115 lines
5.6 KiB
HTML
115 lines
5.6 KiB
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1">
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<title>
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llfifo v4_0
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</title>
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<link href="$DriverApiDocsCssPath" rel="stylesheet" type="text/css">
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</head>
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<h3 class="PageHeader">Xilinx Processor IP Library</h3>
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<hl>Software Drivers</hl>
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<hr class="whs1">
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<!-- Generated by Doxygen 1.4.5 -->
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<div class="tabs">
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<ul>
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<li id="current"><a href="index.html"><span>Main Page</span></a></li>
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<li><a href="annotated.html"><span>Classes</span></a></li>
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<li><a href="files.html"><span>Files</span></a></li>
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</ul></div>
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<h1>llfifo v4_0</h1>
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<p>
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The Xilinx Dual Channel Fifo driver component. This driver supports the Virtex-5(TM) and Virtex-4(TM) XPS_ll_Fifo and the AxiFifo.<p>
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For a full description of the bridge features, please see the HW spec. This driver supports the following features:<ul>
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<li>Memory mapped access to host interface registers</li><li>API for polled frame transfers</li><li>API for interrupt driven frame transfers</li><li>Virtual memory support</li><li>Full duplex operation</li></ul>
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<p>
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<h2>Driver Description</h2>
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<p>
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This driver enables higher layer software to access the XPS_llFifo core using any alignment in the data buffers.<p>
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This driver supports send and receive channels in the same instance structure in the same fashion as the hardware core.<p>
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<h2>Initialization</h2>
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<p>
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An instance of this driver is initialized using a call to Initialize().<p>
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<h2>Usage</h2>
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<p>
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It is fairly simple to use the API provided by this FIFO driver. The only somewhat tricky part is that the calling code must correctly call a couple routines in the right sequence for receive and transmit.<p>
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This sequence is described here. Check the routine functional descriptions for information on how to use a specific API routine.<p>
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<h3>Receive</h3>
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<p>
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A frame is received by using the following sequence:<br>
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1) call XLlFifo_RxOccupancy() to check the occupancy count<br>
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2) call XLlFifo_RxGetLen() to get the length of the next incoming frame<br>
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3) call XLlFifo_Read() one or more times to read the number of bytes reported by XLlFifo_RxGetLen().<br>
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<p>
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For example: <pre>
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while (XLlFifo_RxOccupancy(&RxInstance)) {
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frame_len = XLlFifo_RxGetLen(&RxInstance);
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while (frame_len) {
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unsigned bytes = min(sizeof(buffer), frame_len);
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XLlFifo_Read(&RxInstance, buffer, bytes);
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// ********
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// do something with buffer here
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// ********
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frame_len -= bytes;
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}
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}
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</pre><p>
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This FIFO hardware core does <b>not</b> support a sequence where the calling code calls RxGetLen() twice in a row and then receive the data for two frames. Each frame must be read in by calling RxGetLen() just prior to reading the data.<p>
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<h3>Transmit</h3>
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<p>
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A frame is transmittted by using the following sequence:<br>
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1) call XLlFifo_Write() one or more times to write all the of bytes in the next frame.<br>
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2) call XLlFifo_TxSetLen() to begin the transmission of frame just written.<br>
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<p>
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For example: <pre>
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frame_left = frame_len;
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while (frame_left) {
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unsigned bytes = min(sizeof(buffer), frame_left);
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XLlFifo_Write(&TxInstance, buffer, bytes);
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// ********
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// do something here to refill buffer
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// ********
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frame_left -= bytes;
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}
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XLlFifo_TxSetLen(&RxInstance, frame_len);
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</pre><p>
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This FIFO hardware core does <b>not</b> support a sequence where the calling code writes the data for two frames and then calls TxSetLen() twice in a row. Each frame must be written by writting the data for one frame and then calling TxSetLen().<p>
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<h2>Interrupts</h2>
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<p>
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This driver does not handle interrupts from the FIFO hardware. The software layer above may make use of the interrupts by setting up its own handlers for the interrupts.<p>
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<pre>
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MODIFICATION HISTORY:</pre><p>
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<pre> Ver Who Date Changes
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----- ---- -------- -------------------------------------------------------
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1.00a jvb 10/12/06 First release
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1.01a sdm 08/22/08 Removed support for static interrupt handlers from the
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MDD file
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1.02a jz 12/04/09 Hal phase 1 support
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2.01a asa 09/17/10 Added code for resetting Local Link/AXI Streaming
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interface for CR574868
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2.02a asa 12/27/11 Changed the function XStrm_Read in xtreamer.c to reset
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HeadIndex to zero when all bytes have been read.
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Changed the macro XStrm_IsRxInternalEmpty in file
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xtreamer.h to use FrmByteCnt instead of HeadIndex.
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When FrmByteCnt is zero, this means all internal buffers
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in streamer are empty. Earlier implementation using
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HeadIndex was not very clear and could give improper
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results for some cases.
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Changed the macro XLlFifo_IsRxEmpty in file xllfifo.h
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These changes are done to fix the CR 604650.
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2.03a asa 14/08/12 Added XLLF_TDR_OFFSET, XLLF_RDR_OFFSET
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defines for the new registers, and XLLF_INT_TFPF_MASK,
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XLLF_INT_TFPE_MASK, XLLF_INT_RFPF_MASK and
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XLLF_INT_RFPE_MASK for the new version of the
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AXI4-Stream FIFO core (v2.01a and later)</pre><p>
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<pre> 3.00a adk 08/10/13 Added support for AXI4 Datainterface.Changes are
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In <a class="el" href="xllfifo_8c.html">Xllfifo.c</a> file XLlFifo_RxGetWord,XLlFifo_TxPutword.
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In XLlfifo.h file updated XLlfifo structure for
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Axi4BaseAddress and for Datainterface type provided
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polling and interrupt examples. XLlfifo_IsRxDone Macro
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Is added in the XLlfifo.h file for polledmode exmaple.
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Added Static initialzation for the driver.
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XLlFifo_Initialize is still used to make the driver
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backward compatible.
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4.0 adk 19/12/13 Updated as per the New Tcl API's</pre><p>
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<pre> </pre> Copyright @ 1995-2014 Xilinx, Inc. All rights reserved.
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