pulse_8c-source.html

国外牛人公开的ＡＶＲ代码

00144 }
00145 
00146 <span class="keywordtype">void</span> pulseT1BRun(u16 nPulses)
00147 {
00148     <span class="comment">// set the number of pulses we want and the mode</span>
00149     <span class="keywordflow">if</span>(nPulses)
00150     {
00151         <span class="comment">// if the nPulses is non-zero, use "counted" mode</span>
00152         PulseT1BMode |= PULSE_MODE_COUNTED;
00153         PulseT1BCount = nPulses&lt;&lt;1;
00154     }
00155     <span class="keywordflow">else</span>
00156     {
00157         <span class="comment">// if nPulses is zero, run forever</span>
00158         PulseT1BMode &amp;= ~PULSE_MODE_COUNTED;
00159         PulseT1BCount = 1&lt;&lt;1;
00160     }
00161     <span class="comment">// set OutputCompare action to toggle OC1B pin</span>
00162     <span class="comment">// (note: with all the A's and B's flying around, TCCR1A is not a bug)</span>
00163     cbi(TCCR1A,COM1B1);
00164     sbi(TCCR1A,COM1B0);
00165 
00166     <span class="comment">// now the "enabling" stuff</span>
00167 
00168     <span class="comment">// set the output compare one pulse cycle ahead of current timer position </span>
00169     <span class="comment">// to make sure we don't have to wait until the timer overflows and comes</span>
00170     <span class="comment">// back to the current value</span>
00171     <span class="comment">// set future output compare time to TCNT1 + PulseT1APeriodTics</span>
00172     <span class="comment">//outw(OCR1B, inw(TCNT1) + PulseT1BPeriodTics);</span>
00173     OCR1B += PulseT1BPeriodTics;
00174 
00175     <span class="comment">// enable OutputCompare interrupt</span>
00176     sbi(TIMSK, OCIE1B);
00177 }
00178 
00179 <span class="keywordtype">void</span> pulseT1AStop(<span class="keywordtype">void</span>)
00180 {
00181     <span class="comment">// stop output regardless of remaining pulses or mode</span>
00182     <span class="comment">// go to "counted" mode</span>
00183     PulseT1AMode |= PULSE_MODE_COUNTED;
00184     <span class="comment">// set pulses to zero</span>
00185     PulseT1ACount = 0;
00186 }
00187 
00188 <span class="keywordtype">void</span> pulseT1BStop(<span class="keywordtype">void</span>)
00189 {
00190     <span class="comment">// stop output regardless of remaining pulses or mode</span>
00191     <span class="comment">// go to "counted" mode</span>
00192     PulseT1BMode |= PULSE_MODE_COUNTED;
00193     <span class="comment">// set pulses to zero</span>
00194     PulseT1BCount = 0;
00195 }
00196 
00197 u16 pulseT1ARemaining(<span class="keywordtype">void</span>)
00198 {
00199     <span class="comment">// return the number of pulses remaining for channel A</span>
00200     <span class="comment">// add 1 to make sure we round up, &gt;&gt;1 equivalent to /2</span>
00201     <span class="keywordflow">return</span> (PulseT1ACount+1)&gt;&gt;1;
00202 }
00203 
00204 u16 pulseT1BRemaining(<span class="keywordtype">void</span>)
00205 {
00206     <span class="comment">// return the number of pulses remaining for channel A</span>
00207     <span class="comment">// add 1 to make sure we round up, &gt;&gt;1 equivalent to /2</span>
00208     <span class="keywordflow">return</span> (PulseT1BCount+1)&gt;&gt;1;
00209 }
00210 
00211 <span class="keywordtype">void</span> pulseT1AService(<span class="keywordtype">void</span>)
00212 {
00213     <span class="comment">// check if TimerPulseACount is non-zero</span>
00214     <span class="comment">//      (i.e. pulses are still requested)</span>
00215     <span class="keywordflow">if</span>(PulseT1ACount)
00216     {
00217         <span class="comment">//u16 OCValue;</span>
00218         <span class="comment">// read in current value of output compare register OCR1A</span>
00219         <span class="comment">//OCValue =  inp(OCR1AL);       // read low byte of OCR1A</span>
00220         <span class="comment">//OCValue += inp(OCR1AH)&lt;&lt;8;    // read high byte of OCR1A</span>
00221         <span class="comment">// increment OCR1A value by PulseT1APeriodTics</span>
00222         <span class="comment">//OCValue += PulseT1APeriodTics;</span>
00223         <span class="comment">// set future output compare time to this new value</span>
00224         <span class="comment">//outp((OCValue&gt;&gt;8),        OCR1AH);    // write high byte</span>
00225         <span class="comment">//outp((OCValue &amp; 0x00FF),OCR1AL);  // write low byte</span>
00226 
00227         <span class="comment">// the following line should be identical in operation</span>
00228         <span class="comment">// to the lines above, but for the moment, I'm not convinced</span>
00229         <span class="comment">// this method is bug-free.  At least it's simpler!</span>
00230         <span class="comment">//outw(OCR1A, inw(OCR1A) + PulseT1APeriodTics);</span>
00231         <span class="comment">// change again</span>
00232         OCR1A += PulseT1APeriodTics;
00233                         
00234         <span class="comment">// decrement the number of pulses executed</span>
00235         <span class="keywordflow">if</span>(PulseT1AMode &amp; PULSE_MODE_COUNTED)
00236             PulseT1ACount--;
00237     }
00238     <span class="keywordflow">else</span>
00239     {
00240         <span class="comment">// pulse count has reached zero</span>
00241         <span class="comment">// disable the output compare's action on OC1A pin</span>
00242         cbi(TCCR1A,COM1A1);
00243         cbi(TCCR1A,COM1A0);
00244         <span class="comment">// and disable the output compare's interrupt to stop pulsing</span>
00245         cbi(TIMSK, OCIE1A);
00246     }
00247 }
00248 
00249 <span class="keywordtype">void</span> pulseT1BService(<span class="keywordtype">void</span>)
00250 {
00251     <span class="comment">// check if TimerPulseACount is non-zero</span>
00252     <span class="comment">//      (i.e. pulses are still requested)</span>
00253     <span class="keywordflow">if</span>(PulseT1BCount)
00254     {
00255         <span class="comment">//u16 OCValue;</span>
00256         <span class="comment">// read in current value of output compare register OCR1B</span>
00257         <span class="comment">//OCValue =  inp(OCR1BL);       // read low byte of OCR1B</span>
00258         <span class="comment">//OCValue += inp(OCR1BH)&lt;&lt;8;    // read high byte of OCR1B</span>
00259         <span class="comment">// increment OCR1B value by PulseT1BPeriodTics</span>
00260         <span class="comment">//OCValue += PulseT1BPeriodTics; </span>
00261         <span class="comment">// set future output compare time to this new value</span>
00262         <span class="comment">//outp((OCValue&gt;&gt;8),        OCR1BH);    // write high byte</span>
00263         <span class="comment">//outp((OCValue &amp; 0x00FF),OCR1BL);  // write low byte</span>
00264 
00265         <span class="comment">// the following line should be identical in operation</span>
00266         <span class="comment">// to the lines above, but for the moment, I'm not convinced</span>
00267         <span class="comment">// this method is bug-free.  At least it's simpler!</span>
00268         <span class="comment">//outw(OCR1B, inw(OCR1B) + PulseT1BPeriodTics);</span>
00269         <span class="comment">// change again</span>
00270         OCR1B += PulseT1BPeriodTics;
00271 
00272         
00273         <span class="comment">// decrement the number of pulses executed</span>
00274         <span class="keywordflow">if</span>(PulseT1BMode &amp; PULSE_MODE_COUNTED)
00275             PulseT1BCount--;
00276     }
00277     <span class="keywordflow">else</span>
00278     {
00279         <span class="comment">// pulse count has reached zero</span>
00280         <span class="comment">// disable the output compare's action on OC1B pin</span>
00281         cbi(TCCR1A,COM1B1);
00282         cbi(TCCR1A,COM1B0);
00283         <span class="comment">// and disable the output compare's interrupt to stop pulsing</span>
00284         cbi(TIMSK, OCIE1B);
00285     }
00286 }
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