README
^^^^^^
o Installation
- Installing Cygwin
- Download and Unpack
- Semi-Optional apps/ Package
- Installation Directories with Spaces in the Path
- Notes about Header Files
o Configuring NuttX
- Instantiating "Canned" Configurations
- NuttX Configuration Tool
o Toolchains
- Cross-Development Toolchains
- NuttX Buildroot Toolchain
o Shells
o Building NuttX
- Building
- Re-building
- Build Targets
o Cygwin Build Problems
- Strange Path Problems
- Window Native Toolchain Issues
o Documentation
INSTALLATION
^^^^^^^^^^^^
Installing Cygwin
-----------------
NuttX may be installed and built on a Linux system or on a Windows
system if Cygwin is installed. Installing Cygwin on your Windows PC
is simple, but time consuming. See http://www.cygwin.com/ for
installation instructions. Basically you just need to download a
tiny setup.exe program and it does the real, internet installation
for you.
Some Cygwin installation tips:
1. Install at C:\cygwin
2. Install EVERYTHING: "Only the minimal base packages from the
Cygwin distribution are installed by default. Clicking on categories
and packages in the setup.exe package installation screen will
provide you with the ability to control what is installed or updated.
Clicking on the "Default" field next to the "All" category will
provide you with the opportunity to install every Cygwin package.
Be advised that this will download and install hundreds of megabytes
to your computer."
If you use the "default" installation, you will be missing many
of the Cygwin utilities that you will need to build NuttX. The
build will fail in numerous places because of missing packages.
After installing Cygwin, you will get lots of links for installed
tools and shells. I use the RXVT native shell. It is fast and reliable
and does not require you to run the Cygwin X server (which is neither
fast nor reliable). The rest of these instructions assume that you
are at a bash command line prompt in either Linux or in Cygwin shell.
Download and Unpack
-------------------
Download and unpack the NuttX tarball. If you are reading this, then
you have probably already done that. After unpacking, you will end
up with a directory called nuttx-version (where version is the NuttX
version number). You might want to rename that directory nuttx to
match the various instructions in the documentation and some scripts
in the source tree.
Semi-Optional apps/ Package
---------------------------
All NuttX libraries and example code used to be in included within
the NuttX source tree. As of NuttX-6.0, this application code was
moved into a separate tarball, the apps tarball. If you are just
beginning with NuttX, then you will want to download the versioned
apps tarball along with the NuttX tarball. If you already have your
own product application directory, then you may not need the apps
tarball.
It is call "Semi-optional" because if you don't have some apps/
directory, NuttX will *fail* to build!
Download the unpack the apps tarball in the same directly where you
unpacked the NuttX tarball. After you unpack the apps tarball, you
will have a new directory called apps-version (where the version
should exactly match the version of the NuttX tarball). Again, you
might want to rename the directory to simply apps/ to match what
you read in the documentation
After unpacking the apps tarball, you will have two directories side
by side like this:
|
+----+----+
| |
nuttx/ apps/
This is important because the NuttX build will expect to find the
apps directory in that (default) location. )That default location
can be changed by editing your NuttX configuration file, but that
is another story).
Installation Directories with Spaces in the Path
------------------------------------------------
The nuttx build directory should reside in a path that contains no
spaces in any higher level directory name. For example, under
Cygwin, your home directory might be formed from your first and last
names like: "/home/First Last". That will cause strange errors when
the make system tries to build.
[Actually, that problem is probably not to difficult to fix. Some
Makefiles probably just need some paths within double quotes]
I work around spaces in the home directory name, by creating a
new directory that does not contain any spaces, such as /home/nuttx.
Then I install NuttX in /home/nuttx and always build from
/home/nuttx/nuttx.
Notes about Header Files
------------------------
Other C-Library Header Files.
Some toolchains are built with header files extracted from a C-library
distribution (such as newlib). These header files must *not* be used
with NuttX because NuttX provides its own, built-in C-Library. For
toolchains that do include built-in header files from a foreign C-
Library, NuttX must be compiled without using the standard header files
that are distributed with your toolchain. This prevents including
conflicting, incompatible header files (such as stdio.h).
Header Files Provided by Your Toolchain.
Certain header files, such as setjmp.h, stdarg.h, and math.h, may still
be needed from your toolchain and your compiler may not, however, be able
to find these if you compile NuttX without using standard header file.
If that is the case, one solution is to copy those header file from
your toolchain into the NuttX include directory.
Duplicated Header Files.
There are also a few header files that can be found in the nuttx/include
directory which are duplicated by the header files from your toolchain.
stdint.h and stdbool.h are examples. If you prefer to use the stdint.h
and stdbool.h header files from your toolchain, those could be copied
into the nuttx/include/ directory. Using most other header files from
your toolchain would probably cause errors.
math.h
Even though you should not use a foreign C-Library, you may still need
to use other, external libraries with NuttX. In particular, you may
need to use the math library, libm.a. The math libary header file,
math.h, is a special case. If you do nothing, the standard math.h
header file that is provided with your toolchain will be used.
If you have a custom, architecture specific math.h header file, then
that header file should be placed at arch/<cpu>/include/math.h. There
is a stub math.h header file located at include/nuttx/math.h. This stub
header file can be used to "redirect" the inclusion to an architecture-
specific math.h header file. If you add an architecture specific math.h
header file then you should also define CONFIG_ARCH_MATH_H=y in your
NuttX Configuration file. If CONFIG_ARCH_MATH_H is selected, then the
top-level Makefile will copy the stub math.h header file from
include/nuttx/matn.h to include/math.h where it will become the system
math.h header file. The stub math.h header file does nothing other
than to include that archicture-specific math.h header file as the
system math.h header file.
stdarg.h
In most cases, the correct version of stdarg.h is the version provided with your toolchain. However, sometimes there are issues with with using your toolchains stdarg.h. For example, it may attempt to draw in header files that do not exist in NuttX or perhaps the header files that is uses are not compatible with the NuttX header files. In those cases, you can use an architecture-specific stdarg.h header file by defining CONFIG_ARCH_STDARG_H=y.
See the discussion above for the math.h header. This setting works exactly
the same for the stdarg.h header file.
CONFIGURING NUTTX
^^^^^^^^^^^^^^^^^
Instantiating "Canned" Configurations
-------------------------------------
"Canned" NuttX configuration files are retained in:
configs/<board-name>/<config-dir>
Where <board-name> is the name of your development board and <config-dir>.
Configuring NuttX requires only copying three files from the <config-dir>
to the directly where you installed NuttX (TOPDIR):
Copy configs/<board-name>/<config-dir>/Make.def to ${TOPDIR}/Make.defs
Make.defs describes the rules needed by you tool chain to compile
and link code. You may need to modify this file to match the
specific needs of your toolchain.
Copy configs/<board-name>/<config-dir>/setenv.sh to ${TOPDIR}/setenv.sh
setenv.sh is an optional convenience file that I use to set
the PATH variable to the toolchain binaries. You may chose to
use setenv.sh or not. If you use it, then it may need to be
modified to include the path to your toolchain binaries.
Copy configs/<board-name>/<config-dir>/defconfig to ${TOPDIR}/.config
The defconfig file holds the actual build configuration. This
file is included by all other make files to determine what is
included in the build and what is not. This file is also used
to generate a C configuration header at include/nuttx/config.h.
General information about configuring NuttX can be found in:
${TOPDIR}/configs/README.txt
${TOPDIR}/configs/<board-name>/README.txt
There is a configuration script in the tools/ directory that makes this
easier. It is used as follows:
cd ${TOPDIR}/tools
./configure.sh <board-name>/<config-dir>
NuttX Configuration Tool
------------------------
An automated tool is under development to support re-configuration
of NuttX. This tool, however, is not yet quite ready for general
usage.
This automated tool is based on the kconfig-frontends application
available at http://ymorin.is-a-geek.org/projects/kconfig-frontends
(A snapshot of this tool is also available at ../misc/tools). This
application provides a tool called 'mconf' that is used by the NuttX
top-level Makefile. The following make target is provided:
make menuconfig
This make target will bring up NuttX configuration menus. The
'menuconfig' target depends on two things:
1. The Kconfig configuration data files that appear in almost all
NuttX directories. These data files are the part that is still
under development (patches are welcome!). The Kconfig files
contain configuration information for the configuration settings
relevant to the directory in which the Kconfig file resides.
NOTE: For a description of the syntax of this configuration file,
see ../misc/tools/kconfig-language.txt.
2. The 'mconf' tool. 'mconf' is part of the kconfig-frontends
package. You can download that package from the website
http://ymorin.is-a-geek.org/projects/kconfig-frontends or you
can use the snapshot in ../misc/tools.
Building may be as simple as 'configure; make; make install'
but there may be some build complexities, especially if you
are building under Cygwin. See the more detailed build
instructions at ../misc/tools/README.txt
The 'make install' step will, by default, install the 'mconf'
tool at /usr/local/bin/mconf. Where ever you choose to
install 'mconf', make certain that your PATH variable includes
a path to that installation directory.
TOOLCHAINS
^^^^^^^^^^
Cross-Development Toolchains
----------------------------
In order to build NuttX for your board, you will have to obtain a cross-
compiler to generate code for your target CPU. For each board,
configuration, there is a README.txt file (at configs/<board-name>/README.txt).
That README file contains suggestions and information about appropriate
tools and development environments for use with your board.
In any case, the script, setenv.sh that was deposited in the top-
level directory when NuttX was configured should be edited to set
the path to where you installed the toolchain. The use of setenv.sh
is optional but can save a lot of confusion in the future.
NuttX Buildroot Toolchain
-------------------------
For many configurations, a DIY set of tools is available for NuttX. These
tools can be downloaded from the NuttX SourceForge file repository. After
unpacking the buildroot tarball, you can find instructions for building
the tools in the buildroot/configs/README.txt file.
Check the README.txt file in the configuration director for your board
to see if you can use the buildroot toolchain with your board (this
README.txt file is located in configs/<board-name>/README.txt).
This toolchain is available for both the Linux and Cygwin development
environments.
Advantages: (1) NuttX header files are built into the tool chain,
and (2) related support tools like NXFLAT tools and the ROMFS
genromfs tools can be built into your toolchain.
Disadvantages: This tool chain is not was well supported as some other
toolchains. GNU tools are not my priority and so the buildroot tools
often get behind. For example, the is still no EABI support in the
NuttX buildroot toolchain for ARM.
SHELLS
^^^^^^
The NuttX build relies on some shell scripts. Some are inline in the
Makefiles and many are exectuble scripts in the tools/. directory. The
scripts were all developed using bash and many contain bash shell
dependencies.
Most of the scripts begin with #!/bin/bash to specifically select the
bash shell. Some still have #!/bin/sh but I haven't heard any complaints
so these must not have bash dependencies.
There are two shell issues that I have heard of:
1. Linux where /bin/sh refers to an incompatible shell (like ksh or csh).
In this case, bash is probably avaiable and the #!/bin/bash at the
beginning of the file should do the job. If any scripts with #!/bin/sh
fail, try changing that ti #!/bin/bash and let me know about the change.
2. FreeBSD with the Bourne Shell and no bash shell.
The other, reverse case has also been reported on FreeBSD setups that
have the Bourne shell, but not bash. In this base, #!/bin/bash fails
but #!/bin/sh works okay. My recommendation in this case is to create
a symbolic link at /bin/bash that refers to the Bourne shell.
There may still be issues, however, with certain the bash-centric scripts
that will require modifications.
BUILDING NUTTX
^^^^^^^^^^^^^^
Building
--------
NuttX builds in-place in the source tree. You do not need to create
any special build directories. Assuming that your Make.defs is setup
properly for your tool chain and that setenv.sh contains the path to where
your cross-development tools are installed, the following steps are all that
are required to build NuttX:
cd ${TOPDIR}
. ./setenv.sh
make
At least one configuration (eagle100) requires additional command line
arguments on the make command. Read ${TOPDIR}/configs/<board-name>/README.txt
to see if that applies to your target.
Re-building
-----------
Re-building is normally simple -- just type make again.
But there are some things that can "get you" when you use the Cygwin
development environment with Windows native tools. The native Windows
tools do not understand Cygwin's symbolic links, so the NuttX make system
does something weird: It copies the configuration directories instead of
linking to them (it could, perhaps, use the NTFS 'mklink' command, but it
doesn't).
A consequence of this is that you can easily get confused when you edit
a file in one of the linked (i.e., copied) directories, re-build NuttX,
and then not see your changes when you run the program. That is because
build is still using the version of the file in the copied directory, not
your modified file! To work around this annoying behavior, do the
following when you re-build:
make clean_context all
This 'make' command will remove of the copied directories, re-copy them,
then make NuttX.
Build Targets
-------------
Below is a summary of the build targets available in the top-level
NuttX Makefile:
all
The default target builds the NuttX executable in the selected output
formats.
clean
Removes derived object files, archives, executables, and temporary
files, but retains the configuration and context files and directories.
distclean
Does 'clean' then also removes all configuration and context files.
This essentially restores the directory structure to its original,
unconfigured stated.
Application housekeeping targets. The APPDIR variable refers to the user
application directory. A sample apps/ directory is included with NuttX,
however, this is not treated as part of NuttX and may be replaced with a
different application directory. For the most part, the application
directory is treated like any other build directory in the Makefile script.
However, as a convenience, the following targets are included to support
housekeeping functions in the user application directory from the NuttX
build directory.
apps_clean
Perform the clean operation only in the user application directory
apps_distclean
Perform the distclean operation only in the user application directory.
The apps/.config file is preserved so that this is not a "full" distclean
but more of a configuration "reset."
export
The export target will package the NuttX libraries and header files into
an exportable package. Caveats: (1) These needs some extension for the KERNEL
build. (2) The logic in tools/mkexport.sh only supports GCC and, for example,
explicitly assumes that the archiver is 'ar'
download
This is a helper target that will rebuild NuttX and download it to the target
system in one step. The operation of this target depends completely upon
implementation of the DOWNLOAD command in the user Make.defs file. It will
generate an error an error if the DOWNLOAD command is not defined.
The following targets are used internally by the make logic but can be invoked
from the command under certain conditions if necessary.
depend
Create build dependencies. (NOTE: There is currently no support for build
dependencies under Cygwin using Windows-native toolchains.)
context
The context target is invoked on each target build to assure that NuttX is
properly configured. The basic configuration steps include creation of the
the config.h and version.h header files in the include/nuttx directory and
the establishment of symbolic links to configured directories.
clean_context
This is part of the distclean target. It removes all of the header files
and symbolic links created by the context target.
CYGWIN BUILD PROBLEMS
^^^^^^^^^^^^^^^^^^^^^
Strange Path Problems
---------------------
If you see strange behavior when building under Cygwin then you may have
a problem with your PATH variable. For example, if you see failures to
locate files that are clearly present, that may mean that you are using
the wrong version of a tool. For example, you may not be using Cygwin's
'make' program at /usr/bin/make. Try:
$ which make
/usr/bin/make
When you install some toolchains (such as Yargarto or CodeSourcery tools),
they may modify your PATH variable to include a path to their binaries.
At that location, they make have GNUWin32 versions of the tools. So you
might actually be using a version of make that does not understand Cygwin
paths.
The solution is either:
1. Edit your PATH to remove the path to the GNUWin32 tools, or
2. Put /usr/local/bin, /usr/bin, and /bin at the front of your path:
$ export PATH=/usr/local/bin:/usr/bin:/bin:$PATH
Window Native Toolchain Issues
------------------------------
There are many popular Windows native toolchains that may be used with NuttX.
Examples include CodeSourcery (for Windows), devkitARM, and several vendor-
provied toolchains. There are several limitations with using a and Windows
based toolchain in a Cygwin environment. The three biggest are:
1. The Windows toolchain cannot follow Cygwin paths. Path conversions are
performed automatically in the Cygwin makefiles using the 'cygpath' utility
but you might easily find some new path problems. If so, check out 'cygpath -w'
2. Windows toolchains cannot follow Cygwin symbolic links. Many symbolic links
are used in Nuttx (e.g., include/arch). The make system works around these
problems for the Windows tools by copying directories instead of linking them.
But this can also cause some confusion for you: For example, you may edit
a file in a "linked" directory and find that your changes had no effect.
That is because you are building the copy of the file in the "fake" symbolic
directory. If you use a Windows toolchain, you should get in the habit of
making like this:
make clean_context all
An alias in your .bashrc file might make that less painful. The rebuild
is not a long as you might think because there is no dependency checking
if you are using a native Windows toolchain. That bring us to #3:
3. Dependencies are not made when using Windows versions of the GCC. This is
because the dependencies are generated using Windows pathes which do not
work with the Cygwin make.
Support has been added for making dependencies with the windows-native toolchains.
That support can be enabled by modifying your Make.defs file as follows:
- MKDEP = $(TOPDIR)/tools/mknulldeps.sh
+ MKDEP = $(TOPDIR)/tools/mkdeps.sh --winpaths "$(TOPDIR)"
If you have problems with the dependency build (for example, if you are not
building on C:), then you may need to modify tools/mkdeps.sh
General Pre-built Toolchain Issues
To continue with the list of "Window Native Toolchain Issues" we can add
the following. These, however, are really just issues that you will have
if you use any pre-built toolchain (vs. building the NuttX toolchain from
the NuttX buildroot package):
There may be incompatibilities with header files, libraries, and compiler
built-in functions at detailed below. For the most part, these issues
are handled in the existing make logic. But if you are breaking new ground,
then you may incounter these:
4. Header Files. Most pre-built toolchains will build with a foreign C
library (usually newlib, but maybe uClibc or glibc if you are using a
Linux toolchain). This means that the header files from the foreign
C library will be built into the toolchain. So if you "include <stdio.h>",
you will get the stdio.h from the incompatible, foreign C library and
not the nuttx stdio.h (at nuttx/include/stdio.h) that you wanted.
This can cause really confusion in the buildds and you must always be
sure the -nostdinc is included in the CFLAGS. That will assure that
you take the include files only from
5. Libraries. What was said above header files applies to libraries.
You do not want to include code from the libraries of any foreign
C libraries built into your toolchain. If this happens you will get
perplexing errors about undefined sysmbols. To avoid these errors,
you will need to add -nostdlib to your CFLAGS flags to assure that
you only take code from the NuttX libraries.
This, however, may causes other issues for libraries in the toolchain
that you do want (like libgcc.a or libm.a). These are special-cased
in most Makefiles, but you could still run into issues of missing
libraries.
6. Built-Ins. Some compilers target a particular operating system.
Many people would, for example, like to use the same toolchain to
develop Linux and NuttX software. Compilers built for other
operating systems may generate incompatible built-in logic and,
for this reason, -fno-builtin should also be included in your
C flags
And finally you may not be able to use NXFLAT.
7. NXFLAT. If you use a pre-built toolchain, you will lose all support
for NXFLAT. NXFLAT is a binary format described in
Documentation/NuttXNxFlat.html. It may be possible to build
standalone versions of the NXFLAT tools; there are a few examples
of this in the misc/buildroot/configs directory. However, it
is possible that there could be interoperability issues with
your toolchain since they will be using different versions of
binutials and possibly different ABIs.
DOCUMENTATION
^^^^^^^^^^^^^
Additional information can be found in the Documentation/ directory and
also in README files that are scattered throughout the source tree. The
documentation is in HTML and can be access by loading the following file
into your Web browser:
Documentation/index.html
NuttX documentation is also available online at http://www.nuttx.org.
Below is a guide to the available README files in the NuttX source tree:
nuttx
|
|- arch/
| |
| |- arm/
| | `- src
| | `- lpc214x/README.txt
| |- avr/
| | `- README.txt
| |- sh/
| | |- include/
| | | |-m16c/README.txt
| | | |-sh1/README.txt
| | | `-README.txt
| | |- src/
| | | |-common/README.txt
| | | |-m16c/README.txt
| | | |-sh1/README.txt
| | | `-README.txt
| |- x86/
| | |- include/
| | | `-README.txt
| | `- src/
| | `-README.txt
| `- z80/
| | `- src/
| | `- z80/README.txt
| `- README.txt
|- configs/
| |- amber/
| | `- README.txt
| |- avr32dev1/
| | `- README.txt
| |- c5471evm/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- compal_e88
| | `- README.txt
| |- compal_e99
| | `- README.txt
| |- demo0s12ne64/
| | `- README.txt
| |- ea3131/
| | `- README.txt
| |- ea3152/
| | `- README.txt
| |- eagle100/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- ekk-lm3s9b96/
| | `- README.txt
| |- ez80f910200kitg/
| | |- ostest/README.txt
| | `- README.txt
| |- ez80f910200zco/
| | |- dhcpd/README.txt
| | |- httpd/README.txt
| | |- nettest/README.txt
| | |- nsh/README.txt
| | |- ostest/README.txt
| | |- poll/README.txt
| | `- README.txt
| |- hymini-stm32v/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- lincoln60/
| | `- README.txt
| |- kwikstik-k40/
| | `- README.txt
| |- lm3s6432-s2e/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- lm3s6965-ek/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- lm3s8962-ek/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- lpcxpresso-lpc1768/
| | `- README.txt
| |- lpc4330-xplorer/
| | `- README.txt
| |- m68332evb/
| | |- include/README.txt
| | `- src/README.txt
| |- mbed/
| | `- README.txt
| |- mcu123-lpc214x/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- micropendous3/
| | `- README.txt
| |- mirtoo/
| | `- README.txt
| |- mx1ads/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- ne63badge/
| | `- README.txt
| |- ntosd-dm320/
| | |- doc/README.txt
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- nucleus2g/
| | `- README.txt
| |- olimex-lpc1766stk/
| | `- README.txt
| |- olimex-lpc2378/
| | |- include/README.txt
| | `- README.txt
| |- olimex-strp711/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- pcblogic-pic32mx/
| | `- README.txt
| |- pic32-starterkit/
| | `- README.txt
| |- pjrc-8051/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- qemu-i486/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- rgmp/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- sam3u-ek/
| | `- README.txt
| |- sim/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- skp16c26/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- stm3210e-eval/
| | |- include/README.txt
| | |- RIDE/README.txt
| | |- src/README.txt
| | `- README.txt
| |- stm3220g-eval/
| | `- README.txt
| |- stm3240g-eval/
| | `- README.txt
| |- stm32f4discovery/
| | `- README.txt
| |- sure-pic32mx/
| | `- README.txt
| |- teensy/
| | `- README.txt
| |- twr-k60n512/
| | `- README.txt
| |- us7032evb1/
| | |- bin/README.txt
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- vsn/
| | |- src/README.txt
| | `- README.txt
| |- xtrs/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- z16f2800100zcog/
| | |- ostest/README.txt
| | |- pashello/README.txt
| | `- README.txt
| |- z80sim/
| | |- include/README.txt
| | |- src/README.txt
| | `- README.txt
| |- z8encore000zco/
| | |- ostest/README.txt
| | `- README.txt
| |- z8f64200100kit/
| | |- ostest/README.txt
| | `- README.txt
| `- README.txt
|- drivers/
| |- lcd/
| | `- README.txt
| |- sercomm/
| | `- README.txt
| |- syslog/
| | `- README.txt
| `- README.txt
|- fs/
| |- mmap/
| | `- README.txt
| `- nxffs/
| `- README.txt
|- graphics/
| `- README.txt
|- lib/
| `- README.txt
|- libxx/
| `- README.txt
|- syscall/
| `- README.txt
`- tools/
`- README.txt
apps
|- examples/
| |- pashello/README.txt
| `- README.txt
|- graphics/
| `- tiff/README.txt
|- interpreters/
| |- ficl
| | `- README.txt
| `- README.txt
|- modbus/
| `- README.txt
|- netutils/
| |- ftpc
| | `- README.txt
| |- telnetd
| | `- README.txt
| `- README.txt
|- nshlib/
| `- README.txt
|- system/
| |- i2c/README.txt
| |- free/README.txt
| `- install
| `- README.txt
|- vsn/
| |- poweroff
| | `- README.txt
| |- ramtron
| | `- README.txt
| |- sdcard
| | `- README.txt
| `- sysinfo
| `- README.txt
`- README.txt
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