NuttX.html

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      <h1><big><font color="#3c34ec"><i>NuttX RTOS</i></font></big></h1>
      <p>Last Updated: March 17, 2011</p>
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  <h1>Table of Contents</h1>
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  <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?
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  <td>
    <a href="#group">NuttX Discussion Group</a>.<br>
    Do you want to talk about NuttX features?  Do you need some help?  Problems?  Bugs?
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    <a href="#downloads">Downloads</a>.<br>
    Where can I get NuttX?  What is the current development status?
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    <a href="#platforms">Supported Platforms</a>.<br>
    What target platforms has NuttX been ported to?
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    <a href="#environments">Development Environments</a>.<br>
    What kinds of host cross-development platforms can be used with NuttX?
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    <a href="#footprint">Memory Footprint</a>.<br>
    Just how big is it?  Do I have enough memory to use NuttX?
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    <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)
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    <a href="#history">Release History</a><br>
    What has changed in the last release of NuttX?
    What unreleased changes are pending in SVN?
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    <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).
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    <a href="#documentation">Other Documentation</a>.<br>
    What other NuttX documentation is available?
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    <a href="#trademarks">Trademarks</a>.<br>
    Some of the words used in this document belong to other people.
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    <a name="overview"><h1>Overview</h1></a>
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<p>
  <b>Goals</b>.
  Nuttx is a real timed embedded operating system (RTOS).
  Its goals are:
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    <b>Small Footprint</b>
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    <p>
      Usable in all but the tightest micro-controller environments,
      The focus is on the tiny-to-small, deeply embedded environment.
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    <b>Rich Feature OS Set</b>
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    <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.
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    <b>Highly Scalable</b>
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      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.
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    <b>Standards Compliance</b>
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    <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>).
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    <p>
      Because of this standards conformance, software developed under other
      standard OSs (such as Linux) should port easily to NuttX.
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    <b>Real-Time</b>
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      Fully pre-emptible, fixed priority and round-robin scheduling.
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    <b>Totally Open</b>
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      Non-restrictive BSD license.
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    <b>GNU Toolchains</b>
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    <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.
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<p>
  <b>Feature Set</b>.
  Key features of NuttX include:
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    <b>Standards Compliant Core Task Management</b>
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      <li>Modular, micro-kernel</li>
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      <li>Fully pre-emptible.</li>
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      <li>Naturally scalable.</li>
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      <li>Highly configurable.</li>
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      <li>Easily extensible to new processor architectures, SoC architecture, or board architectures.
          A <a href="NuttxPortingGuide.html">Porting Guide</a> is in development.</li>
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      <li>FIFO and round-robin scheduling.</li>
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      <li>Realtime, deterministic, with support for priority inheritance</li>
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      <li>POSIX/ANSI-like task controls, named message queues, counting semaphores, clocks/timers, signals, pthreads, environment variables, filesystem.</li>
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      <li>VxWorks-like task management and watchdog timers.</li>
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      <li>BSD socket interface.</li>
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      <li>Extensions to manage pre-emption.</li>
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      <li>On-demand paging.</li>
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    <p>
      <li>Well documented in the NuttX <a href="NuttxUserGuide.html">User Guide</a>.</li>
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    <b>File system</b>
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      <li>Tiny in-memory, root pseudo-file-system.</li>
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      <li>Supports character and block drivers.</li>
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      <li>Network, USB (host), USB (device), serial, CAN, driver architectures.</li>
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    <p>
      <li>RAMDISK, pipes, FIFO, <code>/dev/null</code>, <code>/dev/zero</code> drivers.</li>
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      <li>Mount-able volumes.  Bind mountpoint, filesystem, and block device driver.</li>
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      <li>FAT12/16/32 filesystem support.</li>
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      <li>Generic driver for SPI-based MMC/SD/SDH cards.</li>
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      <li>ROMFS filesystem support.</li>
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    <p>
      <li><a href="NuttXNxFlat.html">NXFLAT</a>.
      A new binary format call NXFLAT that can be used to 
      execute separately linked programs in place in a file system.
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    <b>C Library</b>
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      <li>Fully integrated into the OS.</li>
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    <b>Networking</b>
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      <li>TCP/IP, UDP, ICMP, IGMPv2 (client) stacks.</li>
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      <li>SLIP</li>
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      <li>Small footprint (based on uIP).</li>
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      <li>BSD compatible socket layer.</li>
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      <li>Networking utilities (DHCP, SMTP, TELNET, TFTP, HTTP)</li>
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    <p>
      <li>
        A NuttX port of Jeff Poskanzer's <a href="http://acme.com/software/thttpd">THTTPD</a> HTTP server
        integrated with <a href="NuttXNxFlat.html">NXFLAT</a> to provide true, embedded CGI.
      </li>
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