uartsw2_8c-source.html

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00155     UartswTxBitNum = 9;
00156     
00157     <span class="comment">// set the start bit</span>
00158 <span class="preprocessor">    #ifdef UARTSW_INVERT</span>
00159 <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>);
00160 <span class="preprocessor">    #else</span>
00161 <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>);
00162 <span class="preprocessor">    #endif</span>
00163 <span class="preprocessor"></span>    <span class="comment">// schedule the next bit</span>
00164     outb(OCR2, inb(TCNT2) + UartswBaudRateDiv);
00165     <span class="comment">// enable OC2 interrupt</span>
00166     sbi(TIMSK, OCIE2);
00167 }
00168 <span class="comment"></span>
00169 <span class="comment">//! gets a byte (if available) from the uart receive buffer</span>
<a name="l00170"></a><a class="code" href="uartsw2_8c.html#a15">00170</a> <span class="comment"></span>u08 <a class="code" href="uartsw_8c.html#a15">uartswReceiveByte</a>(u08* rxData)
00171 {
00172     <span class="comment">// make sure we have a receive buffer</span>
00173     <span class="keywordflow">if</span>(uartswRxBuffer.<a class="code" href="structstruct__cBuffer.html#o1">size</a>)
00174     {
00175         <span class="comment">// make sure we have data</span>
00176         <span class="keywordflow">if</span>(uartswRxBuffer.<a class="code" href="structstruct__cBuffer.html#o2">datalength</a>)
00177         {
00178             <span class="comment">// get byte from beginning of buffer</span>
00179             *rxData = <a class="code" href="group__buffer.html#ga2">bufferGetFromFront</a>(&amp;uartswRxBuffer);
00180             <span class="keywordflow">return</span> TRUE;
00181         }
00182         <span class="keywordflow">else</span>
00183         {
00184             <span class="comment">// no data</span>
00185             <span class="keywordflow">return</span> FALSE;
00186         }
00187     }
00188     <span class="keywordflow">else</span>
00189     {
00190         <span class="comment">// no buffer</span>
00191         <span class="keywordflow">return</span> FALSE;
00192     }
00193 }
00194 
<a name="l00195"></a><a class="code" href="uartsw2_8c.html#a16">00195</a> <span class="keywordtype">void</span> <a class="code" href="uartsw_8c.html#a16">uartswTxBitService</a>(<span class="keywordtype">void</span>)
00196 {
00197     <span class="keywordflow">if</span>(UartswTxBitNum)
00198     {
00199         <span class="comment">// there are bits still waiting to be transmitted</span>
00200         <span class="keywordflow">if</span>(UartswTxBitNum &gt; 1)
00201         {
00202             <span class="comment">// transmit data bits (inverted, LSB first)</span>
00203 <span class="preprocessor">            #ifdef UARTSW_INVERT</span>
00204 <span class="preprocessor"></span>            <span class="keywordflow">if</span>( !(UartswTxData &amp; 0x01) )
00205 <span class="preprocessor">            #else</span>
00206 <span class="preprocessor"></span>            <span class="keywordflow">if</span>( (UartswTxData &amp; 0x01) )
00207 <span class="preprocessor">            #endif</span>
00208 <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>);
00209             <span class="keywordflow">else</span>
00210                 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>);
00211             <span class="comment">// shift bits down</span>
00212             UartswTxData = UartswTxData&gt;&gt;1;
00213         }
00214         <span class="keywordflow">else</span>
00215         {
00216             <span class="comment">// transmit stop bit</span>
00217 <span class="preprocessor">            #ifdef UARTSW_INVERT</span>
00218 <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>);
00219 <span class="preprocessor">            #else</span>
00220 <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>);
00221 <span class="preprocessor">            #endif</span>
00222 <span class="preprocessor"></span>        }
00223         <span class="comment">// schedule the next bit</span>
00224         outb(OCR2, inb(OCR2) + UartswBaudRateDiv);
00225         <span class="comment">// count down</span>
00226         UartswTxBitNum--;
00227     }
00228     <span class="keywordflow">else</span>
00229     {
00230         <span class="comment">// transmission is done</span>
00231         <span class="comment">// clear busy flag</span>
00232         UartswTxBusy = FALSE;
00233         <span class="comment">// disable OC2 interrupt</span>
00234         cbi(TIMSK, OCIE2);
00235     }
00236 }
00237 
<a name="l00238"></a><a class="code" href="uartsw2_8c.html#a17">00238</a> <span class="keywordtype">void</span> <a class="code" href="uartsw_8c.html#a17">uartswRxBitService</a>(<span class="keywordtype">void</span>)
00239 {
00240     <span class="comment">// this function runs on either:</span>
00241     <span class="comment">// - a rising edge interrupt</span>
00242     <span class="comment">// - Timer 0 output compare</span>
00243     <span class="keywordflow">if</span>(!UartswRxBusy)
00244     {
00245         <span class="comment">// UART was not previously busy,</span>
00246         <span class="comment">// this must be is a start bit</span>
00247         
00248         <span class="comment">// disable INT2 interrupt</span>
00249         cbi(GICR, INT2);
00250         <span class="comment">// schedule data bit sampling 1.5 bit periods from now</span>
00251         outb(OCR0, inb(TCNT0) + UartswBaudRateDiv + UartswBaudRateDiv/2);
00252         <span class="comment">// clear OC0 interrupt flag</span>
00253         sbi(TIFR, OCF0);
00254         <span class="comment">// enable OC0 interrupt</span>
00255         sbi(TIMSK, OCIE0);
00256         <span class="comment">// set busy flag</span>
00257         UartswRxBusy = TRUE;
00258         <span class="comment">// reset bit counter</span>
00259         UartswRxBitNum = 0;
00260         <span class="comment">// reset data</span>
00261         UartswRxData = 0;
00262     }
00263     <span class="keywordflow">else</span>
00264     {
00265         <span class="comment">// start bit has already been received</span>
00266         <span class="comment">// we're in the data bits</span>
00267         
00268         <span class="comment">// shift data byte to make room for new bit</span>
00269         UartswRxData = UartswRxData&gt;&gt;1;
00270 
00271         <span class="comment">// sample the data line</span>
00272 <span class="preprocessor">        #ifdef UARTSW_INVERT</span>
00273 <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>)) )
00274 <span class="preprocessor">        #else</span>
00275 <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>)) )
00276 <span class="preprocessor">        #endif</span>
00277 <span class="preprocessor"></span>        {
00278             <span class="comment">// serial line is marking</span>
00279             <span class="comment">// record '1' bit</span>
00280             UartswRxData |= 0x80;
00281         }
00282 
00283         <span class="comment">// increment bit counter</span>
00284         UartswRxBitNum++;
00285         <span class="comment">// schedule next bit sample</span>
00286         outb(OCR0, inb(OCR0) + UartswBaudRateDiv);
00287 
00288         <span class="comment">// check if we have a full byte</span>
00289         <span class="keywordflow">if</span>(UartswRxBitNum &gt;= 8)
00290         {
00291             <span class="comment">// save data in receive buffer</span>
00292             <a class="code" href="group__buffer.html#ga5">bufferAddToEnd</a>(&amp;uartswRxBuffer, UartswRxData);
00293             <span class="comment">// disable OC0 interrupt</span>
00294             cbi(TIMSK, OCIE0);
00295             <span class="comment">// clear INT2 interrupt flag</span>
00296             sbi(GIFR, INTF2);
00297             <span class="comment">// enable INT interrupt</span>
00298             sbi(GICR, INT2);
00299             <span class="comment">// clear busy flag</span>
00300             UartswRxBusy = FALSE;
00301         }
00302     }
00303 }
00304 
00305 <a class="code" href="a2d_8c.html#a10">SIGNAL</a>(SIG_INTERRUPT2)
00306 {
00307     <span class="comment">// run RxBit service routine</span>
00308     <a class="code" href="uartsw_8c.html#a17">uartswRxBitService</a>();
00309 }
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