Github/fatfs
1
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

FatFs R0.14a, released December 5, 2020

Browse Source
This commit is contained in:
Christopher Williams
2021-01-14 18:05:43 -07:00
parent cf1fa00811
commit 8aa4448e7e
36 changed files with 524 additions and 410 deletions
Download Patch File Download Diff File Expand all files Collapse all files
documents/00index_e.html
+21 -12
View File
@@ -22,8 +22,8 @@
<h4>Features</h4>
<ul>
<li>DOS/Windows compatible FAT/exFAT filesystem.</li>
<li>Platform independent. Easy to port.</li>
<li>Very small footprint for program code and work area.</li>
<li>Platform independent. <a href="doc/appnote.html#port">Easy to port</a>.</li>
<li>Very small <a href="doc/appnote.html#memory">footprint</a> for program code and work area.</li>
<li>Various <a href="doc/config.html">configuration options</a> to support for:
<ul>
<li>Long file name in ANSI/OEM or Unicode.</li>
@@ -105,25 +105,33 @@
<div class="para">
<h3>Media Access Interface</h3>
<img src="res/layers2.png" class="rset" width="245" height="220" alt="layer">
<p>Since FatFs module is the <em>filesystem layer</em> independent of platforms and storage media, it is completely separated from the physical devices, such as memory card, harddisk and any type of storage device. The low level device control module is <em>not any part of FatFs module</em> and it needs to be provided by implementer. FatFs accesses the storage devices via a simple media access interface shown below. Also sample implementations for some platforms are available in the downloads. A function checker for low level disk I/O module is available <a href="res/app4.c">here</a>.</p>
<p>Since FatFs module is the <em>filesystem layer</em> independent of platforms and storage media, it is completely separated from the physical devices, such as memory card, harddisk and any type of storage device. The storage device control module is <em>not any part of FatFs module</em> and it needs to be provided by implementer. FatFs controls the storage devices via a simple media access interface shown below. Also sample implementations for some platforms are available in the downloads. A function checker for storage device control module is available <a href="res/app4.c">here</a>.</p>
<ul>
<li><a href="doc/dstat.html">disk_status</a> - Get device status</li>
<li><a href="doc/dinit.html">disk_initialize</a> - Initialize device</li>
<li><a href="doc/dread.html">disk_read</a> - Read sector(s)</li>
<li><a href="doc/dwrite.html">disk_write</a> - Write sector(s)</li>
<li><a href="doc/dioctl.html">disk_ioctl</a> - Control device dependent functions</li>
<li><a href="doc/fattime.html">get_fattime</a> - Get current time</li>
<li>Storage Device Controls
<ul>
<li><a href="doc/dstat.html">disk_status</a> - Get device status</li>
<li><a href="doc/dinit.html">disk_initialize</a> - Initialize device</li>
<li><a href="doc/dread.html">disk_read</a> - Read data</li>
<li><a href="doc/dwrite.html">disk_write</a> - Write data</li>
<li><a href="doc/dioctl.html">disk_ioctl</a> - Control device dependent functions</li>
</ul>
</li>
<li>Real Time Clock
<ul>
<li><a href="doc/fattime.html">get_fattime</a> - Get current time</li>
</ul>
</li>
</ul>
</div>
<div class="para">
<h3>Resources</h3>
<p>The FatFs module is a free software opened for education, research and development. You can use, modify and/or redistribute it for personal projects or commercial products without any restriction under your responsibility. For further information, refer to the application note.</p>
<p>The FatFs module is a free software opened for education, research and development. You can use, modify and/or redistribute it for any purpose without any restriction under your responsibility. For further information, refer to the application note.</p>
<ul>
<li><em>Read First: <a href="doc/appnote.html">FatFs module application note</a></em></li>
<li>Download: <a href="http://elm-chan.org/fsw/ff/archives.html">Archives</a></li>
<li>Community: <a href="http://elm-chan.org/fsw/ff/bd/">FatFs User Forum</a></li>
<li>Downloads: <a href="http://elm-chan.org/fsw/ff/archives.html">Previous Releases</a>↗ </li>
<li>Community: <a href="http://elm-chan.org/fsw/ff/bd/">FatFs User Forum</a>↗ </li>
<li><a href="https://msdn.microsoft.com/en-us/windows/hardware/gg463080.aspx">FAT32 Specification by Microsoft</a>↗ (The authorized document on FAT filesystem)</li>
<li><a href="http://elm-chan.org/docs/fat_e.html">The basics of FAT filesystem</a></li>
<li><a href="http://elm-chan.org/docs/exfat_e.html">The basics of exFAT filesystem</a></li>
@@ -135,5 +143,6 @@
<li><a href="res/rwtest2.png">Benchmark 2</a> (LPC2368/72MHz with MMC via MCI)</li>
</div>
</body>
</html>
documents/doc/appnote.html
+175 -173
View File
@@ -25,7 +25,7 @@
<li><a href="#fs1">Performance Effective File Access</a></li>
<li><a href="#fs2">Considerations on Flash Memory Media</a></li>
<li><a href="#critical">Critical Section</a></li>
<li><a href="#fs3">Extended Use of FatFs API</a></li>
<li><a href="#fs3">Various Usable Functions for FatFs Projects</a></li>
<li><a href="#license">About FatFs License</a></li>
</ol>
@@ -54,8 +54,8 @@ The FatFs module is a middleware written in ANSI C (C89). There is no platform d
<dt><tt>DWORD</tt></dt><dd>32-bit unsigned integer in range of 0 to 2<sup>32</sup> - 1.</dd>
<dt><tt>QWORD</tt></dt><dd>64-bit unsigned integer in range of 0 to 2<sup>64</sup> - 1.</dd>
<dt><tt>UINT</tt></dt><dd>Alias of <tt>unsigned int</tt> used to specify any number.</dd>
<dt><tt>WCHAR</tt></dt><dd>Alias of <tt>WORD</tt> used to specify a UTF-16 character unit.</dd>
<dt><tt>TCHAR</tt></dt><dd>Alias of <tt>char</tt>, <tt>WCHAR</tt> or <tt>DWORD</tt> used to specify a character unit.</dd>
<dt><tt>WCHAR</tt></dt><dd>Alias of <tt>WORD</tt> used to specify a UTF-16 code unit.</dd>
<dt><tt>TCHAR</tt></dt><dd>Alias of <tt>char</tt>, <tt>WCHAR</tt> or <tt>DWORD</tt> used to specify a character encoding unit.</dd>
<dt><tt>FSIZE_t</tt></dt><dd>Alias of <tt>DWORD</tt> or <tt>QWORD</tt> used to address file offset and to specify file size.</dd>
<dt><tt>LBA_t</tt></dt><dd>Alias of <tt>DWORD</tt> or <tt>QWORD</tt> used to address sectors in LBA and to specify number of sectors.</dd>
</dl>
@@ -67,7 +67,7 @@ The FatFs module is a middleware written in ANSI C (C89). There is no platform d
<p><img src="../res/funcs.png" width="750" height="420" alt="functional diagram"></p>
<h4>Required Functions</h4>
<p>You need to provide only low level disk I/O functions required by FatFs module and nothing else. If a working disk I/O module for the target system is already provided, you need to write only glue functions to attach it to the FatFs module. If not, you need to port another disk I/O module or write it from scratch. Most of defined functions are not that always required. For instance, any write function is not required at read-only configuration. Following table shows which function is required depends on the configuration options.</p>
<p>You need to provide only MAI functions required by FatFs module and nothing else. If any working device control module for the target system is available, you need to write only glue functions to attach it to the FatFs module. If not, you need to port another device control module or write it from scratch. Most of MAI functions are not that always required. For instance, any write function is not required in read-only configuration. Following table shows which function is required depends on the configuration options.</p>
<table class="lst2">
<tr><th>Function</th><th>Required when</th><th>Note</th></tr>
<tr><td>disk_status<br>disk_initialize<br>disk_read</td><td>Always</td><td rowspan="5">Disk I/O functions.<br>Samples available in ffsample.zip.<br>There are many implementations on the web.</td></tr>
@@ -103,17 +103,17 @@ The FatFs module is a middleware written in ANSI C (C89). There is no platform d
<tr><th></th><th>ARM7<small><br>32bit</small></th><th>ARM7<small><br>Thumb</small></th><th>CM3<small><br>Thumb-2</small></th><th>AVR</th><th>H8/300H</th><th>PIC24</th><th>RL78</th><th>V850ES</th><th>SH-2A</th><th>RX600</th><th>IA-32</th></tr>
<tr class="cal"> <td>Compiler</td><td>GCC</td><td>GCC</td><td>GCC</td><td>GCC</td><td>CH38</td><td>C30</td><td>CC78K0R</td><td>CA850</td><td>SHC</td><td>RXC</td><td>MSC</td></tr>
<!-- ARM Thumb CM3 AVR H8 PIC24 RL78 V850ES SH-2A RX600 IA-32 -->
<tr class="ral"><td class="cal">text (Full, R/W)</td><td>10.4k</td><td>6.7k</td><td>6.3k</td><td>12.4k</td> <td>9.9k</td><td>11.2k</td><td>13.0k</td><td>8.7k</td><td>9.0k</td><td>6.5k</td><td>8.9k</td></tr>
<tr class="ral"><td class="cal">text (Min, R/W)</td> <td>7.0k</td><td>4.7k</td><td>4.4k</td> <td>8.4k</td> <td>6.9k</td> <td>7.8k</td> <td>9.4k</td><td>6.0k</td><td>6.2k</td><td>4.6k</td><td>6.3k</td></tr>
<tr class="ral"><td class="cal">text (Full, R/O)</td> <td>4.8k</td><td>3.1k</td><td>2.8k</td> <td>5.7k</td> <td>4.7k</td> <td>5.3k</td> <td>6.4k</td><td>4.2k</td><td>4.0k</td><td>3.1k</td><td>4.2k</td></tr>
<tr class="ral"><td class="cal">text (Min, R/O)</td> <td>3.6k</td><td>2.4k</td><td>2.2k</td> <td>4.4k</td> <td>3.6k</td> <td>4.1k</td> <td>5.0k</td><td>3.3k</td><td>3.1k</td><td>2.4k</td><td>3.3k</td></tr>
<tr class="ral"><td class="cal">text (Full, R/W)</td><td>10.6k</td><td>6.8k</td><td>6.4k</td><td>12.4k</td><td>10.1k</td><td>11.4k</td><td>13.1k</td><td>8.9k</td><td>9.1k</td><td>6.5k</td><td>9.0k</td></tr>
<tr class="ral"><td class="cal">text (Min, R/W)</td> <td>7.2k</td><td>4.8k</td><td>4.6k</td> <td>8.5k</td> <td>7.1k</td> <td>8.0k</td> <td>9.6k</td><td>6.3k</td><td>6.3k</td><td>4.7k</td><td>6.4k</td></tr>
<tr class="ral"><td class="cal">text (Full, R/O)</td> <td>5.0k</td><td>3.2k</td><td>2.9k</td> <td>6.0k</td> <td>4.8k</td> <td>5.5k</td> <td>6.6k</td><td>4.4k</td><td>4.1k</td><td>3.2k</td><td>4.3k</td></tr>
<tr class="ral"><td class="cal">text (Min, R/O)</td> <td>3.8k</td><td>2.5k</td><td>2.3k</td> <td>4.4k</td> <td>3.8k</td> <td>4.2k</td> <td>5.2k</td><td>3.4k</td><td>3.3k</td><td>2.5k</td><td>3.5k</td></tr>
<tr class="ral"><td class="cal">bss</td><td>V*4 + 2</td><td>V*4 + 2</td><td>V*4 + 2</td><td>V*2 + 2</td><td>V*4 + 2</td><td>V*2 + 2</td><td>V*2 + 2</td><td>V*4 + 2</td><td>V*4 + 2</td><td>V*4 + 2</td><td>V*4 + 2</td></tr>
<tr class="ral"><td class="cal">Work area<br><small>(FF_FS_TINY == 0)</small></td><td>V*564<br>+ F*552</td><td>V*564<br>+ F*552</td><td>V*564<br>+ F*552</td><td>V*560<br>+ F*546</td><td>V*560<br>+ F*546</td><td>V*560<br>+ F*546</td><td>V*560<br>+ F*546</td><td>V*564<br>+ F*552</td><td>V*564<br>+ F*552</td><td>V*564<br>+ F*552</td><td>V*564<br>+ F*552</td></tr>
<tr class="ral"><td class="cal">Work area<br><small>(FF_FS_TINY == 1)</small></td><td>V*564<br>+ F*40</td><td>V*564<br>+ F*40</td><td>V*564<br>+ F*40</td><td>V*560<br>+ F*34</td><td>V*560<br>+ F*34</td><td>V*560<br>+ F*34</td><td>V*560<br>+ F*34</td><td>V*564<br>+ F*40</td><td>V*564<br>+ F*40</td><td>V*564<br>+ F*40</td><td>V*564<br>+ F*40</td></tr>
</table>
<p>These are the memory usage of FatFs module without lower layer on some target systems in following condition. <em>V</em> denotes number of mounted volumes and <em>F</em> denotes number of open files. Every samples here are optimezed in code size.</p>
<pre>
FatFs R0.13a options:
FatFs R0.14a options:
FF_FS_READONLY 0 (Read/Write) or 1 (Read only)
FF_FS_MINIMIZE 0 (Full, with all basic functions) or 3 (Min, with fully minimized)
FF_FS_TINY 0 (Default) or 1 (Tiny file object)
@@ -166,167 +166,169 @@ And any other options are left unchanged from original setting.
<div class="para doc" id="lfn">
<h3>Long File Name</h3>
<p>FatFs module supports the long file name (LFN) extension of the FAT filesystem. The two different file names, short file name (SFN) and LFN, of a file is transparent on the API. The support for LFN feature is disabled by default. To enable the LFN, set <tt><a href="config.html#use_lfn">FF_USE_LFN</a></tt> to 1, 2 or 3, and add <tt>ffunicode.c</tt> to the project. The LFN feature requiers a certain working buffer. The buffer size can be configured by <tt><a href="config.html#max_lfn">FF_MAX_LFN</a></tt> according to the available memory. The length of an LFN can be up to 255 characters, so that the <tt>FF_MAX_LFN</tt> should be set to 255 for all existing file names. If the size of working buffer is insufficient for the input file name, the file function fails with <tt>FR_INVALID_NAME</tt>. When use any re-entry to the API with LFN feature, <tt>FF_USE_LFN</tt> must be set to 2 or 3. In this case, the file function allocates the working buffer on the stack or heap. The LFN working buffer occupies <tt>(FF_MAX_LFN + 1) * 2</tt> bytes and additional <tt>(FF_MAX_LFN + 44) / 15 * 32</tt> bytes when exFAT is enabled.</p>
<h4>Impact upon Module Size</h4>
<table class="lst2 rset">
<caption>With LFN at CM3 + gcc</caption>
<tr><th><tt>FF_CODE_PAGE</tt></th><th>Code size</th></tr>
<tr><td>437-869 (SBCS)</td><td>+3.3k</td></tr>
<tr><td>932 (Japanese)</td><td>+62k</td></tr>
<tr><td>936 (Simplified Chinese)</td><td>+177k</td></tr>
<tr><td>949 (Korean)</td><td>+140k</td></tr>
<tr><td>950 (Traditional Chinese)</td><td>+111k</td></tr>
<tr><td>0 (All code pages)</td><td>+486k</td></tr>
</table>
<p>When the LFN is enabled, the module size will be increased depends on the configured code page. Right table shows the increment of code size in some code pages. Especially, in the CJK region, tens of thousands of characters are being used. Unfortunately, it requires a huge OEM-Unicode bidirectional conversion table and the module size will be drastically increased as shown in the table.</p>
<p>As the result, the FatFs with LFN enabled with DBCS code pages will not able to be ported on the most 8-bit MCU systems. If the target system is in legacy-free, in only Unicode and any ANSI/OEM code is not used at all, the code page setting gets meaningless. You will able to reduce the code size by configureing FatFs for Unicode with any SBCS code page.</p>
<p>There ware some restrictions on using LFN for open source project because the LFN extension on the FAT filesystem was a patent of Microsoft Corporation. But the related patents all have expired and using the LFN feature has got free for any projects.</p>
</div>
<div class="para doc" id="unicode">
<h3>Unicode API</h3>
<p>By default, FatFs uses ANSI/OEM code set on the API even at LFN configuration. FatFs can also switch the character encoding on the API to Unicode by configuration option <tt><a href="config.html#lfn_unicode">FF_LFN_UNICODE</a></tt>. This means that FatFs is compliant with the full featured LFN specification. The data type <tt>TCHAR</tt> specifies path name strings on the API is an alias of either <tt>char</tt>(ANSI/OEM or UTF-8), <tt>WCHAR</tt>(UTF-16) or <tt>DWORD</tt>(UTF-32) depends on that option. For more information, refer to the description in the <a href="filename.html#uni">file name</a>.</p>
<p>Note that setting of code page, <tt><a href="config.html#code_page">FF_CODE_PAGE</a></tt>, has actually no meaning when FatFs is configured for the Unicode API. It should be set 437 anyway. However it still affects code conversion of string I/O functions at <tt><a href="config.html#strf_encode">FF_STRF_ENCODE</a> == 0</tt> and backward compatibility with legacy systems, so that code page may need to be configured properly if it is considered a problem.</p>
</div>
<div class="para doc" id="exfat">
<h3>exFAT Filesystem</h3>
<p>The exFAT (Microsoft's Extended File Allocation Table) filesystem is a succession of the FAT/FAT32 filesystem which has been widely used in embedded systems, consumer devices and portable storage media. It is adopted by SDA (SD Association) as the filesystem for SDXC card, 64 GB and larger, and they are being shipped with this format. Therefore the exFAT is one of the standard filesystems for removable media as well as FAT. The exFAT filesystem allows the file size beyond the 4 GB limit what FAT filesystem allows up to and some filesystem overhead, especially cluster allocation delay, are reduced as well. These features allow to record the large data without dividing into some files and improve the write throughput to the file.</p>
<p>Note that the exFAT filesystem is a patent of Microsoft Corporation. The exFAT feature of FatFs is an implementation based on <cite>US. Pat. App. Pub. No. 2009/0164440 A1</cite>. FatFs module can switch the exFAT on or off by a configuration option, <tt><a href="config.html#fs_exfat">FF_FS_EXFAT</a></tt>. When enable the exFAT for the commercial products, a license by Microsoft will be needed depends on the final destination of the products.</p>
<p><em>Remarks: Enabling exFAT discards C89 compatibility and it wants C99 because of need for 64-bit integer type.</em></p>
</div>
<div class="para doc" id="lba64">
<h3>64-bit LBA</h3>
<p>LBA (Logical Block Addressing) is an addressing method to specify the location of data block, called sector, on the storage media. It is a simple linear address beginning from 0 as the first block of data. The host system does not need to consider how the data block is located and managed in the storage device. FatFs supports only LBA for the media access. 32-bit LBA is a common size at the interface of the most storage devices. It can address up to 2<sup>32</sup> blocks, 2 TB in 512 bytes/sector. When a storage device beyond 2 TB is used, increasing sector size or 64-bit LBA will be needed to address the entire block of the storage device.</p>
<p>By default, FatFs uses 32-bit LBA for media access interface. FatFs can also switch it to 64-bit LBA by a configuration option <tt><a href="config.html#fs_lba64">FF_LBA64</a></tt>. It also enables GPT (GUID Partition Table) for partiotion management on the storage media. For further information about GPT, refer to <tt><a href="mkfs.html">f_mkfs</a></tt> and <tt><a href="fdisk.html">f_fdisk</a></tt> function.</p>
</div>
<div class="para doc" id="reentrant">
<h3>Re-entrancy</h3>
<p>The file operations of two tasks to the <em>different volumes</em> each other is always re-entrant regardless of the configurations except when LFN is enabled with static working buffer (<tt>FF_USE_LFN = 1</tt>). It can work concurrently without any mutual exclusion.</p>
<p>The file operations of two tasks to the <em>same volume</em> is not re-entrant in default. FatFs can also be configured to make it thread-safe by option <tt><a href="config.html#fs_reentrant">FF_FS_REENTRANT</a></tt>. In this case, also the OS dependent synchronization control functions, <tt>ff_cre_syncobj/ff_del_syncobj/ff_req_grant/ff_rel_grant</tt>, need to be added to the project. There are some examples in the <tt>ffsystem.c</tt>. When a file function is called while the volume is being accessed by another task, the file function to the volume will be suspended until that task leaves the file function. If the wait time exceeded a period defined by <tt>FF_TIMEOUT</tt>, the file function will abort with <tt>FR_TIMEOUT</tt>. The timeout feature might not be supported on the some RTOSs.</p>
<p>There is an exception on the re-entrancy for <tt>f_mount/f_mkfs</tt> function. These volume management functions are not re-entrant to the same volume. When use these functions, other tasks need to avoid to access the volume.</p>
<div class="rset">
<table class="lst2">
<tr><th><tt>Function</tt></th><th>Case 1</th><th>Case 2</th><th>Case 3</th></tr>
<tr><td>disk_status</td><td>Yes</td><td>Yes</td><td>Yes(*)</td></tr>
<tr><td>disk_initialize</td><td>No</td><td>Yes</td><td>Yes(*)</td></tr>
<tr><td>disk_read</td><td>No</td><td>Yes</td><td>Yes(*)</td></tr>
<tr><td>disk_write</td><td>No</td><td>Yes</td><td>Yes(*)</td></tr>
<tr><td>disk_ioctl</td><td>No</td><td>Yes</td><td>Yes(*)</td></tr>
<tr><td>get_fattime</td><td>No</td><td>Yes</td><td>Yes</td></tr>
</table>
<small>
Case 1: Same volume.<br>
Case 2: Different volume on the same drive.<br>
Case 3: Different volume on the different drive.<br>
(*) In only different drive number.
</small>
</div>
<p>Remarks: This section describes on the re-entrancy of the FatFs module itself. The <tt>FF_FS_REENTRANT</tt> option enables only exclusive use of each filesystem objects and FatFs does not that prevent to re-enter the low level disk functions. Thus the low level disk I/O layer needs to be always thread-safe when FatFs API is re-entered for different volumes. Right table shows which low level function can be re-entered when FatFs API is re-entered on some conditions.</p>
</div>
<div class="para doc" id="dup">
<h3>Duplicated File Open</h3>
<p>FatFs module does not support the read/write collision control of duplicated open to a file. The duplicated open is permitted only when each of open method to a file is read mode. The duplicated open with one or more write mode to a file is always prohibited, and also open file must not be renamed or deleted. A violation of these rules can cause data collaption.</p>
<p>The file lock control can be enabled by <tt><a href="config.html#fs_lock">FF_FS_LOCK</a></tt> option. The value of option defines the number of open objects to manage simultaneously. In this case, if any opening, renaming or removing against the file shareing rule that described above is attempted, the file function will be rejected with <tt>FR_LOCKED</tt>. If number of open objects, files and sub-directories, is equal to <tt>FF_FS_LOCK</tt>, an extra <tt>f_open/f_opendir</tt> function will fail with <tt>FR_TOO_MANY_OPEN_FILES</tt>.</p>
</div>
<div class="para doc" id="fs1">
<h3>Performance Effective File Access</h3>
<p>For good read/write throughput on the small embedded systems with limited size of memory, application programmer should consider what process is done in the FatFs module. The file data on the volume is transferred in following sequence by <tt>f_read</tt> function.</p>
<p>Figure 1. Sector unaligned read (short)<br>
<img src="../res/f1.png" width="490" height="110" alt="">
</p>
<p>Figure 2. Sector unaligned read (long)<br>
<img src="../res/f2.png" width="490" height="140" alt="">
</p>
<p>Figure 3. Fully sector aligned read<br>
<img src="../res/f3.png" width="490" height="119" alt="">
</p>
<p>The file I/O buffer is a sector buffer to read/write a part of data on the sector. The sector buffer is either file private sector buffer on each file object or shared sector buffer in the filesystem object. The buffer configuration option <tt><a href="config.html#fs_tiny">FF_FS_TINY</a></tt> determins which sector buffer is used for the file data transfer. When tiny buffer configuration (1) is selected, data memory consumption is reduced <tt>FF_MAX_SS</tt> bytes each file object. In this case, FatFs module uses only a sector buffer in the filesystem object for file data transfer and FAT/directory access. The disadvantage of the tiny buffer configuration is: the FAT data cached in the sector buffer will be lost by file data transfer and it must be reloaded at every cluster boundary. However it will be suitable for most application from view point of the decent performance and low memory comsumption.</p>
<p>Figure 1 shows that a partial sector, sector unaligned part of the file, is transferred via the file I/O buffer. At long data transfer shown in Figure 2, middle of transfer data that covers one or more sector is transferred to the application buffer directly. Figure 3 shows that the case of entier transfer data is aligned to the sector boundary. In this case, file I/O buffer is not used. On the direct transfer, the maximum extent of sectors are read with <tt>disk_read</tt> function at a time but the multiple sector transfer is divided at cluster boundary even if it is contiguous.</p>
<p>Therefore taking effort to sector aligned read/write accesss eliminates buffered data transfer and the read/write performance will be improved. Besides the effect, cached FAT data will not be flushed by file data transfer at the tiny configuration, so that it can achieve same performance as non-tiny configuration with small memory footprint.</p>
</div>
<div class="para doc" id="fs2">
<h3>Considerations on Flash Memory Media</h3>
<p>To maximize the write performance of flash memory media, such as SDC, CFC and U Disk, it must be controlled in consideration of its characteristitcs.</p>
<h4>Using Mutiple-Sector Write</h4>
<div class="rset">
Figure 6. Comparison between Multiple/Single Sector Write<br>
<img src="../res/f6.png" width="630" height="148" alt="fig.6">
</div>
<p>The write throughput of the flash memory media becomes the worst at single sector write transaction. The write throughput increases as the number of sectors per a write transaction as shown in Figure 6. This effect more appers at faster interface speed and the performance ratio often becomes grater than ten. <a href="../res/rwtest2.png">This result</a> is clearly explaining how fast is multiple block write (W:16K, 32 sectors) than single block write (W:100, 1 sector), and also larger card tends to be slow at single block write. Number of write transactions also affects life time of the flash memory media. When compared at same amount of write data, the single sector write in Figure 6 above wears flash memory media 16 times more than multiple sector write in Figure 6 below. Single sector write is pretty pain for the flash memory media.</p>
<p>Therefore the application program should write the data in large block as possible. The ideal write chunk size and alighment is size of sector, and size of cluster is the best. Of course all layers between the application and the storage device must have consideration on multiple sector write, however most of open-source memory card drivers lack it. Do not split a multiple sector write request into single sector write transactions or the write throughput gets poor. Note that FatFs module and its sample disk drivers supprt multiple sector read/write operation. </p>
<h4>Forcing Memory Erase</h4>
<p>When remove a file with <tt>f_unlink</tt> function, the data clusters occupied by the file are marked 'free' on the FAT. But the data sectors containing the file data are not that applied any process, so that the file data left occupies a part of the flash memory array as 'live block'. If the file data can be erased on removing the file, those data blocks will be turned into the free block pool. This may skip internal block erase operation to the data block on next write operation. As the result the write performance might be improved. FatFs can manage this function by setting <tt><a href="config.html#use_trim">FF_USE_TRIM</a></tt> to 1. Note that this is an expectation of internal process of the storage device and not that always effective. Most applications will not need this function. Also <tt>f_unlink</tt> function can take a time when remove a large file.</p>
</div>
<div class="para doc" id="critical">
<h3>Critical Section</h3>
<p>If a write operation to the FAT volume is interrupted due to an accidental failure, such as sudden blackout, wrong media removal and unrecoverable disk error, the FAT structure on the volume can be broken. Following images shows the critical section of the FatFs module.</p>
<div class="lset">
Figure 4. Long critical section<br>
<img src="../res/f4.png" width="320" height="436" alt="fig.4">
</div>
<div class="lset">
Figure 5. Minimized critical section<br>
<img src="../res/f5.png" width="320" height="436" alt="fig.5">
</div>
<br class="clr">
<p>An interruption in the red section can cause a cross link; as a result, the object being changed can be lost. If an interruption in the yellow section is occured, there is one or more possibility listed below.</p>
<ul>
<li>The file data being rewrited is collapsed.</li>
<li>The file being appended returns initial state.</li>
<li>The file created as new is gone.</li>
<li>The file created as new or overwritten remains but no content.</li>
<li>Efficiency of disk use gets worse due to lost clusters.</li>
</ul>
<p>Each case does not affect any file not opened in write mode. To minimize risk of data loss, the critical section can be minimized by minimizing the time that file is opened in write mode or using <tt>f_sync</tt> function as shown in Figure 5.</p>
</div>
<div class="para doc" id="fs3">
<h3>Extended Use of FatFs API</h3>
<p>These are examples of extended use of FatFs APIs. New item will be added whenever a useful code is found.</p>
<ol>
<li><a href="http://elm-chan.org/fsw/ff/res/app1.c">Open or create a file for append</a> (for R0.12 and earlier)</li>
<li><a href="http://elm-chan.org/fsw/ff/res/app2.c">Delete a non-empty sub-directory</a> (for R0.12 and later)</li>
<li><a href="http://elm-chan.org/fsw/ff/res/app3.c">Allocate contiguous area to the file</a> (for R0.11a and earlier)</li>
<li><a href="http://elm-chan.org/fsw/ff/res/app5.c">Test if the file is contiguous or not</a></li>
<li><a href="http://elm-chan.org/fsw/ff/res/app4.c">Compatibility checker for low level disk I/O module</a></li>
<li><a href="http://elm-chan.org/fsw/ff/res/app6.c">Performance checker for low level disk I/O module</a></li>
<li><a href="http://elm-chan.org/fsw/ff/res/mkfatimg.zip">FAT volume image creator</a></li>
</ol>
</div>
<div class="para doc" id="license">
<h3>About FatFs License</h3>
<p>FatFs has being developped as a personal project of the author, ChaN. It is free from the code anyone else wrote at current release. Following code block shows a copy of the FatFs license document that included in the source files.</p>
<pre>
/*----------------------------------------------------------------------------/
/ FatFs - Generic FAT Filesystem Module Rx.xx /
/-----------------------------------------------------------------------------/
/
/ Copyright (C) 20xx, ChaN, all right reserved.
/
/ FatFs module is an open source software. Redistribution and use of FatFs in
/ source and binary forms, with or without modification, are permitted provided
/ that the following condition is met:
/
/ 1. Redistributions of source code must retain the above copyright notice,
/ this condition and the following disclaimer.
/
/ This software is provided by the copyright holder and contributors "AS IS"
/ and any warranties related to this software are DISCLAIMED.
/ The copyright owner or contributors be NOT LIABLE for any damages caused
/ by use of this software.
/----------------------------------------------------------------------------*/
</pre>
<p>Therefore FatFs license is one of the BSD-style licenses but there is a significant feature. FatFs is mainly intended for embedded systems. In order to extend the usability for commercial products, the redistributions of FatFs in binary form, such as embedded code, binary library and any forms without source code, does not need to include about FatFs in the documentations. This is equivalent to the 1-clause BSD license. Of course FatFs is compatible with the most of open source software licenses including GNU GPL. When you redistribute the FatFs source code with any changes or create a fork, the license can also be changed to GNU GPL, BSD-style license or any open source software license that not conflict with FatFs license.</p>
</div>
<p class="foot"><a href="../00index_e.html">Return Home</a></p>
</body>
</html>
<p>FatFs module supports the long file name (LFN) extension of the FAT filesystem. The two different file names, short file name (SFN) and LFN, of a file is transparent on the API. The support for LFN feature is disabled by default. To enable the LFN, set <tt><a href="config.html#use_lfn">FF_USE_LFN</a></tt> to 1, 2 or 3, and add <tt>ffunicode.c</tt> to the project. The LFN feature requiers a certain working buffer. The buffer size can be configured by <tt><a href="config.html#max_lfn">FF_MAX_LFN</a></tt> according to the available memory. The length of an LFN can be up to 255 characters, so that the <tt>FF_MAX_LFN</tt> should be set to 255 for all existing file names. If the size of working buffer is insufficient for the input file name, the file function fails with <tt>FR_INVALID_NAME</tt>. When use any re-entry to the API with LFN feature, <tt>FF_USE_LFN</tt> must be set to 2 or 3. In this case, the file function allocates the working buffer on the stack or heap. The LFN working buffer occupies <tt>(FF_MAX_LFN + 1) * 2</tt> bytes and additional <tt>(FF_MAX_LFN + 44) / 15 * 32</tt> bytes when exFAT is enabled.</p>
<h4>Impact upon Module Size</h4>
<table class="lst2 rset">
<caption>With LFN at CM3 + gcc</caption>
<tr><th><tt>FF_CODE_PAGE</tt></th><th>Code size</th></tr>
<tr><td>437-869 (SBCS)</td><td>+3.3k</td></tr>
<tr><td>932 (Japanese)</td><td>+62k</td></tr>
<tr><td>936 (Simplified Chinese)</td><td>+177k</td></tr>
<tr><td>949 (Korean)</td><td>+140k</td></tr>
<tr><td>950 (Traditional Chinese)</td><td>+111k</td></tr>
<tr><td>0 (All code pages)</td><td>+486k</td></tr>
</table>
<p>When the LFN is enabled, the module size will be increased depends on the configured code page. Right table shows the increment of code size in some code pages. Especially, in the CJK region, tens of thousands of characters are being used. Unfortunately, it requires a huge OEM-Unicode bidirectional conversion table and the module size will be drastically increased as shown in the table.</p>
<p>As the result, the FatFs with LFN enabled with DBCS code pages will not able to be ported on the most 8-bit MCU systems. If the target system is in legacy-free, in only Unicode and any ANSI/OEM code is not used at all, the code page setting gets meaningless. You will able to reduce the code size by configureing FatFs for Unicode with any SBCS code page.</p>
<p>There ware some restrictions on using LFN for open source project, because the LFN extension on the FAT filesystem was a patent of Microsoft Corporation. However the related patents all have expired and using the LFN feature is free for any projects.</p>
</div>
<div class="para doc" id="unicode">
<h3>Unicode API</h3>
<p>By default, FatFs uses ANSI/OEM code set on the API even in LFN configuration. FatFs can also switch the character encoding on the API to Unicode by configuration option <tt><a href="config.html#lfn_unicode">FF_LFN_UNICODE</a></tt>. This means that FatFs is compliant with the full featured LFN specification. The data type <tt>TCHAR</tt> specifies path name strings on the API is an alias of either <tt>char</tt>(ANSI/OEM or UTF-8), <tt>WCHAR</tt>(UTF-16) or <tt>DWORD</tt>(UTF-32) depends on that option. For more information, refer to the description in the <a href="filename.html#uni">file name</a>.</p>
<p>Note that setting of code page, <tt><a href="config.html#code_page">FF_CODE_PAGE</a></tt>, has actually no meaning when FatFs is configured for the Unicode API. It should be set 437 anyway. However it still affects code conversion of string I/O functions at <tt><a href="config.html#strf_encode">FF_STRF_ENCODE</a> == 0</tt> and backward compatibility with legacy systems, so that code page may need to be configured properly if it is considered a problem.</p>
</div>
<div class="para doc" id="exfat">
<h3>exFAT Filesystem</h3>
<p>The exFAT (Microsoft's Extended File Allocation Table) filesystem is a succession of the FAT/FAT32 filesystem which has been widely used in embedded systems, consumer devices and portable storage media. It is adopted by SDA (SD Association) as the filesystem for SDXC card, 64 GB and larger, and they are being shipped with this format. Therefore the exFAT is one of the standard filesystems for removable media as well as FAT. The exFAT filesystem allows the file size beyond the 4 GB limit what FAT filesystem allows up to and some filesystem overhead, especially cluster allocation delay, are reduced as well. These features allow to record the large data without dividing into some files and improve the write throughput to the file.</p>
<p>Note that the exFAT filesystem is a patent of Microsoft Corporation. The exFAT feature of FatFs is an implementation based on <cite>US. Pat. App. Pub. No. 2009/0164440 A1</cite>. FatFs module can switch the exFAT on or off by a configuration option, <tt><a href="config.html#fs_exfat">FF_FS_EXFAT</a></tt>. When enable the exFAT for the commercial products, a license by Microsoft will be needed depends on the final destination of the products.</p>
<p><em>Remarks: Enabling exFAT discards C89 compatibility and it wants C99 because of need for 64-bit integer type.</em></p>
</div>
<div class="para doc" id="lba64">
<h3>64-bit LBA</h3>
<p>LBA (Logical Block Addressing) is an addressing method to specify the location of data block, called sector, on the storage media. It is a simple linear address beginning from 0 as the first block of data. The host system does not need to consider how the data block is located and managed in the storage device. FatFs supports only LBA for the media access. 32-bit LBA is a common size at the interface of the most storage devices. It can address up to 2<sup>32</sup> blocks, 2 TB in 512 bytes/sector. When a storage device larger than 2 TB is used, larger sector size or 64-bit LBA will be needed to address the entire block of the storage device.</p>
<p>By default, FatFs works in 32-bit LBA for media access interface. FatFs can also switch it to 64-bit LBA by a configuration option <tt><a href="config.html#fs_lba64">FF_LBA64</a></tt>. It also enables GPT (GUID Partition Table) for partiotion management on the storage device. For further information about GPT, refer to <tt><a href="mkfs.html">f_mkfs</a></tt> and <tt><a href="fdisk.html">f_fdisk</a></tt> function.</p>
</div>
<div class="para doc" id="reentrant">
<h3>Re-entrancy</h3>
<p>The file operations of two tasks to the <em>different volumes</em> each other is always re-entrant regardless of the configurations except when LFN is enabled with static working buffer (<tt>FF_USE_LFN = 1</tt>). It can work concurrently without any mutual exclusion.</p>
<p>The file operations of two tasks to the <em>same volume</em> is not re-entrant in default. FatFs can also be configured to make it thread-safe by option <tt><a href="config.html#fs_reentrant">FF_FS_REENTRANT</a></tt>. In this case, also the OS dependent synchronization control functions, <tt>ff_cre_syncobj/ff_del_syncobj/ff_req_grant/ff_rel_grant</tt>, need to be added to the project. There are some examples in the <tt>ffsystem.c</tt>. When a file function is called while the volume is being accessed by another task, the file function to the volume will be suspended until that task leaves the file function. If the wait time exceeded a period defined by <tt>FF_TIMEOUT</tt>, the file function will abort with <tt>FR_TIMEOUT</tt>. The timeout feature might not be supported on the some RTOSs.</p>
<p>There is an exception on the re-entrancy for <tt>f_mount/f_mkfs</tt> function. These volume management functions are not re-entrant to the same volume. When use these functions, other tasks need to avoid to access the volume.</p>
<div class="rset">
<table class="lst2">
<tr><th><tt>Function</tt></th><th>Case 1</th><th>Case 2</th><th>Case 3</th></tr>
<tr><td>disk_status</td><td>Yes</td><td>Yes</td><td>Yes(*)</td></tr>
<tr><td>disk_initialize</td><td>No</td><td>Yes</td><td>Yes(*)</td></tr>
<tr><td>disk_read</td><td>No</td><td>Yes</td><td>Yes(*)</td></tr>
<tr><td>disk_write</td><td>No</td><td>Yes</td><td>Yes(*)</td></tr>
<tr><td>disk_ioctl</td><td>No</td><td>Yes</td><td>Yes(*)</td></tr>
<tr><td>get_fattime</td><td>No</td><td>Yes</td><td>Yes</td></tr>
</table>
<small>
Case 1: Same volume.<br>
Case 2: Different volume on the same drive.<br>
Case 3: Different volume on the different drive.<br>
(*) In only different drive number.
</small>
</div>
<p>Remarks: This section describes on the re-entrancy of the FatFs module itself. The <tt>FF_FS_REENTRANT</tt> option enables only exclusive use of each filesystem objects and FatFs does not that prevent to re-enter the storage device control functions. Thus the device control layer needs to be always thread-safe when FatFs API is re-entered for different volumes. Right table shows which control function can be re-entered when FatFs API is re-entered on some conditions.</p>
</div>
<div class="para doc" id="dup">
<h3>Duplicated File Open</h3>
<p>FatFs module does not support the read/write collision control of duplicated open to a file. The duplicated open is permitted only when each of open method to a file is read mode. The duplicated open with one or more write mode to a file is always prohibited, and also open file must not be renamed or deleted. A violation of these rules can cause data collaption.</p>
<p>The file lock control can be enabled by <tt><a href="config.html#fs_lock">FF_FS_LOCK</a></tt> option. The value of option defines the number of open objects to manage simultaneously. In this case, if any opening, renaming or removing against the file shareing rule that described above is attempted, the file function will be rejected with <tt>FR_LOCKED</tt>. If number of open objects, files and sub-directories, is equal to <tt>FF_FS_LOCK</tt>, an extra <tt>f_open/f_opendir</tt> function will fail with <tt>FR_TOO_MANY_OPEN_FILES</tt>.</p>
</div>
<div class="para doc" id="fs1">
<h3>Performance Effective File Access</h3>
<p>For good read/write throughput on the small embedded systems with limited size of memory, application programmer should consider what process is done in the FatFs module. The file data on the volume is transferred in following sequence by <tt>f_read</tt> function.</p>
<p>Figure 1. Sector unaligned read (short)<br>
<img src="../res/f1.png" width="490" height="110" alt="">
</p>
<p>Figure 2. Sector unaligned read (long)<br>
<img src="../res/f2.png" width="490" height="140" alt="">
</p>
<p>Figure 3. Fully sector aligned read<br>
<img src="../res/f3.png" width="490" height="119" alt="">
</p>
<p>The file I/O buffer is a sector buffer to read/write a part of data on the sector. The sector buffer is either file private sector buffer on each file object or shared sector buffer in the filesystem object. The buffer configuration option <tt><a href="config.html#fs_tiny">FF_FS_TINY</a></tt> determins which sector buffer is used for the file data transfer. When tiny buffer configuration (1) is selected, data memory consumption is reduced <tt>FF_MAX_SS</tt> bytes each file object. In this case, FatFs module uses only a sector buffer in the filesystem object for file data transfer and FAT/directory access. The disadvantage of the tiny buffer configuration is: the FAT data cached in the sector buffer will be lost by file data transfer and it must be reloaded at every cluster boundary. However it will be suitable for most application from view point of the decent performance and low memory comsumption.</p>
<p>Figure 1 shows that a partial sector, sector unaligned part of the file, is transferred via the file I/O buffer. At long data transfer shown in Figure 2, middle of transfer data that covers one or more sector is transferred to the application buffer directly. Figure 3 shows that the case of entier transfer data is aligned to the sector boundary. In this case, file I/O buffer is not used. On the direct transfer, the maximum extent of sectors are read with <tt>disk_read</tt> function at a time but the multiple sector transfer is divided at cluster boundary even if it is contiguous.</p>
<p>Therefore taking effort to sector aligned read/write accesss eliminates buffered data transfer and the read/write performance will be improved. Besides the effect, cached FAT data will not be flushed by file data transfer at the tiny configuration, so that it can achieve same performance as non-tiny configuration with small memory footprint.</p>
</div>
<div class="para doc" id="fs2">
<h3>Considerations on Flash Memory Media</h3>
<p>To maximize the write performance of flash memory media, such as SDC, CFC and U Disk, it must be controlled in consideration of its characteristitcs.</p>
<h4>Using Mutiple-Sector Write</h4>
<div class="rset">
Figure 6. Comparison between Multiple/Single Sector Write<br>
<img src="../res/f6.png" width="630" height="148" alt="fig.6">
</div>
<p>The write throughput of the flash memory media becomes the worst at single sector write transaction. The write throughput increases as the number of sectors per a write transaction as shown in Figure 6. This effect more appers at faster interface speed and the performance ratio often becomes grater than ten. <a href="../res/rwtest2.png">This result</a> is clearly explaining how fast is multiple block write (W:16K, 32 sectors) than single block write (W:100, 1 sector), and also larger card tends to be slow at single block write. Number of write transactions also affects life time of the flash memory media. When compared at same amount of write data, the single sector write in Figure 6 above wears flash memory media 16 times more than multiple sector write in Figure 6 below. Single sector write is pretty pain for the flash memory media.</p>
<p>Therefore the application program should write the data in large block as possible. The ideal write chunk size and alighment is size of sector, and size of cluster is the best. Of course all layers between the application and the storage device must have consideration on multiple sector write, however most of open-source memory card drivers lack it. Do not split a multiple sector write request into single sector write transactions or the write throughput gets poor. Note that FatFs module and its sample disk drivers supprt multiple sector read/write operation. </p>
<h4>Forcing Memory Erase</h4>
<p>When remove a file with <tt>f_unlink</tt> function, the data clusters occupied by the file are marked 'free' on the FAT. But the data sectors containing the file data are not that applied any process, so that the file data left occupies a part of the flash memory array as 'live block'. If the file data can be erased on removing the file, those data blocks will be turned into the free block pool. This may skip internal block erase operation to the data block on next write operation. As the result the write performance might be improved. FatFs can manage this function by setting <tt><a href="config.html#use_trim">FF_USE_TRIM</a></tt> to 1. Note that this is an expectation of internal process of the storage device and not that always effective. Most applications will not need this function. Also <tt>f_unlink</tt> function can take a time when remove a large file.</p>
</div>
<div class="para doc" id="critical">
<h3>Critical Section</h3>
<p>If a write operation to the FAT volume is interrupted due to an accidental failure, such as sudden blackout, wrong media removal and unrecoverable disk error, the FAT structure on the volume can be broken. Following images shows the critical section of the FatFs module.</p>
<div class="lset">
Figure 4. Long critical section<br>
<img src="../res/f4.png" width="320" height="436" alt="fig.4">
</div>
<div class="lset">
Figure 5. Minimized critical section<br>
<img src="../res/f5.png" width="320" height="436" alt="fig.5">
</div>
<br class="clr">
<p>An interruption in the red section can cause a cross link; as a result, the object being changed can be lost. If an interruption in the yellow section is occured, there is one or more possibility listed below.</p>
<ul>
<li>The file data being rewrited is collapsed.</li>
<li>The file being appended returns initial state.</li>
<li>The file created as new is gone.</li>
<li>The file created as new or overwritten remains but no content.</li>
<li>Efficiency of disk use gets worse due to lost clusters.</li>
</ul>
<p>Each case does not affect any file not opened in write mode. To minimize risk of data loss, the critical section can be minimized by minimizing the time that file is opened in write mode or using <tt>f_sync</tt> function as shown in Figure 5.</p>
</div>
<div class="para doc" id="fs3">
<h3>Various Usable Functions for FatFs Projects</h3>
<p>These are examples of extended use of FatFs APIs. New item will be added when useful code example is found.</p>
<ol>
<li><a href="http://elm-chan.org/fsw/ff/res/app1.c">Open or Create File for Append</a> (superseded by FA_APPEND flag added in R0.12)</li>
<li><a href="http://elm-chan.org/fsw/ff/res/app2.c">Delete Non-empty Sub-directory</a> (for R0.12 and later)</li>
<li><a href="http://elm-chan.org/fsw/ff/res/app3.c">Create Contiguous File</a> (superseded by f_expand function added in R0.12)</li>
<li><a href="http://elm-chan.org/fsw/ff/res/app5.c">Test if the File is Contiguous or Not</a></li>
<li><a href="http://elm-chan.org/fsw/ff/res/app4.c">Compatibility Checker for Storage Device Control Module</a></li>
<li><a href="http://elm-chan.org/fsw/ff/res/app6.c">Performance Checker for Storage Device Control Module</a></li>
<li><a href="http://elm-chan.org/fsw/ff/res/mkfatimg.zip">FAT Volume Image Creator</a> (Pre-creating built-in FAT volume)</li>
<li>Virtual Drive Feature (refer to lpc176x/ in <a href="../ffsample.zip">ffsample.zip</a>)</li>
<li><a href="http://elm-chan.org/fsw/ff/res/uniconv.zip">Embedded Unicode String Utilities</a> (OEMxxx→Unicode, Unicode→OEMxxx, Unicode→Unicode)</li>
</ol>
</div>
<div class="para doc" id="license">
<h3>About FatFs License</h3>
<p>FatFs has being developped as a personal project of the author, ChaN. It is free from the code anyone else wrote at current release. Following code block shows a copy of the FatFs license document that included in the source files.</p>
<pre>
/*----------------------------------------------------------------------------/
/ FatFs - Generic FAT Filesystem Module Rx.xx /
/-----------------------------------------------------------------------------/
/
/ Copyright (C) 20xx, ChaN, all right reserved.
/
/ FatFs module is an open source software. Redistribution and use of FatFs in
/ source and binary forms, with or without modification, are permitted provided
/ that the following condition is met:
/
/ 1. Redistributions of source code must retain the above copyright notice,
/ this condition and the following disclaimer.
/
/ This software is provided by the copyright holder and contributors "AS IS"
/ and any warranties related to this software are DISCLAIMED.
/ The copyright owner or contributors be NOT LIABLE for any damages caused
/ by use of this software.
/----------------------------------------------------------------------------*/
</pre>
<p>Therefore FatFs license is one of the BSD-style licenses but there is a significant feature. FatFs is mainly intended for embedded systems. In order to extend the usability for commercial products, the redistributions of FatFs in binary form, such as embedded code, binary library and any forms without source code, does not need to include about FatFs in the documentations. This is equivalent to the 1-clause BSD license. Of course FatFs is compatible with the most of open source software licenses including GNU GPL. When you redistribute the FatFs source code with any changes or create a fork, the license can also be changed to GNU GPL, BSD-style license or any open source software license that compatible with FatFs license.</p>
</div>
<p class="foot"><a href="../00index_e.html">Return Home</a></p>
</body>
</html>
documents/doc/chdir.html
+2 -2
View File
@@ -25,7 +25,7 @@ FRESULT f_chdir (
<h4>Parameters</h4>
<dl class="par">
<dt>path</dt>
<dd>Pointer to the null-terminated string that specifies the <a href="filename.html">directory</a> to go.</dd>
<dd>Pointer to the null-terminated string that specifies the <a href="filename.html">directory</a> to be set as current directory.</dd>
</dl>
</div>
@@ -50,7 +50,7 @@ FRESULT f_chdir (
<div class="para desc">
<h4>Description</h4>
<p>The <tt>f_chdir</tt> function changes the current directory of the logical drive. Also the current drive is changed at Unix style volume ID, <tt><a href="config.html#str_volume_id">FF_STR_VOLUME_ID</a> == 2</tt>. The current directory of each logical drive is initialized to the root directory on mount.</p>
<p>The <tt>f_chdir</tt> function changes the current directory of the logical drive. Also the current drive will be changed when Unix style volume ID, <tt><a href="config.html#str_volume_id">FF_STR_VOLUME_ID</a> == 2</tt>, is selected. The current directory of each logical drive is initialized to the root directory on mount.</p>
<p>Note that the current directory is retained in the each file system object and the current drive is retained in a static variable, so that it also affects other tasks that use the file functions.</p>
</div>
documents/doc/config.html
+13 -12
View File
@@ -118,7 +118,7 @@
<h3>Namespace and Locale Configurations</h3>
<h4 id="code_page">FF_CODE_PAGE</h4>
<p>This option specifies the OEM code page to be used on the target system. Incorrect setting of the code page can cause a file open failure. If any non-ASCII character is not used for the path name, there is no difference between any code page settings. Set it 437 anyway.</p>
<p>This option specifies the OEM code page used on the target system. Incorrect setting of the code page can cause a file open failure. If any non-ASCII character is not used for the path name or character encoding is in Unicode, there is no difference between any code page settings. Set it 437 anyway.</p>
<table class="lst1">
<tr><th>Value</th><th>Code page</th></tr>
<tr><td>0</td><td>Includes all code pages below and set by <tt>f_setcp()</tt></td></tr>
@@ -156,10 +156,10 @@
</table>
<h4 id="max_lfn">FF_MAX_LFN</h4>
<p>LFN function requiers certain internal working buffer for the file name. This option defines size of the buffer and the value can be in range of 12 to 255 in UTF-16 encoding unit of the LFN. The buffer occupies <tt>(FF_MAX_LFN + 1) * 2</tt> bytes and additional <tt>(FF_MAX_LFN + 44) / 15 * 32</tt> bytes when exFAT is enabled. It is recommended to be set 255 to fully support the LFN specification. This option has no effect when LFN is not enabled.</p>
<p>LFN function requiers certain internal working buffer for the file name. This option defines size of the buffer and the value can be in range of 12 to 255 characters (actually in UTF-16 code units) of the LFN. The buffer occupies <tt>(FF_MAX_LFN + 1) * 2</tt> bytes and additional <tt>(FF_MAX_LFN + 44) / 15 * 32</tt> bytes when exFAT is enabled. It is recommended to be set 255 to fully support the LFN specification. This option has no effect when LFN is not enabled.</p>
<h4 id="lfn_unicode">FF_LFN_UNICODE</h4>
<p>This option switches character encoding for the file name on the API. When Unicode is selected, <tt>FF_CODE_PAGE</tt> has actually no meaning except for compatibility with legacy systems, such as MS-DOS and any system without support for LFN. FatFs supports the code point up to U+10FFFF.</p>
<p>This option switches character encoding for the file name on the API. FatFs supports the code point up to U+10FFFF. This option also affects behavior of string I/O functions (see <tt>FF_STRF_ENCODE</tt>).</p>
<table class="lst2">
<tr><th>Value</th><th>Character Encoding</th><th><tt>TCHAR</tt></th></tr>
<tr><td>0</td><td>ANSI/OEM in current CP</td><td>char</td></tr>
@@ -167,14 +167,15 @@
<tr><td>2</td><td>Unicode in UTF-8</td><td>char</td></tr>
<tr><td>3</td><td>Unicode in UTF-32</td><td>DWORD</td></tr>
</table>
<p>This option also affects behavior of string I/O functions (see <tt>FF_STRF_ENCODE</tt>). When LFN is not enabled, this option has no effect and FatFs works at ANSI/OEM code on the API. For more information, read <a href="filename.html#uni">here</a>.</p>
<p>When Unicode is selected, <tt>FF_CODE_PAGE</tt> has actually no meaning except for compatibility with legacy systems, such as MS-DOS and any system without support for LFN.</p>
<p>When LFN is not enabled, this option has no effect and FatFs works in ANSI/OEM code on the API. For more information, read <a href="filename.html#uni">here</a>.</p>
<h4 id="lfn_buf">FF_LFN_BUF, FF_SFN_BUF</h4>
<p>This set of options defines size of file name members, <tt>fname[]</tt> and <tt>altname[]</tt>, in the <tt><a href="sfileinfo.html">FILINFO</a></tt> structure which is used to read out the directory items. These values should be suffcient for the file names to read. The maximum possible length of read file name depends on the character encoding on the API as follows:</p>
<p>This set of options defines size of file name members, <tt>fname[]</tt> and <tt>altname[]</tt>, in the <tt><a href="sfileinfo.html">FILINFO</a></tt> structure which is used to read out the directory items. These values should be suffcient for the file names to read. The maximum possible length of read file name depends on the character encoding scheme on the API as follows:</p>
<table class="lst2">
<tr><th>Encoding</th><th>LFN length</th><th>SFN length</th></tr>
<tr><td>ANSI/OEM at SBCS</td><td>255 items</td><td>12 items</td></tr>
<tr><td>ANSI/OEM at DBCS</td><td>510 items</td><td>12 items</td></tr>
<tr><td>ANSI/OEM in SBCS</td><td>255 items</td><td>12 items</td></tr>
<tr><td>ANSI/OEM in DBCS</td><td>510 items</td><td>12 items</td></tr>
<tr><td>Unicode in UTF-16/32</td><td>255 items</td><td>12 items</td></tr>
<tr><td>Unicode in UTF-8</td><td>765 items</td><td>34 items</td></tr>
</table>
@@ -249,16 +250,16 @@ const char* VolumeStr[FF_VOLUMES] = {"ram","flash","sdc","usb"};
<p>Normal (0) or Tiny (1). The tiny configuration reduces size of the <tt>FIL</tt> structure, file object, <tt>FF_MAX_SS</tt> bytes each. Instead of private sector buffer eliminated from the file object, common sector buffer in the <tt>FATFS</tt> structure, filesystem object, is used for the file data transfer.</p>
<h4 id="fs_exfat">FF_FS_EXFAT</h4>
<p>This option switches support for exFAT filesystem in addition to the FAT/FAT32 filesystem, Enabled (1) or Disabled (0). To enable exFAT, also LFN must be enabled and configureing <tt>FF_LFN_UNICODE &gt;= 1</tt> and <tt>FF_MAX_LFN == 255</tt> is recommended for full-featured exFAT function. Note that enabling exFAT discards ANSI C (C89) compatibility because of need for 64-bit integer type.</p>
<p>This option switches support for exFAT filesystem in addition to the FAT/FAT32 filesystem, Enabled (1) or Disabled (0). To enable exFAT, also LFN must be enabled and configureing <tt>FF_LFN_UNICODE &gt;= 1</tt> and <tt>FF_MAX_LFN == 255</tt> is recommended for full-featured exFAT function. Note that enabling exFAT discards ANSI C (C89) compatibility and wants C99 because of need for 64-bit integer type.</p>
<h4 id="fs_nortc">FF_FS_NORTC</h4>
<p>Use RTC (0) or Do not use RTC (1). This option controls timestamp function. If the system does not have any RTC function or valid timestamp is not needed, set <tt>FF_FS_NORTC</tt> to 1 to disable the timestamp function. Every objects modified by FatFs will have a fixed timestamp defined by <tt>FF_NORTC_MON</tt>, <tt>FF_NORTC_MDAY</tt> and <tt>FF_NORTC_YEAR</tt>. To use the timestamp function, set <tt>FF_FS_NORTC == 0</tt> and add <tt>get_fattime</tt> function to the project to get current time form the RTC. This option has no effect at read-only configuration.</p>
<p>Use RTC (0) or Do not use RTC (1). This option controls timestamp function. If the system does not have any RTC function or valid timestamp is not needed, set <tt>FF_FS_NORTC</tt> to 1 to disable the timestamp function. Every objects modified by FatFs will have a fixed timestamp defined by <tt>FF_NORTC_MON</tt>, <tt>FF_NORTC_MDAY</tt> and <tt>FF_NORTC_YEAR</tt>. To use the timestamp function, set <tt>FF_FS_NORTC == 0</tt> and add <tt>get_fattime</tt> function to the project to get current time form the RTC. This option has no effect in read-only configuration.</p>
<h4 id="nortc_time">FF_NORTC_MON, FF_NORTC_MDAY, FF_NORTC_YEAR</h4>
<p>This set of options defines the time to be used at no RTC systems. This option has no effect at read-only configuration or <tt>FF_FS_NORTC == 0</tt>.</p>
<p>This set of options defines the time to be used in no RTC systems. This option has no effect in read-only configuration or <tt>FF_FS_NORTC == 0</tt>.</p>
<h4 id="fs_nofsinfo">FF_FS_NOFSINFO</h4>
<p>0 to 3. If you need to know correct free space on the FAT32 volume, set bit 0 of this option, and <tt>f_getfree</tt> function at first time after volume mount will force a full FAT scan. Bit 1 controls the use of last allocated cluster number.</p>
<p>0 to 3. If you need to know correct free space on the FAT32 volume, set bit 0 of this option, and <tt>f_getfree</tt> function at first time after volume mount will force a full FAT scan. Bit 1 controls the use of last allocated cluster number for new allocation.</p>
<table class="lst1">
<tr><th>Value</th><th>Description</th></tr>
<tr><td>bit0=0</td><td>Use free cluster count in the FSINFO if available.</td></tr>
@@ -268,7 +269,7 @@ const char* VolumeStr[FF_VOLUMES] = {"ram","flash","sdc","usb"};
</table>
<h4 id="fs_lock">FF_FS_LOCK</h4>
<p>This option switches file lock function to control duplicated file open and illegal operations to open objects. Note that the file lock function is independent of re-entrancy. This option must be 0 at read-only configuration.</p>
<p>This option switches file lock function to control duplicated file open and illegal operations to open objects. Note that the file lock function is independent of re-entrancy. This option must be 0 in read-only configuration.</p>
<table class="lst1">
<tr><th>Value</th><th>Description</th></tr>
<tr><td>0</td><td>Disable file lock function. To avoid collapsing file by wrong file operation, application program needs to avoid illegal open, remove and rename to the open objects.</td></tr>
documents/doc/dioctl.html
+9 -9
View File
@@ -57,9 +57,9 @@ DRESULT disk_ioctl (
<table class="lst">
<caption>Standard ioctl command used by FatFs</caption>
<tr><th>Command</th><th>Description</th></tr>
<tr><td>CTRL_SYNC</td><td>Makes sure that the device has finished pending write process. If the disk I/O layer or storage device has a write-back cache, the cached data not written back must be flushed to the media immediately. Nothing to do for this command if each write operation to the media is completed within the <tt>disk_write</tt> function.</td></tr>
<tr><td>CTRL_SYNC</td><td>Makes sure that the device has finished pending write process. If the disk I/O layer or storage device has a write-back cache, the dirty cache data must be committed to media immediately. Nothing to do for this command if each write operation to the media is completed within the <tt>disk_write</tt> function.</td></tr>
<tr><td>GET_SECTOR_COUNT</td><td>Retrieves number of available sectors, the largest allowable LBA + 1, on the drive into the <tt>LBA_t</tt> variable pointed by <tt class="arg">buff</tt>. This command is used by <tt>f_mkfs</tt> and <tt>f_fdisk</tt> function to determine the size of volume/partition to be created. It is required when <tt>FF_USE_MKFS == 1</tt>.</td></tr>
<tr><td>GET_SECTOR_SIZE</td><td>Retrieves sector size used for read/write function into the <tt>WORD</tt> variable pointed by <tt class="arg">buff</tt>. Valid sector sizes are 512, 1024, 2048 and 4096. This command is required only if <tt>FF_MAX_SS &gt; FF_MIN_SS</tt>. When <tt>FF_MAX_SS == FF_MIN_SS</tt>, this command will be never used and the read/write function must work in <tt>FF_MAX_SS</tt> bytes/sector only.</td></tr>
<tr><td>GET_SECTOR_SIZE</td><td>Retrieves sector size, minimum data unit for generic read/write, into the <tt>WORD</tt> variable pointed by <tt class="arg">buff</tt>. Valid sector sizes are 512, 1024, 2048 and 4096. This command is required only if <tt>FF_MAX_SS &gt; FF_MIN_SS</tt>. When <tt>FF_MAX_SS == FF_MIN_SS</tt>, this command will be never used and the read/write function must work in <tt>FF_MAX_SS</tt> bytes/sector.</td></tr>
<tr><td>GET_BLOCK_SIZE</td><td>Retrieves erase block size of the flash memory media in unit of sector into the <tt>DWORD</tt> variable pointed by <tt class="arg">buff</tt>. The allowable value is 1 to 32768 in power of 2. Return 1 if the erase block size is unknown or non flash memory media. This command is used by only <tt>f_mkfs</tt> function and it attempts to align data area on the erase block boundary. It is required when <tt>FF_USE_MKFS == 1</tt>.</td></tr>
<tr><td>CTRL_TRIM</td><td>Informs the device the data on the block of sectors is no longer needed and it can be erased. The sector block is specified in an <tt>LBA_t</tt> array {&lt;Start LBA&gt;, &lt;End LBA&gt;} pointed by <tt class="arg">buff</tt>. This is an identical command to Trim of ATA device. Nothing to do for this command if this funcion is not supported or not a flash memory device. FatFs does not check the result code and the file function is not affected even if the sector block was not erased well. This command is called on remove a cluster chain and in the <tt>f_mkfs</tt> function. It is required when <tt>FF_USE_TRIM == 1</tt>.</td></tr>
</table>
@@ -76,13 +76,13 @@ DRESULT disk_ioctl (
<tr><td>CTRL_EJECT</td><td>Ejects media cartridge. <tt>STA_NOINIT</tt> and <tt>STA_NODISK</tt> in status flag are set after the function succeeded.</td></tr>
<tr><td>CTRL_GET_SMART</td><td>Reads SMART information.</td></tr>
<tr><td>MMC_GET_TYPE</td><td>Gets card type. The type flags, bit0:MMCv3, bit1:SDv1, bit2:SDv2+ and bit3:LBA, is stored to a BYTE variable pointed by <tt class="arg">buff</tt>. (MMC/SDC specific command)</td></tr>
<tr><td>MMC_GET_CSD</td><td>Reads CSD register into a 16-byte buffer pointed by <tt class="arg">buff</tt>. (MMC/SDC specific command)</td></tr>
<tr><td>MMC_GET_CID</td><td>Reads CID register into a 16-byte buffer pointed by <tt class="arg">buff</tt>. (MMC/SDC specific command)</td></tr>
<tr><td>MMC_GET_OCR</td><td>Reads OCR register into a 4-byte buffer pointed by <tt class="arg">buff</tt>. (MMC/SDC specific command)</td></tr>
<tr><td>MMC_GET_SDSTAT</td><td>Reads SDSTATUS register into a 64-byte buffer pointed by <tt class="arg">buff</tt>. (SDC specific command)</td></tr>
<tr><td>ATA_GET_REV</td><td>Gets the revision string into a 16-byte buffer pointed by <tt class="arg">buff</tt>. (ATA/CFC specific command)</td></tr>
<tr><td>ATA_GET_MODEL</td><td>Gets the model string into a 40-byte buffer pointed by <tt class="arg">buff</tt>. (ATA/CFC specific command)</td></tr>
<tr><td>ATA_GET_SN</td><td>Gets the serial number string into a 20-byte buffer pointed by <tt class="arg">buff</tt>. (ATA/CFC specific command)</td></tr>
<tr><td>MMC_GET_CSD</td><td>Reads CSD register and sets it into a 16-byte buffer pointed by <tt class="arg">buff</tt>. (MMC/SDC specific command)</td></tr>
<tr><td>MMC_GET_CID</td><td>Reads CID register and sets it into a 16-byte buffer pointed by <tt class="arg">buff</tt>. (MMC/SDC specific command)</td></tr>
<tr><td>MMC_GET_OCR</td><td>Reads OCR register and sets it into a 4-byte buffer pointed by <tt class="arg">buff</tt>. (MMC/SDC specific command)</td></tr>
<tr><td>MMC_GET_SDSTAT</td><td>Reads SDSTATUS register and sets it into a 64-byte buffer pointed by <tt class="arg">buff</tt>. (SDC specific command)</td></tr>
<tr><td>ATA_GET_REV</td><td>Gets the revision string and sets it into a 16-byte buffer pointed by <tt class="arg">buff</tt>. (ATA/CFC specific command)</td></tr>
<tr><td>ATA_GET_MODEL</td><td>Gets the model string and sets it into a 40-byte buffer pointed by <tt class="arg">buff</tt>. (ATA/CFC specific command)</td></tr>
<tr><td>ATA_GET_SN</td><td>Gets the serial number string and sets it into a 20-byte buffer pointed by <tt class="arg">buff</tt>. (ATA/CFC specific command)</td></tr>
<tr><td>ISDIO_READ</td><td>Reads a block of iSDIO registers specified by command structure pointed by <tt class="arg">buff</tt>. (FlashAir specific command)</td></tr>
<tr><td>ISDIO_WRITE</td><td>Writes a block of data to iSDIO registers specified by command structure pointed by <tt class="arg">buff</tt>. (FlashAir specific command)</td></tr>
<tr><td>ISDIO_MRITE</td><td>Changes bits in an iSDIO register specified by command structure pointed by <tt class="arg">buff</tt>. (FlashAir specific command)</td></tr>
documents/doc/dstat.html
+3 -3
View File
@@ -25,7 +25,7 @@ DSTATUS disk_status (
<h4>Parameter</h4>
<dl class="par">
<dt>pdrv</dt>
<dd>Physical drive number to identify the target device. Always zero at single drive system.</dd>
<dd>Physical drive number to identify the target device. Always zero in single drive system.</dd>
</dl>
</div>
@@ -37,9 +37,9 @@ DSTATUS disk_status (
<dt>STA_NOINIT</dt>
<dd>Indicates that the device has not been initialized and not ready to work. This flag is set on system reset, media removal or failure of <a href="dinit.html"><tt>disk_initialize</tt></a> function. It is cleared on <tt>disk_initialize</tt> function succeeded. Any media change that occurs asynchronously must be captured and reflect it to the status flags, or auto-mount function will not work correctly. If the system does not support media change detection, application program needs to explicitly re-mount the volume with <tt>f_mount</tt> function after each media change.</dd>
<dt>STA_NODISK</dt>
<dd>Indicates that no medium in the drive. This is always cleared at fixed disk drive. Note that FatFs does not refer this flag.</dd>
<dd>Indicates that no medium in the drive. This is always cleared when the drive is non-removable class. Note that FatFs does not refer this flag.</dd>
<dt>STA_PROTECT</dt>
<dd>Indicates that the medium is write protected. This is always cleared at the drives without write protect function. Not valid if <tt>STA_NODISK</tt> is set.</dd>
<dd>Indicates that the medium is write protected. This is always cleared when the drive has no write protect function. Not valid if <tt>STA_NODISK</tt> is set.</dd>
</dl>
</div>
documents/doc/dwrite.html
+1 -1
View File
@@ -60,7 +60,7 @@ DRESULT disk_write (
<h4>Description</h4>
<p>The specified memory address is not that always aligned to word boundary because the argument is defined as <tt>BYTE*</tt>. For more information, refer to the description of <a href="dread.html"><tt>disk_read</tt></a> function.</p>
<p>Generally, a multiple sector write request (<tt class="arg">count</tt><tt> &gt; 1</tt>) must not be split into single sector transactions to the storage device, or the file write throughput will be drastically decreased.</p>
<p>FatFs expects delayed write function of the disk control layer. The write operation to the media does not need to be completed at return from this function by what write operation is in progress or data is only stored into the write-back cache. But write data on the <tt class="arg">buff</tt> is invalid after return from this function. The write completion request is done by <tt>CTRL_SYNC</tt> command of <tt><a href="dioctl.html">disk_ioctl</a></tt> function. Therefore, if a delayed write function is implemented, the write throughput of the filesystem will be improved.</p>
<p>FatFs expects delayed write function of the disk control layer. The write operation to the media does not need to be completed when return from this function by what write operation is in progress or data is only stored into the write-back cache. But write data on the <tt class="arg">buff</tt> is invalid after return from this function. The write completion request is done by <tt>CTRL_SYNC</tt> command of <tt><a href="dioctl.html">disk_ioctl</a></tt> function. Therefore, if a delayed write function is implemented, the write throughput of the filesystem will be improved.</p>
<p><em>Remarks: Application program MUST NOT call this function, or FAT structure on the volume can be collapsed.</em></p>
</div>
documents/doc/expand.html
+6 -6
View File
@@ -19,7 +19,7 @@
FRESULT f_expand (
FIL* <span class="arg">fp</span>, <span class="c">/* [IN] File object */</span>
FSIZE_t <span class="arg">fsz</span>, <span class="c">/* [IN] File size expanded to */</span>
BYTE <span class="arg">opt</span> <span class="c">/* [IN] Operation mode */</span>
BYTE <span class="arg">opt</span> <span class="c">/* [IN] Allocation mode */</span>
);
</pre>
</div>
@@ -32,7 +32,7 @@ FRESULT f_expand (
<dt>fsz</dt>
<dd>Number of bytes in size to prepare or allocate for the file. The data type <tt>FSIZE_t</tt> is an alias of either <tt>DWORD</tt>(32-bit) or <tt>QWORD</tt>(64-bit) depends on the configuration option <tt>FF_FS_EXFAT</tt>.</dd>
<dt>opt</dt>
<dd>Operation mode. Prepare only (0) or Allocate now (1).</dd>
<dd>Allocation mode. Prepare to allocate (0) or Allocate now (1).</dd>
</dl>
</div>
@@ -52,16 +52,16 @@ FRESULT f_expand (
<div class="para desc">
<h4>Description</h4>
<p>The <tt>f_expand</tt> function prepares or allocates a contiguous data area to the file. When <tt class="arg">opt</tt> is 1, the function allocates a contiguous data area to the file. Unlike expansion of file by <tt>f_lseek</tt> function, the file must be truncated prior to use this function and read/write pointer of the file stays at offset 0 after the function. The file content allocated with this function is <em>undefined</em> because no data is written to the file in this process. The function can fail with <tt>FR_DENIED</tt> due to some reasons below.</p>
<p>The <tt>f_expand</tt> function prepares or allocates a contiguous data area to the file. When <tt class="arg">opt</tt> is 1, the data area is allocated to the file in this function. Unlike expansion of file size by <tt>f_lseek</tt> function, the file must be truncated prior to use this function and read/write pointer of the file stays at offset 0 after the function call. The file content allocated with this function is <em>undefined</em> because no data is written to the file in this process. The function can fail with <tt>FR_DENIED</tt> due to some reasons below.</p>
<ul>
<li>No free contiguous space was found.</li>
<li>Size of the file was not zero.</li>
<li>The file has been opened in read-only mode.</li>
<li>Not allowable file size. (&gt;= 4 GB on FAT volume)</li>
</ul>
<p>When <tt class="arg">opt</tt> is 0, the function finds a contiguous data area and set it as suggested point for next allocation instead of allocating it to the file. The next cluster allocation is started at beginning of the contiguous area found by this function. Thus the write file is guaranteed be contiguous and no allocation delay until the size reaches that size at least unless any other changes to the volume is performed.</p>
<p>The contiguous file would have an advantage at time-critical read/write operations. It eliminates some overheads in the filesystem and the storage media caused by random access due to fragmented file data. Especially FAT access for the contiguous file on the exFAT volume is completely eliminated and storage media will be accessed sequentially.</p>
<p>Also the contiguous file can be easily accessed directly via low-level disk functions. But this is not recommended in consideration for future compatibility. Use <a href="../res/app5.c">this function</a> to examine if the file is contiguous or not.</p>
<p>When <tt class="arg">opt</tt> is 0, the function finds a contiguous data area and set it as suggested point for next allocation. The subsequent cluster allocation begins at top of the contiguous area found by this function. Thus the file allocation is guaranteed be contiguous and without allocation delay until the file size reaches this size unless any other changes to the volume is performed.</p>
<p>The contiguous file has an advantage for time-critical read/write operations. It eliminates some overheads in the filesystem and the storage device caused by random access for fragmented file.</p>
<p>Also the contiguous file can be easily accessed directly via low-level disk functions. However, this is not recommended in consideration of portability and future compatibility. If the file has not been confirmed be contiguous, use <a href="../res/app5.c">this function</a> to examine if the file is contiguous or not.</p>
</div>
<div class="para comp">
documents/doc/fdisk.html
+1 -1
View File
@@ -29,7 +29,7 @@ FRESULT f_fdisk (
<dt>pdrv</dt>
<dd>Specifies the <em>physical drive</em> to be divided. This is not the logical drive number but the drive identifier passed to the low level disk functions.</dd>
<dt>ptbl</dt>
<dd>List of partitions to create on the drive. The data type <tt>LBA_t</tt> is alias of <tt>DWORD</tt> or <tt>QWORD</tt> depends on the configuration option <tt><a href="config.html#fs_lba64">FF_LBA64</a></tt>.</dd>
<dd>List of partition size to create on the drive. The data type <tt>LBA_t</tt> is an alias of <tt>DWORD</tt> or <tt>QWORD</tt> depends on the configuration option <tt><a href="config.html#fs_lba64">FF_LBA64</a></tt>.</dd>
<dt>work</dt>
<dd>Pointer to the function work area. The size must be at least <tt><a href="config.html#max_ss">FF_MAX_SS</a></tt> bytes. When a null pointer is given with <tt><a href="config.html#use_lfn">FF_USE_LFN</a> = 3</tt>, a memory block is obtained in this function for the working buffer.</dd>
</dl>
documents/doc/filename.html
+3 -3
View File
@@ -68,9 +68,9 @@ Example: "0:", "1:" and "2:" are associated with three partitions on the physica
"3:" is associated with physical drive 1 (removable drive)
PARTITION VolToPart[FF_VOLUMES] = {
{0, 1}, <span class="c">/* "0:" ==> 1st partition of physical drive 0 */</span>
{0, 2}, <span class="c">/* "1:" ==> 2nd partition of physical drive 0 */</span>
{0, 3}, <span class="c">/* "2:" ==> 3rd partition of physical drive 0 */</span>
{0, 1}, <span class="c">/* "0:" ==> 1st partition on physical drive 0 */</span>
{0, 2}, <span class="c">/* "1:" ==> 2nd partition on physical drive 0 */</span>
{0, 3}, <span class="c">/* "2:" ==> 3rd partition on physical drive 0 */</span>
{1, 0} <span class="c">/* "3:" ==> Physical drive 1 */</span>
};
</pre>
documents/doc/findfirst.html
+15 -8
View File
@@ -61,12 +61,19 @@ FRESULT f_findfirst (
<div class="para desc">
<h4>Description</h4>
<p>After the directory specified by <tt class="arg">path</tt> could be opened, it starts to search the directory for items with the name specified by <tt class="arg">pattern</tt>. If the first item is found, the information about the object is stored into the file information structure <tt class="arg">fno</tt>.</p>
<p>The matching pattern can contain wildcard characters (<tt>?</tt> and <tt>*</tt>). A <tt>?</tt> matches an any character and an <tt>*</tt> matches an any string in length of zero or longer. When support of long file name is enabled, only <tt>fname[]</tt> is tested at <tt>FF_USE_FIND == 1</tt> and also <tt>altname[]</tt> is tested at <tt>FF_USE_FIND == 2</tt>. In this revision, there are some differences listed below between FatFs and standard systems in matching condition.</p>
<p>After the directory specified by <tt class="arg">path</tt> could be opened, it starts to search the directory for items with the matching pattern specified by <tt class="arg">pattern</tt>. If the first item is found, the information about the item is stored into the file information structure <tt class="arg">fno</tt>. If not found, <tt>fno-&gt;fname[]</tt> has a null string.</p>
<p>The matching pattern string can contain wildcard terms. For example:</p>
<ul>
<li><tt>"*.*"</tt> never matches any name without extension while it matches any name with or without extension at the standard systems.</li>
<li>Any pattern terminated with a period never matches any name while it matches the name without extensiton at the standard systems.</li>
<li><a href="filename.html#case">DBCS extended characters</a> are compared in case-sensitive at LFN with ANSI/OEM API.</li>
<li><tt>?</tt> - An any character.</li>
<li><tt>???</tt> - Any string in length of three characters.</li>
<li><tt>*</tt> - Any string in length of zero or longer.</li>
<li><tt>????*</tt> - Any string in length of four characters or longer.</li>
</ul>
<p>Since the matching algorithm uses recursion, number of wildcard terms in the matching pattern is limited to four. Any pattern with too many wildcard terms does not match any name. In LFN configuration, only <tt>fname[]</tt> is tested when <tt>FF_USE_FIND == 1</tt> and also <tt>altname[]</tt> is tested when <tt>FF_USE_FIND == 2</tt>. There are some differences listed below between FatFs and standard systems in matching condition.</p>
<ul>
<li><tt>"*.*"</tt> never matches any name without extension while it matches any name with or without extension in standard systems.</li>
<li>Any pattern terminated with a period never matches any name while it matches the name without extensiton in standard systems.</li>
<li><a href="filename.html#case">DBCS extended characters</a> are compared in case-sensitive when LFN is enabled with ANSI/OEM API.</li>
</ul>
</div>
@@ -85,13 +92,13 @@ FRESULT f_findfirst (
void find_image_file (void)
{
FRESULT fr; <span class="c">/* Return value */</span>
DIR dj; <span class="c">/* Directory search object */</span>
DIR dj; <span class="c">/* Directory object */</span>
FILINFO fno; <span class="c">/* File information */</span>
fr = <em>f_findfirst</em>(&amp;dj, &amp;fno, "", "dsc*.jpg"); <span class="c">/* Start to search for photo files */</span>
fr = <em>f_findfirst</em>(&amp;dj, &amp;fno, "", "dsc*.jp*"); <span class="c">/* Start to search for photo files */</span>
while (fr == FR_OK &amp;&amp; fno.fname[0]) { <span class="c">/* Repeat while an item is found */</span>
printf("%s\n", fno.fname); <span class="c">/* Display the object name */</span>
printf("%s\n", fno.fname); <span class="c">/* Print the object name */</span>
fr = f_findnext(&amp;dj, &amp;fno); <span class="c">/* Search for next item */</span>
}
documents/doc/forward.html
+1 -1
View File
@@ -65,7 +65,7 @@ FRESULT f_forward (
<div class="para use">
<h4>Example (Audio playback)</h4>
<h4>Example</h4>
<pre>
<span class="c">/*------------------------------------------------------------------------*/</span>
<span class="c">/* Sample code of data transfer function to be called back from f_forward */</span>
documents/doc/getlabel.html
+1 -1
View File
@@ -34,7 +34,7 @@ FRESULT f_getlabel (
<tr><td>Configuration</td><td>FF_FS_EXFAT == 0</td><td>FF_FS_EXFAT == 1</td></tr>
<tr><td>FF_USE_LFN == 0</td><td>12 items</td><td>-</td></tr>
<tr><td>FF_LFN_UNICODE == 0</td><td>12 items</td><td>23 items</td></tr>
<tr><td>FF_LFN_UNICODE == 1/3</td><td>12 items</td><td>12 items</td></tr>
<tr><td>FF_LFN_UNICODE == 1,3</td><td>12 items</td><td>12 items</td></tr>
<tr><td>FF_LFN_UNICODE == 2</td><td>34 items</td><td>34 items</td></tr>
</table>
</dd>
documents/doc/lseek.html
+13 -5
View File
@@ -21,6 +21,11 @@ FRESULT f_lseek (
FSIZE_t <span class="arg">ofs</span> <span class="c">/* [IN] File read/write pointer */</span>
);
</pre>
<pre>
FRESULT f_rewind (
FIL* <span class="arg">fp</span>, <span class="c">/* [IN] File object */</span>
);
</pre>
</div>
<div class="para arg">
@@ -48,14 +53,17 @@ FRESULT f_lseek (
<div class="para desc">
<h4>Description</h4>
<p>File read/write ponter in the open file object points the data byte to be read/written at next read/write operation. It advances as the number of bytes read/written. The <tt>f_lseek</tt> function moves the file read/write pointer without any read/write operation to the file.</p>
<p>When an offset beyond the file size is specified at write mode, the file size is expanded to the specified offset. The file data in the expanded area is <em>undefined</em> because no data is written to the file in this process. This is suitable to pre-allocate a data area to the file quickly for fast write operation. When a contiguous data area needs to be allocated to the file, use <tt>f_expand</tt> function instead. After the <tt>f_lseek</tt> function succeeded, the current read/write pointer should be checked in order to make sure the read/write pointer has been moved correctry. In case of the read/write pointer is not the expected value, either of followings has been occured.</p>
<p>File read/write ponter in the open file object points the data byte to be read/written at next read/write operation. It advances as the number of bytes read/written. The <tt>f_lseek</tt> function moves the file read/write pointer without any read/write operation to the file. The <tt>f_rewind</tt> function is impremented as a macro.</p>
<pre>
#define <em>f_rewind</em>(fp) f_lseek((fp), 0)
</pre>
<p>If an offset beyond the file size is specified in write mode, the file size is expanded to the specified offset. The file data in the expanded part is <em>undefined</em> because no data is written to the file in this process. This is suitable to pre-allocate a data area to the file quickly for fast write operation. When a contiguous data area needs to be allocated to the file, use <tt>f_expand</tt> function instead. After the <tt>f_lseek</tt> function succeeded, the current read/write pointer should be checked in order to make sure the read/write pointer has been moved correctry. In case of the read/write pointer is not the expected value, either of followings has been occured.</p>
<ul>
<li>End of file. The specified <tt class="arg">ofs</tt> was clipped at end of the file because the file has been opened in read-only mode.</li>
<li>Disk full. There is no free space on the volume to expand the file.</li>
</ul>
<p>The fast seek feature enables fast backward/long seek operations without FAT access by using an on-memory CLMT (cluster link map table). It is applied to <tt>f_read</tt> and <tt>f_write</tt> function as well, however, the file size cannot be expanded by <tt>f_write</tt>, <tt>f_lseek</tt> function while the file is at fast seek mode.</p>
<p>The fast seek mode is enabled when the member <tt>cltbl</tt> in the file object is not NULL. The CLMT must be created into the <tt>DWORD</tt> array prior to use the fast seek. To create the CLMT, set address of the <tt>DWORD</tt> array to the member <tt>cltbl</tt> in the open file object, set the size of array in unit of items to the first item and call the <tt>f_lseek</tt> function with <tt class="arg">ofs</tt><tt> = CREATE_LINKMAP</tt>. After the function succeeded and CLMT is created, no FAT access is occured in subsequent <tt>f_read</tt>, <tt>f_write</tt>, <tt>f_lseek</tt> function to the file. The number of items used or required is returned into the first item of the array. The number of items to be used is (number of the file fragments + 1) * 2. For example, when the file is fragmented in 5, 12 items in the array will be used. If the function failed with <tt>FR_NOT_ENOUGH_CORE</tt>, the given array size is insufficient for the file.</p>
<p>The fast seek mode is enabled when <tt>FF_USE_FASTSEEK = 1</tt>. The CLMT must be created into the <tt>DWORD</tt> array prior to use the fast seek mode. To create the CLMT, set address of the <tt>DWORD</tt> array to the member <tt>cltbl</tt> in the open file object, set the size of array in unit of items to the <tt>cltbl[0]</tt> and then call <tt>f_lseek</tt> function with <tt class="arg">ofs</tt><tt> = CREATE_LINKMAP</tt>. After the function succeeded, no FAT access is occured in subsequent <tt>f_read</tt>, <tt>f_write</tt>, <tt>f_lseek</tt> function to the file. The number of items used or required is returned into the <tt>cltbl[0]</tt>. The number of items needed is (number of the file fragments + 1) * 2. For example, 12 items in the array will be used for the file fragmented in 5 portions. If the function failed with <tt>FR_NOT_ENOUGH_CORE</tt>, the size of given array is insufficient for the file.</p>
</div>
@@ -103,7 +111,7 @@ FRESULT f_lseek (
res = f_close(fp);
</pre>
<pre>
<span class="c">/* Using fast seek function */</span>
<span class="c">/* Using fast seek mode */</span>
DWORD clmt[SZ_TBL]; <span class="c">/* Cluster link map table buffer */</span>
@@ -111,7 +119,7 @@ FRESULT f_lseek (
res = <em>f_lseek</em>(fp, ofs1); <span class="c">/* This is normal seek (cltbl is nulled on file open) */</span>
fp-&gt;cltbl = clmt; <span class="c">/* Enable fast seek function (cltbl != NULL) */</span>
fp-&gt;cltbl = clmt; <span class="c">/* Enable fast seek mode (cltbl != NULL) */</span>
clmt[0] = SZ_TBL; <span class="c">/* Set table size */</span>
res = <em>f_lseek</em>(fp, CREATE_LINKMAP); <span class="c">/* Create CLMT */</span>
...
documents/doc/mkfs.html
+19 -18
View File
@@ -13,13 +13,13 @@
<div class="para func">
<h2>f_mkfs</h2>
<p>The f_mkfs fucntion creates an FAT/exFAT volume on the logical drive.</p>
<p>The f_mkfs function creates an FAT/exFAT volume on the logical drive.</p>
<pre>
FRESULT f_mkfs (
const TCHAR* <span class="arg">path</span>, <span class="c">/* [IN] Logical drive number */</span>
const MKFS_PARM <span class="arg">opt</span>,<span class="c">/* [IN] Format options */</span>
void* <span class="arg">work</span>, <span class="c">/* [-] Working buffer */</span>
UINT <span class="arg">len</span> <span class="c">/* [IN] Size of working buffer */</span>
const TCHAR* <span class="arg">path</span>, <span class="c">/* [IN] Logical drive number */</span>
const MKFS_PARM* <span class="arg">opt</span>,<span class="c">/* [IN] Format options */</span>
void* <span class="arg">work</span>, <span class="c">/* [-] Working buffer */</span>
UINT <span class="arg">len</span> <span class="c">/* [IN] Size of working buffer */</span>
);
</pre>
</div>
@@ -28,25 +28,25 @@ FRESULT f_mkfs (
<h4>Parameters</h4>
<dl class="par">
<dt>path</dt>
<dd>Pointer to the null-terminated string specifies the <a href="filename.html">logical drive</a> to be formatted. If it has no drive number in it, it means to specify the default drive. The logical drive may or may not be mounted for the format process.</dd>
<dd>Pointer to the null-terminated string specifies the <a href="filename.html">logical drive</a> to be formatted. If it does not have a drive number in it, it means to specify the default drive. The logical drive may or may not have been mounted for the format process.</dd>
<dt>opt</dt>
<dd>Specifies the structure holding format options. If a null pointer is given, it gives the function all options in default value. The format option structure has five members described below:<br>
<dd>Specifies the structure that is holding format options. If a null pointer is given, it gives the function all options in default value. The format option structure has five members described below:<br>
<dl class="par">
<dt>BYTE fmt</dt>
<dd>Specifies combination of FAT type flags, <tt>FM_FAT</tt>, <tt>FM_FAT32</tt>, <tt>FM_EXFAT</tt> and bitwise-or of these three, <tt>FM_ANY</tt>. <tt>FM_EXFAT</tt> is ignored when exFAT is not enabled. These flags specify which FAT type to be created on the volume. If two or more types are specified, one out of them will be selected depends on the volume size and <tt class="arg">au_size</tt>. The flag <tt>FM_SFD</tt> specifies to create the volume on the drive in SFD format. The default value is <tt>FM_ANY</tt>.</dd>
<dt>DWORD au_size</dt>
<dd>Specifies size of the allocation unit (cluter) in unit of byte. The valid value is power of 2 between the sector size and 128 * sector size inclusive for FAT/FAT32 volume and up to 16 MB for exFAT volume. If a zero (also default value) or any invalid value is given, the default allocation unit size depends on the volume size is used.</dd>
<dd>Specifies size of the allocation unit (cluter) in unit of byte. The valid value is power of 2 between sector size and 128 * sector size inclusive for FAT/FAT32 volume and up to 16 MB for exFAT volume. If a zero (the default value) or any invalid value is given, the default allocation unit size depends on the volume size is used.</dd>
<dt>UINT n_align</dt>
<dd>Specifies alignment of the volume data area (file allocation pool, usually erase block boundary of flash media) in unit of sector. The valid value for this member is between 1 and 32768 inclusive in power of 2. If a zero (also default value) and any invalid value is given, the function obtains the block size from lower layer via <tt>disk_ioctl</tt> function.</dd>
<dd>Specifies alignment of the volume data area (file allocation pool, usually erase block boundary of flash media) in unit of sector. The valid value for this member is between 1 and 32768 inclusive in power of 2. If a zero (the default value) or any invalid value is given, the function obtains the block size from lower layer with <tt>disk_ioctl</tt> function.</dd>
<dt>BYTE n_fat</dt>
<dd>Specifies number of FAT copies on the FAT/FAT32 volume. Valid value for this member is 1 or 2. The default value (0) and any invaid value is considered as 1. If the FAT type is exFAT, this value has no effect.</dd>
<dd>Specifies number of FAT copies on the FAT/FAT32 volume. Valid value for this member is 1 or 2. The default value (0) and any invaid value gives 1. If the FAT type is exFAT, this member has no effect.</dd>
<dt>UINT n_root</dt>
<dd>Specifies number of root directory entries on the FAT volume. Valid value for this member is up to 32768 and aligned to sector size / 32. The default value (0) and any invaid value is considered as 512. If the FAT type is FAT32 or exFAT, this value has no effect.</dd>
<dd>Specifies number of root directory entries on the FAT volume. Valid value for this member is up to 32768 and aligned to sector size / 32. The default value (0) and any invaid value gives 512. If the FAT type is FAT32 or exFAT, this member has no effect.</dd>
</dl>
<dt>work</dt>
<dd>Pointer to the working buffer used for the format process. When a null pointer is given with <tt><a href="config.html#use_lfn">FF_USE_LFN</a> == 3</tt>, the function obtains a memory block in this function for the working buffer.</dd>
<dt>len</dt>
<dd>Size of the working buffer in unit of byte. It needs to be the sector size of the corresponding physical drive at least. Plenty of working buffer reduces number of write transactions to the drive and the format process will finish quickly.</dd>
<dd>Size of the working buffer in unit of byte. It needs to be <tt>FF_MAX_SS</tt> at least. Plenty of working buffer reduces number of write transactions to the drive and the format process will finish quickly.</dd>
</dl>
</div>
@@ -66,11 +66,12 @@ FRESULT f_mkfs (
<div class="para desc">
<h4>Description</h4>
<p>The FAT sub-type, FAT12/FAT16/FAT32, of FAT volume except exFAT is determined by only number of clusters on the volume and nothing else, according to the FAT specification issued by Microsoft. Thus the FAT sub-type of created volume depends on the volume size and the cluster size. In case of the combination of FAT type and cluter size specified by argument cannot be valid on the volume, the function will fail with <tt>FR_MKFS_ABORTED</tt>.</p>
<p>The allocation unit, also called <em>cluster</em>, is a unit of disk space allocation for files. When the size of allocation unit is 32768 bytes, a file with 100 bytes in size occupies 32768 bytes of disk space. The space efficiency of disk usage gets worse as increasing size of allocation unit, but, on the other hand, the read/write performance increases as the size of allocation unit. Therefore the size of allocation unit is a trade-off between space efficiency and performance. For the large storages in GB order, 32768 bytes or larger (this is automatically selected by default) is recommended for most case unless extremely many small files are created on a volume.</p>
<p>When the logical drive to be formatted is associated with a physical drive, this is the default setting, and <tt>FM_SFD</tt> flag is not specified, a partition occupies whole drive space is created and then the FAT volume is created in the partition. When <tt>FM_SFD</tt> flag is specified, the FAT volume is created without any partitioing.</p>
<p>When the logical drive to be formatted is associated with a specific partition by multiple partition feature (<tt><a href="config.html#multi_partition">FF_MULTI_PARTITION</a> == 1</tt>), the FAT volume is created on the partition specified by the <a href="filename.html#vol">volume mapping table</a> and <tt>FM_SFD</tt> flag is ignored. The physical drive needs to be partitioned with <tt>f_fdisk</tt> function or any partitioning tool prior to create the FAT volume with this function.</p>
<p>There are three disk partitioning formats, MBR, SFD and GPT. The MBR format (also known as FDISK format) is usually used for harddisk, memory card and U disk. It can divide a physical drive into one or more partitions with a partition table. The GPT (GUID Partition Table) is a newly defined patitioning format for large storage devices. FatFs suppors the GPT only if 64-bit LBA is enabled. The SFD (super-floppy disk) is non-partitioned disk format. The FAT volume occupies from LBA 0 of the physical drive without any partitioning. It is usually used for floppy disk, optical disk and most super-floppy media. Some systems support only either one of the two formats, partitioned or non-partitioned, and the other is not supported.</p>
<p>The FAT sub-type, FAT12/FAT16/FAT32, of FAT volume except exFAT is determined by only number of clusters on the volume and nothing else, according to the FAT specification issued by Microsoft. Thus the FAT sub-type of created volume depends on the volume size and the cluster size. In case of the combination of FAT type and cluter size specified by argument is not valid for the volume size, the function will fail with <tt>FR_MKFS_ABORTED</tt>.</p>
<p>The allocation unit, also known as <em>cluster</em>, is a unit of disk space allocation for files. When the size of allocation unit is 32768 bytes, a file with 100 bytes in size occupies 32768 bytes of disk space. The space efficiency of disk usage gets worse as increasing size of allocation unit, but, on the other hand, the read/write performance increases. Therefore the size of allocation unit is a trade-off between space efficiency and performance. For the large volumes in GB order, 32768 bytes or larger, automatically selected by default, is recommended for most case unless extremely many small files are created in the volume.</p>
<p>When the logical drive to be formatted is associated with a physical drive (<tt><a href="config.html#multi_partition">FF_MULTI_PARTITION</a> = 0</tt>) and <tt>FM_SFD</tt> flag is not specified, a partition occupies entire disk space is created and then the FAT volume is created in the partition. When <tt>FM_SFD</tt> flag is specified, the FAT volume is created without any disk partitioning.</p>
<p>When the logical drive to be formatted is associated with a specific partition by multiple partition feature (<tt>FF_MULTI_PARTITION = 1</tt>), the FAT volume is created in the partition of the drive specified by <a href="filename.html#vol">volume mapping table</a> and <tt>FM_SFD</tt> flag is ignored. The corresponding physical drive needs to be partitioned with <tt>f_fdisk</tt> function or any partitioning tool prior to create the FAT volume with this function.</p>
<p>There are three standard disk partitioning formats, MBR, GPT and SFD. The MBR format, also known as FDISK format, is usually used for harddisk, memory card and U disk. It can divide a physical drive into one or more partitions with a partition table. The GPT (GUID Partition Table) is a newly defined patitioning format for large storage devices. FatFs suppors the GPT only when 64-bit LBA is enabled. SFD (Super-Floppy Disk) is non-partitioned disk format. The FAT volume occupies the entire physical drive without any disk partitioning. It is usually used for floppy disk, optical disk and most super-floppy media. Some combination of systems and media support only either partitioned format or non-partitioned format and the other is not supported.</p>
<p>Some systems manage the partitions in the on-board storage in non-standard format. The partitions are mapped as physical drives identified by <tt class="arg">pdrv</tt> in <tt>disk_*</tt> functions. For such systems, SFD format is suitable to create the FAT volume in the partition.</p>
</div>
<div class="para comp">
@@ -95,7 +96,7 @@ int main (void)
res = <em>f_mkfs</em>("", 0, work, sizeof work);
if (res) ...
<span class="c">/* Register work area */</span>
<span class="c">/* Give a work area to the default drive */</span>
f_mount(&amp;fs, "", 0);
<span class="c">/* Create a file as new */</span>
documents/doc/mount.html
+12 -3
View File
@@ -13,7 +13,7 @@
<div class="para func">
<h2>f_mount</h2>
<p>The f_mount fucntion registers/unregisters filesystem object to the FatFs module.</p>
<p>The f_mount fucntion gives work area to the FatFs module.</p>
<pre>
FRESULT f_mount (
FATFS* <span class="arg">fs</span>, <span class="c">/* [IN] Filesystem object */</span>
@@ -21,6 +21,11 @@ FRESULT f_mount (
BYTE <span class="arg">opt</span> <span class="c">/* [IN] Initialization option */</span>
);
</pre>
<pre>
FRESULT f_unmount (
const TCHAR* <span class="arg">path</span>, <span class="c">/* [IN] Logical drive number */</span>
);
</pre>
</div>
<div class="para arg">
@@ -50,7 +55,7 @@ FRESULT f_mount (
<div class="para desc">
<h4>Description</h4>
<p>FatFs requires work area (<em>filesystem object</em>) for each logical drives (FAT volumes). Prior to perform any file/directory operations, a filesystem object needs to be registered with <tt>f_mount</tt> function to the logical drive. The file/directory API functions get ready to work after this procedure. If there is any open object of file or directory on the logical drive, the object will be invalidated by this function. Some management functions, <tt>f_mkfs</tt>, <tt>f_fdisk</tt> and <tt>f_setcp</tt>, do not want a filesystem object.</p>
<p>FatFs requires work area (<em>filesystem object</em>) for each logical drives (FAT volumes). Prior to perform any file/directory operations, a filesystem object needs to be registered with <tt>f_mount</tt> function for the logical drive. The file/directory API functions get ready to work after this procedure. Some volume management functions, <tt>f_mkfs</tt>, <tt>f_fdisk</tt> and <tt>f_setcp</tt>, do not want a filesystem object.</p>
<p>The <tt>f_mount</tt> function registers/unregisters a filesystem object to the FatFs module as follows:</p>
<ol>
<li>Determines the logical drive which specified by <tt class="arg">path</tt>.</li>
@@ -58,6 +63,7 @@ FRESULT f_mount (
<li>Clears and registers the new work area to the volume if <tt class="arg">fs</tt> is not NULL.</li>
<li>Performs volume mount process to the volume if forced mounting is specified.</li>
</ol>
<p>If there is any open object of file or directory on the logical drive, the object will be invalidated by this function.</p>
<p>If forced mounting is not specified (<tt>opt = 0</tt>), this function always succeeds regardless of the physical drive status. It only clears (de-initializes) the given work area and registers its address to the internal table and no activity of the physical drive in this function. The volume mount process will be attempted on subsequent file/directroy function if the filesystem object is not initialized. (delayed mounting) The volume mount processes, initialize the corresponding physical drive, find the FAT volume in it and then initialize the work area, is performed in the subsequent file/directory functions when either of following conditions is true.</p>
<ul>
<li>Filesystem object has not been initialized. It is de-initialized by <tt>f_mount</tt> function.</li>
@@ -65,7 +71,10 @@ FRESULT f_mount (
</ul>
<p>If the function with forced mounting (<tt>opt = 1</tt>) failed with <tt>FR_NOT_READY</tt>, it means that the filesystem object has been registered successfully but the volume is currently not ready to work. The volume mount process will be attempted on subsequent file/directroy function.</p>
<p>If implementation of the disk I/O layer lacks asynchronous media change detection, application program needs to perform <tt>f_mount</tt> function after each media change to force cleared the filesystem object.</p>
<p>To unregister the work area, specify a NULL to the <tt class="arg">fs</tt>, and then the work area can be discarded.</p>
<p>To unregister the work area, specify a NULL to the <tt class="arg">fs</tt>, and then the work area can be discarded. <tt>f_unmount</tt> function is implemented as a macro.</p>
<pre>
#define <em>f_unmount</em>(path) f_mount(0, path, 0)
</pre>
</div>
documents/doc/open.html
+9 -9
View File
@@ -42,7 +42,7 @@ FRESULT f_open (
<tr><td>FA_OPEN_ALWAYS</td><td>Opens the file if it is existing. If not, a new file will be created.</td></tr>
<tr><td>FA_OPEN_APPEND</td><td>Same as <tt>FA_OPEN_ALWAYS</tt> except the read/write pointer is set end of the file.</td></tr>
</table>
Mode flags of POSIX fopen() corresponds to FatFs mode flags as follows:<br>
Mode flags in POSIX fopen() function corresponds to FatFs mode flags as follows:<br>
<table class="lst2">
<tr><th>POSIX</th><th>FatFs</th></tr>
<tr><td>"r"</td><td>FA_READ</td></tr>
@@ -111,7 +111,7 @@ int main (void)
FRESULT fr; <span class="c">/* FatFs return code */</span>
<span class="c">/* Register work area to the default drive */</span>
<span class="c">/* Gives a work area to the default drive */</span>
f_mount(&amp;FatFs, "", 0);
<span class="c">/* Open a text file */</span>
@@ -141,7 +141,7 @@ int main (void)
UINT br, bw; <span class="c">/* File read/write count */</span>
<span class="c">/* Register work area for each logical drive */</span>
<span class="c">/* Gives work area to each logical drive */</span>
f_mount(&amp;fs0, "0:", 0);
f_mount(&amp;fs1, "1:", 0);
@@ -155,10 +155,10 @@ int main (void)
<span class="c">/* Copy source to destination */</span>
for (;;) {
fr = f_read(&amp;fsrc, buffer, sizeof buffer, &amp;br); <span class="c">/* Read a chunk of source file */</span>
if (fr || br == 0) break; <span class="c">/* error or eof */</span>
fr = f_write(&amp;fdst, buffer, br, &amp;bw); <span class="c">/* Write it to the destination file */</span>
if (fr || bw &lt; br) break; <span class="c">/* error or disk full */</span>
f_read(&amp;fsrc, buffer, sizeof buffer, &amp;br); <span class="c">/* Read a chunk of data from the source file */</span>
if (br == 0) break; <span class="c">/* error or eof */</span>
f_write(&amp;fdst, buffer, br, &amp;bw); <span class="c">/* Write it to the destination file */</span>
if (bw &lt; br) break; <span class="c">/* error or disk full */</span>
}
<span class="c">/* Close open files */</span>
@@ -166,8 +166,8 @@ int main (void)
f_close(&amp;fdst);
<span class="c">/* Unregister work area prior to discard it */</span>
f_mount(0, "0:", 0);
f_mount(0, "1:", 0);
f_unmount("0:");
f_unmount("1:");
return (int)fr;
}
documents/doc/printf.html
+6 -5
View File
@@ -39,7 +39,7 @@ int f_printf (
<div class="para ret">
<h4>Return Values</h4>
<p>When the string was written successfuly, it returns number of character encoding units written to the file. When the function failed due to disk full or any error, an <tt>EOF (-1)</tt> will be returned.</p>
<p>When the string was written successfuly, it returns number of character encoding units written to the file. When the function failed due to disk full or any error, a negative value will be returned.</p>
</div>
@@ -47,12 +47,13 @@ int f_printf (
<h4>Description</h4>
<p>The format control directive is a sub-set of standard library shown as follows:</p>
<pre>
%[flag][width][type]
%[flag][width][prefix][type]
</pre>
<dl>
<dt>flag</dt><dd>Padding options. A <tt>-</tt> specifies left justified. A <tt>0</tt> specifies zero padded.</dd>
<dt>width</dt><dd>Minimum width of the field, <tt>1-99</tt> or <tt>*</tt>. If the width of generated string is less than the specified value, rest field is padded with white spaces or zeros. An <tt>*</tt> specifies the value comes from an argument in int type.</dd>
<dt>type</dt><dd><tt>c s d u o x b</tt> and prefix <tt>l</tt> specify type of the argument, character, string, signed integer in decimal, unsigned integer in decimal, unsigned integer in octal, unsigned integer in hexdecimal and unsigned integer in binary respectively. If <tt>sizeof (long)</tt> is greater than <tt>sizeof (int)</tt> (this is typical of 8/16-bit systems), a prefix <tt>l</tt> needs to be explicitly specified for long integer argument. These characters except for <tt>x</tt> are case insensitive.</dd>
<dt>flag</dt><dd>Padding options. A <tt>'0'</tt> specifies zero padded. A <tt>'-'</tt> specifies left justified.</dd>
<dt>width</dt><dd>Minimum width of the field, <tt>'1'-'99'</tt> or <tt>'*'</tt>. If the width of generated string is less than the specified value, rest field is padded with white spaces or zeros. An <tt>*</tt> specifies the value comes from an argument in int type. The default value is zero.</dd>
<dt>prefix</dt><dd>Size prefix <tt>'l'</tt> for long integer argument. If <tt>sizeof (long) == sizeof (int)</tt> (this is typical of 32-bit systems), the size prefix can be omitted.</dd>
<dt>type</dt><dd><tt>'c','s','d','u','o','x','b'</tt>, specify type of the argument and output format, character, string, signed integer in decimal, unsigned integer in decimal, unsigned integer in octal, unsigned integer in hexdecimal and unsigned integer in binary respectively. These characters except <tt>'x'</tt> are case insensitive. An <tt>'X'</tt> generates a hexdecimal in up-case.</dd>
</dl>
<p>When FatFs is configured for Unicode API (<tt><a href="config.html#lfn_unicode">FF_LFN_UNICODE</a> &gt;= 1</tt>), character encoding on the string fuctions, <tt>f_putc</tt>, <tt>f_puts</tt>, <tt>f_printf</tt> and <tt>f_gets</tt> function, is also switched to Unicode. The Unicode characters in multiple encoding unit, such as surrogate pair and multi-byte sequence, should not be divided into two function calls, or the character will be lost. The character encoding <em>on the file</em> to be written via this function is selected by <tt><a href="config.html#strf_encode">FF_STRF_ENCODE</a></tt>. The characters with wrong encoding or invalid for the output encoding will be lost.</p>
</div>
documents/doc/putc.html
+1 -1
View File
@@ -35,7 +35,7 @@ int f_putc (
<div class="para ret">
<h4>Return Values</h4>
<p>When the character was written successfuly, it returns number of character encoding units written to the file. When the function failed due to disk full or any error, an <tt>EOF (-1)</tt> will be returned.</p>
<p>When the character was written successfuly, it returns number of character encoding units written to the file. When the function failed due to disk full or any error, a negative value will be returned.</p>
</div>
documents/doc/puts.html
+1 -1
View File
@@ -35,7 +35,7 @@ int f_puts (
<div class="para ret">
<h4>Return Value</h4>
<p>When the string was written successfuly, it returns number of character encoding units written to the file. When the function failed due to disk full or any error, an EOF (-1) will be returned.</p>
<p>When the string was written successfuly, it returns number of character encoding units written to the file. When the function failed due to disk full or any error, a negative value will be returned.</p>
</div>
documents/doc/read.html
+8 -2
View File
@@ -34,7 +34,7 @@ FRESULT f_read (
<dt>btr</dt>
<dd>Number of bytes to read in range of <tt>UINT</tt> type.</dd>
<dt>br</dt>
<dd>Pointer to the <tt>UINT</tt> variable that receives number of bytes read. This value is always valid after the function call regardless of the function return code.</dd>
<dd>Pointer to the <tt>UINT</tt> variable that receives number of bytes read. This value is always valid after the function call regardless of the function return code. If the return value is equal to <tt class="arg">btr</tt>, the function return code should be <tt>FR_OK</tt>.</dd>
</dl>
</div>
@@ -54,7 +54,7 @@ FRESULT f_read (
<div class="para desc">
<h4>Description</h4>
<p>The function starts to read data from the file at the position pointed by the read/write pointer. The read/write pointer advances as number of bytes read. After the function succeeded, <tt class="arg">*br</tt> should be checked to detect end of the file. In case of <tt class="arg">*br</tt> &lt; <tt class="arg">btr</tt>, it means the read/write pointer reached end of the file during read operation.</p>
<p>The function starts to read data from the file at the file offset pointed by read/write pointer. The read/write pointer advances as number of bytes read. After the function succeeded, <tt class="arg">*br</tt> should be checked to detect end of the file. In case of <tt class="arg">*br</tt> &lt; <tt class="arg">btr</tt>, it means the read/write pointer reached end of the file during read operation.</p>
</div>
@@ -64,6 +64,12 @@ FRESULT f_read (
</div>
<div class="para use">
<h4>Example</h4>
<p>Refer to the example in <tt>f_open</tt>.</p>
</div>
<div class="para ref">
<h4>See Also</h4>
<p><tt><a href="open.html">f_open</a>, <a href="gets.html">fgets</a>, <a href="write.html">f_write</a>, <a href="close.html">f_close</a>, <a href="sfile.html">FIL</a></tt></p>
documents/doc/readdir.html
+16 -7
View File
@@ -20,6 +20,11 @@ FRESULT f_readdir (
FILINFO* <span class="arg">fno</span> <span class="c">/* [OUT] File information structure */</span>
);
</pre>
<pre>
FRESULT f_rewinddir (
DIR* <span class="arg">dp</span>, <span class="c">/* [IN] Directory object */</span>
);
</pre>
</div>
<div class="para arg">
@@ -48,15 +53,19 @@ FRESULT f_readdir (
<div class="para desc">
<h4>Description</h4>
<p>The <tt>f_readdir</tt> function reads a directory item, informations about the object. Items in the directory can be read in sequence by <tt>f_readdir</tt> function calls. Dot entries (<tt>"."</tt> and <tt>".."</tt>) in the sub-directory are filtered out and they will never appear in the read items. When all directory items have been read and no item to read, a null string is stored into the <tt>fno-&gt;fname[]</tt> without any error. When a null pointer is given to the <tt class="arg">fno</tt>, the read index of the directory object is rewinded.</p>
<p>When support of long file name (LFN) is enabled, a member <tt>altname[]</tt> is defined in the file information structure to store the short file name of the object. If the long file name is not accessible due to some reason listed below, short file name is stored to the <tt>fname[]</tt> and <tt>altname[]</tt> has a null string.</p>
<p>The <tt>f_readdir</tt> function reads a directory item, informations about the object. Items in the directory can be read in sequence by <tt>f_readdir</tt> function calls. When all items in the directory have been read and no item to read, a null string is stored into the <tt>fno-&gt;fname[]</tt> without any error. When a null pointer is given to the <tt class="arg">fno</tt>, the read index of the directory object is rewinded. The <tt>f_rewinddir</tt> function is implemented as a macro.</p>
<pre>
#define <em>f_rewinddir</em>(dp) f_readdir((dp), 0)
</pre>
<p>When LFN is enabled, a member <tt>altname[]</tt> is defined in the file information structure to store the short file name of the object. If the long file name is not accessible due to some reason listed below, short file name is stored to the <tt>fname[]</tt> and <tt>altname[]</tt> has a null string.</p>
<ul>
<li>The item has no LFN. (Not the case at exFAT volume)</li>
<li>Setting of <a href="config.html#max_lfn"><tt>FF_MAX_LFN</tt></a> is insufficient to handle the LFN. (Not the case at <tt>FF_MAX_LFN == 255</tt>)</li>
<li>Setting of <a href="config.html#lfn_buf"><tt>FF_LFN_BUF</tt></a> is insufficient to store the LFN.</li>
<li>The LFN contains some character not defined in current code page. (Not the case at <tt>FF_LFN_UNICODE &gt;= 1</tt>)</li>
<li>The item has no LFN. (Not the case in exFAT volume)</li>
<li><a href="config.html#max_lfn"><tt>FF_MAX_LFN</tt></a> is insufficient to handle the LFN. (Not the case in <tt>FF_MAX_LFN == 255</tt>)</li>
<li><a href="config.html#lfn_buf"><tt>FF_LFN_BUF</tt></a> is insufficient to output the LFN.</li>
<li>The LFN contains some character not defined in current CP. (Not the case in <tt>FF_LFN_UNICODE != 0</tt>)</li>
</ul>
<p>There is a problem on reading a directory of exFAT volume. The exFAT does not support short file name. This means no name can be returned on the condition above. If it is the case, "?" is returned into the <tt>fname[]</tt> to indicate that the object is not accessible. To avoid this problem, configure FatFs <tt><a href="config.html#lfn_unicode">FF_LFN_UNICODE</a> &gt;= 1</tt> and <tt>FF_MAX_LFN == 255</tt> to support the full feature of LFN specification.</p>
<p>There is a problem on read a directory of exFAT volume. The exFAT does not support short file name. This means no name can be returned on the condition above. If it is the case, "?" is returned as the file name to indicate that the object is not accessible. To avoid this problem, configure FatFs <tt><a href="config.html#lfn_unicode">FF_LFN_UNICODE</a> != 0</tt> and <tt>FF_MAX_LFN == 255</tt> to support the full feature of LFN specification.</p>
<p>Dot entries (<tt>"."</tt> and <tt>".."</tt>) in the sub-directory of FAT volume are filtered out and they will never appear in the read items because exFAT lacks dot entries in the sub-directory.</p>
</div>
documents/doc/sfileinfo.html
+1 -1
View File
@@ -68,7 +68,7 @@
</table>
</dd>
<dt>fname[]</dt>
<dd>Null-terminated object name. A null string is stored when no item to read and it indicates this structure is invalid. The size of <tt>fname[]</tt> and <tt>altname[]</tt> each can be configured at LFN configuration.</dd>
<dd>Null-terminated object name. A null string is stored when no item to read and it indicates this structure is invalid. The size of <tt>fname[]</tt> and <tt>altname[]</tt> each can be configured in LFN configuration.</dd>
<dt>altname[]</dt>
<dd>Alternative object name is stored if available. This member is not available in non-LFN configuration.</dd>
</dl>
documents/doc/write.html
+8 -2
View File
@@ -34,7 +34,7 @@ FRESULT f_write (
<dt>btw</dt>
<dd>Specifies number of bytes to write in range of <tt>UINT</tt> type.</dd>
<dt>bw</dt>
<dd>Pointer to the <tt>UINT</tt> variable that receives the number of bytes written. This value is always valid after the function call regardless of the function return code.</dd>
<dd>Pointer to the <tt>UINT</tt> variable that receives the number of bytes written. This value is always valid after the function call regardless of the function return code. If the return value is equal to <tt class="arg">btw</tt>, the function return code should be <tt>FR_OK</tt>.</dd>
</dl>
</div>
@@ -54,7 +54,7 @@ FRESULT f_write (
<div class="para desc">
<h4>Description</h4>
<p>The function starts to write data to the file at the position pointed by the read/write pointer. The read/write pointer advances as number of bytes written. After the function succeeded, <tt class="arg">*bw</tt> should be checked to detect the disk full. In case of <tt class="arg">*bw</tt> &lt; <tt class="arg">btw</tt>, it means the volume got full during the write operation. The function can take a time when the volume is full or close to full.</p>
<p>The function starts to write data to the file at the file offset pointed by read/write pointer. The read/write pointer advances as number of bytes written. After the function succeeded, <tt class="arg">*bw</tt> should be checked to detect the disk full. In case of <tt class="arg">*bw</tt> &lt; <tt class="arg">btw</tt>, it means the volume got full during the write operation. The function can take a time when the volume is full or close to full.</p>
</div>
@@ -64,6 +64,12 @@ FRESULT f_write (
</div>
<div class="para use">
<h4>Example</h4>
<p>Refer to the example in <tt>f_open</tt>.</p>
</div>
<div class="para ref">
<h4>See Also</h4>
<p><tt><a href="open.html">f_open</a>, <a href="read.html">f_read</a>, <a href="putc.html">fputc</a>, <a href="puts.html">fputs</a>, <a href="printf.html">fprintf</a>, <a href="close.html">f_close</a>, <a href="sfile.html">FIL</a></tt></p>
documents/res/app5.c
+1 -1
View File
@@ -21,7 +21,7 @@ FRESULT test_contiguous_file (
#else
clsz = (DWORD)fp->obj.fs->csize * fp->obj.fs->ssize;
#endif
fsz = fp->obj.objsize;
fsz = f_size(fp);
if (fsz > 0) {
clst = fp->obj.sclust - 1; /* A cluster leading the first cluster for first test */
while (fsz) {
documents/res/funcs.png
BIN
View File
Binary file not shown.
Side by Side Swipe Overlay

Before

Width:  |  Height:  |  Size: 22 KiB

After

Width:  |  Height:  |  Size: 26 KiB

documents/res/layers2.png
BIN
View File
Binary file not shown.
Side by Side Swipe Overlay

Before

Width:  |  Height:  |  Size: 3.7 KiB

After

Width:  |  Height:  |  Size: 4.8 KiB

documents/res/modules.png
BIN
View File
Binary file not shown.
Side by Side Swipe Overlay

Before

Width:  |  Height:  |  Size: 15 KiB

After

Width:  |  Height:  |  Size: 15 KiB

documents/updates.txt
+41
View File
@@ -1,3 +1,9 @@
R0.14a (December 05, 2020)
Limited number of recursive calls in f_findnext().
Fixed old floppy disks formatted with MS-DOS 2.x and 3.x cannot be mounted.
Fixed some compiler warnings.
R0.14 (October 14, 2019)
Added support for 64-bit LBA and GUID partition table (FF_LBA64 = 1)
Changed some API functions, f_mkfs() and f_fdisk().
@@ -12,12 +18,14 @@ R0.13c (October 14, 2018)
Fixed creating a sub-directory in the fragmented sub-directory on the exFAT volume collapses FAT chain of the parent directory. (appeared at R0.12)
Fixed f_getcwd() cause output buffer overrun when the buffer has a valid drive number. (appeared at R0.13b)
R0.13b (April 07, 2018)
Added support for UTF-32 encoding on the API. (FF_LFN_UNICODE = 3)
Added support for Unix style volume prefix. (FF_STR_VOLUME_ID = 2)
Fixed accesing any object on the exFAT root directory beyond the cluster boundary can fail. (appeared at R0.12c)
Fixed f_setlabel() does not reject some invalid characters. (appeared at R0.09b)
R0.13a (October 14, 2017)
Added support for UTF-8 encoding on the API. (FF_LFN_UNICODE = 2)
Added options for file name output buffer. (FF_LFN_BUF, FF_SFN_BUF).
@@ -26,6 +34,7 @@ R0.13a (October 14, 2017)
Fixed f_unlink() can cause lost clusters at fragmented file on the exFAT volume. (appeared at R0.12c)
Fixed f_setlabel() rejects some valid characters for exFAT volume. (appeared at R0.12)
R0.13 (May 21, 2017)
Changed heading character of configuration keywords "_" to "FF_".
Removed ASCII-only configuration, FF_CODE_PAGE = 1. Use FF_CODE_PAGE = 437 instead.
@@ -37,12 +46,14 @@ R0.13 (May 21, 2017)
Fixed exFAT FAT entry can be collapsed when write or lseek operation to the existing file is done. (appeared at R0.12c)
Fixed creating a file can fail when a new cluster allocation to the exFAT directory occures. (appeared at R0.12c)
R0.12c (March 04, 2017)
Improved write throughput at the fragmented file on the exFAT volume.
Made memory usage for exFAT be able to be reduced as decreasing _MAX_LFN.
Fixed successive f_getfree() can return wrong count on the FAT12/16 volume. (appeared at R0.12)
Fixed configuration option _VOLUMES cannot be set 10. (appeared at R0.10c)
R0.12b (September 4, 2016)
Made f_rename() be able to rename objects with the same name but case.
Fixed an error in the case conversion teble of code page 866. (ff.c)
@@ -53,6 +64,7 @@ R0.12b (September 4, 2016)
Fixed large file allocation/removing on the exFAT volume collapses allocation bitmap. (appeared at R0.12)
Fixed some internal errors in f_expand() and f_lseek(). (appeared at R0.12)
R0.12a (July 10, 2016)
Added support for creating exFAT volume with some changes of f_mkfs().
Added a file open method FA_OPEN_APPEND. An f_lseek() following f_open() is no longer needed.
@@ -61,6 +73,7 @@ R0.12a (July 10, 2016)
Fixed wrong memory read in create_name(). (appeared at R0.12)
Fixed compilation fails at some configurations, _USE_FASTSEEK and _USE_FORWARD.
R0.12 (April 12, 2016)
Added support for exFAT file system. (_FS_EXFAT)
Added f_expand(). (_USE_EXPAND)
@@ -68,6 +81,7 @@ R0.12 (April 12, 2016)
Added an option _USE_CHMOD and removed an option _WORD_ACCESS.
Fixed errors in the case conversion teble of Unicode (cc*.c).
R0.11a (September 5, 2015)
Fixed wrong media change can lead a deadlock at thread-safe configuration.
Added code page 771, 860, 861, 863, 864, 865 and 869. (_CODE_PAGE)
@@ -75,21 +89,25 @@ R0.11a (September 5, 2015)
Fixed errors in the case conversion teble of code page 437 and 850 (ff.c).
Fixed errors in the case conversion teble of Unicode (cc*.c).
R0.11 (February 9, 2015)
Added f_findfirst() and f_findnext(). (_USE_FIND)
Fixed f_unlink() does not remove cluster chain of the file. (appeared at R0.10c)
Fixed _FS_NORTC option does not work properly. (appeared at R0.10c)
R0.10c (November 9, 2014)
Added a configuration option for the platforms without RTC. (_FS_NORTC)
Fixed volume label created by Mac OS X cannot be retrieved with f_getlabel(). (appeared at R0.09b)
Fixed a potential problem of FAT access that can appear on disk error.
Fixed null pointer dereference on attempting to delete the root direcotry. (appeared at R0.08)
R0.10b (May 19, 2014)
Fixed a hard error in the disk I/O layer can collapse the directory entry.
Fixed LFN entry is not deleted on delete/rename an object with its lossy converted SFN. (appeared at R0.07)
R0.10a (January 15, 2014)
Added arbitrary strings as drive number in the path name. (_STR_VOLUME_ID)
Added an option for minimum sector size. (_MIN_SS)
@@ -99,6 +117,7 @@ R0.10a (January 15, 2014)
Fixed volume lock is left acquired after return from f_closedir(). (appeared at R0.10)
Fixed creation of a directory entry with LFN fails on too many SFN collisions. (appeared at R0.07)
R0.10 (October 2, 2013)
Added an option for character encoding on the file. (_STRF_ENCODE)
Added f_closedir().
@@ -110,24 +129,29 @@ R0.10 (October 2, 2013)
Fixed f_write() can be truncated when the file size is close to 4GB.
Fixed f_open(), f_mkdir() and f_setlabel() can return incorrect result code on error.
R0.09b (January 24, 2013)
Added f_getlabel() and f_setlabel(). (_USE_LABEL = 1)
R0.09a (August 27, 2012)
Fixed assertion failure due to OS/2 EA on FAT12/16 volume.
Changed file functions reject null object pointer to avoid crash.
Changed option name _FS_SHARE to _FS_LOCK.
R0.09 (September 6, 2011)
f_mkfs() supports multiple partition on a physical drive.
Added f_fdisk(). (_MULTI_PARTITION = 2)
R0.08b (January 15, 2011)
Fast seek function is also applied to f_read() and f_write().
f_lseek() reports required table size on creating CLMP.
Extended format syntax of f_printf().
Ignores duplicated directory separators in given path names.
R0.08a (August 16, 2010)
Added f_getcwd(). (_FS_RPATH = 2)
Added sector erase function. (_USE_ERASE)
@@ -135,6 +159,7 @@ R0.08a (August 16, 2010)
Fixed a wrong directory entry is created on non-LFN cfg when the given name contains ';'.
Fixed f_mkfs() creates wrong FAT32 volume.
R0.08 (May 15, 2010)
Added a memory configuration option. (_USE_LFN)
Added support of file lock. (_FS_SHARE)
@@ -143,6 +168,7 @@ R0.08 (May 15, 2010)
Changed fname member in the FILINFO structure on Unicode cfg.
String functions support UTF-8 encoding files on Unicode cfg.
R0.07e (November 3, 2009)
Separated out configuration options from ff.h to ffconf.h.
Added a configuration option, _LFN_UNICODE.
@@ -150,6 +176,7 @@ R0.07e (November 3, 2009)
Fixed name matching error on the 13 char boundary.
Changed f_readdir() to return the SFN with always upper case on non-LFN cfg.
R0.07c (Junuary 21, 2009)
Fixed f_unlink() may return FR_OK on error.
Fixed wrong cache control in f_lseek().
@@ -158,10 +185,12 @@ R0.07c (Junuary 21, 2009)
Added f_chdrive().
Added proper case conversion to extended characters.
R0.07a (April 14, 2009)
Separated out OS dependent code on re-entrant configuration.
Added multiple sector size support.
R0.07 (April 1, 2009)
Merged Tiny-FatFs into FatFs as a buffer configuration option.
Added long file name support.
@@ -172,11 +201,13 @@ R0.07 (April 1, 2009)
Changed result code of critical errors.
Renamed string functions to avoid name collision.
R0.06 (April 1, 2008)
Added f_forward. (Tiny-FatFs)
Added string functions: fgets, fputc, fputs and fprintf.
Improved performance of f_lseek on moving to the same or following cluster.
R0.05a (February 3, 2008)
Added f_truncate.
Added f_utime.
@@ -184,12 +215,14 @@ R0.05a (February 3, 2008)
Fixed btr in f_read can be mistruncated.
Fixed cached sector is left not flushed when create and close without write.
R0.05 (August 26, 2007)
Changed arguments of f_read, f_write.
Changed arguments of f_mkfs. (FatFs)
Fixed f_mkfs on FAT32 creates incorrect FSInfo. (FatFs)
Fixed f_mkdir on FAT32 creates incorrect directory. (FatFs)
R0.04b (May 5, 2007)
Added _USE_NTFLAG option.
Added FSInfo support.
@@ -197,6 +230,7 @@ R0.04b (May 5, 2007)
Fixed DBCS name can result FR_INVALID_NAME.
Fixed short seek (<= csize) collapses the file object.
R0.04a (April 1, 2007)
Supported multiple partitions on a plysical drive. (FatFs)
Added minimization level 3.
@@ -204,31 +238,38 @@ R0.04a (April 1, 2007)
Fixed an endian sensitive code in f_mkfs. (FatFs)
Fixed a problem corresponds to FAT32 support. (Tiny-FatFs)
R0.04 (February 4, 2007)
Supported multiple drive system. (FatFs)
Changed some APIs for multiple drive system.
Added f_mkfs. (FatFs)
Added _USE_FAT32 option. (Tiny-FatFs)
R0.03a (December 11, 2006)
Improved cluster scan algolithm to write files fast.
Fixed f_mkdir creates incorrect directory on FAT32.
R0.03 (September 22, 2006)
Added f_rename.
Changed option _FS_MINIMUM to _FS_MINIMIZE.
R0.02a (June 10, 2006)
Added a configuration option _FS_MINIMUM.
R0.02 (Jun 01, 2006)
Added FAT12.
Removed unbuffered mode.
Fixed a problem on small (<32M) patition.
R0.01 (April 29, 2006)
First release
R0.00 (February 26, 2006)
Prototype (not released)