Newer
Older
<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>
</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?
<tr>
<td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
<td>
<a href="#group">NuttX Discussion Group</a>.<br>
Do you want to talk about NuttX features? Do you need some help? Problems? Bugs?
</td>
</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>
<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>
<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>
<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>
<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>
<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>
<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.
<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>
<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>
</table></center>
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<a name="overview"><h1>Overview</h1></a>
</td>
</tr>
</table>
Nuttx is a real timed embedded operating system (RTOS).
Its goals are:
<p>
<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>
<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>
The goal is to provide implementations of most standard POSIX OS interfaces
to support a rich, multi-threaded development environment for deeply embedded
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>
<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>
<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>
<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>
<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>
<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>
<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>
</p>
</tr>
<tr>
<td><br></td>
<td>
<p>
</p>
</tr>
<tr>
<td><br></td>
<td>
<p>
<tr>
<td><br></td>
<td>
<p>
<li>Highly configurable.</li>
</p>
</tr>
<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>
</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>
</p>
</tr>
<tr>
<td><br></td>
<td>
<p>
</p>
</tr>
<tr>
<td><br></td>
<td>
<p>
<tr>
<td><br></td>
<td>
<p>
<li>On-demand paging.</li>
</p>
</tr>
<li>Well documented in the NuttX <a href="NuttxUserGuide.html">User Guide</a>.</li>
<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>
</p>
</tr>
<tr>
<td><br></td>
<td>
<p>
</p>
</tr>
<tr>
<td><br></td>
<td>
<p>
<li>Network, USB (device), serial, CAN, driver architecture.</li>
<tr>
<td><br></td>
<td>
<p>
<li>RAMDISK, pipes, FIFO, <code>/dev/null</code>, <code>/dev/zero</code> drivers.</li>
</p>
</tr>
<li>Mount-able volumes. Bind mountpoint, filesystem, and block device driver.</li>
</p>
</tr>
<tr>
<td><br></td>
<td>
<p>
<li>Generic driver for SPI-based MMC/SD/SDH cards.</li>
<tr>
<td><br></td>
<td>
<p>
<li>ROMFS filesystem support.</li>
</p>
</tr>
<tr>
<td><br></td>
<td>
<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.
</p>
</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>
<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>
</p>
</tr>
<tr>
<td><br></td>
<td>
<p>
</p>
</tr>
<tr>
<td><br></td>
<td>
<p>
</p>
</tr>
<tr>
<td><br></td>
<td>
<p>
<tr>
<td><br></td>
<td>
<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>
</p>
</tr>
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
<tr>
<td valign="top" width="22"><img height="20" width="20" src="favicon.ico"></td>
<td bgcolor="#5eaee1">
<b>FLASH Support</b>
</td>
</tr>
<tr>
<td><br></td>
<td>
<p>
<li><i>MTD</i>-inspired interface for <i>M</i>emory <i>T</i>echnology <i>D</i>evices.</li>
</p>
</tr>
<tr>
<td><br></td>
<td>
<p>
<li><i>FTL</i>. Simple <i>F</i>lash <i>T</i>ranslation <i>L</i>ayer support file systems on FLASH.</li>
</p>
</tr>
<tr>
<td><br></td>
<td>
<p>
<li>Support for SPI-based FLASH devices.</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, LPC313x, STMicro STM32 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>
<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>LCD drivers for both parallel and SPI LCDs and OLEDs.</li>
</p>
</tr>
NX: A graphics library, tiny windowing system and tiny font support that works with either framebuffer or LCD drivers.
Documented in the <a href="NXGraphicsSubsystem.html">NX Graphics Subsystem</a>
manual.
</li>
<p>
<b>NuttX Add-Ons</b>.
The following packages are available to extend the basic NuttX feature set:
<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>
<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?
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
</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).
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
<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 width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<a name="group"><h1>NuttX Discussion Group</h1></a>
</td>
</tr>
</table>
<p>
Most Nuttx-related discussion occurs on the <a href="http://tech.groups.yahoo.com/group/nuttx/" target="_top"><i>Yahoo!</i> NuttX group</a>.
You are cordially invited to <a href="http://groups.yahoo.com/group/nuttx/join" target="_top">join</a>.
I make a special effort to answer any questions and provide any help that I can.
</p>
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<a name="downloads"><h1>Downloads</h1></a>
</td>
</tr>
</table>
This 57<sup>th</sup> release of NuttX, Version 5.10, was made on September 7, 2010 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>.
These unreleased changes are listed <a href="#pendingchanges">here</a>.
<p>
This release includes a combination of some new features as well as several bugfixes.
New features include:
<b>TI/Luminary Stellaris LM3S9B96</b>.
Header file changes contributed by Tiago Maluta.
<b>TI/Luminary Stellaris LM3S8962</b>.
Header file changes and support for the Stellaris LM3S8962 Ethernet+CAN Evaluation Board contributed by Larry Arnold.
<b>On-Demand Paging Support</b>.
The basic logic for the On-Demand Paging feature is complete, implemented for the NXP LPC3131, and partially tested.
See <a href="http://www.nuttx.org/NuttXDemandPaging.html">On-Demand Paging Documentation</a>.
Some additional test infrastructure will be needed in order to complete the verification.
See the EA3131 <a href="http://nuttx.cvs.sourceforge.net/viewvc/nuttx/nuttx/configs/ea3131/README.txt?view=log">README</a> file for details.
<b>Two Pass Build Support</b>.
The make system now supports a two pass build where a relocatable, partially linked object is created on the first pass and that object is linked with the NuttX libraris to produce the final executable on the second pass.
This two pass build is currently only used to support the On-Demand paging feature:
The first pass link forces critical logic into the locked text region;
the second pass builds the NuttX executable more-or-less as normal.
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
<b><code>CONFIG_APP_DIR</code></b>.
Generalized the way in which applications are built and linked with NuttX.
The new configuration <code>CONFIG_APP_DIR</code> replaces <code>CONFIG_EXAMPLE</code>.
<code>CONFIG_EXAMPLE</code> used to identify the sub-directory within the NuttX <code>examples/</code> directory that held the example application to be built.
That made it awkward to configure to build an application that resided outside of the NuttX <code>examples/</code> directory.
<code>CONFIG_APP_DIR</code> is more general;
it can be used to refer to any directory containing the application to be built.
<ul>
<p><small>
For people who have their own configurations and/or Makefiles, you will need to make a couple of changes:
<ul>
<li>
Replace all occurrences of <code>CONFIG_EXAMPLE=foobar</code> with <code>CONFIG_APP_DIR=examples/foobar</code> in all of the configuration files.
</li>
<li>
Replace any occurrences of <code>examples/$(CONFIG_EXAMPLE)</code> with <code>$(CONFIG_APP_DIR)</code>
</li>
<li>
Replace any occurrences of <code>lib$(CONFIG_EXAMPLE)$(LIBEXT)</code> with <code>libapp$(LIBEXT)</code> in your Makefiles.
</li>
<li>
Check any other occurrences of <code>CONFIG_EXAMPLE</code>.
</li>
</ul>
</small></p>
</ul>
<b>Other</b>.
Several bugfixes are included as well as code changes to eliminate some warnings.
See the ChangeLog for details.
<table width ="100%">
<tr bgcolor="#e4e4e4">
<td>
<a name="platforms"><h1>Supported Platforms</h1></a>
</td>
</tr>
</table>
<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>
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.
<ul>
<p>
<b>STATUS:</b>
Does not support interrupts but is otherwise fully functional.
</p>
</ul>
<td valign="top"><img height="20" width="20" src="favicon.ico"></td>
<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.
<ul>
<p>
<b>STATUS:</b>
This port is complete, verified, and included in the initial NuttX release.
</p>
</ul>
<tr>
<td><br></td>
<td><hr></td>
</tr>
patacongo
committed
<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.
patacongo
committed
</p>
<ul>
<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>
</ul>
patacongo
committed
</td>
</tr>
<tr>
<td><br></td>
<td><hr></td>
</tr>
<tr>
<td><br></td>
<td>
<p>
<b>NXP LPC2378</b>.
Support is provided for the NXP LPC2378 MCU. In particular,
support is provided for the Olimex-LPC2378 development board.
This port was contributed by Rommel Marcelo is was first released in NuttX-5.3.
This port also used the GNU arm-elf toolchain* under Linux or Cygwin.
</p>
<ul>
<p>
<b>STATUS:</b>
This port boots and passes the OS test (examples/ostest) and includes a
working implementation of the NuttShell (<a href="NuttShell.html">NSH</a>).
The port is complete and verified.
As of NuttX 5.3, the port includes only basic timer interrupts and serial console support.
</p>
<p>
<b>Development Environments:</b> (Same as for the NXP LPC214x).
</p>
</ul>
</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>
<ul>
<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 only partially tested. Additional features are needed: USB driver, MMC integration,
to name two (the slot on the board appears to accept on MMC card dimensions; I have only
SD cards).
An SPI-based ENC29J60 Ethernet driver for add-on hardware is under development and
should be available in the NuttX 5.5 release.
</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>
</ul>