README ^^^^^^ o Environments - Installing Cygwin - Ubuntu Bash under Windows 10 o Installation - Download and Unpack - Semi-Optional apps/ Package - Installation Directories with Spaces in the Path - Downloading from Repositories - Related Repositories - Notes about Header Files o Configuring NuttX - Instantiating "Canned" Configurations - Refreshing Configurations - NuttX Configuration Tool - Finding Selections in the Configuration Menus - Reveal Hidden Configuration Options - Make Sure that You on on the Right Platform - Comparing Two Configurations - Incompatibilities with Older Configurations - NuttX Configuration Tool under DOS o Toolchains - Cross-Development Toolchains - NuttX Buildroot Toolchain o Shells o Building NuttX - Building - Re-building - Build Targets and Options - Native Windows Build - Installing GNUWin32 o Cygwin Build Problems - Strange Path Problems - Window Native Toolchain Issues o Documentation ENVIRONMENTS ^^^^^^^^^^^^ NuttX requires a POSIX development environment such as you would find uder Linux or OSX. NuttX may be also be installed and built on Windows system if you also provde such a POSIX develoment environment. Options for a POSIX development environment under Windows include: - An installation Linux on a virtual machine in Windows. - The Cygwin environment. Instructions for installation of Cygwin on a Windows system are provided in the following paragraph, "Installing Cygwin". - The MSYS environment. However, I have little experience that configuration and it will not be discussed in this README file. See http://www.mingw.org/wiki/MSYS if you are interested in using MSYS. People report to me that they have used MSYS successfully. - Ubuntu/bash shell under Windows 10. This is a new option under Windows 10. See the section "Ubuntu Bash under Windows 10" below. - NuttX can also be installed and built on a native Windows system, but with some potential tool-related issues (see the discussion "Native Windows Build" under "Building NuttX" below). Installing Cygwin ----------------- 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, network 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. NOTE: You don't really have to install EVERYTHING but I cannot answer the question "Then what should I install?" I don't know the answer to that and so will continue to recommend installing EVERYTHING. You should certainly be able to omit "Science", "Math", and "Publishing". You can try omitting KDE, Gnome, GTK, and other graphics packages if you don't plan to use them. 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). Unless otherwise noted, the rest of these instructions assume that you are at a bash command line prompt in either Linux or in Cygwin shell. UPDATE: The last time I installed EVERTHING, the download was about 5GiB. The server I selected was also very slow so it took over a day to do the whole install! Ubuntu Bash under Windows 10 ---------------------------- A better version of a command-line only Ubuntu under Windows 10 (beta) has recently been made available from Microsoft. Installation ------------ Installation instructions abound on the Internet complete with screen shots. I will attempt to duplicate those instructions in full here. Here are the simplified installation steps: - Open "Settings". - Click on "Update & security". - Click on "For Developers". - Under "Use developer features", select the "Developer mode" option to setup the environment to install Bash. - A message box should pop up. Click "Yes" to turn on developer mode. - After the necessary components install, you'll need to restart your computer. Once your computer reboots: - Open "Control Panel". - Click on "Programs". - Click on "Turn Windows features on or off". - A list of features will pop up, check the "Windows Subsystem for Linux (beta)" option. - Click OK. - Once the components installed on your computer, click the "Restart now" button to complete the task. After your computer restarts, you will notice that Bash will not appear in the "Recently added" list of apps, this is because Bash isn't actually installed yet. Now that you have setup the necessary components, use the following steps to complete the installation of Bash: - Open "Start", do a search for bash.exe, and press "Enter". - On the command prompt, type y and press Enter to download and install Bash from the Windows Store. This will take awhile. - Then you'll need to create a default UNIX user account. This account doesn't have to be the same as your Windows account. Enter the username in the required field and press Enter (you can't use the username "admin"). - Close the "bash.exe" command prompt. Now that you completed the installation and setup, you can open the Bash tool from the Start menu like you would with any other app. Accessing Windows Files ----------------------- File sysems will be mounted under "/mnt" so for example "C:\Program Files" appears at "/mnt/c/Program Files". This is as opposed to Cgwin where the same directory would appear at "/cygdrive/c/Program Files". With these differences (perhaps a few other Windows quirks) the Ubuntu install works just like Ubuntu running natively on your PC. Currently there is no host configuration for Bash running under Windows 10 but setting the host to either Linux or Cygwin in your configuratino file should work fine. Install Linux Software. ----------------------- Use "sudo apt-get install ". As examples, this is how you would get GIT: $ sudo apt-get install git This will get you an ARM compiler: $ sudo apt-get install gcc-arm-none-eabi NOTE: That is just an example. I am not sure if apt-get will give you a current or usable compiler. You should carefully select your toolchain for the needs of your project.] Integrating with Windows Tools ------------------------------ If you want to integrate with Windows native tools, then you will need deal with the same kind of craziness as with integrating Cygwin with native toolchains. If you set the host PC to Cygwin in this case, then the NuttX build system should deal with that craziness for you. See the section "Cygwin Build Problems" below. INSTALLATION ^^^^^^^^^^^^ There are two ways to get NuttX: You may download released, stable tarballs from wither the Bitbucket or Sourceforge download locations. Or you may get NuttX by cloning the Bitbucket GIT repositories. Let's consider the released tarballs first: 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. Download locations: https://bitbucket.org/nuttx/nuttx/downloads https://sourceforge.net/projects/nuttx/files/nuttx/ 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! You do not necessarily need to use the NuttX apps tarball but may, instead, provide your own custom application directory. Such a custom directory would need to include a valid Makefile to support the build and a valid Kconfig file to support the configuration. More about these file later. Download then unpack the apps tarball in the same directory 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 (and renaming) 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 modifying 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-code. Downloading from Repositories ----------------------------- Cloning the Repository The current NuttX du jour is available in from a GIT repository. Here are instructions for cloning the core NuttX RTOS (corresponding to the nuttx tarball discussed above):: git clone https://bitbucket.org/nuttx/nuttx.git nuttx And the semi-optional apps/ application directory and be cloned like: git clone https://bitbucket.org/nuttx/apps.git apps That will give you the same directory structure like this: | +----+----+ | | nuttx/ apps/ Configuring the Clones The following steps need to be performed for each of the repositories. After changing to the clone directory: Set your identity: git config --global user.name "My Name" git config --global user.email my.name@example.com Colorized diffs are much easier to read: git config --global color.branch auto git config --global color.diff auto git config --global color.interactive auto git config --global color.status auto Checkout other settings git config --list Cloning NuttX Inside Cygwin If you are cloning the NuttX repository, it is recommended to avoid automatic end of lines conversions by git. These conversions may break some scripts like configure.sh. Before cloning, do the following: git config --global core.autocrlf false Related Repositories -------------------- These are standalone repositories: * https://bitbucket.org/nuttx/apps This directory holds an optional package of applications and libraries can be used with the NuttX RTOS. There is a README.txt file there that will provide a more information about that package. * https://bitbucket.org/nuttx/nxwidgets This is the NuttX C++ graphics support. This includes NxWM, the tiny NuttX Window Manager. * https://bitbucket.org/nuttx/uclibc This repository contains a version of the uClibc++ C++ library. This code originates from http://cxx.uclibc.org/ and has been adapted for NuttX by the RGMP team (http://rgmp.sourceforge.net/wiki/index.php/Main_Page). * https://bitbucket.org/nuttx/buildroot A environment that you can to use to build a custom, NuttX GNU toolchain. * https://bitbucket.org/nuttx/tools There are snapshots of some tools here that you will need to work with NuttX: kconfig-frontends, genromfs, and others. * https://bitbucket.org/nuttx/drivers A few drivers that are not integrated into the main NuttX source tree due to licensing issues. * https://bitbucket.org/nuttx/pascal Yes, this really is a Pascal compiler. The Pascal p-code run-time and pcode debugger can be built as a part of NuttX. Notes about Header Files ------------------------ Other C-Library Header Files. When a GCC toolchain is built, it must be built against a C library. The compiler together with the contents of the C library completes the C language definition and provides the complete C development environment. NuttX provides its own, built-in C library. So the complete, consistent C language definition for use with NuttX comes from the combination of the compiler and the header files provided by the NuttX C library. When a GCC toolchain is built, it incorporates the C library header files into the compiler internal directories and, in this way, the C library really becomes a part of the toolchain. If you use the NuttX buildroot toolchain as described below under under "NuttX Buildroot Toolchain", your GCC toolchain will build against the NuttX C library and will incorporate the NuttX C library header files as part of the toolchain. If you use some other, third-party tool chain, this will not be the case, however. Those toolchains were probably built against some other, incompatible C library distribution (such as newlib). Those tools will have incorporated the incompatible C library header files as part of the toolchain. These incompatible header files must *not* be used with NuttX because the will conflict with definitions in the NuttX built-in C-Library. For such toolchains that include 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. The math.h and stdarg.h are probably the two most trouble some header files to deal with. These troublesome header files are discussed in more detail below. 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. NuttX supports a generic, built-in math library that can be enabled using CONFIG_LIBM=y. However, you may still want to use a higher performance external math library that has been tuned for your CPU. Sometimes such such tuned math libraries are bundled with your toolchain. The math libary header file, math.h, is a then 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//include/math.h. There is a stub math.h header file located at include/nuttx/lib/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/lib/math.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 architecture-specific math.h header file as the system math.h header file. float.h If you enable the generic, built-in math library, then that math library will expect your toolchain to provide the standard float.h header file. The float.h header file defines the properties of your floating point implementation. It would always be best to use your toolchain's float.h header file but if none is available, a default float.h header file will provided if this option is selected. However, there is no assurance that the settings in this float.h are actually correct for your platform! 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// Where is the name of your development board and is the name of the sub-directory containing a specific configuration for that board. Configuring NuttX requires only copying three files from the to the directory where you installed NuttX (TOPDIR) (and sometimes one additional file to the directory the NuttX application package (APPSDIR)): Copy configs///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///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///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//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 / There is an alternative Windows batch file that can be used in the windows native environment like: cd ${TOPDIR}\tools configure.bat \ See tools/README.txt for more information about these scripts. Refreshing Configurations ------------------------- Configurations can get out of date. As new configuration settings are added or removed or as dependencies between configuration settings change, the contents of a default configuration can become out of synch with the build systems. Hence, it is a good practice to "refresh" each configuration after configuring and before making. To refresh the configuration, use the NuttX Configuration Tool like this: make oldconfig AFTER you have instantiated the NuttX configuration as described above. The configuration step copied the .config file into place in the top-level NuttX directory; 'make oldconfig' step will then operate on that .config file to bring it up-to-date. If you configuration is out of date, you will be prompted by 'make oldconfig' to resolve the issues detected by the configuration tool, that is, to provide values for the new configuration options in the build system. Doing this can save you a lot of problems down the road due to obsolete settings in the default board configuration file. The NuttX configuration tool is discussed in more detail in the following paragraph. Confused about what the correct value for a new configuration item should be? Enter ? in response to the 'make oldconfig' prompt and it will show you the help text that goes with the option. If you don't want to make any decisions are are willing to just accept the recommended default value for each new configuration item, an even easier way is: make oldefconfig The olddefconfig target will simply bring you configuration up to date with the current Kconfig files, setting any new options to the default value. No questions asked. NuttX Configuration Tool ------------------------ An automated tool has been incorported to support re-configuration of NuttX. 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 fromo the tools repository at https://bitbucket.org/nuttx/tools). This application provides a tool called 'kconfig-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. WARNING: Never do 'make menuconfig' on a configuration that has not been converted to use the kconfig-frontends tools! This will damage your configuration (see http://www.nuttx.org/doku.php?id=wiki:howtos:convertconfig). How do we tell a new configuration from an old one? See "Incompatibilities with Older Configurations" below. The 'menuconfig' make 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 kconfig-language.txt in the tools repository at https://bitbucket.org/nuttx/tools 2. The 'kconfig-mconf' tool. 'kconfig-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 the tools repository at https://bitbucket.org/nuttx/tools. Building kconfig-frontends under Linux 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 in the top-level README.txt file of the tools repository at https://bitbucket.org/nuttx/tools. The 'make install' step will, by default, install the 'kconfig-mconf' tool at /usr/local/bin/mconf. Where ever you choose to install 'kconfig-mconf', make certain that your PATH variable includes a path to that installation directory. The kconfig-frontends tools will not build in a native Windows environment directly "out-of-the-box". For the Windows native case, you should should the modified version of kconfig-frontends that can be found at http://uvc.de/posts/linux-kernel-configuration-tool-mconf-under-windows.html The basic configuration order is "bottom-up": - Select the build environment, - Select the processor, - Select the board, - Select the supported peripherals - Configure the device drivers, - Configure the application options on top of this. This is pretty straight forward for creating new configurations but may be less intuitive for modifying existing configurations. If you have an environment that supports the Qt or GTK graphical systems (probably KDE or gnome, respectively, or Cygwin under Windows with Qt or GTK installed), then you can also build the graphical kconfig-frontends, kconfig-qconf and kconfig-gconf. In these case, you can start the graphical configurator with either: make qconfig or make gconfig Some keyboard shortcus supported by kconfig-mconf, the tool that runs when you do 'make menuconfig': - '?' will bring up the mconfig help display. - '/' can be used find configuration selections. - 'Z' can be used to reveal hidden configuration options These last to shortcuts are described further in the following paragraphs. Finding Selections in the Configuration Menus --------------------------------------------- The NuttX configuration options have gotten complex and it can be very difficult to find options in the menu trees if you are not sure where to look. The "basic configuration order" describe above can help to narrow things down. But if you know exactly what configuration setting you want to select, say CONFIG_XYZ, but not where to find it, then the 'make memconfig' version of the tool offers some help: By pressing the '/' key, the tool will bring up a menu that will allow you to search for a configuration item. Just enter the string CONFIG_XYZ and press 'ENTER'. It will show you not only where to find the configuration item, but also all of the dependencies related to the configuration item. Reveal Hidden Configuration Options ----------------------------------- If you type 'Z', then kconfig-mconf will change what is displayed. Normally, only enabled features that have all of their dependencies met are displayed. That is, of course, not very useful if you would like to discover new options or if you are looking for an option and do not realize that the dependencies have not yet been selected and, hence, it is not displayed. But if you enter 'Z', then every option will be shown, whether or not its dependencies have been met. You can the see everything that could be selected with the right dependency selections. These additional options will be shown the '-' for the selection and for the value (since it cannot be selected and has no value). About all you do is to select the option to see what the dependencies are. Make Sure that You on on the Right Platform ------------------------------------------- Saved configurations may run on Linux, Cygwin (32- or 64-bit), or other platforms. The platform characteristics can be changed use 'make menuconfig'. Sometimes this can be confusing due to the differences between the platforms. Enter sethost.sh sethost.sh is a simple script that changes a configuration to your host platform. This can greatly simplify life if you use many different configurations. For example, if you are running on Linux and you configure like this: $ cd tools $ ./configure.sh board/configuration $ cd .. The you can use the following command to both (1) make sure that the configuration is up to date, AND (2) the configuration is set up correctly for Linux: $ tools/sethost.sh -l Or, if you are on a Windows/Cygwin 64-bit platform: $ tools/sethost.sh -w Other options are available from the help option built into the script. You can see all options with: $ tools/sethost.sh -h Comparing Two Configurations ---------------------------- If you try to compare to configurations using 'diff', you will probably not be happy with the result. There are superfluous things added to the configuration files that makes comparisons with the human eye difficult. There is a tool at nuttx/tools/cmpconfig.c that can be build to simplify these comparisons. The output from this difference tools will show only the meaningful differences between two configuration files. This tools built as follows: cd nuttx/tools make -f Makefile.host This will crate a program called 'cmpconfig' or 'comconfig.exe' on Windows. Why would you want to compare two configuration files? Here are a few of reasons why I do this: 1. When I create a new configuration I usually base it on an older configuration and I want to know, "What are the options that I need to change to add the new feature to the older configurations?" For example, suppose that I have a boardA/nsh configuration and I want to create a boardA/nxwm configuration. Suppose I already have boardB/nsh and boardB/nxwm configurations. Then by comparing the boardB/nsh with the boardB/nxwm I can see the modifications that I would need to make to my boardA/nsh to create a new boardA/nxwm. 2. But the most common reason that I use the 'cmpconfig' program to to check the results of "refreshing" a configuration with 'make oldconfig' (see the paragraph "Refreshing Configurations" above). The 'make oldconfig' command will make changes to my configuration and using 'cmpconfig', I can see precisely what those changes were and if any should be of concern to me. 3. The 'cmpconfig' tool can also be useful when converting older, legacy manual configurations to the current configurations based on the kconfig-frontends tools. See the following paragraph. Incompatibilities with Older Configurations ------------------------------------------- ***** WARNING ***** The current NuttX build system supports *only* the new configuration files generated using the kconfig-frontends tools. Support for the older, legacy, manual configurations was eliminated in NuttX 7.0; all configuration must now be done using the kconfig-frontends tool. The older manual configurations and the new kconfig-frontends configurations are not compatible. Old legacy configurations can *not* be used with the kconfig-frontends tool and, hence, cannot be used with releases of NuttX 7.0 and beyond: If you run 'make menuconfig' with a legacy configuration the resulting configuration will probably not be functional. Q: How can I tell if a configuration is a new kconfig-frontends configuration or an older, manual configuration? A: Only old, manual configurations will have an appconfig file Q: How can I convert a older, manual configuration into a new, kconfig-frontends toolchain. A: Refer to http://www.nuttx.org/doku.php?id=wiki:howtos:convertconfig ***** WARNING ***** As described above, whenever you use a configuration, you really should always refresh the configuration the following command *before* you make NuttX: make oldconfig This will make sure that the configuration is up-to-date in the event that it has lapsed behind the current NuttX development (see the paragraph "Refreshing Configurations" above). But this only works with *new* configuration files created with the kconfig-frontends tools Never do 'make oldconfig' (OR 'make menuconfig') on a configuration that has not been converted to use the kconfig-frontends tools! This will damage your configuration (see http://www.nuttx.org/doku.php?id=wiki:howtos:convertconfig). NuttX Configuration Tool under DOS ---------------------------------- Recent versions of NuttX support building NuttX from a native Windows console window (see "Native Windows Build" below). But kconfig-frontends is a Linux tool. At one time this was a problem for Windows users, but now there is a specially modified version of the kconfig-frontends tools that can be used: http://uvc.de/posts/linux-kernel-configuration-tool-mconf-under-windows.html It is also possible to use the version of kconfig-frontends built under Cygwin outside of the Cygwin "sandbox" in a native Windows environment: 1. You can run the configuration tool using Cygwin. However, the Cygwin Makefile.win will complain so to do this will, you have to manually edit the .config file: a. Delete the line: CONFIG_WINDOWS_NATIVE=y b. Change the apps/ directory path, CONFIG_APPS_DIR to use Unix style delimiters. For example, change "..\apps" to "../apps" And of course, after you use the configuration tool you need to restore CONFIG_WINDOWS_NATIVE=y and the correct CONFIG_APPS_DIR. 2) You can, with some effort, run the Cygwin kconfig-mconf tool directly in the Windows console window. In this case, you do not have to modify the .config file, but there are other complexities: a. You need to temporarily set the Cgywin directories in the PATH variable then run kconfig-mconf manually like: kconfig-mconf Kconfig There is a Windows batch file at tools/kconfig.bat that automates these steps: tools/kconfig menuconfig b. There is an issue with accessing DOS environment variables from the Cygwin kconfig-mconf running in the Windows console. The following change to the top-level Kconfig file seems to work around these problems: config APPSDIR string - option env="APPSDIR" + default "../apps" 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//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 Bitbucket.org 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//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, the ROMFS genromfs tools, and the kconfig-frontends 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, until recently there was no EABI support in the NuttX buildroot toolchain for ARM. NOTE: For Cortex-M3/4, there are OABI and EABI versions of the buildroot toolchains. If you are using the older OABI toolchain the prefix for the tools will be arm-nuttx-elf-; for the EABI toolchain the prefix will be arm-nuttx-eabi-. If you are using the older OABI toolchain with an ARM Cortex-M3/4, you will need to set CONFIG_ARMV7M_OABI_TOOLCHAIN in the .config file in order to pick the right tool prefix. If the make system ever picks the wrong prefix for your toolchain, you can always specify the prefix on the command to override the default like: make CROSSDEV=arm-nuttx-elf SHELLS ^^^^^^ The NuttX build relies on some shell scripts. Some are inline in the Makefiles and many are executable 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 available and the #!/bin/bash at the beginning of the file should do the job. If any scripts with #!/bin/sh fail, try changing that to #!/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//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! Older versions of NuttX did not support dependiencies in this configuration. So a simple work around this annoying behavior in this case was 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. However, more recent versions of NuttX do support dependencies for the Cygwin build. As a result, the above command will cause everything to be rebuilt (beause it removes and will cause recreating the include/nuttx/config.h header file). A much less gracefully but still effective command in this case is the following for the ARM configuration: rm -rf arch/arm/src/chip arch/arm/src/board This "kludge" simple removes the copied directories. These directories will be re-created when you do a normal 'make' and your edits will then be effective. Build Targets and Options ------------------------- 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. Build Options: Of course, the value any make variable an be overridden from the make command line. However, there is one particular variable assignment option that may be useful to you: V=1 This is the build "verbosity flag." If you specify V=1 on the make command line, you will see the exact commands used in the build. This can be very useful when adding new boards or tracking down compile time errors and warnings (Contributed by Richard Cochran). Native Windows Build -------------------- The beginnings of a Windows native build are in place but still not often used as of this writing. The build was functional but because of lack of use may find some issues to be resolved with this build configuration. The windows native build logic initiated if CONFIG_WINDOWS_NATIVE=y is defined in the NuttX configuration file: This build: - Uses all Windows style paths - Uses primarily Windows batch commands from cmd.exe, with - A few extensions from GNUWin32 In this build, you cannot use a Cygwin or MSYS shell. Rather the build must be performed in a Windows console window. Here is a better terminal than the standard issue, CMD.exe terminal: ConEmu which can be downloaded from: https://sourceforge.net/projects/conemu/ or https://conemu.github.io/ . Build Tools. The build still relies on some Unix-like commands. I use the GNUWin32 tools that can be downloaded from http://gnuwin32.sourceforge.net/ using the 'Download all' selection. Individual packages can be download instead if you know what you are doing and want a faster download (No, I can't tell you which packages you should or should not download). Host Compiler: I use the MingGW GCC compiler which can be downloaded from http://www.mingw.org/. If you are using GNUWin32, then it is recommended the you not install the optional MSYS components as there may be conflicts. This capability should still be considered a work in progress because: (1) It has not been verified on all targets and tools, and (2) it still lacks some of the creature-comforts of the more mature environments. There is an alternative to the setenv.sh script available for the Windows native environment: tools/configure.bat. See tools/README.txt for additional information. Installing GNUWin32 ------------------- The Windows native build will depend upon a few Unix-like tools that can be provided either by MSYS or GNUWin32. The GNUWin32 are available from http://gnuwin32.sourceforge.net/. GNUWin32 provides ports of tools with a GPL or similar open source license to modern MS-Windows (Microsoft Windows 2000 / XP / 2003 / Vista / 2008 / 7). See http://gnuwin32.sourceforge.net/packages.html for a list of all of the tools available in the GNUWin32 package. The SourceForge project is located here: http://sourceforge.net/projects/gnuwin32/. The project is still being actively supported (although some of the Windows ports have gotten very old). Some commercial toolchains include a subset of the GNUWin32 tools in the installation. My recommendation is that you download the GNUWin32 tools directly from the sourceforge.net website so that you will know what you are using and can reproduce your build environment. GNUWin32 Installation Steps: The following steps will download and execute the GNUWin32 installer. 1. Download GetGNUWin32-x.x.x.exe from http://sourceforge.net/projects/getgnuwin32/files/. This is the installer. The current version as of this writing is 0.6.3. 2. Run the installer. 3. Accept the license. 4. Select the installation directory. My recommendation is the directory that contains this README file (). 5. After running GetGNUWin32-0.x.x.exe, you will have a new directory /GetGNUWin32 Note that the GNUWin32 installer didn't install GNUWin32. Instead, it installed another, smarter downloader. That downloader is the GNUWin32 package management tool developed by the Open SSL project. The following steps probably should be performed from inside a DOS shell. 6. Change to the directory created by GetGNUWin32-x.x.x.exe cd GetGNUWin32 7. Execute the download.bat script. The download.bat script will download about 446 packages! Enough to have a very complete Linux-like environment under the DOS shell. This will take awhile. This step only downloads the packages and the next step will install the packages. download 8. This step will install the downloaded packages. The argument of the install.bat script is the installation location. C:\gnuwin32 is the standard install location: install C:\gnuwin32 NOTE: This installation step will install *all* GNUWin32 packages... far more than you will ever need. If disc space is a problem for you, you might need to perform a manual installation of the individual ZIP files that you will find in the /GetGNUWin32/packages directory. 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: 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 encounter 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 ", 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 builds 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 symbols. 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 buildroot repository at https://bitbucket.org/nuttx/buildroot However, it is possible that there could be interoperability issues with your toolchain since they will be using different versions of binutils and possibly different ABIs. Building Original Linux Boards in Cygwin Some default board configurations are set to build under Linux and others to build under Windows with Cygwin. Various default toolchains may also be used in each configuration. It is possible to change the default setup. Here, for example, is what you must do in order to compile a default Linux configuration in the Cygwin environment using the CodeSourceery for Windows toolchain. After instantiating a "canned" NuttX configuration, run the target 'menuconfig' and set the following items: Build Setup->Build Host Platform->Windows Build Setup->Windows Build Environment->Cygwin System Type->Toolchain Selection->CodeSourcery GNU Toolchain under Windows In Windows 7 it may be required to open the Cygwin shell as Administrator ("Run As" option, right button) you find errors like "Permission denied". Recovering from Bad Configurations Many people make the mistake of configuring NuttX with the "canned" configuration and then just typing 'make' with disastrous consequences; the build may fail with mysterious, uninterpretable, and irrecoverable build errors. If, for example, you do this with an unmodified Linux configuration in a Windows/Cgwin environment, you will corrupt the build environment. The environment will be corrupted because of POSIX vs Windows path issues and with issues related to symbolic links. If you make the mistake of doing this, the easiest way to recover is to just start over: Do 'make distclean' to remove every trace of the corrupted configuration, reconfigure from scratch, and make certain that the set the configuration correctly for your platform before attempting to make again. Just fixing the configuration file after you have instantiated the bad configuration with 'make' is not enough. 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 | |- renesas/ | | |- include/ | | | `-README.txt | | |- src/ | | | `-README.txt | |- x86/ | | |- include/ | | | `-README.txt | | `- src/ | | `-README.txt | `- z80/ | | `- src/ | | |- z80/README.txt | | `- z180/README.txt, z180_mmu.txt | `- README.txt |- audio/ | `-README.txt |- binfmt/ | `-libpcode/ | `-README.txt |- configs/ | |- amber/ | | `- README.txt | |- arduino-mega2560/ | | `- README.txt | |- arduino-due/ | | `- README.txt | |- avr32dev1/ | | `- README.txt | |- bambino-200e/ | | `- README.txt | |- c5471evm/ | | `- README.txt | |- cc3200-launchpad/ | | `- README.txt | |- cloudctrl | | `- README.txt | |- demo0s12ne64/ | | `- README.txt | |- dk-tm4c129x/ | | `- README.txt | |- ea3131/ | | `- README.txt | |- ea3152/ | | `- README.txt | |- eagle100/ | | `- README.txt | |- efm32-g8xx-stk/ | | `- README.txt | |- efm32gg-stk3700/ | | `- 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 | |- fire-stm32v2/ | | `- README.txt | |- freedom-k64f/ | | `- README.txt | |- freedom-kl25z/ | | `- README.txt | |- freedom-kl26z/ | | `- README.txt | |- hymini-stm32v/ | | `- README.txt | |- kwikstik-k40/ | | `- README.txt | |- launchxl-tms57004/ | | `- README.txt | |- lincoln60/ | | `- README.txt | |- lm3s6432-s2e/ | | `- README.txt | |- lm3s6965-ek/ | | `- README.txt | |- lm3s8962-ek/ | | `- README.txt | |- lpc4330-xplorer/ | | `- README.txt | |- lpc4337-ws/ | | `- README.txt | |- lpc4357-evb/ | | `- README.txt | |- lpc4370-link2/ | | `- README.txt | |- lpcxpresso-lpc1115/ | | `- README.txt | |- lpcxpresso-lpc1768/ | | `- README.txt | |- maple/ | | `- README.txt | |- mbed/ | | `- README.txt | |- mcu123-lpc214x/ | | `- README.txt | |- micropendous3/ | | `- README.txt | |- mikroe-stm32f/ | | `- README.txt | |- mirtoo/ | | `- README.txt | |- misoc/ | | `- README.txt | |- moteino-mega/ | | `- README.txt | |- mx1ads/ | | `- README.txt | |- ne63badge/ | | `- README.txt | |- ntosd-dm320/ | | |- doc/README.txt | | `- README.txt | |- nucleo-144/ | | `- README.txt | |- nucleo-f4x1re/ | | `- README.txt | |- nutiny-nuc120/ | | `- README.txt | |- olimex-efm32g880f129-stk/ | | `- README.txt | |- olimex-lpc1766stk/ | | `- README.txt | |- olimex-lpc2378/ | | `- README.txt | |- olimex-lpc-h3131/ | | `- README.txt | |- olimex-stm32-h405/ | | `- README.txt | |- olimex-stm32-h407/ | | `- README.txt | |- olimex-stm32-p107/ | | `- README.txt | |- olimex-stm32-p207/ | | `- README.txt | |- olimex-stm32-p407/ | | `- README.txt | |- olimex-strp711/ | | `- README.txt | |- open1788/ | | `- README.txt | |- p112/ | | `- README.txt | |- pcblogic-pic32mx/ | | `- README.txt | |- pcduino-a10/ | | `- README.txt | |- pic32mx-starterkit/ | | `- README.txt | |- pic32mx7mmb/ | | `- README.txt | |- pic32mz-starterkit/ | | `- README.txt | |- qemu-i486/ | | `- README.txt | |- sabre-6quad/ | | `- README.txt | |- sama5d2-xult/ | | `- README.txt | |- sama5d3x-ek/ | | `- README.txt | |- sama5d3-xplained/ | | `- README.txt | |- sama5d4-ek/ | | `- README.txt | |- samd20-xplained/ | | `- README.txt | |- samd21-xplained/ | | `- README.txt | |- saml21-xplained/ | | `- README.txt | |- sam3u-ek/ | | `- README.txt | |- sam4cmp-db | | `- README.txt | |- sam4e-ek/ | | `- README.txt | |- sam4l-xplained/ | | `- README.txt | |- sam4s-xplained/ | | `- README.txt | |- sam4s-xplained-pro/ | | `- README.txt | |- same70-xplained/ | | `- README.txt | |- samv71-xult/ | | `- README.txt | |- sim/ | | |- include/README.txt | | `- README.txt | |- shenzhou/ | | `- README.txt | |- skp16c26/ | | `- README.txt | |- spark/ | | `- README.txt | |- stm3210e-eval/ | | |- RIDE/README.txt | | `- README.txt | |- stm3220g-eval/ | | |-ide/nsh/iar/README.txt | | |-ide/nsh/uvision/README.txt | | `- README.txt | |- stm3240g-eval/ | | `- README.txt | |- stm32_tiny/ | | `- README.txt | |- stm32f103-minumum/ | | `- README.txt | |- stm32f3discovery/ | | `- README.txt | |- stm32f4discovery/ | | `- README.txt | |- stm32f411e-disco/ | | `- README.txt | |- stm32f429i-disco/ | | |- ide/ltcd/uvision/README.txt | | |- ltdc/README.txt | | `- README.txt | |- stm32f746g-disco/ | | `- README.txt | |- stm32l476-mdk/ | | `- README.txt | |- stm32l476vg-disco/ | | `- README.txt | |- stm32ldiscovery/ | | `- README.txt | |- stm32vldiscovery/ | | `- README.txt | |- sure-pic32mx/ | | `- README.txt | |- teensy-2.0/ | | `- README.txt | |- teensy-3.x/ | | `- README.txt | |- teensy-lc/ | | `- README.txt | |- tm4c123g-launchpad/ | | `- README.txt | |- tm4c1294-launchpad/ | | `- README.txt | |- twr-k60n512/ | | `- README.txt | |- u-blox-co27/ | | `- README.txt | |- ubw32/ | | `- README.txt | |- us7032evb1/ | | `- README.txt | |- viewtool-stm32f107/ | | `- README.txt | |- xtrs/ | | `- README.txt | |- z16f2800100zcog/ | | |- ostest/README.txt | | |- pashello/README.txt | | `- README.txt | |- z80sim/ | | `- README.txt | |- z8encore000zco/ | | |- ostest/README.txt | | `- README.txt | |- z8f64200100kit/ | | |- ostest/README.txt | | `- README.txt | |- zkit-arm-1769/ | | `- README.txt | |- zp214xpa/ | | `- README.txt | `- README.txt |- drivers/ | |- eeprom/ | | `- README.txt | |- lcd/ | | | README.txt | | `- pcf8574_lcd_backpack_readme.txt | |- mtd/ | | `- README.txt | |- sensors/ | | `- README.txt | |- syslog/ | | `- README.txt | `- README.txt |- fs/ | |- binfs/ | | `- README.txt | |- mmap/ | | `- README.txt | |- nxffs/ | | `- README.txt | |- smartfs/ | | `- README.txt | |- procfs/ | | `- README.txt | `- unionfs/ | `- README.txt |- graphics/ | `- README.txt |- lib/ | `- README.txt |- libc/ | |- zoneinfo | | `- README.txt | `- README.txt |- libnx/ | `- README.txt |- libxx/ | `- README.txt |- mm/ | |- shm/ | | `- README.txt | `- README.txt |- net/ | `- README.txt |- syscall/ | `- README.txt `- tools/ `- README.txt Below is a guide to the available README files in the semi-optional apps/ source tree: apps/ |- examples/ | |- bastest/README.txt | |- json/README.txt | |- pashello/README.txt | `- README.txt |- gpsutils/ | `- minmea/README.txt |- graphics/ | |- tiff/README.txt | `- traveler/tools/tcledit/README.txt |- interpreters/ | |- bas | | `- README.txt | |- ficl | | `- README.txt | `- README.txt |- modbus/ | `- README.txt |- netutils/ | |- discover | | `- README.txt | |- ftpc | | `- README.txt | |- json | | `- README.txt | |- telnetd | | `- README.txt | `- README.txt |- nshlib/ | `- README.txt |- NxWidgets/ | `- README.txt |- system/ | |- cdcacm | | `- README.txt | |- i2c | | `- README.txt | |- inifile | | `- README.txt | |- install | | `- README.txt | |- nxplayer | | `- README.txt | |- symtab/ | | `- README.txt | |- usbmsc | | `- README.txt | `- zmodem | `- README.txt `- README.txt Additional README.txt files in the other, related repositories: NxWidgets/ |- Doxygen | `- README.txt |- tools | `- README.txt |- UnitTests | `- README.txt `- README.txt buildroot/ `- README.txt tools/ `- README.txt uClibc++/ `- README.txt pascal/ `- README.txt