path: root/nuttx/Documentation/NuttX.html



<html>
<head>
<title>NuttX</title>
</head>
<body background="backgd.gif">
<hr><hr>
<table width ="100%">
  <tr align="center" bgcolor="#e4e4e4">
    <td>
      <h1><big><font color="#3c34ec"><i>NuttX RTOS</i></font></big></h1>
      <p>Last Updated: June 11, 2009</p>
    </td>
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<hr><hr>
<table width ="100%">
  <tr bgcolor="#e4e4e4">
    <td>
  <h1>Table of Contents</h1>
    </td>
  </tr>
</table>

<center><table width ="80%">
<tr>
<td>
<table>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#overview">Overview</a>.<br>
    What is NuttX?  Look at all those files and features... How can it be a tiny OS?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#downloads">Downloads</a>.<br>
    Where can I get NuttX?  What is the current development status?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#platforms">Supported Platforms</a>.<br>
    What target platforms has NuttX been ported to?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#environments">Development Environments</a>.<br>
    What kinds of host cross-development platforms can be used with NuttX?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#footprint">Memory Footprint</a>.<br>
    Just how big is it?  Do I have enough memory to use NuttX?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#licensing">Licensing</a>.<br>
    Are there any licensing restrictions for the use of NuttX? (Almost none)
    Will there be problems if I link my proprietary code with NuttX? (No)
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#history">Release History</a><br>
    What has changed in the last release of NuttX?
    What unreleased changes are pending in CVS?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#TODO">Bugs, Issues, <i>Things-To-Do</i></a>.<br>
    Software is never finished nor ever tested well enough.
    (Do you want to help develop NuttX?  If so, send me an email).
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#documentation">Other Documentation</a>.<br>
    What other NuttX documentation is available?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#trademarks">Trademarks</a>.<br>
    Some of the words used in this document belong to other people.
  </td>
</tr>
</table>
</td>
</tr>
</table></center>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="overview"><h1>Overview</h1></a>
  </td>
  </tr>
</table>

<p>
  <b>Goals</b>.
  Nuttx is a real timed embedded operating system (RTOS).
  Its goals are:
<p>
<center><table width="90%">
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Small Footprint</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      Usable in all but the tightest micro-controller environments,
      The focus is on the tiny-to-small, deeply embedded environment.
    </p>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Rich Feature OS Set</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      The goal is to provide implementations of most standard POSIX OS interfaces
      to support a rich, multi-threaded development environment for deeply embedded
      processors.
    </p>
      NON-GOALS: (1) It is not a goal to provide the rich level of OS
      features like those provided with Linux.
      Small footprint is more important than features.
      Standard compliance is more important than small footprint.
      (2) There is no MMU-based support for processes.
      At present, NuttX assumes a flat address space.
    </p>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Highly Scalable</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      Fully scalable from tiny (8-bit) to moderate embedded (32-bit).
      Scalability with rich feature set is accomplished with:
      Many tiny source files, link from static libraries, highly configurable, use of
      weak symbols when available.
    </p>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Standards Compliance</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      NuttX strives to achieve a high degree of standards compliance.
      The primary governing standards are POSIX and ANSI standards.
      Additional standard APIs from Unix and other common RTOS's are
      adopted for functionality not available under these standards
      or for functionality that is not appropriate for the deeply-embedded
      RTOS (such as <code>fork()</code>).
    </p>
    <p>
      Because of this standards conformance, software developed under other
      standard OSs (such as Linux) should port easily to NuttX.
    </p>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Real-Time</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      Fully pre-emptible, fixed priority and round-robin scheduling.
    </p>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Totally Open</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      Non-restrictive BSD license.
    </p>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>GNU Toolchains</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      Compatible GNU toolchains based on <a href="http://buildroot.uclibc.org/">buildroot</a>
      available for
      <a href="https://sourceforge.net/project/showfiles.php?group_id=189573&package_id=224585">download</a>
      to provide a complete development environment for many architectures.
    </p>
</tr>
</table></center>

<p>
  <b>Feature Set</b>.
  Key features of NuttX include:
<p>
<center><table width="90%">

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Standards Compliant Core Task Management</b>
  </td>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Modular, micro-kernel</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Fully pre-emptible.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Naturally scalable.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Highly configurable.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Easily extensible to new processor architectures, SoC architecture, or board architectures.
          A <a href="NuttxPortingGuide.html">Porting Guide</a> is in development.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>FIFO and round-robin scheduling.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Realtime, deterministic, with support for priority inheritance</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>POSIX/ANSI-like task controls, named message queues, counting semaphores, clocks/timers, signals, pthreads, environment variables, filesystem.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>VxWorks-like task management and watchdog timers.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>BSD socket interface.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Extensions to manage pre-emption.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Well documented in the NuttX <a href="NuttxUserGuide.html">User Guide</a>.</li>
    </p>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>File system</b>
  </td>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Tiny in-memory, root pseudo-file-system.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Supports character and block drivers.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Network, USB (device), serial, CAN, driver architecture.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>RAMDISK, pipes, FIFO, <code>/dev/null</code>, <code>/dev/zero</code> drivers.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Mount-able volumes.  Bind mountpoint, filesystem, and block device driver.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>FAT12/16/32 filesystem support.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Generic driver for SPI-based MMC/SD/SDH cards.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>ROMFS filesystem support.</li>
    </p>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>C Library</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Fully integrated into the OS.</li>
    </p>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Networking</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>TCP/IP, UDP, ICMP stacks.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Small footprint (based on uIP).</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>BSD compatible socket layer.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Networking utilities (DHCP, SMTP, TELNET, TFTP, HTTP)</li>
    </p>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>USB Device Support</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li><i>Gadget</i>-like architecture for USB device controller drivers and device-dependent USB class drivers.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>USB device controller drivers available for the NXP LPC214x and TI DM320.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Device-dependent USB class drivers available for USB serial and for USB mass storage.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Built-in USB trace functionality for USB debug.</li>
    </p>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Graphics Support</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Framebuffer drivers.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>
         NX: A graphics library, tiny windowing system and tiny font support.
         Documented in the <a href="NXGraphicsSubsystem.html">NX Graphics Subsystem</a>
         manual.
      </li>
    </p>
</tr>
</table></center>

<p>
  <b>NuttX Add-Ons</b>.
  The following packages are available to extend the basic NuttX feature set:
</p>
<center><table width="90%">

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>NuttShell (NSH)</b>
  </td>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>A small, scalable, bash-like shell for NuttX with rich feature set and small footprint.
        See the <a href="NuttShell.html">NuttShell User Guide</a>.</li>
    </p>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Pascal Compiler with NuttX runtime P-Code interpreter add-on</b>
  </td>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>The Pascal add-on is available for download from the
        <a href="http://sourceforge.net/project/showfiles.php?group_id=189573">SourceForge</a>
        website.</li>
    </p>
  </td>
</tr>
</table></center>

<p>
  <b>Look at all those files and features... How can it be a tiny OS?</b>.
  The NuttX feature list (above) is fairly long and if you look at the NuttX
  source tree, you will see that there are hundreds of source files comprising
  NuttX.  How can NuttX be a tiny OS with all of that?
</p>
<center><table width="90%">

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Lots of Features -- More can be smaller!</b>
  </td>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      The philosophy behind that NuttX is that lots of features are great... <i>BUT</i>
      also that if you don't use those features, then you should not have to pay a penalty
      for the unused features.
      And, with NuttX, you don't!  If you don't use a feature, it will not
      be included in the final executable binary.
      You only have to pay the penalty of increased footprint for the features
      that you actually use.
    </p>
    <p>
      Using a variety of technologies, NuttX can scale from the very tiny to
      the moderate-size system.  I have executed NuttX with some simple applications
      in as little as 32Kb <i>total</i> memory (code and data).
      On the other hand, typical, richly featured NuttX builds require more like 64Kb
      (and if all of the features are used, this can push 100Kb).
    </p>
  </td>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Many, many files -- More really is smaller!</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      One may be intimidated by the size NuttX source tree.  There are hundreds of source files!
      How can that be a tiny OS?
      Actually, the large number of files is one of the tricks to keep NuttX small and
      as scalable as possible.
      Most files contain only a single function. 
      Sometimes just one tiny function with only a few lines of code.
      Why?
    </p>
    <ul>
      <li>
        <b>Static Libraries</b>.
        Because in the NuttX build processed, objects are compiled and saved into
        <i>static libraries</i> (<i>archives</i>).
        Then, when the file executable is linked, only the object files that are needed
        are extracted from the archive and added to the final executable.
        By having many, many tiny source files, you can assure that no code that you do
        not execute is ever included in the link.
        And by having many, tiny source files you have better granularity --
        if you don't use that tiny function of even just a few lines of code, it will
        not be included in the binary.
      </li>
    </ul>
  </td>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Other Tricks</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      As mentioned above, the use of many, tiny source files and linking from static
      libraries keeps the size of NuttX down.
      Other tricks used in NuttX include:
    </p>
    <ul>
      <li>
         <b>Configuration Files</b>.
         Before you build NuttX, you must provide a configuration file that specifies
         what features you plan to use and which features you do not.
         This configuration file contains a long list of settings that control
         what is built into NuttX and what is not.
         There are hundreds of such settings
         (see the <a href="NuttxPortingGuide.html#apndxconfigs">NuttX Porting Guide</a>
         for a partial list that excludes platform specific settings).
         These many, many configuration options allow NuttX to be highly tuned to
         meet size requirements.
         The downside to all of these configuration options is that it greatly
         complicates the maintenance of NuttX -- but that is my problem, not yours.
      </li>
      <li>
         <b>Weak Symbols</b>
         The GNU toolchain supports <i>weak</i> symbols and these also help to keep
         the size of NuttX down.
         Weak symbols prevent object files from being drawn into the link even if they
         are accessed from source code.
         Careful use of weak symbols is another trick for keep unused code out of the
         final binary.
      </li>
    </ul>
  </td>
</tr>

</table></center>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="downloads"><h1>Downloads</h1></a>
  </td>
  </tr>
</table>

<p><b>nuttx-0.4.7</b>.
  The 39<sup>th</sup> release of NuttX (nuttx-0.4.7) was made on May 29, 2009 and is available for download
  from the <a href="http://sourceforge.net/project/showfiles.php?group_id=189573">SourceForge</a>
  website.
  The change log associated with the release is available <a href="#currentrelease">here</a>.
  Unreleased changes after this release are available in CVS.
  These unreleased changes are listed <a href="#pendingchanges">here</a>.
</p>
<p>
  This release focuses on cleaning up and extending the Eagle100/LM3S6918 port released
  in nuttx-0.4.6 and on improved MMC/SD support.  New features include:
  <ul>
    <li>
      Improved reliably and additional drivers for the Eagle-100 board (LM3S6918
      ARM Cortex-M3).  Additional drivers include Ethernet, SSI, and support for
      the on-board LEDs and microSD cards.
    </li>
    <li>
      The SPI-based MMC/SD driver was extended to support SDHC Version 2.xx cards.
    </li>
  </ul>
</p>
<p>
  In addition, this release includes several important bugfixes for the LM3S6918, the LPC2148,
  the SPI-based MMC/SD driver, and to FAT32.  See the ChangeLog for details of these bugfixes.
</p>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="platforms"><h1>Supported Platforms</h1></a>
  </td>
  </tr>
</table>

<center><table width="90%">
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Linux User Mode</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      A user-mode port of NuttX to the x86 Linux/Cygwin platform is available.
      The purpose of this port is primarily to support OS feature development.
    </p>
    <p>
      <b>STATUS:</b>
      Does not support interrupts but is otherwise fully functional.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>ARM7TDMI</b>.
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>TI TMS320C5471</b> (also called <b>C5471</b> or <b>TMS320DA180</b> or <b>DA180</b>).
      NuttX operates on the ARM7 of this dual core processor.
      This port uses the <a href="http://www.spectrumdigital.com/">Spectrum Digital</a>
      evaluation board with a GNU arm-elf toolchain* under Linux or Cygwin.
    </p>
    <p>
      <b>STATUS:</b>
      This port is complete, verified, and included in the initial NuttX release.
    </p>
   </td>
</tr>
<tr>
  <td><br></td>
  <td><hr></td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>NXP LPC214x</b>.
      Support is provided for the NXP LPC214x family of processors.  In particular,
      support is provided for the mcu123.com lpc214x evaluation board (LPC2148).
      This port also used the GNU arm-elf toolchain* under Linux or Cygwin.
    </p>
    <p>
      <b>STATUS:</b>
      This port boots and passes the OS test (examples/ostest).
      The port is complete and verified.  As of NuttX 0.3.17, the port includes:
      timer interrupts, serial console, USB driver, and SPI-based MMC/SD card
      support.  A verified NuttShell <a href="NuttShell.html">(NSH)</a>
      configuration is also available.
    </p>
    <p>
      <b>Development Environments:</b>
      1) Linux with native Linux GNU toolchain, 2) Cygwin with Cygwin GNU toolchain, or 3) Cygwin
      with Windows native toolchain (CodeSourcery or devkitARM).  A DIY toolchain for Linux
      or Cygwin is provided by the NuttX
      <a href="http://sourceforge.net/project/showfiles.php?group_id=189573&package_id=224585">buildroot</a>
      package.
    </p>
  </td>
</tr>
<tr>
  <td><br></td>
  <td><hr></td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>STMicro STR71x</b>.
      Support is provided for the STMicro STR71x family of processors.  In particular,
      support is provided for the Olimex STR-P711 evaluation board.
      This port also used the GNU arm-elf toolchain* under Linux or Cygwin.
    </p>
    <p>
      <b>STATUS:</b>
      Integration is complete on the basic port (boot logic, system time, serial console).
      Two configurations have been verified: (1) The board boots and passes the OS test
      with console output visible on UART0, and the NuttShell <a href="NuttShell.html">(NSH)</a>
      is fully functional with interrupt driven serial console.  An SPI driver is available
      but untested (because the Olimex card slot appears to accept only MMC cards; I have
      only SD cards).  Additional features are needed: USB driver, MMC integration, to name two.
    </p>
    <p>
      <b>Development Environments:</b>
      1) Linux with native Linux GNU toolchain, 2) Cygwin with Cygwin GNU toolchain, or 3) Cygwin
      with Windows native toolchain (CodeSourcery or devkitARM).  A DIY toolchain for Linux
      or Cygwin is provided by the NuttX
      <a href="http://sourceforge.net/project/showfiles.php?group_id=189573&package_id=224585">buildroot</a>
      package.
    </p>
  </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>ARM920T</b>.
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Freescale MC9328MX1</b> or <b>i.MX1</b>.
      This port uses the Freescale MX1ADS development board with a GNU arm-elf toolchain*
      under either Linux or Cygwin.
    </p>
    <p>
      <b>STATUS:</b>
        This port is in progress.  Coding is complete on the basic port (timer, serial console, SPI).
        Verified support for the i.MX1 will be announced in a future release of NuttX (work has
        been temporarily stopped to support the Luminary LM3S6918).
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>ARM926EJS</b>.
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>TI TMS320DM320</b> (also called <b>DM320</b>).
      NuttX operates on the ARM9 of this dual core processor.
      This port uses the
      <a href="http://wiki.neurostechnology.com/index.php/Developer_Welcome">Neuros OSD</a>
      with a GNU arm-elf toolchain* under Linux or Cygwin.
    </p>
    <p>
      <b>STATUS:</b>
        The basic port (timer interrupts, serial ports, network, framebuffer, etc.) is complete.
        All implemented features have been verified with the exception of the USB device-side
        driver; that implementation is complete but untested.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>ARM Cortex-M3</b>.
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Luminary LM3S6918</b>.
      This port uses the <a href=" http://www.micromint.com/">Micromint</a> Eagle-100 development
      board with a GNU arm-elf toolchain* under either Linux or Cygwin.
    </p>
    <p>
      <b>STATUS:</b>
        The initial, release of this port was included in NuttX  version 0.4.6.
        The current port includes timer, serial console, Ethernet, SSI, and microSD support.
        There are working configurations the NuttX OS test, to run the <a href="NuttShell.html">NuttShell
        (NSH)</a>, the NuttX networking test, and the uIP web server.
    </p>
    <p>
      <b>Development Environments:</b>
      1) Linux with native Linux GNU toolchain, 2) Cygwin with Cygwin GNU toolchain, or 3) Cygwin
      with Windows native toolchain (CodeSourcery or devkitARM).  A DIY toolchain for Linux
      or Cygwin is provided by the NuttX
      <a href="http://sourceforge.net/project/showfiles.php?group_id=189573&package_id=224585">buildroot</a>
      package.
    </p>
   </td>
</tr>

<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>8052 Microcontroller</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>PJRC 87C52 Development Board</b>.
      This port uses the <a href="http://www.pjrc.com/">PJRC</a> 87C52 development system
      and the <a href="http://sdcc.sourceforge.net/">SDCC</a> toolchain under Linux or Cygwin.
    </p>
    <p>
     <b>STATUS:</b>
      This port is complete but not stable with timer interrupts enabled.
      There seems to be some issue when the stack pointer enters into the indirect IRAM
      address space during interrupt handling.
      This architecture has not been built in some time will likely have some compilation
      problems because of SDCC compiler differences.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Renesas/Hitachi SuperH</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>SH-1 SH7032</b>.
      This port uses the Hitachi SH-1 Low-Cost Evaluation Board (SH1_LCEVB1), US7032EVB,
      with a GNU arm-elf toolchain* under Linux or Cygwin.
    </p>
    <p>
     <b>STATUS:</b>
      This port is available as of release 0.3.18 of NuttX.  The port is basically complete
      and many examples run correctly.  However, there are remaining instabilities that
      make the port un-usable.  The nature of these is not understood; the behavior is
      that certain SH-1 instructions stop working as advertised.  This could be a silicon
      problem, some pipeline issue that is not handled properly by the gcc 3.4.5 toolchain
      (which has very limit SH-1 support to begin with), or perhaps with the CMON debugger.
      At any rate, I have exhausted all of the energy that I am willing to put into this cool
      old processor for the time being.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Renesas M16C/26</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Renesas M16C/26 Microncontroller</b>.
      This port uses the Renesas SKP16C26 Starter kit and the GNU M32C toolchain. 
      The development environment is either Linux or Cygwin under WinXP.
    </p>
    <p>
      <b>STATUS:</b>
      Initial source files released in nuttx-0.4.2.
      At this point, the port has not been integrated;	the target cannot be built
      because the GNU <code>m16c-elf-ld</code> link fails with  the following message:
    </p>
    <ul>
    <code>m32c-elf-ld: BFD (GNU Binutils) 2.19 assertion fail /home/Owner/projects/nuttx/buildroot/toolchain_build_m32c/binutils-2.19/bfd/elf32-m32c.c:482</code>
    </ul>
    <p>Where the reference line is:</p>
    <ul><pre>
/* If the symbol is out of range for a 16-bit address,
   we must have allocated a plt entry.  */
BFD_ASSERT (*plt_offset != (bfd_vma) -1);
</pre></ul>
    <p>
      No workaround is known at this time.  This is a show stopper for M16C for
      the time being.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Zilog Z16F</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Zilog z16f Microncontroller</b>.
      This port use the Zilog z16f2800100zcog development kit and the Zilog
      ZDS-II Windows command line tools.
      The development environment is Cygwin under WinXP.
    </p>
    <p>
      <b>STATUS:</b>
      The initial release of support for the z16f was made available in NuttX version 0.3.7.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Zilog eZ80 Acclaim!</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Zilog eZ80Acclaim! Microncontroller</b>.
      There are two eZ80Acclaim! ports:
    </p>
    <ul>
      <li>One uses the ZiLOG ez80f0910200kitg development kit, and
      <li>The other uses the ZiLOG ez80f0910200zcog-d development kit.
    </ul>
    <p>
      Both boards are based on the eZ80F091 part and both use the Zilog ZDS-II
      Windows command line tools.
      The development environment is Cygwin under WinXP.
    </p>
    <p>
      <b>STATUS:</b>
      Integration and testing of NuttX on the  ZiLOG ez80f0910200zcog-d is complete.
      The first integrated version was released in NuttX version 0.4.2 (with important early bugfixes
      in 0.4.3 and 0.4.4).
      As of this writing, that port provides basic board support with a serial console, SPI, and eZ80F91 EMAC driver.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Zilog Z8Encore!</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Zilog Z8Encore! Microncontroller</b>.
      This port uses the either:
    </p>
    <ul>
      <li>Zilog z8encore000zco development kit, Z8F6403 part, or</li>
      <li>Zilog z8f64200100kit development kit, Z8F6423 part</li>
    </ul>
    <p>
      and the Zilog ZDS-II Windows command line tools.
      The development environment is Cygwin under WinXP.
    </p>
    <p>
      <b>STATUS:</b>
      This release has been verified only on the ZiLOG ZDS-II Z8Encore! chip simulation
      as of nuttx-0.3.9.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Zilog Z80</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Z80 Instruction Set Simulator</b>.
      This port uses the <a href="http://sdcc.sourceforge.net/">SDCC</a> toolchain
      under Linux or Cygwin (verified using version 2.6.0).
      This port has been verified using only a Z80 instruction simulator.
      That simulator can be found in the NuttX CVS
      <a href="http://nuttx.cvs.sourceforge.net/nuttx/misc/sims/z80sim/">here</a>.
    </p>
    <p>
     <b>STATUS:</b>
      This port is complete and stable to the extent that it can be tested
      using an instruction set simulator.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Other ports</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      There are partial ports for the TI TMS320DM270 and for MIPS.
    </p>
   </td>
</tr>
</table></center>

<blockquote>* A highly modified <a href="http://buildroot.uclibc.org/">buildroot</a>
is available that may be used to build a NuttX-compatible ELF toolchain under
Linux or Cygwin.  Configurations are available in that buildroot to support ARM,
m68k, m68hc11, m68hc12, and SuperH ports.</blockquote>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="environments"><h1>Development Environments</h1></a>
  </td>
  </tr>
</table>

<center><table width="90%">
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Linux + GNU make + GCC/binutils</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      The is the most natural development environment for NuttX.
      Any version of the GCC/binutils toolchain may be used.
      There is a  highly modified <a href="http://buildroot.uclibc.org/">buildroot</a>
      available for download from the
      <a href="http://sourceforge.net/project/showfiles.php?group_id=189573">NuttX SourceForge</a>
      page.
      This download may be used to build a NuttX-compatible ELF toolchain under Linux or Cygwin.
      That toolchain will support ARM, m68k, m68hc11, m68hc12, and SuperH ports.
      The buildroot CVS may be accessed in the 
      <a href="http://nuttx.cvs.sourceforge.net/nuttx/misc/buildroot/">NuttX CVS</a>.
    </p>
   </td>
</tr>

<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Linux + GNU make + SDCC</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      Also very usable is the Linux environment using the 
      <a href="http://sdcc.sourceforge.net/">SDCC</a> compiler.
      The SDCC compiler provides support for the 8051/2, z80, hc08, and other microcontrollers.
      The SDCC-based logic is less well exercised and you will likely find some compilation
      issues if you use parts of NuttX with SDCC that have not been well-tested.
    </p>
   </td>
</tr>

<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Cygwin + GNU make + GCC/binutils</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      This combination works well too.
      It works just as well as the native Linux environment except
      that compilation and build times are a little longer.
      The custom NuttX buildroot referenced above may be build in
      the Cygwin environment as well.
    </p>
  </td>
</tr>

<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Cygwin + GNU make + SDCC</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
       I have never tried this combination, but it would probably work just fine.
    </p>
  </td>
</tr>

<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Cygwin + GNU make + Windows Native Toolchain</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      This is a tougher environment.
      In this case, the Windows native toolchain is unaware of the the
      Cygwin <i>sandbox</i> and, instead, operates in the native Windows environment.
      The primary difficulties with this are:
    </p>
    <ul>
      <li>
        <b>Paths</b>.
        Full paths for the native toolchain must follow Windows standards.
        For example, the path <code>/home/my\ name/nuttx/include</code> my have to be
        converted to something like <code>'C:\cygwin\home\my name\nuttx\include'</code>
        to be usable by the toolchain.
      </li>
      <p>
        Fortunately, this conversion is done simply using the <code>cygpath</code> utility.
      </p>
      <li>
        <b>Symbolic Links</b>
        NuttX depends on symbolic links to install platform-specific directories in the build system.
        On Linux, true symbolic links are used.
        On Cygwin, emulated symbolic links are used.
        Unfortunately, for native Windows applications that operate outside of the
        Cygwin <i>sandbox</i>, these symbolic links cannot be used.
      </li>
      <p>
        The NuttX make system works around this limitation by copying the platform
        specific directories in place.
        These copied directories make work a little more complex, but otherwise work well.
      </p>
      <li>
        <b>Dependencies</b>
        NuttX uses the GCC compiler's <code>-M</code> option to generate make dependencies.  These
        dependencies are retained in files called <code>Make.deps</code> throughout the system.
        For compilers other than GCC, there is no support for making dependencies in this way.
        For Windows native GCC compilers, the generated dependencies are windows paths and not
        directly usable in the Cygwin make.  By default, dependencies are surpressed for these
        compilers as well.
      </li>
      <p><small>
        NOTE: dependencies are suppress by setting the make variable <code>MKDEPS</code> to point
        to the do-nothing dependency script, <code>tools/mknulldeps.sh</code>.
        Dependencies can be enabled for the Windows native GCC compilers by setting
        <code>MKDEPS</code> to point to <code>$(TOPDIR)/tools/mkdeps.sh --winpaths $(TOPDIR)</code>.
      </small></p>
    </ul>
    <p>
      At present, only the Zilog Z16F, z8Encore, and eZ80Acclaim ports use a non-GCC native Windows
      toolchain(the Zilog ZDS-II toolchain).
      Support for Windows native GCC toolchains (CodeSourcery and devkitARM) is currently implemented
      for the NXP LPC214x, STMicro STR71x, and Luminary LMS6918 ARM ports.
      (but could easily be extended to any other GCC-based platform with a small effort).
    </p>
  </td>
</tr>

<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Other Environments?</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      The primary environmental dependency of NuttX are (1) GNU make,
      (2) bash scripting, and (3) Linux utilities (such as sed).
      If you have other platforms that support GNU make or make
      utilities that are compatible with GNU make, then it is very
      likely that NuttX would work in that environment as well (with some
      porting effort). If GNU make is not supported, then some significant
      modification of the Make system would be required.
    </p>
  </td>
</tr>
</table></center>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="footprint"><h1>Memory Footprint</h1></a>
  </td>
  </tr>
</table>

<ul>
<p><b>C5471 (ARM7)</b>
  The build for this ARM7 target that includes most of the OS features and
  a broad range of OS tests.  The size of this executable as given by the
  Linux <tt>size</tt> command is (3/9/07):
</p>
<pre>
   text    data     bss     dec     hex filename
  53272     428    3568   57268    dfb4 nuttx
</pre>
<p><b>DM320 (ARM9)</b>
  This build for the ARM9 target includes a significant subset of OS
  features, a filesystem, Ethernet driver, full TCP/IP, UDP and (minimal)
  ICMP stacks (via uIP) and a small network test application: (11/8/07,
  configuration netconfig, examples/nettest)
</p>
<pre>
   text    data     bss     dec     hex filename
  49472     296    3972   53740    d1ec nuttx
</pre>
<p>
  Another build for the ARM9 target includes a minimal OS feature
  set, Ethernet driver, full TCP/IP and (minimal) ICMP stacks, and
  a small webserver: (11/20/07, configuration uipconfig, examples/uip)
</p>
<pre>
   text    data     bss     dec     hex filename
  52040      72    4148   56260    dbc4 nuttx
</pre>
<p><b>87C52</b>
  A reduced functionality OS test for the 8052 target requires only
  about 18-19Kb:
</p>
<pre>
Stack starts at: 0x21 (sp set to 0x20) with 223 bytes available.

Other memory:
   Name             Start    End      Size     Max
   ---------------- -------- -------- -------- --------
   PAGED EXT. RAM                         0      256
   EXTERNAL RAM     0x0100   0x02fd     510     7936
   ROM/EPROM/FLASH  0x2100   0x6e55   19798    24384
</pre>
</ul>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="licensing"><h1>Licensing</h1></a>
  </td>
  </tr>
</table>

<ul>
<p>
  NuttX is available under the highly permissive
  <a href="http://en.wikipedia.org/wiki/BSD_license">BSD license</a>.
  Other than some fine print that you agree to respect the copyright
  you should feel absolutely free to use NuttX in any environment and
  without any concern for jeopardizing any proprietary software that
  you may link with it.
</p>
</ul>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="history"><h1>Release History</h1></a>
  </td>
  </tr>
</table>

<ul>
<p>
   The current NuttX Change Log is available in CVS <a href="http://nuttx.cvs.sourceforge.net/*checkout*/nuttx/nuttx/ChangeLog">here</a>.
   ChangeLog snapshots associated with the current release are available below.
</p>
</ul>

<center><table width ="80%">
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
   <td>
      <a href="ChangeLog.txt">Change Logs for All NuttX Releases</a><br>
   </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
   <td>
      <a href="#currentrelease">ChangeLog for Current Releases</a><br>
   </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
   <td>
      <a href="#pendingchanges">Unreleased Changes</a>
   </td>
</tr>
</table></center>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="currentrelease">ChangeLog for Current Release</a>
  </td>
  </tr>
</table>

<pre><ul>
nuttx-0.4.7 2009-05-29 Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;

	* arch/arm/src/lm3s: Added an Ethernet driver for the LM3S6918
	* configs/eagle100/nettest: Added an examples/nettest configuration for the
	  Micromint Eagle100 board.
	* Documentation/NuttxPortingGuide.html: Added a section on NuttX device drivers.
	* configs/eagle100/httpd: Added an examples/uip configuration for the
	  Micromint Eagle100 board.
	* arch/arm/src/lm3s: Added an SSI driver for the LM3S6918
	* examples/nsh: Added MMC/SD support for the LM3S6918
	* arch/arm/src/lm3s: Fix logic for setting and clearing output GPIOs (critical
	  fix!).
	* drivers/mmcsd: Found numerous errors in current MMC/SD SPI driver.  Bad frequency
	  calculation based on CSD settings, inappropriate timeouts, odd code that looks like
	  a bad search and replace.  Also needs support for SDHC ver 2.x.  New MMC/SD is
	  largely redesigned and probably non-functional in the first check-in.
	* drivers/mmcsd: Changes verified on 4Gb Kingston microSHDC card and on a 2Gb
	  SanDisk microSDC card on the Eagle100 platform.
	* fs/fat: With the 4Gb card, the first tests of FAT32 were (finally) performed.
	  Found and corrected a problem that prevented use of FAT32: It was not updating
	  the sector cache before checking the FAT32 FSINFO sector.
	* configs/eagle100/*/Make.defs:  Added configuration options that should make
	  it possible to build NuttX for the Eagle100 using CodeSourcery 2009q1 toolchain
	  and the devkitARM GNU toolchain.
	* configs/mcu123-lpc214x/src: Corrected some logic in the LPC2148 SPI receive block
	  logic.  Re-verified SDC ver1.x support with 1Gb Toshiba SDC, 1Gb PNY SDC, and
	  4Gb Kingston SDHC.  There are CMD0 issues with the 2Gb SanDisk SDC on this board.
	* fs/fs_mount.c: Corrected error handling that could cause a deadlock on certain
	  mount() failures.

pascal-0.1.2 2008-02-10 Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;

	* Add logic to build and link with the ZDS-II toolchain
	  use with the z16f.
	* Make sure that POFF header structures are aligned
	* Standardized POFF file format to big-endian
	* Break up large switch statements to lower complexity
	  and eliminate a compiler bug
	* Changes so that runtime compiles with SDCC.

buildroot-0.1.6 2009-xx-xx &lt;spudmonkey@racsa.co.cr&gt;

	* Added config/arm7tdmi-defconfig-4.2.4
	* Added config/arm920t-defconfig-4.3.3
	* Correct error in arm-defconfig gcc-3.4.6 build. The gcc-3.4.6 configuration
	  does not not take --with-abi
	* Correct error in gcc-3.4.6/gcc/collect.c.  Calls open with O_CREAT but
	  does not specify mode.  Newer host compilers can error out on this.
</pre></ul>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="pendingchanges">Unreleased Changes</a>
  </td>
  </tr>
</table>

<pre><ul>
nuttx-0.4.8 2009-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;

	* lib/lib_*stream.c: Extend internal stream logic to support incoming streams.
	* arch/arm/src/str71x: Serial output is now correct and timer interrupts are
	  working.  The test at configs/olimex-strp711/ostest passes.  This means that
	  the basic STR-P711 port is complete.
	* configs/olimex-strp711/nsh:  Add and verifed a NuttShell (NSH) configuration
	  for the STR-P711.
	* arch/arm/str71x/str71x_serial.c:  The STR711 interrupt driven serial driver
	  finally works after some extradinary measures to handle missed interrupts.
	  NSH is fully functional on the Olimex STR-P711 board.
	* example/nsh: Moved architecture specific files from NSH directory to board-
	  specific directories.
	* config/olimex-strp711/src/up_nsh.c:  Add an NSH board specific directory for
	  for the Olimex STR7P11 board.
	* Fixed build of LM3X6918 using the CodeSourcery Windows native toolchain.  There
	  were lots of issues with Cygwin paths and Cygwin symbolic links.  These changes
	  may work with the devarmKIT as well, but that remains untested.
	* The NXP LPC2148 and STR711 targets can now also be built using the CodeSourcery
	  or devkitARM Windows native toolchains.

pascal-0.1.3 2009-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;

buildroot-0.1.7 2009-xx-xx &lt;spudmonkey@racsa.co.cr&gt;

	* configs/avr-defconfig-4.3.3: Added support for AVR to support a NuttX
	  port of the ATmega128.
</pre></ul>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="TODO"><h1>Bugs, Issues, <i>Things-To-Do</i></h1></a>
  </td>
  </tr>
</table>

<ul>
<p>
   The current list of NuttX <i>Things-To-Do</i> in CVS <a href="http://nuttx.cvs.sourceforge.net/*checkout*/nuttx/nuttx/TODO">here</a>.
   A snapshot of the <i>To-Do</i> list associated with the current release are available <a href="TODO.txt">here</a>.
</p>
</ul>
<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="documentation"><h1>Other Documentation</h1></a>
  </td>
  </tr>
</table>

<ul><table>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td><a href="NuttxUserGuide.html">User Guide</a></td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td><a href="NuttxPortingGuide.html">Porting Guide</a></td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td><a href="NuttShell.html">NuttShell (NSH)</a></td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td><a href="NXGraphicsSubsystem.html">NX Graphics Subsystem</a></td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td><a href="ChangeLog.txt">Change Log</a></td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td><a href="TODO.txt">To-Do List</a></td>
</tr>
</center></ul>

<small>
<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="trademarks"><h1>Trademarks</h1></a>
  </td>
  </tr>
</table>
<ul>
  <li>ARM, ARM7 ARM7TDMI, ARM9, ARM920T, ARM926EJS Cortex-M3 are trademarks of Advanced RISC Machines, Limited.</li>
  <li>Cygwin is a trademark of Red Hat, Incorporated.</li>
  <li>Linux is a registered trademark of Linus Torvalds.</li>
  <li>Eagle-100 is a trademark of <a href=" http://www.micromint.com/">Micromint USA, LLC</a>.
  <li>LPC2148 is a trademark of NXP Semiconductors.</li>
  <li>TI is a tradename of Texas Instruments Incorporated.</li>
  <li>UNIX is a registered trademark of The Open Group.</li>
  <li>VxWorks is a registered trademark of Wind River Systems, Incorporated.</li>
  <li>ZDS, ZNEO, Z16F, Z80, and Zilog are a registered trademark of Zilog, Inc.</li>
</ul>
<p>
  NOTE: NuttX is <i>not</i> licensed to use the POSIX trademark.  NuttX uses the POSIX
  standard as a development guideline only.
</p>
</small>

</body>
</html>
<html>
<head>
<title>NuttX</title>
</head>
<body background="backgd.gif">
<hr><hr>
<table width ="100%">
  <tr align="center" bgcolor="#e4e4e4">
    <td>
      <h1><big><font color="#3c34ec"><i>NuttX RTOS</i></font></big></h1>
      <p>Last Updated: June 11, 2009</p>
    </td>
  </tr>
</table>
<hr><hr>
<table width ="100%">
  <tr bgcolor="#e4e4e4">
    <td>
  <h1>Table of Contents</h1>
    </td>
  </tr>
</table>

<center><table width ="80%">
<tr>
<td>
<table>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#overview">Overview</a>.<br>
    What is NuttX?  Look at all those files and features... How can it be a tiny OS?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#downloads">Downloads</a>.<br>
    Where can I get NuttX?  What is the current development status?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#platforms">Supported Platforms</a>.<br>
    What target platforms has NuttX been ported to?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#environments">Development Environments</a>.<br>
    What kinds of host cross-development platforms can be used with NuttX?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#footprint">Memory Footprint</a>.<br>
    Just how big is it?  Do I have enough memory to use NuttX?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#licensing">Licensing</a>.<br>
    Are there any licensing restrictions for the use of NuttX? (Almost none)
    Will there be problems if I link my proprietary code with NuttX? (No)
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#history">Release History</a><br>
    What has changed in the last release of NuttX?
    What unreleased changes are pending in CVS?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#TODO">Bugs, Issues, <i>Things-To-Do</i></a>.<br>
    Software is never finished nor ever tested well enough.
    (Do you want to help develop NuttX?  If so, send me an email).
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#documentation">Other Documentation</a>.<br>
    What other NuttX documentation is available?
  </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td>
    <a href="#trademarks">Trademarks</a>.<br>
    Some of the words used in this document belong to other people.
  </td>
</tr>
</table>
</td>
</tr>
</table></center>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="overview"><h1>Overview</h1></a>
  </td>
  </tr>
</table>

<p>
  <b>Goals</b>.
  Nuttx is a real timed embedded operating system (RTOS).
  Its goals are:
<p>
<center><table width="90%">
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Small Footprint</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      Usable in all but the tightest micro-controller environments,
      The focus is on the tiny-to-small, deeply embedded environment.
    </p>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Rich Feature OS Set</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      The goal is to provide implementations of most standard POSIX OS interfaces
      to support a rich, multi-threaded development environment for deeply embedded
      processors.
    </p>
      NON-GOALS: (1) It is not a goal to provide the rich level of OS
      features like those provided with Linux.
      Small footprint is more important than features.
      Standard compliance is more important than small footprint.
      (2) There is no MMU-based support for processes.
      At present, NuttX assumes a flat address space.
    </p>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Highly Scalable</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      Fully scalable from tiny (8-bit) to moderate embedded (32-bit).
      Scalability with rich feature set is accomplished with:
      Many tiny source files, link from static libraries, highly configurable, use of
      weak symbols when available.
    </p>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Standards Compliance</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      NuttX strives to achieve a high degree of standards compliance.
      The primary governing standards are POSIX and ANSI standards.
      Additional standard APIs from Unix and other common RTOS's are
      adopted for functionality not available under these standards
      or for functionality that is not appropriate for the deeply-embedded
      RTOS (such as <code>fork()</code>).
    </p>
    <p>
      Because of this standards conformance, software developed under other
      standard OSs (such as Linux) should port easily to NuttX.
    </p>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Real-Time</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      Fully pre-emptible, fixed priority and round-robin scheduling.
    </p>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Totally Open</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      Non-restrictive BSD license.
    </p>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>GNU Toolchains</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      Compatible GNU toolchains based on <a href="http://buildroot.uclibc.org/">buildroot</a>
      available for
      <a href="https://sourceforge.net/project/showfiles.php?group_id=189573&package_id=224585">download</a>
      to provide a complete development environment for many architectures.
    </p>
</tr>
</table></center>

<p>
  <b>Feature Set</b>.
  Key features of NuttX include:
<p>
<center><table width="90%">

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Standards Compliant Core Task Management</b>
  </td>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Modular, micro-kernel</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Fully pre-emptible.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Naturally scalable.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Highly configurable.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Easily extensible to new processor architectures, SoC architecture, or board architectures.
          A <a href="NuttxPortingGuide.html">Porting Guide</a> is in development.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>FIFO and round-robin scheduling.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Realtime, deterministic, with support for priority inheritance</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>POSIX/ANSI-like task controls, named message queues, counting semaphores, clocks/timers, signals, pthreads, environment variables, filesystem.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>VxWorks-like task management and watchdog timers.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>BSD socket interface.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Extensions to manage pre-emption.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Well documented in the NuttX <a href="NuttxUserGuide.html">User Guide</a>.</li>
    </p>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>File system</b>
  </td>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Tiny in-memory, root pseudo-file-system.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Supports character and block drivers.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>Network, USB (device), serial, CAN, driver architecture.</li>
    </p>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>RAMDISK, pipes, FIFO, <code>/dev/null</code>, <code>/dev/zero</code> drivers.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Mount-able volumes.  Bind mountpoint, filesystem, and block device driver.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>FAT12/16/32 filesystem support.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Generic driver for SPI-based MMC/SD/SDH cards.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>ROMFS filesystem support.</li>
    </p>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>C Library</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Fully integrated into the OS.</li>
    </p>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Networking</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>TCP/IP, UDP, ICMP stacks.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Small footprint (based on uIP).</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>BSD compatible socket layer.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Networking utilities (DHCP, SMTP, TELNET, TFTP, HTTP)</li>
    </p>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>USB Device Support</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li><i>Gadget</i>-like architecture for USB device controller drivers and device-dependent USB class drivers.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>USB device controller drivers available for the NXP LPC214x and TI DM320.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Device-dependent USB class drivers available for USB serial and for USB mass storage.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Built-in USB trace functionality for USB debug.</li>
    </p>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Graphics Support</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>Framebuffer drivers.</li>
    </p>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <li>
         NX: A graphics library, tiny windowing system and tiny font support.
         Documented in the <a href="NXGraphicsSubsystem.html">NX Graphics Subsystem</a>
         manual.
      </li>
    </p>
</tr>
</table></center>

<p>
  <b>NuttX Add-Ons</b>.
  The following packages are available to extend the basic NuttX feature set:
</p>
<center><table width="90%">

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>NuttShell (NSH)</b>
  </td>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>A small, scalable, bash-like shell for NuttX with rich feature set and small footprint.
        See the <a href="NuttShell.html">NuttShell User Guide</a>.</li>
    </p>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Pascal Compiler with NuttX runtime P-Code interpreter add-on</b>
  </td>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      <li>The Pascal add-on is available for download from the
        <a href="http://sourceforge.net/project/showfiles.php?group_id=189573">SourceForge</a>
        website.</li>
    </p>
  </td>
</tr>
</table></center>

<p>
  <b>Look at all those files and features... How can it be a tiny OS?</b>.
  The NuttX feature list (above) is fairly long and if you look at the NuttX
  source tree, you will see that there are hundreds of source files comprising
  NuttX.  How can NuttX be a tiny OS with all of that?
</p>
<center><table width="90%">

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Lots of Features -- More can be smaller!</b>
  </td>
</tr>

<tr>
  <td><br></td>
  <td>
    <p>
      The philosophy behind that NuttX is that lots of features are great... <i>BUT</i>
      also that if you don't use those features, then you should not have to pay a penalty
      for the unused features.
      And, with NuttX, you don't!  If you don't use a feature, it will not
      be included in the final executable binary.
      You only have to pay the penalty of increased footprint for the features
      that you actually use.
    </p>
    <p>
      Using a variety of technologies, NuttX can scale from the very tiny to
      the moderate-size system.  I have executed NuttX with some simple applications
      in as little as 32Kb <i>total</i> memory (code and data).
      On the other hand, typical, richly featured NuttX builds require more like 64Kb
      (and if all of the features are used, this can push 100Kb).
    </p>
  </td>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Many, many files -- More really is smaller!</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      One may be intimidated by the size NuttX source tree.  There are hundreds of source files!
      How can that be a tiny OS?
      Actually, the large number of files is one of the tricks to keep NuttX small and
      as scalable as possible.
      Most files contain only a single function. 
      Sometimes just one tiny function with only a few lines of code.
      Why?
    </p>
    <ul>
      <li>
        <b>Static Libraries</b>.
        Because in the NuttX build processed, objects are compiled and saved into
        <i>static libraries</i> (<i>archives</i>).
        Then, when the file executable is linked, only the object files that are needed
        are extracted from the archive and added to the final executable.
        By having many, many tiny source files, you can assure that no code that you do
        not execute is ever included in the link.
        And by having many, tiny source files you have better granularity --
        if you don't use that tiny function of even just a few lines of code, it will
        not be included in the binary.
      </li>
    </ul>
  </td>
</tr>

<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Other Tricks</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      As mentioned above, the use of many, tiny source files and linking from static
      libraries keeps the size of NuttX down.
      Other tricks used in NuttX include:
    </p>
    <ul>
      <li>
         <b>Configuration Files</b>.
         Before you build NuttX, you must provide a configuration file that specifies
         what features you plan to use and which features you do not.
         This configuration file contains a long list of settings that control
         what is built into NuttX and what is not.
         There are hundreds of such settings
         (see the <a href="NuttxPortingGuide.html#apndxconfigs">NuttX Porting Guide</a>
         for a partial list that excludes platform specific settings).
         These many, many configuration options allow NuttX to be highly tuned to
         meet size requirements.
         The downside to all of these configuration options is that it greatly
         complicates the maintenance of NuttX -- but that is my problem, not yours.
      </li>
      <li>
         <b>Weak Symbols</b>
         The GNU toolchain supports <i>weak</i> symbols and these also help to keep
         the size of NuttX down.
         Weak symbols prevent object files from being drawn into the link even if they
         are accessed from source code.
         Careful use of weak symbols is another trick for keep unused code out of the
         final binary.
      </li>
    </ul>
  </td>
</tr>

</table></center>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="downloads"><h1>Downloads</h1></a>
  </td>
  </tr>
</table>

<p><b>nuttx-0.4.7</b>.
  The 39<sup>th</sup> release of NuttX (nuttx-0.4.7) was made on May 29, 2009 and is available for download
  from the <a href="http://sourceforge.net/project/showfiles.php?group_id=189573">SourceForge</a>
  website.
  The change log associated with the release is available <a href="#currentrelease">here</a>.
  Unreleased changes after this release are available in CVS.
  These unreleased changes are listed <a href="#pendingchanges">here</a>.
</p>
<p>
  This release focuses on cleaning up and extending the Eagle100/LM3S6918 port released
  in nuttx-0.4.6 and on improved MMC/SD support.  New features include:
  <ul>
    <li>
      Improved reliably and additional drivers for the Eagle-100 board (LM3S6918
      ARM Cortex-M3).  Additional drivers include Ethernet, SSI, and support for
      the on-board LEDs and microSD cards.
    </li>
    <li>
      The SPI-based MMC/SD driver was extended to support SDHC Version 2.xx cards.
    </li>
  </ul>
</p>
<p>
  In addition, this release includes several important bugfixes for the LM3S6918, the LPC2148,
  the SPI-based MMC/SD driver, and to FAT32.  See the ChangeLog for details of these bugfixes.
</p>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="platforms"><h1>Supported Platforms</h1></a>
  </td>
  </tr>
</table>

<center><table width="90%">
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Linux User Mode</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      A user-mode port of NuttX to the x86 Linux/Cygwin platform is available.
      The purpose of this port is primarily to support OS feature development.
    </p>
    <p>
      <b>STATUS:</b>
      Does not support interrupts but is otherwise fully functional.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>ARM7TDMI</b>.
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>TI TMS320C5471</b> (also called <b>C5471</b> or <b>TMS320DA180</b> or <b>DA180</b>).
      NuttX operates on the ARM7 of this dual core processor.
      This port uses the <a href="http://www.spectrumdigital.com/">Spectrum Digital</a>
      evaluation board with a GNU arm-elf toolchain* under Linux or Cygwin.
    </p>
    <p>
      <b>STATUS:</b>
      This port is complete, verified, and included in the initial NuttX release.
    </p>
   </td>
</tr>
<tr>
  <td><br></td>
  <td><hr></td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>NXP LPC214x</b>.
      Support is provided for the NXP LPC214x family of processors.  In particular,
      support is provided for the mcu123.com lpc214x evaluation board (LPC2148).
      This port also used the GNU arm-elf toolchain* under Linux or Cygwin.
    </p>
    <p>
      <b>STATUS:</b>
      This port boots and passes the OS test (examples/ostest).
      The port is complete and verified.  As of NuttX 0.3.17, the port includes:
      timer interrupts, serial console, USB driver, and SPI-based MMC/SD card
      support.  A verified NuttShell <a href="NuttShell.html">(NSH)</a>
      configuration is also available.
    </p>
    <p>
      <b>Development Environments:</b>
      1) Linux with native Linux GNU toolchain, 2) Cygwin with Cygwin GNU toolchain, or 3) Cygwin
      with Windows native toolchain (CodeSourcery or devkitARM).  A DIY toolchain for Linux
      or Cygwin is provided by the NuttX
      <a href="http://sourceforge.net/project/showfiles.php?group_id=189573&package_id=224585">buildroot</a>
      package.
    </p>
  </td>
</tr>
<tr>
  <td><br></td>
  <td><hr></td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>STMicro STR71x</b>.
      Support is provided for the STMicro STR71x family of processors.  In particular,
      support is provided for the Olimex STR-P711 evaluation board.
      This port also used the GNU arm-elf toolchain* under Linux or Cygwin.
    </p>
    <p>
      <b>STATUS:</b>
      Integration is complete on the basic port (boot logic, system time, serial console).
      Two configurations have been verified: (1) The board boots and passes the OS test
      with console output visible on UART0, and the NuttShell <a href="NuttShell.html">(NSH)</a>
      is fully functional with interrupt driven serial console.  An SPI driver is available
      but untested (because the Olimex card slot appears to accept only MMC cards; I have
      only SD cards).  Additional features are needed: USB driver, MMC integration, to name two.
    </p>
    <p>
      <b>Development Environments:</b>
      1) Linux with native Linux GNU toolchain, 2) Cygwin with Cygwin GNU toolchain, or 3) Cygwin
      with Windows native toolchain (CodeSourcery or devkitARM).  A DIY toolchain for Linux
      or Cygwin is provided by the NuttX
      <a href="http://sourceforge.net/project/showfiles.php?group_id=189573&package_id=224585">buildroot</a>
      package.
    </p>
  </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>ARM920T</b>.
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Freescale MC9328MX1</b> or <b>i.MX1</b>.
      This port uses the Freescale MX1ADS development board with a GNU arm-elf toolchain*
      under either Linux or Cygwin.
    </p>
    <p>
      <b>STATUS:</b>
        This port is in progress.  Coding is complete on the basic port (timer, serial console, SPI).
        Verified support for the i.MX1 will be announced in a future release of NuttX (work has
        been temporarily stopped to support the Luminary LM3S6918).
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>ARM926EJS</b>.
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>TI TMS320DM320</b> (also called <b>DM320</b>).
      NuttX operates on the ARM9 of this dual core processor.
      This port uses the
      <a href="http://wiki.neurostechnology.com/index.php/Developer_Welcome">Neuros OSD</a>
      with a GNU arm-elf toolchain* under Linux or Cygwin.
    </p>
    <p>
      <b>STATUS:</b>
        The basic port (timer interrupts, serial ports, network, framebuffer, etc.) is complete.
        All implemented features have been verified with the exception of the USB device-side
        driver; that implementation is complete but untested.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>ARM Cortex-M3</b>.
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Luminary LM3S6918</b>.
      This port uses the <a href=" http://www.micromint.com/">Micromint</a> Eagle-100 development
      board with a GNU arm-elf toolchain* under either Linux or Cygwin.
    </p>
    <p>
      <b>STATUS:</b>
        The initial, release of this port was included in NuttX  version 0.4.6.
        The current port includes timer, serial console, Ethernet, SSI, and microSD support.
        There are working configurations the NuttX OS test, to run the <a href="NuttShell.html">NuttShell
        (NSH)</a>, the NuttX networking test, and the uIP web server.
    </p>
    <p>
      <b>Development Environments:</b>
      1) Linux with native Linux GNU toolchain, 2) Cygwin with Cygwin GNU toolchain, or 3) Cygwin
      with Windows native toolchain (CodeSourcery or devkitARM).  A DIY toolchain for Linux
      or Cygwin is provided by the NuttX
      <a href="http://sourceforge.net/project/showfiles.php?group_id=189573&package_id=224585">buildroot</a>
      package.
    </p>
   </td>
</tr>

<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>8052 Microcontroller</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>PJRC 87C52 Development Board</b>.
      This port uses the <a href="http://www.pjrc.com/">PJRC</a> 87C52 development system
      and the <a href="http://sdcc.sourceforge.net/">SDCC</a> toolchain under Linux or Cygwin.
    </p>
    <p>
     <b>STATUS:</b>
      This port is complete but not stable with timer interrupts enabled.
      There seems to be some issue when the stack pointer enters into the indirect IRAM
      address space during interrupt handling.
      This architecture has not been built in some time will likely have some compilation
      problems because of SDCC compiler differences.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Renesas/Hitachi SuperH</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>SH-1 SH7032</b>.
      This port uses the Hitachi SH-1 Low-Cost Evaluation Board (SH1_LCEVB1), US7032EVB,
      with a GNU arm-elf toolchain* under Linux or Cygwin.
    </p>
    <p>
     <b>STATUS:</b>
      This port is available as of release 0.3.18 of NuttX.  The port is basically complete
      and many examples run correctly.  However, there are remaining instabilities that
      make the port un-usable.  The nature of these is not understood; the behavior is
      that certain SH-1 instructions stop working as advertised.  This could be a silicon
      problem, some pipeline issue that is not handled properly by the gcc 3.4.5 toolchain
      (which has very limit SH-1 support to begin with), or perhaps with the CMON debugger.
      At any rate, I have exhausted all of the energy that I am willing to put into this cool
      old processor for the time being.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Renesas M16C/26</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Renesas M16C/26 Microncontroller</b>.
      This port uses the Renesas SKP16C26 Starter kit and the GNU M32C toolchain. 
      The development environment is either Linux or Cygwin under WinXP.
    </p>
    <p>
      <b>STATUS:</b>
      Initial source files released in nuttx-0.4.2.
      At this point, the port has not been integrated;	the target cannot be built
      because the GNU <code>m16c-elf-ld</code> link fails with  the following message:
    </p>
    <ul>
    <code>m32c-elf-ld: BFD (GNU Binutils) 2.19 assertion fail /home/Owner/projects/nuttx/buildroot/toolchain_build_m32c/binutils-2.19/bfd/elf32-m32c.c:482</code>
    </ul>
    <p>Where the reference line is:</p>
    <ul><pre>
/* If the symbol is out of range for a 16-bit address,
   we must have allocated a plt entry.  */
BFD_ASSERT (*plt_offset != (bfd_vma) -1);
</pre></ul>
    <p>
      No workaround is known at this time.  This is a show stopper for M16C for
      the time being.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Zilog Z16F</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Zilog z16f Microncontroller</b>.
      This port use the Zilog z16f2800100zcog development kit and the Zilog
      ZDS-II Windows command line tools.
      The development environment is Cygwin under WinXP.
    </p>
    <p>
      <b>STATUS:</b>
      The initial release of support for the z16f was made available in NuttX version 0.3.7.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Zilog eZ80 Acclaim!</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Zilog eZ80Acclaim! Microncontroller</b>.
      There are two eZ80Acclaim! ports:
    </p>
    <ul>
      <li>One uses the ZiLOG ez80f0910200kitg development kit, and
      <li>The other uses the ZiLOG ez80f0910200zcog-d development kit.
    </ul>
    <p>
      Both boards are based on the eZ80F091 part and both use the Zilog ZDS-II
      Windows command line tools.
      The development environment is Cygwin under WinXP.
    </p>
    <p>
      <b>STATUS:</b>
      Integration and testing of NuttX on the  ZiLOG ez80f0910200zcog-d is complete.
      The first integrated version was released in NuttX version 0.4.2 (with important early bugfixes
      in 0.4.3 and 0.4.4).
      As of this writing, that port provides basic board support with a serial console, SPI, and eZ80F91 EMAC driver.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Zilog Z8Encore!</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Zilog Z8Encore! Microncontroller</b>.
      This port uses the either:
    </p>
    <ul>
      <li>Zilog z8encore000zco development kit, Z8F6403 part, or</li>
      <li>Zilog z8f64200100kit development kit, Z8F6423 part</li>
    </ul>
    <p>
      and the Zilog ZDS-II Windows command line tools.
      The development environment is Cygwin under WinXP.
    </p>
    <p>
      <b>STATUS:</b>
      This release has been verified only on the ZiLOG ZDS-II Z8Encore! chip simulation
      as of nuttx-0.3.9.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Zilog Z80</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      <b>Z80 Instruction Set Simulator</b>.
      This port uses the <a href="http://sdcc.sourceforge.net/">SDCC</a> toolchain
      under Linux or Cygwin (verified using version 2.6.0).
      This port has been verified using only a Z80 instruction simulator.
      That simulator can be found in the NuttX CVS
      <a href="http://nuttx.cvs.sourceforge.net/nuttx/misc/sims/z80sim/">here</a>.
    </p>
    <p>
     <b>STATUS:</b>
      This port is complete and stable to the extent that it can be tested
      using an instruction set simulator.
    </p>
   </td>
</tr>
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Other ports</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      There are partial ports for the TI TMS320DM270 and for MIPS.
    </p>
   </td>
</tr>
</table></center>

<blockquote>* A highly modified <a href="http://buildroot.uclibc.org/">buildroot</a>
is available that may be used to build a NuttX-compatible ELF toolchain under
Linux or Cygwin.  Configurations are available in that buildroot to support ARM,
m68k, m68hc11, m68hc12, and SuperH ports.</blockquote>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="environments"><h1>Development Environments</h1></a>
  </td>
  </tr>
</table>

<center><table width="90%">
<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Linux + GNU make + GCC/binutils</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      The is the most natural development environment for NuttX.
      Any version of the GCC/binutils toolchain may be used.
      There is a  highly modified <a href="http://buildroot.uclibc.org/">buildroot</a>
      available for download from the
      <a href="http://sourceforge.net/project/showfiles.php?group_id=189573">NuttX SourceForge</a>
      page.
      This download may be used to build a NuttX-compatible ELF toolchain under Linux or Cygwin.
      That toolchain will support ARM, m68k, m68hc11, m68hc12, and SuperH ports.
      The buildroot CVS may be accessed in the 
      <a href="http://nuttx.cvs.sourceforge.net/nuttx/misc/buildroot/">NuttX CVS</a>.
    </p>
   </td>
</tr>

<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Linux + GNU make + SDCC</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      Also very usable is the Linux environment using the 
      <a href="http://sdcc.sourceforge.net/">SDCC</a> compiler.
      The SDCC compiler provides support for the 8051/2, z80, hc08, and other microcontrollers.
      The SDCC-based logic is less well exercised and you will likely find some compilation
      issues if you use parts of NuttX with SDCC that have not been well-tested.
    </p>
   </td>
</tr>

<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Cygwin + GNU make + GCC/binutils</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      This combination works well too.
      It works just as well as the native Linux environment except
      that compilation and build times are a little longer.
      The custom NuttX buildroot referenced above may be build in
      the Cygwin environment as well.
    </p>
  </td>
</tr>

<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Cygwin + GNU make + SDCC</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
       I have never tried this combination, but it would probably work just fine.
    </p>
  </td>
</tr>

<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Cygwin + GNU make + Windows Native Toolchain</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      This is a tougher environment.
      In this case, the Windows native toolchain is unaware of the the
      Cygwin <i>sandbox</i> and, instead, operates in the native Windows environment.
      The primary difficulties with this are:
    </p>
    <ul>
      <li>
        <b>Paths</b>.
        Full paths for the native toolchain must follow Windows standards.
        For example, the path <code>/home/my\ name/nuttx/include</code> my have to be
        converted to something like <code>'C:\cygwin\home\my name\nuttx\include'</code>
        to be usable by the toolchain.
      </li>
      <p>
        Fortunately, this conversion is done simply using the <code>cygpath</code> utility.
      </p>
      <li>
        <b>Symbolic Links</b>
        NuttX depends on symbolic links to install platform-specific directories in the build system.
        On Linux, true symbolic links are used.
        On Cygwin, emulated symbolic links are used.
        Unfortunately, for native Windows applications that operate outside of the
        Cygwin <i>sandbox</i>, these symbolic links cannot be used.
      </li>
      <p>
        The NuttX make system works around this limitation by copying the platform
        specific directories in place.
        These copied directories make work a little more complex, but otherwise work well.
      </p>
      <li>
        <b>Dependencies</b>
        NuttX uses the GCC compiler's <code>-M</code> option to generate make dependencies.  These
        dependencies are retained in files called <code>Make.deps</code> throughout the system.
        For compilers other than GCC, there is no support for making dependencies in this way.
        For Windows native GCC compilers, the generated dependencies are windows paths and not
        directly usable in the Cygwin make.  By default, dependencies are surpressed for these
        compilers as well.
      </li>
      <p><small>
        NOTE: dependencies are suppress by setting the make variable <code>MKDEPS</code> to point
        to the do-nothing dependency script, <code>tools/mknulldeps.sh</code>.
        Dependencies can be enabled for the Windows native GCC compilers by setting
        <code>MKDEPS</code> to point to <code>$(TOPDIR)/tools/mkdeps.sh --winpaths $(TOPDIR)</code>.
      </small></p>
    </ul>
    <p>
      At present, only the Zilog Z16F, z8Encore, and eZ80Acclaim ports use a non-GCC native Windows
      toolchain(the Zilog ZDS-II toolchain).
      Support for Windows native GCC toolchains (CodeSourcery and devkitARM) is currently implemented
      for the NXP LPC214x, STMicro STR71x, and Luminary LMS6918 ARM ports.
      (but could easily be extended to any other GCC-based platform with a small effort).
    </p>
  </td>
</tr>

<tr>
  <td valign="top"><img height="20" width="20" src="favicon.ico"></td>
  <td bgcolor="#5eaee1">
    <b>Other Environments?</b>
  </td>
</tr>
<tr>
  <td><br></td>
  <td>
    <p>
      The primary environmental dependency of NuttX are (1) GNU make,
      (2) bash scripting, and (3) Linux utilities (such as sed).
      If you have other platforms that support GNU make or make
      utilities that are compatible with GNU make, then it is very
      likely that NuttX would work in that environment as well (with some
      porting effort). If GNU make is not supported, then some significant
      modification of the Make system would be required.
    </p>
  </td>
</tr>
</table></center>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="footprint"><h1>Memory Footprint</h1></a>
  </td>
  </tr>
</table>

<ul>
<p><b>C5471 (ARM7)</b>
  The build for this ARM7 target that includes most of the OS features and
  a broad range of OS tests.  The size of this executable as given by the
  Linux <tt>size</tt> command is (3/9/07):
</p>
<pre>
   text    data     bss     dec     hex filename
  53272     428    3568   57268    dfb4 nuttx
</pre>
<p><b>DM320 (ARM9)</b>
  This build for the ARM9 target includes a significant subset of OS
  features, a filesystem, Ethernet driver, full TCP/IP, UDP and (minimal)
  ICMP stacks (via uIP) and a small network test application: (11/8/07,
  configuration netconfig, examples/nettest)
</p>
<pre>
   text    data     bss     dec     hex filename
  49472     296    3972   53740    d1ec nuttx
</pre>
<p>
  Another build for the ARM9 target includes a minimal OS feature
  set, Ethernet driver, full TCP/IP and (minimal) ICMP stacks, and
  a small webserver: (11/20/07, configuration uipconfig, examples/uip)
</p>
<pre>
   text    data     bss     dec     hex filename
  52040      72    4148   56260    dbc4 nuttx
</pre>
<p><b>87C52</b>
  A reduced functionality OS test for the 8052 target requires only
  about 18-19Kb:
</p>
<pre>
Stack starts at: 0x21 (sp set to 0x20) with 223 bytes available.

Other memory:
   Name             Start    End      Size     Max
   ---------------- -------- -------- -------- --------
   PAGED EXT. RAM                         0      256
   EXTERNAL RAM     0x0100   0x02fd     510     7936
   ROM/EPROM/FLASH  0x2100   0x6e55   19798    24384
</pre>
</ul>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="licensing"><h1>Licensing</h1></a>
  </td>
  </tr>
</table>

<ul>
<p>
  NuttX is available under the highly permissive
  <a href="http://en.wikipedia.org/wiki/BSD_license">BSD license</a>.
  Other than some fine print that you agree to respect the copyright
  you should feel absolutely free to use NuttX in any environment and
  without any concern for jeopardizing any proprietary software that
  you may link with it.
</p>
</ul>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="history"><h1>Release History</h1></a>
  </td>
  </tr>
</table>

<ul>
<p>
   The current NuttX Change Log is available in CVS <a href="http://nuttx.cvs.sourceforge.net/*checkout*/nuttx/nuttx/ChangeLog">here</a>.
   ChangeLog snapshots associated with the current release are available below.
</p>
</ul>

<center><table width ="80%">
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
   <td>
      <a href="ChangeLog.txt">Change Logs for All NuttX Releases</a><br>
   </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
   <td>
      <a href="#currentrelease">ChangeLog for Current Releases</a><br>
   </td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
   <td>
      <a href="#pendingchanges">Unreleased Changes</a>
   </td>
</tr>
</table></center>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="currentrelease">ChangeLog for Current Release</a>
  </td>
  </tr>
</table>

<pre><ul>
nuttx-0.4.7 2009-05-29 Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;

	* arch/arm/src/lm3s: Added an Ethernet driver for the LM3S6918
	* configs/eagle100/nettest: Added an examples/nettest configuration for the
	  Micromint Eagle100 board.
	* Documentation/NuttxPortingGuide.html: Added a section on NuttX device drivers.
	* configs/eagle100/httpd: Added an examples/uip configuration for the
	  Micromint Eagle100 board.
	* arch/arm/src/lm3s: Added an SSI driver for the LM3S6918
	* examples/nsh: Added MMC/SD support for the LM3S6918
	* arch/arm/src/lm3s: Fix logic for setting and clearing output GPIOs (critical
	  fix!).
	* drivers/mmcsd: Found numerous errors in current MMC/SD SPI driver.  Bad frequency
	  calculation based on CSD settings, inappropriate timeouts, odd code that looks like
	  a bad search and replace.  Also needs support for SDHC ver 2.x.  New MMC/SD is
	  largely redesigned and probably non-functional in the first check-in.
	* drivers/mmcsd: Changes verified on 4Gb Kingston microSHDC card and on a 2Gb
	  SanDisk microSDC card on the Eagle100 platform.
	* fs/fat: With the 4Gb card, the first tests of FAT32 were (finally) performed.
	  Found and corrected a problem that prevented use of FAT32: It was not updating
	  the sector cache before checking the FAT32 FSINFO sector.
	* configs/eagle100/*/Make.defs:  Added configuration options that should make
	  it possible to build NuttX for the Eagle100 using CodeSourcery 2009q1 toolchain
	  and the devkitARM GNU toolchain.
	* configs/mcu123-lpc214x/src: Corrected some logic in the LPC2148 SPI receive block
	  logic.  Re-verified SDC ver1.x support with 1Gb Toshiba SDC, 1Gb PNY SDC, and
	  4Gb Kingston SDHC.  There are CMD0 issues with the 2Gb SanDisk SDC on this board.
	* fs/fs_mount.c: Corrected error handling that could cause a deadlock on certain
	  mount() failures.

pascal-0.1.2 2008-02-10 Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;

	* Add logic to build and link with the ZDS-II toolchain
	  use with the z16f.
	* Make sure that POFF header structures are aligned
	* Standardized POFF file format to big-endian
	* Break up large switch statements to lower complexity
	  and eliminate a compiler bug
	* Changes so that runtime compiles with SDCC.

buildroot-0.1.6 2009-xx-xx &lt;spudmonkey@racsa.co.cr&gt;

	* Added config/arm7tdmi-defconfig-4.2.4
	* Added config/arm920t-defconfig-4.3.3
	* Correct error in arm-defconfig gcc-3.4.6 build. The gcc-3.4.6 configuration
	  does not not take --with-abi
	* Correct error in gcc-3.4.6/gcc/collect.c.  Calls open with O_CREAT but
	  does not specify mode.  Newer host compilers can error out on this.
</pre></ul>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="pendingchanges">Unreleased Changes</a>
  </td>
  </tr>
</table>

<pre><ul>
nuttx-0.4.8 2009-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;

	* lib/lib_*stream.c: Extend internal stream logic to support incoming streams.
	* arch/arm/src/str71x: Serial output is now correct and timer interrupts are
	  working.  The test at configs/olimex-strp711/ostest passes.  This means that
	  the basic STR-P711 port is complete.
	* configs/olimex-strp711/nsh:  Add and verifed a NuttShell (NSH) configuration
	  for the STR-P711.
	* arch/arm/str71x/str71x_serial.c:  The STR711 interrupt driven serial driver
	  finally works after some extradinary measures to handle missed interrupts.
	  NSH is fully functional on the Olimex STR-P711 board.
	* example/nsh: Moved architecture specific files from NSH directory to board-
	  specific directories.
	* config/olimex-strp711/src/up_nsh.c:  Add an NSH board specific directory for
	  for the Olimex STR7P11 board.
	* Fixed build of LM3X6918 using the CodeSourcery Windows native toolchain.  There
	  were lots of issues with Cygwin paths and Cygwin symbolic links.  These changes
	  may work with the devarmKIT as well, but that remains untested.
	* The NXP LPC2148 and STR711 targets can now also be built using the CodeSourcery
	  or devkitARM Windows native toolchains.

pascal-0.1.3 2009-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;

buildroot-0.1.7 2009-xx-xx &lt;spudmonkey@racsa.co.cr&gt;

	* configs/avr-defconfig-4.3.3: Added support for AVR to support a NuttX
	  port of the ATmega128.
</pre></ul>

<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="TODO"><h1>Bugs, Issues, <i>Things-To-Do</i></h1></a>
  </td>
  </tr>
</table>

<ul>
<p>
   The current list of NuttX <i>Things-To-Do</i> in CVS <a href="http://nuttx.cvs.sourceforge.net/*checkout*/nuttx/nuttx/TODO">here</a>.
   A snapshot of the <i>To-Do</i> list associated with the current release are available <a href="TODO.txt">here</a>.
</p>
</ul>
<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="documentation"><h1>Other Documentation</h1></a>
  </td>
  </tr>
</table>

<ul><table>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td><a href="NuttxUserGuide.html">User Guide</a></td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td><a href="NuttxPortingGuide.html">Porting Guide</a></td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td><a href="NuttShell.html">NuttShell (NSH)</a></td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td><a href="NXGraphicsSubsystem.html">NX Graphics Subsystem</a></td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td><a href="ChangeLog.txt">Change Log</a></td>
</tr>
<tr>
  <td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
  <td><a href="TODO.txt">To-Do List</a></td>
</tr>
</center></ul>

<small>
<table width ="100%">
  <tr bgcolor="#e4e4e4">
  <td>
    <a name="trademarks"><h1>Trademarks</h1></a>
  </td>
  </tr>
</table>
<ul>
  <li>ARM, ARM7 ARM7TDMI, ARM9, ARM920T, ARM926EJS Cortex-M3 are trademarks of Advanced RISC Machines, Limited.</li>
  <li>Cygwin is a trademark of Red Hat, Incorporated.</li>
  <li>Linux is a registered trademark of Linus Torvalds.</li>
  <li>Eagle-100 is a trademark of <a href=" http://www.micromint.com/">Micromint USA, LLC</a>.
  <li>LPC2148 is a trademark of NXP Semiconductors.</li>
  <li>TI is a tradename of Texas Instruments Incorporated.</li>
  <li>UNIX is a registered trademark of The Open Group.</li>
  <li>VxWorks is a registered trademark of Wind River Systems, Incorporated.</li>
  <li>ZDS, ZNEO, Z16F, Z80, and Zilog are a registered trademark of Zilog, Inc.</li>
</ul>
<p>
  NOTE: NuttX is <i>not</i> licensed to use the POSIX trademark.  NuttX uses the POSIX
  standard as a development guideline only.
</p>
</small>

</body>
</html>