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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"><title>AVR321000 Communication with the AVR32 USART: usart.c Source File</title><link href="doxygen.css" rel="stylesheet" type="text/css"><link href="tabs.css" rel="stylesheet" type="text/css"></head><body><!-- Generated by Doxygen 1.5.1 --><div class="tabs"> <ul> <li><a href="main.html"><span>Main Page</span></a></li> <li><a href="annotated.html"><span>Data Structures</span></a></li> <li id="current"><a href="files.html"><span>Files</span></a></li> <li><a href="pages.html"><span>Related Pages</span></a></li> </ul></div><div class="tabs"> <ul> <li><a href="files.html"><span>File List</span></a></li> <li><a href="globals.html"><span>Globals</span></a></li> </ul></div><h1>usart.c</h1><a href="usart_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/*This file has been prepared for Doxygen automatic documentation generation.*/</span><a name="l00022"></a>00022 <span class="comment">/* ************************************************************************</span><a name="l00023"></a>00023 <span class="comment"></span><a name="l00024"></a>00024 <span class="comment">Copyright (c) 2006, Atmel Corporation All rights reserved.</span><a name="l00025"></a>00025 <span class="comment"></span><a name="l00026"></a>00026 <span class="comment">Redistribution and use in source and binary forms, with or without</span><a name="l00027"></a>00027 <span class="comment">modification, are permitted provided that the following conditions are met:</span><a name="l00028"></a>00028 <span class="comment"></span><a name="l00029"></a>00029 <span class="comment">1. Redistributions of source code must retain the above copyright notice,</span><a name="l00030"></a>00030 <span class="comment">this list of conditions and the</span><a name="l00031"></a>00031 <span class="comment">following disclaimer.</span><a name="l00032"></a>00032 <span class="comment"></span><a name="l00033"></a>00033 <span class="comment">2. Redistributions in binary form must reproduce the above copyright notice,</span><a name="l00034"></a>00034 <span class="comment">this list of conditions and the following disclaimer in the documentation</span><a name="l00035"></a>00035 <span class="comment">and/or other materials provided with the distribution.</span><a name="l00036"></a>00036 <span class="comment"></span><a name="l00037"></a>00037 <span class="comment">3. The name of ATMEL may not be used to endorse or promote products</span><a name="l00038"></a>00038 <span class="comment">derived from this software without specific prior written permission.</span><a name="l00039"></a>00039 <span class="comment"></span><a name="l00040"></a>00040 <span class="comment">THIS SOFTWARE IS PROVIDED BY ATMEL ``AS IS'' AND ANY EXPRESS</span><a name="l00041"></a>00041 <span class="comment">OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE</span><a name="l00042"></a>00042 <span class="comment">IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A</span><a name="l00043"></a>00043 <span class="comment">PARTICULAR PURPOSE ARE EXPRESSLY AND SPECIFICALLY</span><a name="l00044"></a>00044 <span class="comment">DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT,</span><a name="l00045"></a>00045 <span class="comment">INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL</span><a name="l00046"></a>00046 <span class="comment">DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF</span><a name="l00047"></a>00047 <span class="comment">SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;</span><a name="l00048"></a>00048 <span class="comment">OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY</span><a name="l00049"></a>00049 <span class="comment">THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,</span><a name="l00050"></a>00050 <span class="comment">OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY</span><a name="l00051"></a>00051 <span class="comment">WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE</span><a name="l00052"></a>00052 <span class="comment"></span><a name="l00053"></a>00053 <span class="comment">POSSIBILITY OF SUCH DAMAGE.</span><a name="l00054"></a>00054 <span class="comment"></span><a name="l00055"></a>00055 <span class="comment">\* ************************************************************************ */</span><a name="l00056"></a>00056 <a name="l00057"></a>00057 <span class="preprocessor">#include "<a class="code" href="usart_8h.html">usart.h</a>"</span><a name="l00058"></a>00058 <a name="l00059"></a>00059 <span class="comment">/*</span><a name="l00060"></a>00060 <span class="comment"> * Description: Check if the usart is in multidrop</span><a name="l00061"></a>00061 <span class="comment"> * Arguments: *usart: Base address of the usart</span><a name="l00062"></a>00062 <span class="comment"> * Returns: 1 if the usart is in multidrop mode, otherwise 0</span><a name="l00063"></a>00063 <span class="comment"> */</span><a name="l00064"></a>00064 <a name="l00065"></a><a class="code" href="usart_8c.html#8130f0bc38f83949813164455b44c215">00065</a> <span class="keyword">static</span> <span class="keywordtype">int</span> <a class="code" href="usart_8c.html#8130f0bc38f83949813164455b44c215">usart_mode_is_multidrop</a>(<span class="keyword">volatile</span> <span class="keyword">struct</span> avr32_usart_t * usart)<a name="l00066"></a>00066 {<a name="l00067"></a>00067 <span class="keywordflow">return</span> ( (usart->mr & 0x00000600) >> AVR32_USART_MR_PAR_OFFSET );<a name="l00068"></a>00068 }<a name="l00069"></a>00069 <a name="l00070"></a><a class="code" href="usart_8h.html#e994c1e7797dda76388176f208a2e6f2">00070</a> <span class="keywordtype">void</span> <a class="code" href="usart_8c.html#e994c1e7797dda76388176f208a2e6f2">usart_reset</a>( <span class="keyword">volatile</span> <span class="keyword">struct</span> avr32_usart_t * usart)<a name="l00071"></a>00071 {<a name="l00072"></a>00072 <span class="comment">/* Disable all usart interrupts, interrupts needed should be set</span><a name="l00073"></a>00073 <span class="comment"> explicitly on every reset */</span><a name="l00074"></a>00074 usart->idr = 0xFFFFffff;<a name="l00075"></a>00075 <a name="l00076"></a>00076 <span class="comment">/* Reset mode and other registers that could cause unpredictable</span><a name="l00077"></a>00077 <span class="comment"> behaviour after reset */</span><a name="l00078"></a>00078 usart->mr = 0;<a name="l00079"></a>00079 usart->rtor = 0;<a name="l00080"></a>00080 usart->ttgr = 0;<a name="l00081"></a>00081 <a name="l00082"></a>00082 <span class="comment">/* Shutdown RX and TX (will be reenabled when setup</span><a name="l00083"></a>00083 <span class="comment"> is completed successfully), reset status bits and turn</span><a name="l00084"></a>00084 <span class="comment"> off DTR and RTS */</span><a name="l00085"></a>00085 usart->cr = (1 << AVR32_USART_CR_RSTRX_OFFSET) |<a name="l00086"></a>00086 (1 << AVR32_USART_CR_RSTTX_OFFSET) |<a name="l00087"></a>00087 (1 << AVR32_USART_CR_RSTSTA_OFFSET) |<a name="l00088"></a>00088 (1 << AVR32_USART_CR_RSTIT_OFFSET) |<a name="l00089"></a>00089 (1 << AVR32_USART_CR_RSTNACK_OFFSET) |<a name="l00090"></a>00090 (1 << AVR32_USART_CR_DTRDIS_OFFSET) |<a name="l00091"></a>00091 (1 << AVR32_USART_CR_RTSDIS_OFFSET);<a name="l00092"></a>00092 }<a name="l00093"></a>00093 <a name="l00094"></a>00094 <a name="l00105"></a><a class="code" href="usart_8c.html#6f965be9b52e86ba6f47f12a0b6d08e7">00105</a> <span class="keyword">static</span> <span class="keywordtype">int</span> <a class="code" href="usart_8c.html#6f965be9b52e86ba6f47f12a0b6d08e7">usart_set_baudrate</a>( <span class="keyword">volatile</span> <span class="keyword">struct</span> avr32_usart_t * usart, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> baudrate, <span class="keywordtype">long</span> cpu_hz)<a name="l00106"></a>00106 {<a name="l00107"></a>00107 <span class="keywordtype">int</span> cd; <span class="comment">/* Clock divider */</span><a name="l00108"></a>00108 <a name="l00109"></a>00109 <span class="comment">/*</span><a name="l00110"></a>00110 <span class="comment"> * ** BAUDRATE CALCULATION **</span><a name="l00111"></a>00111 <span class="comment"> *</span><a name="l00112"></a>00112 <span class="comment"> * Selected Clock Selected Clock</span><a name="l00113"></a>00113 <span class="comment"> * baudrate = ---------------- or baudrate = ----------------</span><a name="l00114"></a>00114 <span class="comment"> * 16 x CD 8 x CD</span><a name="l00115"></a>00115 <span class="comment"> *</span><a name="l00116"></a>00116 <span class="comment"> * (with 16x oversampling) (with 8x oversampling)</span><a name="l00117"></a>00117 <span class="comment"> */</span><a name="l00118"></a>00118 <a name="l00119"></a>00119 <span class="keywordflow">if</span> ( baudrate < (cpu_hz/16) ){<a name="l00120"></a>00120 <span class="comment">/* Use 8x oversampling */</span><a name="l00121"></a>00121 usart->mr |= (1<<AVR32_USART_MR_OVER_OFFSET);<a name="l00122"></a>00122 cd = cpu_hz / (8*baudrate);<a name="l00123"></a>00123 <a name="l00124"></a>00124 <span class="keywordflow">if</span> (cd < 2) {<a name="l00125"></a>00125 <span class="keywordflow">return</span> <a class="code" href="usart_8h.html#50b4e9378f434da8823badca3af2f15d">USART_INVALID_INPUT</a>;<a name="l00126"></a>00126 }<a name="l00127"></a>00127 usart->brgr = (cd << AVR32_USART_BRGR_CD_OFFSET);<a name="l00128"></a>00128 } <span class="keywordflow">else</span> {<a name="l00129"></a>00129 <span class="comment">/* Use 16x oversampling */</span><a name="l00130"></a>00130 usart->mr &= ~(1<<AVR32_USART_MR_OVER_OFFSET);<a name="l00131"></a>00131 cd = cpu_hz / (16*baudrate);<a name="l00132"></a>00132 <a name="l00133"></a>00133 <span class="keywordflow">if</span> (cd > 65535) {<a name="l00134"></a>00134 <span class="comment">/* Baudrate is too low */</span><a name="l00135"></a>00135 <span class="keywordflow">return</span> <a class="code" href="usart_8h.html#50b4e9378f434da8823badca3af2f15d">USART_INVALID_INPUT</a>;<a name="l00136"></a>00136 }<a name="l00137"></a>00137 }<a name="l00138"></a>00138 usart->brgr = (cd << AVR32_USART_BRGR_CD_OFFSET);<a name="l00139"></a>00139 <span class="keywordflow">return</span> <a class="code" href="usart_8h.html#cbf846773f58a382f10f8daf94797059">USART_SUCCESS</a>;<a name="l00140"></a>00140 }<a name="l00141"></a>00141 <a name="l00142"></a>00142 <a name="l00143"></a>00143 <a name="l00144"></a>00144 <a name="l00145"></a>00145 <span class="comment">/*---------------------------------------------------------------------------+</span><a name="l00146"></a>00146 <span class="comment"> | |</span><a name="l00147"></a>00147 <span class="comment"> | INITIALIZATION FUNCTIONS |</span><a name="l00148"></a>00148 <span class="comment"> | |</span><a name="l00149"></a>00149 <span class="comment"> +---------------------------------------------------------------------------*/</span><a name="l00150"></a>00150 ⌨️ 快捷键说明
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