mirror of https://github.com/ArduPilot/ardupilot
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314 lines
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<title>ArduPilot Libraries: FastSerial.cpp Source File</title>
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<h1>FastSerial.cpp</h1> </div>
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</div>
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<div class="contents">
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<a href="_fast_serial_8cpp.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// -*- Mode: C++; c-basic-offset: 8; indent-tabs-mode: nil -*-</span>
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<a name="l00002"></a>00002 <span class="comment">//</span>
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<a name="l00003"></a>00003 <span class="comment">// Interrupt-driven serial transmit/receive library.</span>
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<a name="l00004"></a>00004 <span class="comment">//</span>
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<a name="l00005"></a>00005 <span class="comment">// Copyright (c) 2010 Michael Smith. All rights reserved.</span>
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<a name="l00006"></a>00006 <span class="comment">//</span>
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<a name="l00007"></a>00007 <span class="comment">// Receive and baudrate calculations derived from the Arduino </span>
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<a name="l00008"></a>00008 <span class="comment">// HardwareSerial driver:</span>
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<a name="l00009"></a>00009 <span class="comment">//</span>
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<a name="l00010"></a>00010 <span class="comment">// Copyright (c) 2006 Nicholas Zambetti. All right reserved.</span>
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<a name="l00011"></a>00011 <span class="comment">//</span>
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<a name="l00012"></a>00012 <span class="comment">// Transmit algorithm inspired by work:</span>
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<a name="l00013"></a>00013 <span class="comment">//</span>
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<a name="l00014"></a>00014 <span class="comment">// Code Jose Julio and Jordi Munoz. DIYDrones.com</span>
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<a name="l00015"></a>00015 <span class="comment">//</span>
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<a name="l00016"></a>00016 <span class="comment">// This library is free software; you can redistribute it and/or</span>
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<a name="l00017"></a>00017 <span class="comment">// modify it under the terms of the GNU Lesser General Public</span>
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<a name="l00018"></a>00018 <span class="comment">// License as published by the Free Software Foundation; either</span>
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<a name="l00019"></a>00019 <span class="comment">// version 2.1 of the License, or (at your option) any later version.</span>
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<a name="l00020"></a>00020 <span class="comment">//</span>
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<a name="l00021"></a>00021 <span class="comment">// This library is distributed in the hope that it will be useful,</span>
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<a name="l00022"></a>00022 <span class="comment">// but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
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<a name="l00023"></a>00023 <span class="comment">// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</span>
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<a name="l00024"></a>00024 <span class="comment">// Lesser General Public License for more details.</span>
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<a name="l00025"></a>00025 <span class="comment">//</span>
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<a name="l00026"></a>00026 <span class="comment">// You should have received a copy of the GNU Lesser General Public</span>
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<a name="l00027"></a>00027 <span class="comment">// License along with this library; if not, write to the Free Software</span>
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<a name="l00028"></a>00028 <span class="comment">// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA</span>
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<a name="l00029"></a>00029 <span class="comment">//</span>
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<a name="l00030"></a>00030
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<a name="l00031"></a>00031
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<a name="l00032"></a>00032 <span class="comment">//#include "../AP_Common/AP_Common.h"</span>
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<a name="l00033"></a>00033 <span class="preprocessor">#include "<a class="code" href="_fast_serial_8h.html">FastSerial.h</a>"</span>
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<a name="l00034"></a>00034 <span class="preprocessor">#include "<a class="code" href="_w_program_8h.html">WProgram.h</a>"</span>
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<a name="l00035"></a>00035
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<a name="l00036"></a>00036 <span class="preprocessor">#if defined(UDR3)</span>
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<a name="l00037"></a>00037 <span class="preprocessor"></span><span class="preprocessor"># define FS_MAX_PORTS 4</span>
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<a name="l00038"></a>00038 <span class="preprocessor"></span><span class="preprocessor">#elif defined(UDR2)</span>
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<a name="l00039"></a>00039 <span class="preprocessor"></span><span class="preprocessor"># define FS_MAX_PORTS 3</span>
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<a name="l00040"></a>00040 <span class="preprocessor"></span><span class="preprocessor">#elif defined(UDR1)</span>
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<a name="l00041"></a>00041 <span class="preprocessor"></span><span class="preprocessor"># define FS_MAX_PORTS 2</span>
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<a name="l00042"></a>00042 <span class="preprocessor"></span><span class="preprocessor">#else</span>
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<a name="l00043"></a><a class="code" href="_fast_serial_8cpp.html#a52a40ec3245d529723af3ce0a95bd7b6">00043</a> <span class="preprocessor"></span><span class="preprocessor"># define FS_MAX_PORTS 1</span>
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<a name="l00044"></a>00044 <span class="preprocessor"></span><span class="preprocessor">#endif</span>
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<a name="l00045"></a>00045 <span class="preprocessor"></span>
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<a name="l00046"></a><a class="code" href="_fast_serial_8h.html#ad2687d3a6a3d7444849df9edc5597f6b">00046</a> <a class="code" href="struct_fast_serial_1_1_buffer.html">FastSerial::Buffer</a> <a class="code" href="_fast_serial_8cpp.html#ae8641bf6f22cf7893cb462460417caf9">__FastSerial__rxBuffer</a>[FS_MAX_PORTS];
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<a name="l00047"></a><a class="code" href="_fast_serial_8h.html#a50dd604252dbc7918b4da78e2229e0ce">00047</a> <a class="code" href="struct_fast_serial_1_1_buffer.html">FastSerial::Buffer</a> <a class="code" href="_fast_serial_8cpp.html#ada936bc2cdf111796f90cdb7dcdc54dd">__FastSerial__txBuffer</a>[FS_MAX_PORTS];
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<a name="l00048"></a>00048
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<a name="l00049"></a>00049 <span class="comment">// Default buffer sizes</span>
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<a name="l00050"></a><a class="code" href="_fast_serial_8cpp.html#a739a2a1a0047c98ac1b18ecd25dac092">00050</a> <span class="preprocessor">#define RX_BUFFER_SIZE 128</span>
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<a name="l00051"></a><a class="code" href="_fast_serial_8cpp.html#a9ab33647617098646990fe263600b650">00051</a> <span class="preprocessor"></span><span class="preprocessor">#define TX_BUFFER_SIZE 64</span>
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<a name="l00052"></a><a class="code" href="_fast_serial_8cpp.html#a65c660282414eff7e990f21f6b306cb8">00052</a> <span class="preprocessor"></span><span class="preprocessor">#define BUFFER_MAX 512</span>
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<a name="l00053"></a>00053 <span class="preprocessor"></span>
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<a name="l00054"></a>00054 <span class="comment">// Constructor /////////////////////////////////////////////////////////////////</span>
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<a name="l00055"></a>00055
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<a name="l00056"></a><a class="code" href="class_fast_serial.html#a9f20535e34fab50c1f771b9a41790219">00056</a> <a class="code" href="class_fast_serial.html#a9f20535e34fab50c1f771b9a41790219">FastSerial::FastSerial</a>(<span class="keyword">const</span> uint8_t portNumber,
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<a name="l00057"></a>00057 <span class="keyword">volatile</span> uint8_t *ubrrh,
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<a name="l00058"></a>00058 <span class="keyword">volatile</span> uint8_t *ubrrl,
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<a name="l00059"></a>00059 <span class="keyword">volatile</span> uint8_t *ucsra,
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<a name="l00060"></a>00060 <span class="keyword">volatile</span> uint8_t *ucsrb,
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<a name="l00061"></a>00061 <span class="keyword">const</span> uint8_t u2x,
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<a name="l00062"></a>00062 <span class="keyword">const</span> uint8_t portEnableBits,
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<a name="l00063"></a>00063 <span class="keyword">const</span> uint8_t portTxBits)
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<a name="l00064"></a>00064 {
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<a name="l00065"></a>00065 _ubrrh = ubrrh;
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<a name="l00066"></a>00066 _ubrrl = ubrrl;
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<a name="l00067"></a>00067 _ucsra = ucsra;
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<a name="l00068"></a>00068 _ucsrb = ucsrb;
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<a name="l00069"></a>00069 _u2x = u2x;
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<a name="l00070"></a>00070 _portEnableBits = portEnableBits;
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<a name="l00071"></a>00071 _portTxBits = portTxBits;
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<a name="l00072"></a>00072
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<a name="l00073"></a>00073 <span class="comment">// init buffers</span>
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<a name="l00074"></a>00074 _rxBuffer = &__FastSerial__rxBuffer[portNumber];
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<a name="l00075"></a>00075 _txBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a21455465b69c8fd0225236bd8b949158">head</a> = _txBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#aec076766d7dbdfba4c1116e8329d1c5f">tail</a> = 0;
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<a name="l00076"></a>00076 _txBuffer = &__FastSerial__txBuffer[portNumber];
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<a name="l00077"></a>00077 _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a21455465b69c8fd0225236bd8b949158">head</a> = _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#aec076766d7dbdfba4c1116e8329d1c5f">tail</a> = 0;
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<a name="l00078"></a>00078 }
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<a name="l00079"></a>00079
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<a name="l00080"></a>00080 <span class="comment">// Public Methods //////////////////////////////////////////////////////////////</span>
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<a name="l00081"></a>00081
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<a name="l00082"></a><a class="code" href="class_fast_serial.html#a1ae3f5f5649d7a72daf2806a6ec1cf45">00082</a> <span class="keywordtype">void</span> <a class="code" href="class_fast_serial.html#a1ae3f5f5649d7a72daf2806a6ec1cf45">FastSerial::begin</a>(<span class="keywordtype">long</span> baud)
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<a name="l00083"></a>00083 {
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<a name="l00084"></a>00084 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> rxb, txb;
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<a name="l00085"></a>00085
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<a name="l00086"></a>00086 <span class="comment">// If we are re-configuring an already-open port, preserve the</span>
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<a name="l00087"></a>00087 <span class="comment">// existing buffer sizes.</span>
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<a name="l00088"></a>00088 <span class="keywordflow">if</span> (_open) {
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<a name="l00089"></a>00089 rxb = _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a8797629ef75561f8382aa84d4f62c451">mask</a> + 1;
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<a name="l00090"></a>00090 txb = _txBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a8797629ef75561f8382aa84d4f62c451">mask</a> + 1;
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<a name="l00091"></a>00091 } <span class="keywordflow">else</span> {
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<a name="l00092"></a>00092 rxb = RX_BUFFER_SIZE;
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<a name="l00093"></a>00093 txb = TX_BUFFER_SIZE;
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<a name="l00094"></a>00094 }
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<a name="l00095"></a>00095
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<a name="l00096"></a>00096 <a class="code" href="class_fast_serial.html#a1ae3f5f5649d7a72daf2806a6ec1cf45">begin</a>(baud, <a class="code" href="_fast_serial_8cpp.html#a739a2a1a0047c98ac1b18ecd25dac092">RX_BUFFER_SIZE</a>, <a class="code" href="_fast_serial_8cpp.html#a9ab33647617098646990fe263600b650">TX_BUFFER_SIZE</a>);
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<a name="l00097"></a>00097 }
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<a name="l00098"></a>00098
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<a name="l00099"></a><a class="code" href="class_fast_serial.html#aca4c10e234de6ef56f255dbe8461f8b2">00099</a> <span class="keywordtype">void</span> <a class="code" href="class_fast_serial.html#a1ae3f5f5649d7a72daf2806a6ec1cf45">FastSerial::begin</a>(<span class="keywordtype">long</span> baud, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> rxSpace, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> txSpace)
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<a name="l00100"></a>00100 {
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<a name="l00101"></a>00101 uint16_t ubrr;
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<a name="l00102"></a>00102 <span class="keywordtype">bool</span> use_u2x = <span class="keyword">false</span>;
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<a name="l00103"></a>00103 <span class="keywordtype">int</span> ureg, u2;
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<a name="l00104"></a>00104 <span class="keywordtype">long</span> breg, b2, dreg, d2;
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<a name="l00105"></a>00105
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<a name="l00106"></a>00106 <span class="comment">// if we are currently open, close and restart</span>
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<a name="l00107"></a>00107 <span class="keywordflow">if</span> (_open)
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<a name="l00108"></a>00108 <a class="code" href="class_fast_serial.html#a18dc7ab6584b8e01bed86d74d664e6fa">end</a>();
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<a name="l00109"></a>00109
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<a name="l00110"></a>00110 <span class="comment">// allocate buffers</span>
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<a name="l00111"></a>00111 <span class="keywordflow">if</span> (!_allocBuffer(_rxBuffer, rxSpace ? : <a class="code" href="_fast_serial_8cpp.html#a739a2a1a0047c98ac1b18ecd25dac092">RX_BUFFER_SIZE</a>) ||
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<a name="l00112"></a>00112 !_allocBuffer(_txBuffer, txSpace ? : <a class="code" href="_fast_serial_8cpp.html#a9ab33647617098646990fe263600b650">TX_BUFFER_SIZE</a>)) {
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<a name="l00113"></a>00113 <a class="code" href="class_fast_serial.html#a18dc7ab6584b8e01bed86d74d664e6fa">end</a>();
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<a name="l00114"></a>00114 <span class="keywordflow">return</span>; <span class="comment">// couldn't allocate buffers - fatal</span>
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<a name="l00115"></a>00115 }
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<a name="l00116"></a>00116 _open = <span class="keyword">true</span>;
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<a name="l00117"></a>00117
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<a name="l00118"></a>00118 <span class="comment">// U2X mode is needed for bitrates higher than (F_CPU / 16)</span>
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<a name="l00119"></a>00119 <span class="keywordflow">if</span> (baud > F_CPU / 16) {
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<a name="l00120"></a>00120 use_u2x = <span class="keyword">true</span>;
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<a name="l00121"></a>00121 ubrr = F_CPU / (8 * baud) - 1;
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<a name="l00122"></a>00122 } <span class="keywordflow">else</span> {
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<a name="l00123"></a>00123 <span class="comment">// Determine whether u2x mode would give a closer</span>
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<a name="l00124"></a>00124 <span class="comment">// approximation of the desired speed.</span>
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<a name="l00125"></a>00125
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<a name="l00126"></a>00126 <span class="comment">// ubrr for non-2x mode, corresponding baudrate and delta</span>
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<a name="l00127"></a>00127 ureg = F_CPU / 16 / baud - 1;
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<a name="l00128"></a>00128 breg = F_CPU / 16 / (ureg + 1);
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<a name="l00129"></a>00129 dreg = abs(baud - breg);
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<a name="l00130"></a>00130
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<a name="l00131"></a>00131 <span class="comment">// ubrr for 2x mode, corresponding bitrate and delta</span>
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<a name="l00132"></a>00132 u2 = F_CPU / 8 / baud - 1;
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<a name="l00133"></a>00133 b2 = F_CPU / 8 / (u2 + 1);
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<a name="l00134"></a>00134 d2 = abs(baud - b2);
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<a name="l00135"></a>00135
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<a name="l00136"></a>00136 <span class="comment">// Pick the setting that gives the smallest rate</span>
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<a name="l00137"></a>00137 <span class="comment">// error, preferring non-u2x mode if the delta is</span>
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<a name="l00138"></a>00138 <span class="comment">// identical.</span>
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<a name="l00139"></a>00139 <span class="keywordflow">if</span> (dreg <= d2) {
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<a name="l00140"></a>00140 ubrr = ureg;
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<a name="l00141"></a>00141 } <span class="keywordflow">else</span> {
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<a name="l00142"></a>00142 ubrr = u2;
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<a name="l00143"></a>00143 use_u2x = <span class="keyword">true</span>;
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<a name="l00144"></a>00144 }
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<a name="l00145"></a>00145 }
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<a name="l00146"></a>00146
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<a name="l00147"></a>00147 *_ucsra = use_u2x ? _BV(_u2x) : 0;
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<a name="l00148"></a>00148 *_ubrrh = ubrr >> 8;
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<a name="l00149"></a>00149 *_ubrrl = ubrr;
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<a name="l00150"></a>00150 *_ucsrb |= _portEnableBits;
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<a name="l00151"></a>00151 }
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<a name="l00152"></a>00152
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<a name="l00153"></a><a class="code" href="class_fast_serial.html#a18dc7ab6584b8e01bed86d74d664e6fa">00153</a> <span class="keywordtype">void</span> <a class="code" href="class_fast_serial.html#a18dc7ab6584b8e01bed86d74d664e6fa">FastSerial::end</a>()
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<a name="l00154"></a>00154 {
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<a name="l00155"></a>00155 *_ucsrb &= ~(_portEnableBits | _portTxBits);
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<a name="l00156"></a>00156
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<a name="l00157"></a>00157 _freeBuffer(_rxBuffer);
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<a name="l00158"></a>00158 _freeBuffer(_txBuffer);
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<a name="l00159"></a>00159 _open = <span class="keyword">false</span>;
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<a name="l00160"></a>00160 }
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<a name="l00161"></a>00161
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<a name="l00162"></a>00162 <span class="keywordtype">int</span>
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<a name="l00163"></a><a class="code" href="class_fast_serial.html#a3908f5db6a1e946207a4b92b7c0b9ee5">00163</a> <a class="code" href="class_fast_serial.html#a3908f5db6a1e946207a4b92b7c0b9ee5">FastSerial::available</a>(<span class="keywordtype">void</span>)
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<a name="l00164"></a>00164 {
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<a name="l00165"></a>00165 <span class="keywordflow">if</span> (!_open)
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<a name="l00166"></a>00166 <span class="keywordflow">return</span>(-1);
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<a name="l00167"></a>00167 <span class="keywordflow">return</span>((_rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a21455465b69c8fd0225236bd8b949158">head</a> - _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#aec076766d7dbdfba4c1116e8329d1c5f">tail</a>) & _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a8797629ef75561f8382aa84d4f62c451">mask</a>);
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<a name="l00168"></a>00168 }
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<a name="l00169"></a>00169
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<a name="l00170"></a>00170 <span class="keywordtype">int</span>
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<a name="l00171"></a><a class="code" href="class_fast_serial.html#a6b63b52d3dedb762340675f0dbb29622">00171</a> <a class="code" href="class_fast_serial.html#a6b63b52d3dedb762340675f0dbb29622">FastSerial::read</a>(<span class="keywordtype">void</span>)
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<a name="l00172"></a>00172 {
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<a name="l00173"></a>00173 uint8_t c;
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<a name="l00174"></a>00174
|
|
<a name="l00175"></a>00175 <span class="comment">// if the head and tail are equal, the buffer is empty</span>
|
|
<a name="l00176"></a>00176 <span class="keywordflow">if</span> (!_open || (_rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a21455465b69c8fd0225236bd8b949158">head</a> == _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#aec076766d7dbdfba4c1116e8329d1c5f">tail</a>))
|
|
<a name="l00177"></a>00177 <span class="keywordflow">return</span>(-1);
|
|
<a name="l00178"></a>00178
|
|
<a name="l00179"></a>00179 <span class="comment">// pull character from tail</span>
|
|
<a name="l00180"></a>00180 c = _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a5eb7885018db67980c5b8bd1279d2b3d">bytes</a>[_rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#aec076766d7dbdfba4c1116e8329d1c5f">tail</a>];
|
|
<a name="l00181"></a>00181 _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#aec076766d7dbdfba4c1116e8329d1c5f">tail</a> = (_rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#aec076766d7dbdfba4c1116e8329d1c5f">tail</a> + 1) & _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a8797629ef75561f8382aa84d4f62c451">mask</a>;
|
|
<a name="l00182"></a>00182
|
|
<a name="l00183"></a>00183 <span class="keywordflow">return</span>(c);
|
|
<a name="l00184"></a>00184 }
|
|
<a name="l00185"></a>00185
|
|
<a name="l00186"></a>00186 <span class="keywordtype">int</span>
|
|
<a name="l00187"></a><a class="code" href="class_fast_serial.html#a1bb9d282cdf6abb37c95f3acc314d7a2">00187</a> <a class="code" href="class_fast_serial.html#a1bb9d282cdf6abb37c95f3acc314d7a2">FastSerial::peek</a>(<span class="keywordtype">void</span>)
|
|
<a name="l00188"></a>00188 {
|
|
<a name="l00189"></a>00189
|
|
<a name="l00190"></a>00190 <span class="comment">// if the head and tail are equal, the buffer is empty</span>
|
|
<a name="l00191"></a>00191 <span class="keywordflow">if</span> (!_open || (_rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a21455465b69c8fd0225236bd8b949158">head</a> == _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#aec076766d7dbdfba4c1116e8329d1c5f">tail</a>))
|
|
<a name="l00192"></a>00192 <span class="keywordflow">return</span>(-1);
|
|
<a name="l00193"></a>00193
|
|
<a name="l00194"></a>00194 <span class="comment">// pull character from tail</span>
|
|
<a name="l00195"></a>00195 <span class="keywordflow">return</span>(_rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a5eb7885018db67980c5b8bd1279d2b3d">bytes</a>[_rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#aec076766d7dbdfba4c1116e8329d1c5f">tail</a>]);
|
|
<a name="l00196"></a>00196 }
|
|
<a name="l00197"></a>00197
|
|
<a name="l00198"></a>00198
|
|
<a name="l00199"></a>00199 <span class="keywordtype">void</span>
|
|
<a name="l00200"></a><a class="code" href="class_fast_serial.html#a80a0f8852702174fc9f771da3713c933">00200</a> <a class="code" href="class_fast_serial.html#a80a0f8852702174fc9f771da3713c933">FastSerial::flush</a>(<span class="keywordtype">void</span>)
|
|
<a name="l00201"></a>00201 {
|
|
<a name="l00202"></a>00202 <span class="comment">// don't reverse this or there may be problems if the RX interrupt</span>
|
|
<a name="l00203"></a>00203 <span class="comment">// occurs after reading the value of _rxBuffer->head but before writing</span>
|
|
<a name="l00204"></a>00204 <span class="comment">// the value to _rxBuffer->tail; the previous value of head</span>
|
|
<a name="l00205"></a>00205 <span class="comment">// may be written to tail, making it appear as if the buffer</span>
|
|
<a name="l00206"></a>00206 <span class="comment">// don't reverse this or there may be problems if the RX interrupt</span>
|
|
<a name="l00207"></a>00207 <span class="comment">// occurs after reading the value of head but before writing</span>
|
|
<a name="l00208"></a>00208 <span class="comment">// the value to tail; the previous value of rx_buffer_head</span>
|
|
<a name="l00209"></a>00209 <span class="comment">// may be written to tail, making it appear as if the buffer</span>
|
|
<a name="l00210"></a>00210 <span class="comment">// were full, not empty.</span>
|
|
<a name="l00211"></a>00211 _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a21455465b69c8fd0225236bd8b949158">head</a> = _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#aec076766d7dbdfba4c1116e8329d1c5f">tail</a>;
|
|
<a name="l00212"></a>00212
|
|
<a name="l00213"></a>00213 <span class="comment">// don't reverse this or there may be problems if the TX interrupt</span>
|
|
<a name="l00214"></a>00214 <span class="comment">// occurs after reading the value of _txBuffer->tail but before writing</span>
|
|
<a name="l00215"></a>00215 <span class="comment">// the value to _txBuffer->head.</span>
|
|
<a name="l00216"></a>00216 _txBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#aec076766d7dbdfba4c1116e8329d1c5f">tail</a> = _rxBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a21455465b69c8fd0225236bd8b949158">head</a>;
|
|
<a name="l00217"></a>00217 }
|
|
<a name="l00218"></a>00218
|
|
<a name="l00219"></a>00219 <span class="keywordtype">void</span>
|
|
<a name="l00220"></a><a class="code" href="class_fast_serial.html#a8e41c9efa4f854ac6ffa0e178c1314e9">00220</a> <a class="code" href="class_fast_serial.html#a8e41c9efa4f854ac6ffa0e178c1314e9">FastSerial::write</a>(uint8_t c)
|
|
<a name="l00221"></a>00221 {
|
|
<a name="l00222"></a>00222 int16_t i;
|
|
<a name="l00223"></a>00223
|
|
<a name="l00224"></a>00224 <span class="keywordflow">if</span> (!_open) <span class="comment">// drop bytes if not open</span>
|
|
<a name="l00225"></a>00225 <span class="keywordflow">return</span>;
|
|
<a name="l00226"></a>00226
|
|
<a name="l00227"></a>00227 <span class="comment">// wait for room in the tx buffer</span>
|
|
<a name="l00228"></a>00228 i = (_txBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a21455465b69c8fd0225236bd8b949158">head</a> + 1) & _txBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a8797629ef75561f8382aa84d4f62c451">mask</a>;
|
|
<a name="l00229"></a>00229 while (i == _txBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#aec076766d7dbdfba4c1116e8329d1c5f">tail</a>)
|
|
<a name="l00230"></a>00230 ;
|
|
<a name="l00231"></a>00231
|
|
<a name="l00232"></a>00232 <span class="comment">// add byte to the buffer</span>
|
|
<a name="l00233"></a>00233 _txBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a5eb7885018db67980c5b8bd1279d2b3d">bytes</a>[_txBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a21455465b69c8fd0225236bd8b949158">head</a>] = c;
|
|
<a name="l00234"></a>00234 _txBuffer-><a class="code" href="struct_fast_serial_1_1_buffer.html#a21455465b69c8fd0225236bd8b949158">head</a> = i;
|
|
<a name="l00235"></a>00235
|
|
<a name="l00236"></a>00236 <span class="comment">// enable the data-ready interrupt, as it may be off if the buffer is empty</span>
|
|
<a name="l00237"></a>00237 *_ucsrb |= _portTxBits;
|
|
<a name="l00238"></a>00238 }
|
|
<a name="l00239"></a>00239
|
|
<a name="l00240"></a>00240 <span class="comment">// Buffer management ///////////////////////////////////////////////////////////</span>
|
|
<a name="l00241"></a>00241
|
|
<a name="l00242"></a>00242 <span class="keywordtype">bool</span>
|
|
<a name="l00243"></a>00243 FastSerial::_allocBuffer(Buffer *buffer, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> size)
|
|
<a name="l00244"></a>00244 {
|
|
<a name="l00245"></a>00245 uint8_t shift;
|
|
<a name="l00246"></a>00246
|
|
<a name="l00247"></a>00247 <span class="comment">// init buffer state</span>
|
|
<a name="l00248"></a>00248 buffer->head = buffer->tail = 0;
|
|
<a name="l00249"></a>00249
|
|
<a name="l00250"></a>00250 <span class="comment">// Compute the power of 2 greater or equal to the requested buffer size</span>
|
|
<a name="l00251"></a>00251 <span class="comment">// and then a mask to simplify wrapping operations. Using __builtin_clz</span>
|
|
<a name="l00252"></a>00252 <span class="comment">// would seem to make sense, but it uses a 256(!) byte table.</span>
|
|
<a name="l00253"></a>00253 <span class="comment">// Note that we ignore requests for more than BUFFER_MAX space.</span>
|
|
<a name="l00254"></a>00254 <span class="keywordflow">for</span> (shift = 1; (1U << shift) < min(<a class="code" href="_fast_serial_8cpp.html#a65c660282414eff7e990f21f6b306cb8">BUFFER_MAX</a>, size); shift++)
|
|
<a name="l00255"></a>00255 ;
|
|
<a name="l00256"></a>00256 buffer->mask = (1 << shift) - 1;
|
|
<a name="l00257"></a>00257
|
|
<a name="l00258"></a>00258 <span class="comment">// allocate memory for the buffer - if this fails, we fail</span>
|
|
<a name="l00259"></a>00259 buffer->bytes = (uint8_t *)malloc(buffer->mask + 1);
|
|
<a name="l00260"></a>00260
|
|
<a name="l00261"></a>00261 <span class="keywordflow">return</span>(buffer->bytes != NULL);
|
|
<a name="l00262"></a>00262 }
|
|
<a name="l00263"></a>00263
|
|
<a name="l00264"></a>00264 <span class="keywordtype">void</span>
|
|
<a name="l00265"></a>00265 FastSerial::_freeBuffer(Buffer *buffer)
|
|
<a name="l00266"></a>00266 {
|
|
<a name="l00267"></a>00267 buffer->head = buffer->tail = 0;
|
|
<a name="l00268"></a>00268 buffer->mask = 0;
|
|
<a name="l00269"></a>00269 <span class="keywordflow">if</span> (NULL != buffer->bytes) {
|
|
<a name="l00270"></a>00270 free(buffer->bytes);
|
|
<a name="l00271"></a>00271 buffer->bytes = NULL;
|
|
<a name="l00272"></a>00272 }
|
|
<a name="l00273"></a>00273 }
|
|
<a name="l00274"></a>00274
|
|
</pre></div></div>
|
|
</div>
|
|
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