>"</span>00024 00025 <span class="comment">// Program ROM constants</span>00026 00027 <span class="comment">// Global variables</span>00028 <span class="comment">// servo channel registers</span>00029 u16 ServoPosTics;00030 u16 ServoPeriodTics;00031 u08 ServoChannel;00032 ServoChannelType ServoChannels[SERVO_NUM_CHANNELS];00033 00034 <span class="comment">// functions</span>00035 <span class="comment"></span>00036 <span class="comment">//! initializes software PWM system</span><a name="l00037"></a><a class="code" href="servo_8h.html#a1">00037</a> <span class="comment"></span><span class="keywordtype">void</span> <a class="code" href="servo_8c.html#a4">servoInit</a>(<span class="keywordtype">void</span>)00038 {00039 u08 channel;00040 <span class="comment">// disble the timer1 output compare A interrupt</span>00041 cbi(TIMSK, OCIE1A);00042 <span class="comment">// set the prescaler for timer1</span>00043 <a class="code" href="group__timer.html#ga6">timer1SetPrescaler</a>(<a class="code" href="group__timer.html#ga19">TIMER_CLK_DIV256</a>);00044 <span class="comment">// attach the software PWM service routine to timer1 output compare A</span>00045 <a class="code" href="group__timer.html#ga8">timerAttach</a>(TIMER1OUTCOMPAREA_INT, servoService);00046 <span class="comment">// enable and clear channels</span>00047 <span class="keywordflow">for</span>(channel=0; channel<SERVO_NUM_CHANNELS; channel++)00048 {00049 <span class="comment">// set minimum position as default</span>00050 ServoChannels[channel].duty = SERVO_MIN;00051 <span class="comment">// set default port and pins assignments</span>00052 ServoChannels[channel].port = _SFR_IO_ADDR(SERVO_DEFAULT_PORT);00053 <span class="comment">//ServoChannels[channel].port = (unsigned char)&SERVO_DEFAULT_PORT;</span>00054 ServoChannels[channel].pin = (1<<channel);00055 <span class="comment">// set channel pin to output</span>00056 <span class="comment">// THIS IS OBSOLETED BY THE DYNAMIC CHANNEL TO PORT,PIN ASSIGNMENTS</span>00057 <span class="comment">//outb(SERVODDR, inb(SERVODDR) | (1<<channel));</span>00058 }00059 <span class="comment">// set PosTics</span>00060 ServoPosTics = 0;00061 <span class="comment">// set PeriodTics</span>00062 ServoPeriodTics = SERVO_MAX*9;00063 <span class="comment">// set initial interrupt time</span>00064 u16 OCValue;00065 <span class="comment">// read in current value of output compare register OCR1A</span>00066 OCValue = inb(OCR1AL); <span class="comment">// read low byte of OCR1A</span>00067 OCValue += inb(OCR1AH)<<8; <span class="comment">// read high byte of OCR1A</span>00068 <span class="comment">// increment OCR1A value by nextTics</span>00069 OCValue += ServoPeriodTics; 00070 <span class="comment">// set future output compare time to this new value</span>00071 outb(OCR1AH, (OCValue>>8)); <span class="comment">// write high byte</span>00072 outb(OCR1AL, (OCValue & 0x00FF)); <span class="comment">// write low byte</span>00073 <span class="comment">// enable the timer1 output compare A interrupt</span>00074 sbi(TIMSK, OCIE1A);00075 }00076 <span class="comment"></span>00077 <span class="comment">//! turns off software PWM system</span><a name="l00078"></a><a class="code" href="servo_8h.html#a2">00078</a> <span class="comment"></span><span class="keywordtype">void</span> <a class="code" href="servo_8c.html#a5">servoOff</a>(<span class="keywordtype">void</span>)00079 {00080 <span class="comment">// disable the timer1 output compare A interrupt</span>00081 cbi(TIMSK, OCIE1A);00082 <span class="comment">// detach the service routine</span>00083 <a class="code" href="group__timer.html#ga9">timerDetach</a>(TIMER1OUTCOMPAREA_INT);00084 }00085 <span class="comment"></span>00086 <span class="comment">//! set port and I/O pin for channel</span><a name="l00087"></a><a class="code" href="servo_8h.html#a3">00087</a> <span class="comment"></span><span class="keywordtype">void</span> <a class="code" href="servo_8c.html#a6">servoSetChannelIO</a>(u08 channel, u08 port, u08 pin)00088 {00089 ServoChannels[channel].port = port;00090 ServoChannels[channel].pin = (1<<(pin&0x07));00091 }00092 <span class="comment"></span>00093 <span class="comment">//! set servo position on channel</span><a name="l00094"></a><a class="code" href="servo_8h.html#a4">00094</a> <span class="comment"></span><span class="keywordtype">void</span> <a class="code" href="servo_8c.html#a7">servoSetPosition</a>(u08 channel, u08 position)00095 {00096 <span class="comment">// input should be between 0 and SERVO_POSITION_MAX</span>00097 u16 pos_scaled;00098 <span class="comment">// calculate scaled position</span>00099 pos_scaled = ((u16)position*(SERVO_MAX-SERVO_MIN)/SERVO_POSITION_MAX)+SERVO_MIN;00100 <span class="comment">// set position</span>00101 <a class="code" href="servo_8c.html#a9">servoSetPositionRaw</a>(channel, pos_scaled);00102 }00103 <span class="comment"></span>00104 <span class="comment">//! get servo position on channel</span><a name="l00105"></a><a class="code" href="servo_8h.html#a5">00105</a> <span class="comment"></span>u08 <a class="code" href="servo_8c.html#a8">servoGetPosition</a>(u08 channel)00106 {00107 <span class="keywordflow">return</span> (u08)( ((<a class="code" href="servo_8c.html#a10">servoGetPositionRaw</a>(channel)-SERVO_MIN)*SERVO_POSITION_MAX)/(SERVO_MAX-SERVO_MIN) );00108 }00109 <span class="comment"></span>00110 <span class="comment">//! set servo position on channel (raw unscaled format)</span><a name="l00111"></a><a class="code" href="servo_8h.html#a6">00111</a> <span class="comment"></span><span class="keywordtype">void</span> <a class="code" href="servo_8c.html#a9">servoSetPositionRaw</a>(u08 channel, u16 position)00112 {00113 <span class="comment">// bind to limits</span>00114 position = MAX(position, SERVO_MIN);00115 position = MIN(position, SERVO_MAX);00116 <span class="comment">// set position</span>00117 ServoChannels[channel].duty = position;00118 }00119 <span class="comment"></span>00120 <span class="comment">//! get servo position on channel (raw unscaled format)</span><a name="l00121"></a><a class="code" href="servo_8h.html#a7">00121</a> <span class="comment"></span>u16 <a class="code" href="servo_8c.html#a10">servoGetPositionRaw</a>(u08 channel)00122 {00123 <span class="keywordflow">return</span> ServoChannels[channel].duty;00124 }00125 00126 <span class="keywordtype">void</span> servoService(<span class="keywordtype">void</span>)00127 {00128 u16 nextTics;00129 00130 <span class="keywordflow">if</span>(ServoChannel < SERVO_NUM_CHANNELS)00131 {00132 <span class="comment">// turn off current channel</span>00133 outb(_SFR_IO8(ServoChannels[ServoChannel].port), inb(_SFR_IO8(ServoChannels[ServoChannel].port)) & ~(ServoChannels[ServoChannel].pin));00134 }00135 00136 <span class="comment">// next channel</span>00137 ServoChannel++;00138 00139 <span class="keywordflow">if</span>(ServoChannel != SERVO_NUM_CHANNELS)00140 {00141 <span class="comment">// loop to channel 0 if needed</span>00142 <span class="keywordflow">if</span>(ServoChannel > SERVO_NUM_CHANNELS) ServoChannel = 0;00143 <span class="comment">// turn on new channel</span>00144 outb(_SFR_IO8(ServoChannels[ServoChannel].port), inb(_SFR_IO8(ServoChannels[ServoChannel].port)) | (ServoChannels[ServoChannel].pin));00145 <span class="comment">// schedule turn off time</span>00146 nextTics = ServoChannels[ServoChannel].duty;00147 }00148 <span class="keywordflow">else</span> <span class="comment">//(Channel == SERVO_NUM_CHANNELS)</span>00149 {00150 <span class="comment">// ***we could save time by precalculating this</span>00151 <span class="comment">// schedule end-of-period</span>00152 nextTics = ServoPeriodTics-ServoPosTics;00153 }00154 00155 <span class="comment">// schedule next interrupt</span>00156 u16 OCValue;00157 <span class="comment">// read in current value of output compare register OCR1A</span>00158 OCValue = inb(OCR1AL); <span class="comment">// read low byte of OCR1A</span>00159 OCValue += inb(OCR1AH)<<8; <span class="comment">// read high byte of OCR1A</span>00160 <span class="comment">// increment OCR1A value by nextTics</span>00161 OCValue += nextTics;00162 <span class="comment">// OCR1A+=nextTics;</span>00163 <span class="comment">// set future output compare time to this new value</span>00164 outb(OCR1AH, (OCValue>>8)); <span class="comment">// write high byte</span>00165 outb(OCR1AL, (OCValue & 0x00FF)); <span class="comment">// write low byte</span>00166 <span class="comment">// set our new tic position</span>00167 ServoPosTics += nextTics;00168 <span class="keywordflow">if</span>(ServoPosTics >= ServoPeriodTics) ServoPosTics = 0;00169 }</pre></div><hr size="1"><address style="align: right;"><small>Generated on Mon Oct 24 16:03:55 2005 for Procyon AVRlib by <a href="http://www.doxygen.org/index.html"><img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.4.2 </small></address></body></html>⌨️ 快捷键说明
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