uartsw2_8c-source.html

avr应用测试程序

00155     
00156     <span class="comment">// set the start bit</span>
00157 <span class="preprocessor">    #ifdef UARTSW_INVERT</span>
00158 <span class="preprocessor"></span>    sbi(<a class="code" href="uartsw2conf_8h.html#a2">UARTSW_TX_PORT</a>, <a class="code" href="uartsw2conf_8h.html#a4">UARTSW_TX_PIN</a>);
00159 <span class="preprocessor">    #else</span>
00160 <span class="preprocessor"></span>    cbi(<a class="code" href="uartsw2conf_8h.html#a2">UARTSW_TX_PORT</a>, <a class="code" href="uartsw2conf_8h.html#a4">UARTSW_TX_PIN</a>);
00161 <span class="preprocessor">    #endif</span>
00162 <span class="preprocessor"></span>    <span class="comment">// schedule the next bit</span>
00163     outb(OCR2, inb(TCNT2) + UartswBaudRateDiv);
00164     <span class="comment">// enable OC2 interrupt</span>
00165     sbi(TIMSK, OCIE2);
00166 }
00167 <span class="comment"></span>
00168 <span class="comment">//! gets a byte (if available) from the uart receive buffer</span>
<a name="l00169"></a><a class="code" href="uartsw2_8c.html#a15">00169</a> <span class="comment"></span>u08 <a class="code" href="uartsw_8c.html#a15">uartswReceiveByte</a>(u08* rxData)
00170 {
00171     <span class="comment">// make sure we have a receive buffer</span>
00172     <span class="keywordflow">if</span>(uartswRxBuffer.<a class="code" href="structstruct__cBuffer.html#o1">size</a>)
00173     {
00174         <span class="comment">// make sure we have data</span>
00175         <span class="keywordflow">if</span>(uartswRxBuffer.<a class="code" href="structstruct__cBuffer.html#o2">datalength</a>)
00176         {
00177             <span class="comment">// get byte from beginning of buffer</span>
00178             *rxData = <a class="code" href="group__buffer.html#ga2">bufferGetFromFront</a>(&amp;uartswRxBuffer);
00179             <span class="keywordflow">return</span> TRUE;
00180         }
00181         <span class="keywordflow">else</span>
00182         {
00183             <span class="comment">// no data</span>
00184             <span class="keywordflow">return</span> FALSE;
00185         }
00186     }
00187     <span class="keywordflow">else</span>
00188     {
00189         <span class="comment">// no buffer</span>
00190         <span class="keywordflow">return</span> FALSE;
00191     }
00192 }
00193 
<a name="l00194"></a><a class="code" href="uartsw2_8c.html#a16">00194</a> <span class="keywordtype">void</span> <a class="code" href="uartsw_8c.html#a16">uartswTxBitService</a>(<span class="keywordtype">void</span>)
00195 {
00196     <span class="keywordflow">if</span>(UartswTxBitNum)
00197     {
00198         <span class="comment">// there are bits still waiting to be transmitted</span>
00199         <span class="keywordflow">if</span>(UartswTxBitNum &gt; 1)
00200         {
00201             <span class="comment">// transmit data bits (inverted, LSB first)</span>
00202 <span class="preprocessor">            #ifdef UARTSW_INVERT</span>
00203 <span class="preprocessor"></span>            <span class="keywordflow">if</span>( !(UartswTxData &amp; 0x01) )
00204 <span class="preprocessor">            #else</span>
00205 <span class="preprocessor"></span>            <span class="keywordflow">if</span>( (UartswTxData &amp; 0x01) )
00206 <span class="preprocessor">            #endif</span>
00207 <span class="preprocessor"></span>                sbi(<a class="code" href="uartsw2conf_8h.html#a2">UARTSW_TX_PORT</a>, <a class="code" href="uartsw2conf_8h.html#a4">UARTSW_TX_PIN</a>);
00208             <span class="keywordflow">else</span>
00209                 cbi(<a class="code" href="uartsw2conf_8h.html#a2">UARTSW_TX_PORT</a>, <a class="code" href="uartsw2conf_8h.html#a4">UARTSW_TX_PIN</a>);
00210             <span class="comment">// shift bits down</span>
00211             UartswTxData = UartswTxData&gt;&gt;1;
00212         }
00213         <span class="keywordflow">else</span>
00214         {
00215             <span class="comment">// transmit stop bit</span>
00216 <span class="preprocessor">            #ifdef UARTSW_INVERT</span>
00217 <span class="preprocessor"></span>            cbi(<a class="code" href="uartsw2conf_8h.html#a2">UARTSW_TX_PORT</a>, <a class="code" href="uartsw2conf_8h.html#a4">UARTSW_TX_PIN</a>);
00218 <span class="preprocessor">            #else</span>
00219 <span class="preprocessor"></span>            sbi(<a class="code" href="uartsw2conf_8h.html#a2">UARTSW_TX_PORT</a>, <a class="code" href="uartsw2conf_8h.html#a4">UARTSW_TX_PIN</a>);
00220 <span class="preprocessor">            #endif</span>
00221 <span class="preprocessor"></span>        }
00222         <span class="comment">// schedule the next bit</span>
00223         outb(OCR2, inb(OCR2) + UartswBaudRateDiv);
00224         <span class="comment">// count down</span>
00225         UartswTxBitNum--;
00226     }
00227     <span class="keywordflow">else</span>
00228     {
00229         <span class="comment">// transmission is done</span>
00230         <span class="comment">// clear busy flag</span>
00231         UartswTxBusy = FALSE;
00232         <span class="comment">// disable OC2 interrupt</span>
00233         cbi(TIMSK, OCIE2);
00234     }
00235 }
00236 
<a name="l00237"></a><a class="code" href="uartsw2_8c.html#a17">00237</a> <span class="keywordtype">void</span> <a class="code" href="uartsw_8c.html#a17">uartswRxBitService</a>(<span class="keywordtype">void</span>)
00238 {
00239     <span class="comment">// this function runs on either:</span>
00240     <span class="comment">// - a rising edge interrupt</span>
00241     <span class="comment">// - Timer 0 output compare</span>
00242     <span class="keywordflow">if</span>(!UartswRxBusy)
00243     {
00244         <span class="comment">// UART was not previously busy,</span>
00245         <span class="comment">// this must be is a start bit</span>
00246         
00247         <span class="comment">// disable INT2 interrupt</span>
00248         cbi(GICR, INT2);
00249         <span class="comment">// schedule data bit sampling 1.5 bit periods from now</span>
00250         outb(OCR0, inb(TCNT0) + UartswBaudRateDiv + UartswBaudRateDiv/2);
00251         <span class="comment">// clear OC0 interrupt flag</span>
00252         sbi(TIFR, OCF0);
00253         <span class="comment">// enable OC0 interrupt</span>
00254         sbi(TIMSK, OCIE0);
00255         <span class="comment">// set busy flag</span>
00256         UartswRxBusy = TRUE;
00257         <span class="comment">// reset bit counter</span>
00258         UartswRxBitNum = 0;
00259         <span class="comment">// reset data</span>
00260         UartswRxData = 0;
00261     }
00262     <span class="keywordflow">else</span>
00263     {
00264         <span class="comment">// start bit has already been received</span>
00265         <span class="comment">// we're in the data bits</span>
00266         
00267         <span class="comment">// shift data byte to make room for new bit</span>
00268         UartswRxData = UartswRxData&gt;&gt;1;
00269 
00270         <span class="comment">// sample the data line</span>
00271 <span class="preprocessor">        #ifdef UARTSW_INVERT</span>
00272 <span class="preprocessor"></span>        <span class="keywordflow">if</span>( !(inb(<a class="code" href="uartsw2conf_8h.html#a7">UARTSW_RX_PORTIN</a>) &amp; (1&lt;&lt;<a class="code" href="uartsw2conf_8h.html#a8">UARTSW_RX_PIN</a>)) )
00273 <span class="preprocessor">        #else</span>
00274 <span class="preprocessor"></span>        <span class="keywordflow">if</span>( (inb(<a class="code" href="uartsw2conf_8h.html#a7">UARTSW_RX_PORTIN</a>) &amp; (1&lt;&lt;<a class="code" href="uartsw2conf_8h.html#a8">UARTSW_RX_PIN</a>)) )
00275 <span class="preprocessor">        #endif</span>
00276 <span class="preprocessor"></span>        {
00277             <span class="comment">// serial line is marking</span>
00278             <span class="comment">// record '1' bit</span>
00279             UartswRxData |= 0x80;
00280         }
00281 
00282         <span class="comment">// increment bit counter</span>
00283         UartswRxBitNum++;
00284         <span class="comment">// schedule next bit sample</span>
00285         outb(OCR0, inb(OCR0) + UartswBaudRateDiv);
00286 
00287         <span class="comment">// check if we have a full byte</span>
00288         <span class="keywordflow">if</span>(UartswRxBitNum &gt;= 8)
00289         {
00290             <span class="comment">// save data in receive buffer</span>
00291             <a class="code" href="group__buffer.html#ga5">bufferAddToEnd</a>(&amp;uartswRxBuffer, UartswRxData);
00292             <span class="comment">// disable OC0 interrupt</span>
00293             cbi(TIMSK, OCIE0);
00294             <span class="comment">// clear INT2 interrupt flag</span>
00295             sbi(GIFR, INTF2);
00296             <span class="comment">// enable INT interrupt</span>
00297             sbi(GICR, INT2);
00298             <span class="comment">// clear busy flag</span>
00299             UartswRxBusy = FALSE;
00300         }
00301     }
00302 }
00303 
00304 <a class="code" href="a2d_8c.html#a10">SIGNAL</a>(SIG_INTERRUPT2)
00305 {
00306     <span class="comment">// run RxBit service routine</span>
00307     <a class="code" href="uartsw_8c.html#a17">uartswRxBitService</a>();
00308 }
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