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| author | Leo C | 2018-05-27 21:26:38 +0200 |
|---|---|---|
| committer | Leo C | 2018-05-27 21:26:38 +0200 |
| commit | 289f6a146c0b2087607d8d8659531ea90142779a (patch) | |
| tree | 37b0e9e341a4112582ccda4b8e22d4b2c4a6ee21 /fatfs/doc/en/dread.html | |
| parent | 70702af1370e44e32fb2c3c507e4759a187b4fe5 (diff) | |
| download | z180-stamp-289f6a146c0b2087607d8d8659531ea90142779a.zip | |
Import fatfs R0.13b
Diffstat (limited to 'fatfs/doc/en/dread.html')
| -rw-r--r-- | fatfs/doc/en/dread.html | 72 |
1 files changed, 0 insertions, 72 deletions
diff --git a/fatfs/doc/en/dread.html b/fatfs/doc/en/dread.html deleted file mode 100644 index e7c2d7d..0000000 --- a/fatfs/doc/en/dread.html +++ /dev/null @@ -1,72 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
-<html lang="en">
-<head>
-<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
-<meta http-equiv="Content-Style-Type" content="text/css">
-<link rel="up" title="FatFs" href="../00index_e.html">
-<link rel="alternate" hreflang="ja" title="Japanese" href="../ja/dread.html">
-<link rel="stylesheet" href="../css_e.css" type="text/css" media="screen" title="ELM Default">
-<title>FatFs - disk_read</title>
-</head>
-
-<body>
-
-<div class="para func">
-<h2>disk_read</h2>
-<p>The disk_read function reads sector(s) from the storage device.</p>
-<pre>
-DRESULT disk_read (
- BYTE <span class="arg">pdrv</span>, <span class="c">/* [IN] Physical drive number */</span>
- BYTE* <span class="arg">buff</span>, <span class="c">/* [OUT] Pointer to the read data buffer */</span>
- DWORD <span class="arg">sector</span>, <span class="c">/* [IN] Start sector number */</span>
- UINT <span class="arg">count</span> <span class="c">/* [IN] Number of sectros to read */</span>
-);
-</pre>
-</div>
-
-<div class="para arg">
-<h4>Parameters</h4>
-<dl class="par">
-<dt>pdrv</dt>
-<dd>Physical drive number to identify the target device.</dd>
-<dt>buff</dt>
-<dd>Pointer to the first item of the <em>byte array</em> to store read data.</dd>
-<dt>sector</dt>
-<dd>Start sector number in 32-bit LBA.</dd>
-<dt>count</dt>
-<dd>Number of sectors to read.</dd>
-</dl>
-</div>
-
-
-<div class="para ret">
-<h4>Return Value</h4>
-<dl class="ret">
-<dt>RES_OK (0)</dt>
-<dd>The function succeeded.</dd>
-<dt>RES_ERROR</dt>
-<dd>Any hard error occured during the read operation and could not recover it.</dd>
-<dt>RES_PARERR</dt>
-<dd>Invalid parameter.</dd>
-<dt>RES_NOTRDY</dt>
-<dd>The device has not been initialized.</dd>
-</dl>
-</div>
-
-
-<div class="para desc">
-<h4>Description</h4>
-<p>The data read/write operation to the storage devices is done in unit of <em>sector</em>. FatFs supports the sector size in range of from 512 to 4096 bytes. When FatFs is configured to fixed sector size (<tt>_MIN_SS == MAX_SS</tt>, this will be the most case), the read/write function must work at that sector size. When FatFs is configured to variable sector size (<tt>_MIN_SS != MAX_SS</tt>), sector size is inquired with <tt>disk_ioctl</tt> function following <tt>disk_initialize</tt> function.</p>
-<p>The memory address specified by <tt class="arg">buff</tt> is not that always aligned to word boundary because the argument is defined as <tt>BYTE*</tt>. The unaligned read/write request can occure at <a href="appnote.html#fs1">direct transfer</a>. If the bus architecture, especially DMA controller, does not allow unaligned memory access, it should be solved in this function. There are some workarounds described below to avoid this issue.</p>
-<ul>
-<li>Convert word transfer to byte transfer in this function if needed. - Recommended.</li>
-<li>On the <tt>f_read</tt> calls, avoid long read request that includes a whole of sector. - Any direct transfer never occures.</li>
-<li>On the <tt>f_read</tt> calls, make sure that <tt>(((UINT)data & 3) == (f_tell(fp) & 3))</tt> is true. - Word alignment of <tt>buff</tt> is guaranteed.</li>
-</ul>
-<p>Generally, a multiple sector transfer request must not be split into single sector transactions to the storage device, or you will not get good read throughput.</p>
-</div>
-
-
-<p class="foot"><a href="../00index_e.html">Return</a></p>
-</body>
-</html>
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