i2c_8c-source.html

ATMEL的AVR单片机库文件

00211     <span class="comment">// save data</span>
00212     I2cDeviceAddrRW = (deviceAddr &amp; 0xFE);  <span class="comment">// RW cleared: write operation</span>
00213     <span class="keywordflow">for</span>(i=0; i&lt;length; i++)
00214         I2cSendData[i] = *data++;
00215     I2cSendDataIndex = 0;
00216     I2cSendDataLength = length;
00217     <span class="comment">// send start condition</span>
00218     <a class="code" href="i2c_8c.html#a15">i2cSendStart</a>();
00219 }
00220 
<a name="l00221"></a><a class="code" href="i2c_8h.html#a23">00221</a> <span class="keywordtype">void</span> <a class="code" href="i2c_8h.html#a23">i2cMasterReceive</a>(u08 deviceAddr, u08 length, u08* data)
00222 {
00223     u08 i;
00224     <span class="comment">// wait for interface to be ready</span>
00225     <span class="keywordflow">while</span>(I2cState);
00226     <span class="comment">// set state</span>
00227     I2cState = I2C_MASTER_RX;
00228     <span class="comment">// save data</span>
00229     I2cDeviceAddrRW = (deviceAddr|0x01);    <span class="comment">// RW set: read operation</span>
00230     I2cReceiveDataIndex = 0;
00231     I2cReceiveDataLength = length;
00232     <span class="comment">// send start condition</span>
00233     <a class="code" href="i2c_8c.html#a15">i2cSendStart</a>();
00234     <span class="comment">// wait for data</span>
00235     <span class="keywordflow">while</span>(I2cState);
00236     <span class="comment">// return data</span>
00237     <span class="keywordflow">for</span>(i=0; i&lt;length; i++)
00238         *data++ = I2cReceiveData[i];
00239 }
00240 
<a name="l00241"></a><a class="code" href="i2c_8h.html#a24">00241</a> u08 <a class="code" href="i2c_8h.html#a24">i2cMasterSendNI</a>(u08 deviceAddr, u08 length, u08* data)
00242 {
00243     u08 retval = I2C_OK;
00244 
00245     <span class="comment">// disable TWI interrupt</span>
00246     cbi(TWCR, TWIE);
00247 
00248     <span class="comment">// send start condition</span>
00249     <a class="code" href="i2c_8c.html#a15">i2cSendStart</a>();
00250     <a class="code" href="i2c_8c.html#a17">i2cWaitForComplete</a>();
00251 
00252     <span class="comment">// send device address with write</span>
00253     <a class="code" href="i2c_8h.html#a18">i2cSendByte</a>( deviceAddr &amp; 0xFE );
00254     <a class="code" href="i2c_8c.html#a17">i2cWaitForComplete</a>();
00255 
00256     <span class="comment">// check if device is present and live</span>
00257     <span class="keywordflow">if</span>( inb(TWSR) == TW_MT_SLA_ACK)
00258     {
00259         <span class="comment">// send data</span>
00260         <span class="keywordflow">while</span>(length)
00261         {
00262             <a class="code" href="i2c_8h.html#a18">i2cSendByte</a>( *data++ );
00263             <a class="code" href="i2c_8c.html#a17">i2cWaitForComplete</a>();
00264             length--;
00265         }
00266     }
00267     <span class="keywordflow">else</span>
00268     {
00269         <span class="comment">// device did not ACK it's address,</span>
00270         <span class="comment">// data will not be transferred</span>
00271         <span class="comment">// return error</span>
00272         retval = I2C_ERROR_NODEV;
00273     }
00274 
00275     <span class="comment">// transmit stop condition</span>
00276     <span class="comment">// leave with TWEA on for slave receiving</span>
00277     <a class="code" href="i2c_8c.html#a16">i2cSendStop</a>();
00278     <span class="keywordflow">while</span>( !(inb(TWCR) &amp; BV(TWSTO)) );
00279 
00280     <span class="comment">// enable TWI interrupt</span>
00281     sbi(TWCR, TWIE);
00282 
00283     <span class="keywordflow">return</span> retval;
00284 }
00285 
<a name="l00286"></a><a class="code" href="i2c_8h.html#a25">00286</a> u08 <a class="code" href="i2c_8h.html#a25">i2cMasterReceiveNI</a>(u08 deviceAddr, u08 length, u08 *data)
00287 {
00288     u08 retval = I2C_OK;
00289 
00290     <span class="comment">// disable TWI interrupt</span>
00291     cbi(TWCR, TWIE);
00292 
00293     <span class="comment">// send start condition</span>
00294     <a class="code" href="i2c_8c.html#a15">i2cSendStart</a>();
00295     <a class="code" href="i2c_8c.html#a17">i2cWaitForComplete</a>();
00296 
00297     <span class="comment">// send device address with read</span>
00298     <a class="code" href="i2c_8h.html#a18">i2cSendByte</a>( deviceAddr | 0x01 );
00299     <a class="code" href="i2c_8c.html#a17">i2cWaitForComplete</a>();
00300 
00301     <span class="comment">// check if device is present and live</span>
00302     <span class="keywordflow">if</span>( inb(TWSR) == TW_MR_SLA_ACK)
00303     {
00304         <span class="comment">// accept receive data and ack it</span>
00305         <span class="keywordflow">while</span>(length &gt; 1)
00306         {
00307             <a class="code" href="i2c_8h.html#a19">i2cReceiveByte</a>(TRUE);
00308             <a class="code" href="i2c_8c.html#a17">i2cWaitForComplete</a>();
00309             *data++ = <a class="code" href="i2c_8c.html#a20">i2cGetReceivedByte</a>();
00310             <span class="comment">// decrement length</span>
00311             length--;
00312         }
00313 
00314         <span class="comment">// accept receive data and nack it (last-byte signal)</span>
00315         <a class="code" href="i2c_8h.html#a19">i2cReceiveByte</a>(FALSE);
00316         <a class="code" href="i2c_8c.html#a17">i2cWaitForComplete</a>();
00317         *data++ = <a class="code" href="i2c_8c.html#a20">i2cGetReceivedByte</a>();
00318     }
00319     <span class="keywordflow">else</span>
00320     {
00321         <span class="comment">// device did not ACK it's address,</span>
00322         <span class="comment">// data will not be transferred</span>
00323         <span class="comment">// return error</span>
00324         retval = I2C_ERROR_NODEV;
00325     }
00326 
00327     <span class="comment">// transmit stop condition</span>
00328     <span class="comment">// leave with TWEA on for slave receiving</span>
00329     <a class="code" href="i2c_8c.html#a16">i2cSendStop</a>();
00330 
00331     <span class="comment">// enable TWI interrupt</span>
00332     sbi(TWCR, TWIE);
00333 
00334     <span class="keywordflow">return</span> retval;
00335 }
00336 <span class="comment">/*</span>
00337 <span class="comment">void i2cMasterTransferNI(u08 deviceAddr, u08 sendlength, u08* senddata, u08 receivelength, u08* receivedata)</span>
00338 <span class="comment">{</span>
00339 <span class="comment">    // disable TWI interrupt</span>
00340 <span class="comment">    cbi(TWCR, TWIE);</span>
00341 <span class="comment"></span>
00342 <span class="comment">    // send start condition</span>
00343 <span class="comment">    i2cSendStart();</span>
00344 <span class="comment">    i2cWaitForComplete();</span>
00345 <span class="comment"></span>
00346 <span class="comment">    // if there's data to be sent, do it</span>
00347 <span class="comment">    if(sendlength)</span>
00348 <span class="comment">    {</span>
00349 <span class="comment">        // send device address with write</span>
00350 <span class="comment">        i2cSendByte( deviceAddr &amp; 0xFE );</span>
00351 <span class="comment">        i2cWaitForComplete();</span>
00352 <span class="comment">        </span>
00353 <span class="comment">        // send data</span>
00354 <span class="comment">        while(sendlength)</span>
00355 <span class="comment">        {</span>
00356 <span class="comment">            i2cSendByte( *senddata++ );</span>
00357 <span class="comment">            i2cWaitForComplete();</span>
00358 <span class="comment">            sendlength--;</span>
00359 <span class="comment">        }</span>
00360 <span class="comment">    }</span>
00361 <span class="comment"></span>
00362 <span class="comment">    // if there's data to be received, do it</span>
00363 <span class="comment">    if(receivelength)</span>
00364 <span class="comment">    {</span>
00365 <span class="comment">        // send repeated start condition</span>
00366 <span class="comment">        i2cSendStart();</span>
00367 <span class="comment">        i2cWaitForComplete();</span>
00368 <span class="comment"></span>
00369 <span class="comment">        // send device address with read</span>
00370 <span class="comment">        i2cSendByte( deviceAddr | 0x01 );</span>
00371 <span class="comment">        i2cWaitForComplete();</span>
00372 <span class="comment"></span>
00373 <span class="comment">        // accept receive data and ack it</span>
00374 <span class="comment">        while(receivelength &gt; 1)</span>
00375 <span class="comment">        {</span>
00376 <span class="comment">            i2cReceiveByte(TRUE);</span>
00377 <span class="comment">            i2cWaitForComplete();</span>
00378 <span class="comment">            *receivedata++ = i2cGetReceivedByte();</span>
00379 <span class="comment">            // decrement length</span>
00380 <span class="comment">            receivelength--;</span>
00381 <span class="comment">        }</span>
00382 <span class="comment"></span>
00383 <span class="comment">        // accept receive data and nack it (last-byte signal)</span>
00384 <span class="comment">        i2cReceiveByte(TRUE);</span>
00385 <span class="comment">        i2cWaitForComplete();</span>
00386 <span class="comment">        *receivedata++ = i2cGetReceivedByte();</span>
00387 <span class="comment">    }</span>
00388 <span class="comment">    </span>
00389 <span class="comment">    // transmit stop condition</span>
00390 <span class="comment">    // leave with TWEA on for slave receiving</span>
00391 <span class="comment">    i2cSendStop();</span>
00392 <span class="comment">    while( !(inb(TWCR) &amp; BV(TWSTO)) );</span>
00393 <span class="comment"></span>
00394 <span class="comment">    // enable TWI interrupt</span>
00395 <span class="comment">    sbi(TWCR, TWIE);</span>
00396 <span class="comment">}</span>
00397 <span class="comment">*/</span>
00398 <span class="comment"></span>
00399 <span class="comment">//! I2C (TWI) interrupt service routine</span>
<a name="l00400"></a><a class="code" href="i2c_8c.html#a26">00400</a> <span class="comment"></span><a class="code" href="a2d_8c.html#a10">SIGNAL</a>(SIG_2WIRE_SERIAL)
00401 {
00402     <span class="comment">// read status bits</span>
00403     u08 status = inb(TWSR) &amp; TWSR_STATUS_MASK;
00404 
00405     <span class="keywordflow">switch</span>(status)
00406     {
00407     <span class="comment">// Master General</span>
00408     <span class="keywordflow">case</span> TW_START:                      <span class="comment">// 0x08: Sent start condition</span>
00409     <span class="keywordflow">case</span> TW_REP_START:                  <span class="comment">// 0x10: Sent repeated start condition</span>
00410 <span class="preprocessor">        #ifdef I2C_DEBUG</span>
00411 <span class="preprocessor"></span>        <a class="code" href="rprintf_8h.html#a6">rprintfInit</a>(uart1AddToTxBuffer);
00412         rprintf(<span class="stringliteral">"I2C: M-&gt;START\r\n"</span>);
00413         <a class="code" href="rprintf_8h.html#a6">rprintfInit</a>(uart1SendByte);
00414 <span class="preprocessor">        #endif</span>
00415 <span class="preprocessor"></span>        <span class="comment">// send device address</span>
00416         <a class="code" href="i2c_8h.html#a18">i2cSendByte</a>(I2cDeviceAddrRW);
00417         <span class="keywordflow">break</span>;
00418     
00419     <span class="comment">// Master Transmitter &amp; Receiver status codes</span>
00420     <span class="keywordflow">case</span> TW_MT_SLA_ACK:                 <span class="comment">// 0x18: Slave address acknowledged</span>
00421     <span class="keywordflow">case</span> TW_MT_DATA_ACK:                <span class="comment">// 0x28: Data acknowledged</span>
00422 <span class="preprocessor">        #ifdef I2C_DEBUG</span>
00423 <span class="preprocessor"></span>        <a class="code" href="rprintf_8h.html#a6">rprintfInit</a>(uart1AddToTxBuffer);
00424         rprintf(<span class="stringliteral">"I2C: MT-&gt;SLA_ACK or DATA_ACK\r\n"</span>);
00425         <a class="code" href="rprintf_8h.html#a6">rprintfInit</a>(uart1SendByte);
00426 <span class="preprocessor">        #endif</span>
00427 <span class="preprocessor"></span>        <span class="keywordflow">if</span>(I2cSendDataIndex &lt; I2cSendDataLength)