# NuttX RTOS Last Updated: January 4, 2013

# Table of Contents

| Overview. What is NuttX? Look at all those files and features... How can it be a tiny OS?
| NuttX Discussion Group. Do you want to talk about NuttX features? Do you need some help? Problems? Bugs?
| Downloads. Where can I get NuttX? What is the current development status?
| Supported Platforms. What target platforms has NuttX been ported to?
| Development Environments. What kinds of host cross-development platforms can be used with NuttX?
| Memory Footprint. Just how big is it? Do I have enough memory to use NuttX?
| Licensing. 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)
| Release History What has changed in the last release of NuttX? What unreleased changes are pending in SVN?
| Bugs, Issues, Things-To-Do. Software is never finished nor ever tested well enough. (Do you want to help develop NuttX? If so, send me an email).
| Other Documentation. What other NuttX documentation is available?
| Trademarks. Some of the words used in this document belong to other people.

# Overview

Goals. NuttX is a real timed embedded operating system (RTOS). Its goals are:

| Small Footprint
| Usable in all but the tightest micro-controller environments, The focus is on the tiny-to-small, deeply embedded environment.
| Rich Feature OS Set
| The goal is to provide implementations of most standard POSIX OS interfaces to support a rich, multi-threaded development environment for deeply embedded processors. NON-GOALS: (1) It is not a goal to provide the level of OS features like those provided by Linux. In order to work with smaller MCUs, small footprint must be more important than an extensive feature set. But standard compliance is more important than small footprint. Surely a smaller RTOS could be produced by ignoring standards. Think of NuttX is a tiny Linux work-alike with a much reduced feature set. (2) There is no MMU-based support for processes. At present, NuttX assumes a flat address space.
| Highly Scalable
| 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.
| Standards Compliance
| 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 `fork()`). Because of this standards conformance, software developed under other standard OSs (such as Linux) should port easily to NuttX.
| Real-Time
| Fully pre-emptible, fixed priority and round-robin scheduling.
| Totally Open
| Non-restrictive BSD license.
| GNU Toolchains
| Compatible GNU toolchains based on buildroot available for download to provide a complete development environment for many architectures.

Feature Set. Key features of NuttX include:

| Standards Compliant Core Task Management
| Fully pre-emptible.
| Naturally scalable.
| Highly configurable.
| Easily extensible to new processor architectures, SoC architecture, or board architectures. A Porting Guide is available.
| FIFO and round-robin scheduling.
| Realtime, deterministic, with support for priority inheritance
| POSIX/ANSI-like task controls, named message queues, counting semaphores, clocks/timers, signals, pthreads, environment variables, filesystem.
| VxWorks-like task management and watchdog timers.
| BSD socket interface.
| Extensions to manage pre-emption.
| Optional tasks with address environments (Processes).
| Inheritable "controlling terminals" and I/O re-direction.
| On-demand paging.
| System logging.
| May be built either as an open, flat embedded RTOS or as a separately built, secure micro-kernel with a system call interface.
| Well documented in the NuttX User Guide.
| File system
| Tiny, in-memory, root pseudo-file-system.
| Virtual file system supports drivers and mountpoints.
| Mount-able volumes. Bind mountpoint, filesystem, and block device driver.
| Generic system logging (SYSLOG) support.
| FAT12/16/32 filesystem support with optional FAT long file name support1.
| NFS Client. Client side support for a Network File System (NFS, version 3, UDP).
| NXFFS. The tiny NuttX wear-leveling FLASH file system.
| ROMFS filesystem support.
| A binary loader with support for the following formats: Separately linked ELF modules. Separately linked NXFLAT modules. NXFLAT is a binary format that can be XIP from a file system.
| PATH variable support.
| 1 FAT long file name support may be subject to certain Microsoft patent restrictions if enabled. See the top-level `COPYING` file for details.
| Device Drivers
| Supports character and block drivers as well as specialized driver interfaces.
| Network, USB (host), USB (device), serial, CAN, ADC, DAC, PWM, Quadrature Encoder, and watchdog timer driver architectures.
| RAMDISK, pipes, FIFO, `/dev/null`, `/dev/zero`, `/dev/random`, and loop drivers.
| Generic driver for SPI-based or SDIO-based MMC/SD/SDH cards.
| Power management sub-system.
| ModBus support provided by built-in FreeModBus version 1.5.0.
| C/C++ Libraries
| Standard C Library Fully integrated into the OS.
| Includes floating point support via a Standard Math Library.
| Add-on uClibc++ module provides Standard C++ Library (LGPL).
| Networking
| TCP/IP, UDP, ICMP, IGMPv2 (client) stacks.
| SLIP
| A port cJSON
| Small footprint (based on uIP).
| BSD compatible socket layer.
| Networking utilities (DHCP server and client, SMTP client, TELNET client, FTP server and client, TFTP client, HTTP server and client). Inheritable TELNET sessions (as "controlling terminal")
| NFS Client. Client side support for a Network File System (NFS, version 3, UDP).
| A NuttX port of Jeff Poskanzer's THTTPD HTTP server integrated with the NuttX binary loader to provide true, embedded CGI.
| UDP Network Discover (Contributed by Richard Cochran).
| XML RPC Server (Contributed by Richard Cochran).
| FLASH Support
| MTD-inspired interface for Memory Technology Devices.
| FTL. Simple Flash Translation Layer support file systems on FLASH.
| NXFFS. the NuttX wear-leveling FLASH file system.
| Support for SPI-based FLASH and FRAM devices.
| USB Host Support
| USB host architecture for USB host controller drivers and device-dependent USB class drivers.
| USB host controller drivers available for the NXP LPC17xx.
| Device-dependent USB class drivers available for USB mass storage and HID keyboard.
| USB Device Support
| Gadget-like architecture for USB device controller drivers and device-dependent USB class drivers.
| USB device controller drivers available for the PIC32, NXP LPC17xx, LPC214x, LPC313x, LPC43xx, STMicro STM32 and TI DM320.
| Device-dependent USB class drivers available for USB serial (CDC/ACM and a PL2303 emulation), for USB mass storage, and for a composite CDC/ACM and mass storage device.
| Built-in USB trace functionality for USB debug.
| Graphics Support
| Framebuffer drivers.
| LCD drivers for both parallel and SPI LCDs and OLEDs.
| NX: A graphics library, tiny windowing system and tiny font support that works with either framebuffer or LCD drivers. Documented in the NX Graphics Subsystem manual.
| Font management sub-system.
| NxWidgets: NXWidgets is library of graphic objects, or "widgets," (labels, buttons, text boxes, images, sliders, progress bars, etc.). NXWidgets is written in C++ and integrates seamlessly with the NuttX NX graphics and font management subsystems.
| NxWM: NxWM is the tiny NuttX window manager based on NX and NxWidgets.
| Input Devices
| Touchscreen, USB keyboard, GPIO-based buttons and keypads.
| Analog Devices
| Support for Analog-to-Digital conversion (ADC), Digital-to-Analog conversion (DAC), multiplexers, and amplifiers.
| Motor Control
| Pulse width modulation (PWM) / Pulse count modulation.

NuttX Add-Ons. The following packages are available to extend the basic NuttX feature set:

| NuttShell (NSH)
| A small, scalable, bash-like shell for NuttX with rich feature set and small footprint. See the NuttShell User Guide.
| Pascal Compiler with NuttX runtime P-Code interpreter add-on
| The Pascal add-on is available for download from the SourceForge website.

Look at all those files and features... How can it be a tiny OS?. 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?

| Lots of Features -- More can be smaller!
| The philosophy behind that NuttX is that lots of features are great... BUT 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. 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 32K total memory (code and data). On the other hand, typical, richly featured NuttX builds require more like 64K (and if all of the features are used, this can push 100K).
| Many, many files -- More really is smaller!
| 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? Static Libraries. Because in the NuttX build processed, objects are compiled and saved into static libraries (archives). 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.
| Other Tricks
| 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: Configuration Files. 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 NuttX Porting Guide 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. Weak Symbols The GNU toolchain supports weak 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.

# NuttX Discussion Group

Most NuttX-related discussion occurs on the Yahoo! NuttX group. You are cordially invited to join. I make a special effort to answer any questions and provide any help that I can.

# Downloads

## NuttX-6.24 Release Notes

The 91st release of NuttX, Version 6.24, was made on December 20, 2012, and is available for download from the SourceForge website. Note that the release consists of two tarballs: `nuttx-6.24.tar.gz` and `apps-6.24.tar.gz`. Both may be needed (see the top-level `nuttx/README.txt` file for build information) The change log associated with the release is available here. Unreleased changes after this release are available in SVN. These unreleased changes are also listed here.

This release corresponds with SVN release number: r5447, Note that all SVN information has been stripped from the tarballs. If you need the SVN configuration, you should check out directly from SVN. Revision r5447 should equivalent to release 6.24 of NuttX:

    svn checkout -r5447 svn://svn.code.sf.net/p/nuttx/code/trunk nuttx-code

Or (HTTP):

    svn checkout -r5447 http://svn.code.sf.net/p/nuttx/code/trunk nuttx-code

Additional new features and extended functionality

- RTOS:

  - Implemented the POSIX `pause()` function (still has some compiance issues).
  - Tasking logic is extended to support the notion of address environments. An address environment is the key notion underlying "process" vs. tasks. If tasks are created with address environments (by `binfmt`), the OS will propogate that environment to child threads and will destroy the address environment when all threads in the "process" exists.
  - If support for the `PATH` variable is enabled, the OS start up logic will create an initial environment containing the default `PATH` setting (`CONFIG_PATH_INITIAL`). This initial `PATH` will then be inherited by all tasks.

- `Binfmt`:

  - The NuttX binary loaders have been updated to support the `PATH` environment variable. Now, if the `PATH` is properly defined, programs can be executed from mass storage using only the file name. This feature is added to support more standard behavior (eventually, NSH will support execution of programs in file systems by just entering the file name, perhaps in 6.25?).
  - The NXFLAT and ELF binary loaders have been extended to create address environments for any new tasks executed from the file system. This feature requires that the architecture support a memory management unit (MMU) and the address environment interfaces declared in `include/nuttx/arch.h` (currently, this is only supported by the z180).

- Drivers: LCD driver for the Univision UG-2864AMBAG01 OLED

- STM32: Support for STM32F100 high density chips contributed by Freddie Chopin.

- STM32 Drivers: Added optional RS-485 direction bit control (from Freddie Chopin).

- STM32 Boards:

  - Support for generic STM32F100RC board contributed by Freddie Chopin.
  - `stm32f4discovery/nxlines`: STM32F4Discovery support for the UG-2864AMBAG01 OLED.
  - `stm32f4discovery/winbuild`: A version of the NuttX OS test configured to build natively on Windows.
  - `stm32f4discovery/elf`: Now uses the `PATH` variable to find ELF executables.
  - `configs/cloudctrl`: Added for Darcy Gong's CloudController board

- PIC32 Boards: Update the Mirtoo configuration for Release 2 of the Mirtoo module.

- Calypso: Add Calypso keypad driver (from Denis Carilki).

- ZiLOG:

  - Add support for the z180 chip family and, specifically, for the P112 retro hardware (see http://p112.feedle.net/).
  - All ZiLOG configurations updated to use the current ZDS-II and/or SDCC toolchains.

- Graphics:

  - Add a semaphore handshake so that operations on buffers from the NXMU client will be blocked until the NX server operates on the buffer data (from Petteri Aimonen).
  - `nxtk_subwindowmove()` and `nxtk_getwindow()`: Improvements to clipping logic from Petteri Aimonen.

- C Library: `lib/` sub-directory renamed `libc/` (there is a new `lib/` sub-directory that is used to hold all archives).

- C++: Exception stubs from Petteri Aimonen.

- Applications:

  - Add NSH hexdump command to dump the contents of a file (or character device) to the console (contributed by Petteri Aimonen).
  - Extend the NSH `ifconfig` command plus various DHCPC improvements (from Darcy Gong).

- apps/examples:

  - `ostest`: Replace large tables with algorithmic prime number generation. This allows the roundrobin test to run on platforms with minimal SRAM (Freddie Chopin).
  - `keypadtest`: A new keypad test example contributed by Denis Carikli.
  - `elf` and `nxflat`: If `CONFIG_BINFMT_EXEPATH` is defined, these examples will now use a relative path to the program and expect the `binfmt/` logic to find the absolute path to the program using the `PATH` variable.

- Build system:

  - New top-level Makefiles: `Makefile.unix` and `Makefile.win` (along with numerous changes to other make-related files). This adds basic support for building NuttX natively under from Windows console (rather than in a POSIX-like environment). This build: (1) Uses all Windows style paths, (2) Uses primarily standard Windows batch commands with (3) a few additional commands from GNUWin32 (such as GNU make).

    This capability should still be considered a work in progress because: (1) It has not been verfied on all targets and tools, and (2) it still lacks some of the creature-comforts of the more mature environments (like a functional `configure.sh` script and `make menuconfig` support).

  - Example Windows native builds for STM32F4Discovery, eZ80, z16f, z8, Z80, and Z180.
  - Several configurations have been converted to work the `kconfig-frontends` `mconf` configuration tool: `stm32f4discovery/nxlines`, and all eZ80, z16f, z8, Z80, and Z180 configurations.
  - Architectures now include a common `Toolchain.defs` file that can be used to manage toolchains in a more configurable way (most of this contributed by Mike Smith).

- Build tools:

  - Renamed `tools/winlink.sh` to `tools/copydir.sh`.
  - Several new tools/scripts to support the Windows native build: `tools/mkdeps.bat`, `tools/mkdeps.c`, `tools/link.bat`, `tools/unlink.bat`, and `tools/ copydir.bat`.
  - `tools/incdir.sh` and `tools/incdir.bat` now support an `-s` option to generate system header file paths.
  - `tools/b16.c`: Fixed precision math conversion utility.

Bugfixes (see the change log for details). Some of these are very important (marked critical):

- RTOS: Fix some backward conditional compilation in the work queue logic (Freddie Chopin).

- File System: Uninitialized variable caused assertions (from Lorenz Meier).

- Drivers: Partial fix for STM32 OTG FS device drivers and fix for short, unaligned writes in the flash translation layer (`drivers/mtd/ftl.c`), both from Petteri Aimonen.

- STM32 Drivers:

  - Qencoder driver and TIM3 driver fixes from Ryan Sundberg.
  - Fix timeout delay calculation in the STM32 OTG FS host driver.

- LPC17xx Drivers: Resources not being properly released when I2C driver is un-initialized.

- Graphics:

  - Fix logic when the mouse drags outside of the window; fix another "blocked message" handling case (both from Petteri Aimonen).
  - `nxtk_filltrapwindow()`: Correct an offset problem (also from Peterri Aimonen).
  - `nxglib_splitline()`: Correct the "fat flat line" bug.

- C Library:

  - `nrand()` changes to prevent coefficients from becoming zero which would "lock up" the random number generate.
  - Add rounding functions to the math library (contributed by Petteri Aimonen).

- Build system: Changes to MIN definitions in all `limit.h` header files to avoid integer overflows. For example from (-128) to (-127 - 1) (from Petteri Aimonen).

- Applications: Modbus fixes from Freddie Chopin.

As well as other, less critical bugs. See the ChangeLog for additional, detailed changes.

# Supported Platforms

The short story (Number of ports follow in parentheses). The state of the various ports vary from board-to-board. Follow the links for the details:

Linux user mode simulation (1) ARM ARM7TDMI (5) ARM920T (1) ARM926EJS (3) ARM Cortex-M3 (16) ARM Cortex-M4 (5) Atmel AVR Atmel 8-bit AVR (3) Atmel AVR32 (1) | Freescale M68HCS12 (2) Intel Intel 8052 Microcontroller (1) Intel 80x86 (2) MicroChip PIC32MX (MIPS) (4) Renesas/Hitachi: Renesas/Hitachi SuperH (1/2) Renesas M16C/26 (1/2) | ZiLOG ZiLOG Z16F (1) ZiLOG eZ80 Acclaim! (1) ZiLOG Z8Encore! (2) ZiLOG Z180 (1) ZiLOG Z80 (2)

The details, caveats and fine print follow:

| Linux User Mode.
| 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. STATUS: Does not support interrupts but is otherwise fully functional.
| ARM7TDMI.
| TI TMS320C5471 (also called C5471 or TMS320DA180 or DA180). NuttX operates on the ARM7 of this dual core processor. This port uses the Spectrum Digital evaluation board with a GNU arm-nuttx-elf toolchain* under Linux or Cygwin. STATUS: This port is complete, verified, and included in the initial NuttX release.
| TI Calypso. This port supports the TI "Calypso" MCU used in various cell phones (and, in particular, by the Osmocom-bb project). Like the c5471, NuttX operates on the ARM7 of this dual core processor. STATUS: This port was contributed by Denis Carilki and includes the work of Denis Carikli, Alan Carvalho de Assis, and Stefan Richter. Calypso support first appeared in NuttX-6.17 with LCD drivers. Support for the Calypso keyboard was added in NuttX-6.24 by Denis Carilki.
| NXP LPC214x. Support is provided for the NXP LPC214x family of processors. In particular, support is provided for (1) the mcu123.com lpc214x evaluation board (LPC2148) and (1) the The0.net ZPA213X/4XPA development board (with the The0.net UG-2864AMBAG01 OLED) This port also used the GNU arm-nuttx-elf toolchain* under Linux or Cygwin. STATUS: This port boots and passes the OS test (apps/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 (NSH) configuration is also available. Development Environments: 1) Linux with native Linux GNU toolchain, 2) Cygwin/MSYS with Cygwin GNU toolchain, 3) Cygwin/MSYS with Windows native toolchain (CodeSourcery or devkitARM), or 4) Native Windows. A DIY toolchain for Linux or Cygwin is provided by the NuttX buildroot package.
| NXP LPC2378. 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-nuttx-elf toolchain* under Linux or Cygwin. STATUS: This port boots and passes the OS test (apps/examples/ostest) and includes a working implementation of the NuttShell (NSH). The port is complete and verified. As of NuttX 5.3, the port includes only basic timer interrupts and serial console support. Development Environments: (Same as for the NXP LPC214x).
| STMicro STR71x. 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-nuttx-elf toolchain* under Linux or Cygwin. STATUS: 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 (NSH) 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 ENC28J60 Ethernet driver for add-on hardware is available and but has not been fully verified on the Olimex board (due to issues powering the ENC28J60 add-on board). Development Environments: 1) Linux with native Linux GNU toolchain, 2) Cygwin/MSYS with Cygwin GNU toolchain, 3) Cygwin/MSYS with Windows native toolchain (CodeSourcery or devkitARM), or 4) Native Windows. A DIY toolchain for Linux or Cygwin is provided by the NuttX buildroot package.
| ARM920T.
| Freescale MC9328MX1 or i.MX1. This port uses the Freescale MX1ADS development board with a GNU arm-nuttx-elf toolchain* under either Linux or Cygwin. STATUS: This port has stalled due to development tool issues. Coding is complete on the basic port (timer, serial console, SPI).
| ARM926EJS.
| TI TMS320DM320 (also called DM320). NuttX operates on the ARM9 of this dual core processor. This port uses the Neuros OSD with a GNU arm-nuttx-elf toolchain* under Linux or Cygwin. The port was performed using the OSD v1.0, development board. STATUS: The basic port (timer interrupts, serial ports, network, framebuffer, etc.) is complete. All implemented features have been verified with the exception of the USB device-side driver; that implementation is complete but untested.
| NXP LPC3131. The port for the NXP LPC3131 on the Embedded Artists EA3131 development board was first released in NuttX-5.1 with a GNU arm-nuttx-elf or arm-eabi toolchain* under Linux or Cygwin (but was not functional until NuttX-5.2). STATUS: The basic EA3131 port is complete and verified in NuttX-5.2 This basic port includes basic boot-up, serial console, and timer interrupts. This port was extended in NuttX 5.3 with a USB high speed driver contributed by David Hewson. David also contributed I2C and SPI drivers plus several important LPC313x USB bug fixes that appear in the NuttX 5.6 release. This port has been verified using the NuttX OS test, USB serial and mass storage tests and includes a working implementation of the NuttShell (NSH). Support for on-demand paging has been developed for the EA3131. That support would all execute of a program in SPI FLASH by paging code sections out of SPI flash as needed. However, as of this writing, I have not had the opportunity to verify this new feature.
| NXP LPC315x. Support for the NXP LPC315x family has been incorporated into the code base as of NuttX-6.4. Support has added for the Embedded Artists EA3152 board in NuttX-6.11. STATUS: Basic support is in place for both the LPC3152 MCU and the EA3152 board. Verification of the port was deferred due to tool issues However, because of the high degree of compatibility between the LPC313x and LPC315x family, it is very likely that the support is in place (or at least very close). At this point, verification of the EA3152 port has been overcome by events and may never happen. However, the port is available for anyone who may want to use it.
| ARM Cortex-M3.
| TI Stellaris LM3S6432. This is a port of NuttX to the Stellaris RDK-S2E Reference Design Kit and the MDL-S2E Ethernet to Serial module (contributed by Mike Smith).
| Luminary/TI Stellaris LM3S6918. This port uses the Micromint Eagle-100 development board with a GNU arm-nuttx-elf toolchain* under either Linux or Cygwin. STATUS: The initial, release of this port was included in NuttX version 0.4.6. The current port includes timer, serial console, Ethernet, SSI, and microSD support. There are working configurations the NuttX OS test, to run the NuttShell (NSH), the NuttX networking test, and the uIP web server. Development Environments: 1) Linux with native Linux GNU toolchain, 2) Cygwin/MSYS with Cygwin GNU toolchain, 3) Cygwin/MSYS with Windows native toolchain (CodeSourcery or devkitARM), or 4) Native Windows. A DIY toolchain for Linux or Cygwin is provided by the NuttX buildroot package.
| Luminary/TI Stellaris LM3S6965. This port uses the Stellaris LM3S6965 Ethernet Evalution Kit with a GNU arm-nuttx-elf toolchain* under either Linux or Cygwin. STATUS: This port was released in NuttX 5.5. Features are the same as with the Eagle-100 LM3S6918 described above. The apps/examples/ostest configuration has been successfully verified and an NSH configuration with Telnet support is available. MMC/SD and Networking support was not been thoroughly verified: Current development efforts are focused on porting the NuttX window system (NX) to work with the Evaluation Kits OLED display. NOTE: As it is configured now, you MUST have a network connected. Otherwise, the NSH prompt will not come up because the Ethernet driver is waiting for the network to come up. Development Environments: See the Eagle-100 LM3S6918 above.
| Luminary/TI Stellaris LM3S8962. This port uses the Stellaris EKC-LM3S8962 Ethernet+CAN Evalution Kit with a GNU arm-nuttx-elf toolchain* under either Linux or Cygwin. Contributed by Larry Arnold. STATUS: This port was released in NuttX 5.10. Features are the same as with the Eagle-100 LM3S6918 described above.
| Luminary/TI Stellaris LM3S9B96. Header file support was contributed by Tiago Maluta for this part. Jose Pablo Rojas V. is currently using those header file changes to port NuttX to the TI/Stellaris EKK-LM3S9B96. With any luck, that port should be working and available in the NuttX-6.20 release.
| TI Stellaris LM3S6432S2E. This port uses Serial-to-Ethernet Reference Design Kit (RDK-S2E) and has similar support as for the other Stellaris family members. Configurations are available for the OS test and for the NuttShell (NSH) (see the NSH User Guide). The NSH configuration including networking support with a Telnet NSH console. This port was contributed by Mike Smith. STATUS: This port was will be released in NuttX 6.14.
| STMicro STM32F100x. Chip support for these STM32 "Value Line" family was contributed by Mike Smith and users have reported that they have successful brought up NuttX on there proprietary boards using this logic. This logic was extended to support the high density STM32F100RC chips by Freddie Chopin However, there is no specific board support for this chip families in the NuttX source tree. There is, however, generic support for STM32F100RC boards.
| STMicro STM32F103x. Support for four MCUs and four board configurations are available. MCU support includes all of the high density and connectivity line families. Board supported is available specifically for: STM32F103ZET6, STM32F103RET6, STM32F103VCT, and STM32F103VET6. Boards supported include: A port for the STMicro STM3210E-EVAL development board that features the STM32F103ZET6 MCU. The ISOTEL NetClamps VSN V1.2 ready2go sensor network platform based on the STMicro STM32F103RET6. Contributed by Uros Platise. A port for the HY-Mini STM32v board. This board is based on the STM32F103VCT chip. Contributed by Laurent Latil. The M3 Wildfire development board (STM32F103VET6), version 2. See http://firestm32.taobao.com (the current board is version 3). These ports uses a GNU arm-nuttx-elf toolchain* under either Linux or Cygwin (with native Windows GNU tools or Cygwin-based GNU tools). STATUS: Basic Support/Drivers. The basic STM32 port was released in NuttX version 0.4.12. The basic port includes boot-up logic, interrupt driven serial console, and system timer interrupts. The 0.4.13 release added support for SPI, serial FLASH, and USB device.; The 4.14 release added support for buttons and SDIO-based MMC/SD and verifed DMA support. Verified configurations are available for NuttX OS test, the NuttShell (NSH) example, the USB serial device class, and the USB mass storage device class example. NetClamps VSN. Support for the NetClamps VSN was included in version 5.18 of NuttX. Uros Platise added support for timers, RTC, I2C, FLASH, extended power management and other features. Additional Drivers. Additional drivers and configurations were added in NuttX 6.13 and later releases for the STM32 F1 and F4. F1 compatible drivers include an Ethernet driver, ADC driver, DAC driver, PWM driver, IWDG, WWDG, and CAN drivers. M3 Wildfire. Support for the Wildfire board was included in version 6.22 of NuttX. The board port is basically functional. Not all features have been verified. Support for FAT file system on an an SD card had been verified. The ENC28J60 network is functional (but required lifting the chip select pin on the W25x16 part). Customizations for the v3 version of the Wildfire board are selectable (but untested). Development Environments: 1) Linux with native Linux GNU toolchain, 2) Cygwin/MSYS with Cygwin GNU toolchain, 3) Cygwin/MSYS with Windows native toolchain (RIDE7, CodeSourcery or devkitARM), or 4) Native Windows. A DIY toolchain for Linux or Cygwin is provided by the NuttX buildroot package.
| STMicro STM32F107x. Chip support for the STM32 F1 "Connectivity Line" family has been present in NuttX for some time and users have reported that they have successful brought up NuttX on there proprietary boards using this logic. Olimex STM32-P107 Support for the Olimex STM32-P107 was contributed by Max Holtzberg and first appeared in NuttX-6.21. That port features the STMicro STM32F107VC MCU. STATUS: Configurations for the basic OS test and NSH are available and verified. Networking is functional. Shenzhou IV Work is underway as of this writing to port NuttX to the Shenzhou IV development board (See www.armjishu.com) featuring the STMicro STM32F107VCT MCU. If all goes according to plan, this port should be verified and available in NuttX-6.22. STATUS: In progress. The following have been verified: (1) Basic Cortex-M3 port, (2) Ethernet, (3) On-board LEDs
| STMicro STM32F207IG. Support for the STMicro STM3220G-EVAL development board was contributed by Gary Teravskis and first released in NuttX-6.16. STATUS: The peripherals of the STM32 F2 family are compatible with the STM32 F4 family. See discussion of the STM3240G-EVAL board below for further information.
| Atmel AT91SAM3U. This port uses the Atmel SAM3U-EK development board that features the AT91SAM3U4E MCU. This port uses a GNU arm-nuttx-elf or arm-eabi toolchain* under either Linux or Cygwin (with native Windows GNU tools or Cygwin-based GNU tools). STATUS: The basic SAM3U-EK port was released in NuttX version 5.1. The basic port includes boot-up logic, interrupt driven serial console, and system timer interrupts. That release passes the NuttX OS test and is proven to have a valid OS implementation. A configuration to support the NuttShell is also included. NuttX version 5.4 adds support for the HX8347 LCD on the SAM3U-EK board. This LCD support includes an example using the NX graphics system. NuttX version 6.10 adds SPI support. Subsequent NuttX releases will extend this port and add support for SDIO-based SD cards and USB device (and possible LCD support). These extensions may or may not happen soon as my plate is kind of full now. Development Environments: 1) Linux with native Linux GNU toolchain, 2) Cygwin/MSYS with Cygwin GNU toolchain, 3) Cygwin/MSYS with Windows native toolchain (CodeSourcery or devkitARM), or 4) Native Windows. A DIY toolchain for Linux or Cygwin is provided by the NuttX buildroot package.
| NXP LPC1766, LPC1768, and LPC1769. Drivers are available for CAN, DAC, Ethernet, GPIO, GPIO interrupts, I2C, UARTs, SPI, SSP, USB host, and USB device. Verified LPC17xx onfigurations are available for three boards. The Nucleus 2G board from 2G Engineering (LPC1768), The mbed board from mbed.org (LPC1768, Contributed by Dave Marples), and The LPC1766-STK board from Olimex (LPC1766). The Embedded Artists base board with NXP LPCXpresso LPC1768. The Micromint Lincoln60 board with an NXP LPC1769. The Nucleus 2G board, the mbed board, and the LPCXpresso all feature the NXP LPC1768 MCU; the Olimex LPC1766-STK board features an LPC1766. All use a GNU arm-nuttx-elf or arm-eabi toolchain* under either Linux or Cygwin (with native Windows GNU tools or Cygwin-based GNU tools). STATUS: The following summarizes the features that has been developed and verified on individual LPC17xx-based boards. These features should, however, be common and available for all LPC17xx-based boards. Nucleus2G LPC1768 Some initial files for the LPC17xx family were released in NuttX 5.6, but The first functional release for the NXP LPC1768/Nucleus2G occured with NuttX 5.7 with Some additional enhancements through NuttX-5.9. That initial, 5.6, basic release included timer interrupts and a serial console and was verified using the NuttX OS test (`apps/examples/ostest`). Configurations available include include a verified NuttShell (NSH) configuration (see the NSH User Guide). The NSH configuration supports the Nucleus2G's microSD slot and additional configurations are available to exercise the the USB serial and USB mass storage devices. However, due to some technical reasons, neither the SPI nor the USB device drivers are fully verified. (Although they have since been verfiied on other platforms; this needs to be revisited on the Nucleus2G). mbed LPC1768 Support for the mbed board was contributed by Dave Marples and released in NuttX-5.11. This port includes a NuttX OS test configuration (see `apps/examples/ostest`). Olimex LPC1766-STK Support for that Olimex-LPC1766-STK board was added to NuttX 5.13. The NuttX-5.14 release extended that support with an Ethernet driver. The NuttX-5.15 release further extended the support with a functional USB device driver and SPI-based micro-SD. The NuttX-5.16 release added a functional USB host controller driver and USB host mass storage class driver. The NuttX-5.17 released added support for low-speed USB devicers, interrupt endpoints, and a USB host HID keyboard class driver. Verified configurations are now available for the NuttX OS test, for the NuttShell with networking and microSD support(NSH, see the NSH User Guide), for the NuttX network test, for the THTTPD webserver, for USB serial deive and USB storage devices examples, and for the USB host HID keyboard driver. Support for the USB host mass storage device can optionally be configured for the NSH example. A driver for the Nokia 6100 LCD and an NX graphics configuration for the Olimex LPC1766-STK have been added. However, neither the LCD driver nor the NX configuration have been verified as of the the NuttX-5.17 release. Embedded Artists base board with NXP LPCXpresso LPC1768 An fully verified board configuration is included in NuttX-6.2. The Code Red toolchain is supported under either Linux or Windows. Verifed configurations include DHCPD, the NuttShell (NSH), NuttX graphis (NX), the NuttX OS test, THTTPD, and USB mass storage device. Micromint Lincoln60 board with an NXP LPC1769 This board configuration was contributed and made available in NuttX-6.20. As contributed board support, I am unsure of what all has been verfied and what has not. See the Microment website for more information about the Lincoln60 board. More to come. Development Environments: 1) Linux with native Linux GNU toolchain, 2) Cygwin/MSYS with Cygwin GNU toolchain, 3) Cygwin/MSYS with Windows native toolchain (CodeSourcery devkitARM or Code Red), or 4) Native Windows. A DIY toolchain for Linux or Cygwin is provided by the NuttX buildroot package.
| ARM Cortex-M4.
| FreeScale Kinetis K40. This port uses the Freescale Kinetis KwikStik K40. Refer to the Freescale web site for further information about this board. The Kwikstik is used with the FreeScale Tower System (mostly just to provide a simple UART connection) STATUS: The unverified KwikStik K40 first appeared in NuttX-6.8 As of this writing, the basic port is complete but I accidentally locked my board during the initial bringup. Further development is stalled unless I learn how to unlock the device (or until I get another K40). Additional work remaining includes, among other things: (1) complete the basic bring-up, (2) bring up the NuttShell NSH, (3) develop support for the SDHC-based SD card, (4) develop support for USB host and device, and (2) develop an LCD driver. NOTE: Some of these remaining tasks are shared with the K60 work described below.
| FreeScale Kinetis K60. This port uses the Freescale Kinetis TWR-K60N512 tower system. Refer to the Freescale web site for further information about this board. The TWR-K60N51 includes with the FreeScale Tower System which provides (among other things) a DBP UART connection. STATUS: As of this writing, the basic port is complete and passes the NuttX OS test. An additional, validated configuration exists for the NuttShell (NSH, see the NSH User Guide). This basic TWR-K60N512 first appeared in NuttX-6.8. Ethernet and SD card (SDHC) drivers also exist: The SDHC driver is partially integrated in to the NSH configuration but has some outstanding issues; the Ethernet driver is completely untested. Additional work remaining includes: (1) integrate the Ethernet and SDHC drivers, and (2) develop support for USB host and device. NOTE: Most of these remaining tasks (excluding the Ethernet driver) are the same as the pending K40 tasks described above.
| STMicro STM3240G-EVAL. This port uses the STMicro STM3240G-EVAL board featuring the STM32F407IGH6 MCU. Refer to the STMicro web site for further information about this board. STATUS: NuttX-6.12 The basic port is complete and first appeared in NuttX-6.12. The initial port passes the NuttX OS test and includes a validated configuration for the NuttShell (NSH, see the NSH User Guide) as well as several other configurations. NuttX-6.13-6.16 Additional drivers and configurations were added in NuttX 6.13-6.16. Drivers include an Ethernet driver, ADC driver, DAC driver, PWM driver, CAN driver, F4 RTC driver, Quadrature Encoder, DMA, SDIO with DMA (these should all be compatible with the STM32 F2 family and many should also be compatible with the STM32 F1 family as well). NuttX-6.16 The NuttX 6.16 release also includes and logic for saving/restoring F4 FPU registers in context switches. Networking intensions include support for Telnet NSH sessions and new configurations for DHPCD and the networking test (nettest). NuttX-6.17 The USB OTG device controller driver, and LCD driver and a function I2C driver were added in NuttX 6.17. NuttX-6.18 STM32 IWDG and WWDG watchdog timer drivers were added in NuttX 6.18 (should be compatible with F1 and F2). An LCD driver and a touchscreen driver for the STM3240G-EVAL based on the STMPE811 I/O expander were also added in NuttX 6.18. NuttX-6.21 A USB OTG host controller driver was added in NuttX 6.21.
| STMicro STM32F4-Discovery. This port uses the STMicro STM32F4-Discovery board featuring the STM32F407VGT6 MCU. Refer to the STMicro web site for further information about this board. STATUS: The basic port for the STM32F4-Discovery was contributed by Mike Smith and was first released in NuttX-6.14. Drivers listed for the STM3240G-EVAL may be usable on this plaform as well.
| NXG Technologies LPC4330-Xplorer. This NuttX port is for the LPC4330-Xplorer board from NGX Technologies featuring the NXP LPC4330FET100 MCU. See the NXG website for further information about this board. STATUS: NuttX-6.20 The basic port is complete. The OS test configuration and the basic NSH configurations are present and fully verified. This includes verified support for: SYSTICK system time, pin and GPIO configuration, and a serial console. Several drivers have been copied from the related LPC17xx port but require integration into the LPC43xx: ADC, DAC, GPDMA, I2C, SPI, and SSP. The registers for these blocks are the same in both the LPC43xx and the LPC17xx and they should integrate into the LPC43xx very easily by simply adapting the clocking and pin configuration logic. Other LPC17xx drivers were not brought into the LPC43xx port because these peripherals have been completely redesigned: CAN, Ethernet, USB device, and USB host. So then there is no support for the following LPC43xx peripherals: SD/MMC, EMC, USB0,USB1, Ethernet, LCD, SCT, Timers 0-3, MCPWM, QEI, Alarm timer, WWDT, RTC, Event monitor, and CAN. Some of these can be leveraged from other MCUs that appear to support the same peripheral IP: The LPC43xx USB0 peripheral appears to be the same as the USB OTG peripheral for the LPC31xx. The LPC31xx USB0 device-side driver has been copied from the LPC31xx port but also integration into the LPC43xx (clocking and pin configuration). It should be possible to complete poriting of this LPC31xx driver with a small porting effort. The Ethernet block looks to be based on the same IP as the STM32 Ethernet and, as a result, it should be possible to leverage the NuttX STM32 Ethernet driver with a little more effort. NuttX-6.21 Added support for a SPIFI block driver and for RS-485 option to the serial driver.
| Development Environments: 1) Linux with native Linux GNU toolchain, 2) Cygwin/MSYS with Cygwin GNU Cortex-M3 or 4 toolchain, 3) Cygwin/MSYS with Windows native GNU Cortex-M3 or M4 toolchain (CodeSourcery or devkitARM), or 4) Native Windows. A DIY toolchain for Linux or Cygwin is provided by the NuttX buildroot package. I use FreeScale's CodeWarrior IDE only to work with the JTAG debugger built into the Kinetis boards. I use the Code Red IDE with the some of the NXP parts and the Atollic toolchain with some of the STMicroelectronics parts.
| Atmel AVR.
| SoC Robotics ATMega128. This port of NuttX to the Amber Web Server from SoC Robotics is partially completed. The Amber Web Server is based on an Atmel ATMega128. STATUS: Work on this port has stalled due to toolchain issues. Complete, but untested code for this port appears in the NuttX 6.5 release.
| Micropendous 3 AT90USB64x and AT90USB6128x. This port of NuttX to the Opendous Micropendous 3 board. The Micropendous3 is may be populated with an AT90USB646, 647, 1286, or 1287. I have only the AT90USB647 version for testing. This version have very limited memory resources: 64K of FLASH and 4K of SRAM. STATUS: The basic port was released in NuttX-6.5. This basic port consists only of a "Hello, World!!" example that demonstrates initialization of the OS, creation of a simple task, and serial console output.
| PJRC Teensy++ 2.0 AT90USB1286. This is a port of NuttX to the PJRC Teensy++ 2.0 board. This board was developed by PJRC. The Teensy++ 2.0 is based on an Atmel AT90USB1286 MCU. STATUS: The basic port was released in NuttX-6.5. This basic port consists of a "Hello, World!!" example that demonstrates initialization of the OS, creation of a simple task, and serial console output as well as a somewhat simplified NuttShell (NSH) configuration (see the NSH User Guide). An SPI driver and a USB device driver exist for the AT90USB as well as a USB mass storage configureation. However, this configuration is not fully debugged as of the NuttX-6.5 release.
| AVR-Specific Issues. The basic AVR port is solid and biggest issue for using AVR is its tiny SRAM memory and its Harvard architecture. Because of the Harvard architecture, constant data that resides to flash is inaccessible using "normal" memory reads and writes (only SRAM data can be accessed "normally"). Special AVR instructions are available for accessing data in FLASH, but these have not been integrated into the normal, general purpose OS. Most NuttX test applications are console-oriented with lots of strings used for printf and debug output. These strings are all stored in SRAM now due to these data accessing issues and even the smallest console-oriented applications can quickly fill a 4-8K memory. So, in order for the AVR port to be useful, one of two things would need to be done: Don't use console applications that required lots of strings. The basic AVR port is solid and your typical deeply embedded application should work fine. Or, Create a special version of printf that knows how to access strings that reside in FLASH (or EEPROM).
| Development Environments: 1) Linux with native Linux GNU toolchain, 2) Cygwin/MSYS with Cygwin GNU toolchain, 3) Cygwin/MSYS with Windows native toolchain, or 4) Native Windows. All testing, however, has been performed using the NuttX DIY toolchain for Linux or Cygwin is provided by the NuttX buildroot package. As a result, that toolchain is recommended.
| Atmel AVR32.
| AV32DEV1. This port uses the www.mcuzone.com AVRDEV1 board based on the Atmel AT32UC3B0256 MCU. This port requires a special GNU avr32 toolchain available from atmel.com website. This is a windows native toolchain and so can be used only under Cygwin on Windows. STATUS: This port is has completed all basic development, but there is more that needs to be done. All code is complete for the basic NuttX port including header files for all AT32UC3* peripherals. The untested AVR32 code was present in the 5.12 release of NuttX. Since then, the basic RTOS port has solidified: The port successfully passes the NuttX OS test (apps/examples/ostest). A NuttShell (NSH) configuration is in place (see the NSH User Guide). Testing of that configuration has been postponed (because it got bumped by the Olimex LPC1766-STK port). Current Status: I think I have a hardware problem with my serial port setup. There is a good chance that the NSH port is complete and functional, but I am not yet able to demonstrate that. At present, I get nothing coming in the serial RXD line (probably because the pins are configured wrong or I have the MAX232 connected wrong). The basic, port (including the verified apps/examples/ostest configuration) was be released in NuttX-5.13. A complete port will include drivers for additional AVR32 UC3 devices -- like SPI and USB --- and will be available in a later release, time permitting.
| Freescale M68HCS12.
| MC9S12NE64. Support for the MC9S12NE64 MCU and two boards are included: The Freescale DEMO9S12NE64 Evaluation Board, and The Future Electronics Group NE64 /PoE Badge board. Both use a GNU arm-nuttx-elf toolchain* under Linux or Cygwin. The NuttX buildroot provides a properly patched GCC 3.4.4 toolchain that is highly optimized for the m9s12x family. STATUS: Coding is complete for the MC9S12NE64 and for the NE64 Badge board. However, testing has not yet begun due to issues with BDMs, Code Warrior, and the paging in the build process. Progress is slow, but I hope to see a fully verified MC9S12NE64 port in the near future.
| Intel 8052 Microcontroller.
| PJRC 87C52 Development Board. This port uses the PJRC 87C52 development system and the SDCC toolchain under Linux or Cygwin. STATUS: This port is complete but not stable with timer interrupts enabled. There seems to be some issue when the stack pointer enters into the indirect IRAM address space during interrupt handling. This architecture has not been built in some time will likely have some compilation problems because of SDCC compiler differences.
| Intel 80x86.
| QEMU/Bifferboard i486. This port uses the QEMU i486 and the native Linux, Cywgin, MinGW the GCC toolchain under Linux or Cygwin. STATUS: The basic port was code-complete in NuttX-5.19 and verifed in NuttX-6.0. The port was verified using the OS and NuttShell (NSH) examples under QEMU. The port is reported to be functional on the Bifferboard as well. This is a great, stable starting point for anyone interest in fleshing out the x86 port!
| RGMP. RGMP stands for RTOS and GPOS on Multi-Processor. RGMP is a project for running GPOS and RTOS simultaneously on multi-processor platforms You can port your favorite RTOS to RGMP together with an unmodified Linux to form a hybrid operating system. This makes your application able to use both RTOS and GPOS features. See the RGMP Wiki for further information about RGMP. STATUS: This initial port of NuttX to RGMP was provided in NuttX-6.3. This initial RGP port provides only minimal driver support and does not use the native NuttX interrupt system. This is a great, stable starting point for anyone interest in working with NuttX under RGMP!
| MicroChip PIC32 (MIPS).
| PIC32MX250F128D. A port is in progress from the DTX1-4000L "Mirtoo" module from Dimitech. This module uses MicroChip PIC32MX250F128D and the Dimitech DTX1-4000L EV-kit1 V2. See the Dimitech website for further information. STATUS: The basic port is code complete. Two configurations are available: (1) An OS test configuration and a (2) configuration that support the NuttShell (NSH). The OS test configuration is fully functional and proves that we have a basically healthy NuttX port to the Mirtoo. The NSH configuration includes support for a serial console and for the SST25 serial FLASH and the PGA117 amplifier/multiplexer on board the module. The NSH configuration is set up to use the NuttX wear-leveling FLASH file system (NXFFS). The PGA117, however, is not yet fully integrated to support ADC sampling. See the NSH User Guide for further information about NSH. The first verified port to the Mirtoo module was available with the NuttX 6.20 release.
| PIC32MX460F512L. There one two board ports using this chip: PIC32MX Board from PCB Logic Design Co. This port is for the PIC32MX board from PCB Logic Design Co. and used the PIC32MX460F512L. The board is a very simple -- little more than a carrier for the PIC32 MCU plus voltage regulation, debug interface, and an OTG connector. STATUS: The basic port is code complete and fully verified in NuttX 6.13. Available configurations include the OS test and the NuttShell (NSH - see the NSH User Guide). UBW32 Board from Sparkfun This is the port to the Sparkfun UBW32 board. This port uses the original v2.5 board which is based on the MicroChip PIC32MX460F512L. This older version has been replaced with this newer board. See also the UBW32 web site. STATUS: The basic port is code complete and fully verified in NuttX 6.18. Available configurations include the OS test and the NuttShell (NSH - see the NSH User Guide). USB has not yet been fully tested but on first pass appears to be functional.
| PIC32MX440F512H. This port uses the "Advanced USB Storage Demo Board," Model DB-DP11215, from Sure Electronics. This board features the MicroChip PIC32MX440F512H. See the Sure website for further information about the DB-DP11215 board. (I believe that that the DB-DP11215 may be obsoleted now but replaced with the very similar, DB-DP11212. The DB-DP11212 board differs, I believe, only in its serial port configuration.) STATUS: This NuttX port is code complete and has considerable test testing. The port for this board was completed in NuttX 6.11, but still required a few bug fixes before it will be ready for prime time. The fully verified port first appeared in NuttX 6.13. Available configurations include the OS test and the NuttShell (NSH - see the NSH User Guide). An untested USB device-side driver is available in the source tree. A more complete port would include support of the USB OTG port and of the LCD display on this board. Those drivers are not yet available as of this writing.
| PIC32MX795F512L. There one two board ports using this chip: Microchip PIC32 Ethernet Starter Kit. This port uses the Microchip PIC32 Ethernet Starter Kit (DM320004) with the Expansion I/O board. See the Microchip website for further information. STATUS: This port was started and then shelved for some time until I received the Expansion I/O board. The basic Starter Kit (even with the Multimedia Expansion Board, MEB, DM320005)) has no serial port and most NuttX test configurations depend heavily on console output. Verified configurations for the OS test and the NuttShel (NSH) appeared in NuttX-6.16. Board support includes a verified USB (device-side) driver. Also included are a a verified Ethernet driver, a partially verified USB device controller driver, and an unverifed SPI driver. Stay tuned for updates. Mikroelektronika PIC32MX7 Mulitmedia Board (MMB). A port has been completed for the Mikroelektronika PIC32MX7 Multimedia Board (MMB). See http://www.mikroe.com/ for further information about this board. STATUS: Two verified configurations are available: (1) The basic OS test configuration that verfies the correctness port of NuttX, and (2) an extensive NuttShell (NSH) configuration. The NSH configuration includes: (1) Full network support, (2) Verified SPI driver, (3) SPI-based SD Card support, (4) USB device support (including configuration options for the USB mass storage device and the CDC/ACM serial class), and (5) Support for the MIO873QT2 LCD on the PIC32MX7 MMB. The PIC32MX7 MMB's touchscreen is connected directly to the MCU via ADC pins. A touchscreen driver has been developed using the PIC32's ADC capabilities and can be enabled in the NSH configuration. However, additional verification and tuning of this driver is required. Further display/touchscreen verification would require C++ support (for NxWidgets and NxWM). Since I there is no PIC32 C++ is the free version of the MPLAB C32 toolchain, further graphics development is stalled.
| Development Environment: These ports uses either: The LITE version of the PIC32MX toolchain available for download from the MicroChip website, or The Pinguino MIPS ELF toolchain avaiable from the Pinquino website.
| Renesas/Hitachi SuperH.
| SH-1 SH7032. This port uses the Hitachi SH-1 Low-Cost Evaluation Board (SH1_LCEVB1), US7032EVB, with a GNU ELF toolchain* under Linux or Cygwin. STATUS: This port is available as of release 0.3.18 of NuttX. The port is basically complete and many examples run correctly. However, there are remaining instabilities that make the port un-usable. The nature of these is not understood; the behavior is that certain SH-1 instructions stop working as advertised. This could be a silicon problem, some pipeline issue that is not handled properly by the gcc 3.4.5 toolchain (which has very limit SH-1 support to begin with), or perhaps with the CMON debugger. At any rate, I have exhausted all of the energy that I am willing to put into this cool old processor for the time being.
| Renesas M16C/26.
| Renesas M16C/26 Microncontroller. This port uses the Renesas SKP16C26 Starter kit and the GNU M32C toolchain. The development environment is either Linux or Cygwin under WinXP. STATUS: Initial source files released in nuttx-0.4.2. At this point, the port has not been integrated; the target cannot be built because the GNU `m16c-nuttx-elf-ld` link fails with the following message: `m32c-nuttx-elf-ld: BFD (GNU Binutils) 2.19 assertion fail /home/Owner/projects/nuttx/buildroot/toolchain_build_m32c/binutils-2.19/bfd/elf32-m32c.c:482` Where the reference line is:
    /* If the symbol is out of range for a 16-bit address,
       we must have allocated a plt entry.  */
    BFD_ASSERT (*plt_offset != (bfd_vma) -1);
No workaround is known at this time. This is a show stopper for M16C for the time being.
| Zilog Z16F.
| Zilog z16f Microncontroller. This port use the Zilog z16f2800100zcog development kit and the Zilog ZDS-II Windows command line tools. The development environment is either Windows native or Cygwin under Windows. STATUS: The initial release of support for the z16f was made available in NuttX version 0.3.7.
| Zilog eZ80 Acclaim!.
| Zilog eZ80Acclaim! Microncontroller. There are two eZ80Acclaim! ports: One uses the ZiLOG ez80f0910200kitg development kit, and The other uses the ZiLOG ez80f0910200zcog-d development kit. Both boards are based on the eZ80F091 part and both use the Zilog ZDS-II Windows command line tools. The development environment is either Windows native or Cygwin under Windows. STATUS: Integration and testing of NuttX on the ZiLOG ez80f0910200zcog-d is complete. The first integrated version was released in NuttX version 0.4.2 (with important early bugfixes in 0.4.3 and 0.4.4). As of this writing, that port provides basic board support with a serial console, SPI, and eZ80F91 EMAC driver.
| Zilog Z8Encore!.
| Zilog Z8Encore! Microncontroller. This port uses the either: Zilog z8encore000zco development kit, Z8F6403 part, or Zilog z8f64200100kit development kit, Z8F6423 part and the Zilog ZDS-II Windows command line tools. The development environment is either Windows native or Cygwin under Windows. STATUS: This release has been verified only on the ZiLOG ZDS-II Z8Encore! chip simulation as of nuttx-0.3.9.
| Zilog Z180.
| P112. The P112 is a hobbyist single board computer based on a 16MHz Z80182 with up to 1MB of memory, serial, parallel and diskette IO, and realtime clock, in a 3.5-inch drive form factor.. The P112 computer originated as a commercial product of "D-X Designs Pty Ltd"[ of Australia. Dave Brooks was successfully funded through Kickstarter for and another run of P112 boards in November of 2012. In addition Terry Gulczynski makes additional P112 derivative hobbyist home brew computers. STATUS: Most of the NuttX is in port for both the Z80182 and for the P112 board. Boards from Kickstarter project will not be available, however, until the first quarter of 2013. So it will be some time before this port is verified on hardware.
| Zilog Z80.
| Z80 Instruction Set Simulator. This port uses the SDCC toolchain under Linux or Cygwin (verified using version 2.6.0). This port has been verified using only a Z80 instruction simulator. That simulator can be found in the NuttX SVN here. STATUS: This port is complete and stable to the extent that it can be tested using an instruction set simulator.
| XTRS: TRS-80 Model I/III/4/4P Emulator for Unix. A very similar Z80 port is available for XTRS, the TRS-80 Model I/III/4/4P Emulator for Unix. That port also uses the SDCC toolchain under Linux or Cygwin (verified using version 2.6.0). STATUS: Basically the same as for the Z80 instruction set simulator. This port was contributed by Jacques Pelletier.

> * A highly modified buildroot is available that may be used to build a NuttX-compatible ELF toolchain under Linux or Cygwin. Configurations are available in that buildroot to support ARM, Cortex-M3, avr, m68k, m68hc11, m68hc12, m9s12, blackfin, m32c, h8, and SuperH ports.

# Development Environments

| Linux + GNU `make` + GCC/binutils for Linux
| The is the most natural development environment for NuttX. Any version of the GCC/binutils toolchain may be used. There is a highly modified buildroot available for download from the NuttX SourceForge page. This download may be used to build a NuttX-compatible ELF toolchain under Linux or Cygwin. That toolchain will support ARM, m68k, m68hc11, m68hc12, and SuperH ports. The buildroot SVN may be accessed in the NuttX SVN.
| Linux + GNU `make` + SDCC for Linux
| Also very usable is the Linux environment using the SDCC compiler. The SDCC compiler provides support for the 8051/2, z80, hc08, and other microcontrollers. The SDCC-based logic is less well exercised and you will likely find some compilation issues if you use parts of NuttX with SDCC that have not been well-tested.
| Windows with Cygwin + GNU `make` + GCC/binutils (custom built under Cygwin)
| This combination works well too. It works just as well as the native Linux environment except that compilation and build times are a little longer. The custom NuttX buildroot referenced above may be build in the Cygwin environment as well.
| Windows with Cygwin + GNU `make` + SDCC (custom built under Cygwin)
| I have never tried this combination, but it would probably work just fine.
| Windows with Cygwin + GNU `make` + Windows Native Toolchain
| This is a tougher environment. In this case, the Windows native toolchain is unaware of the Cygwin sandbox and, instead, operates in the native Windows environment. The primary difficulties with this are: Paths. Full paths for the native toolchain must follow Windows standards. For example, the path `/home/my\ name/nuttx/include` my have to be converted to something like `'C:\cygwin\home\my name\nuttx\include'` to be usable by the toolchain. Fortunately, this conversion is done simply using the `cygpath` utility. Symbolic Links NuttX depends on symbolic links to install platform-specific directories in the build system. On Linux, true symbolic links are used. On Cygwin, emulated symbolic links are used. Unfortunately, for native Windows applications that operate outside of the Cygwin sandbox, these symbolic links cannot be used. The NuttX make system works around this limitation by copying the platform specific directories in place. These copied directories make work a little more complex, but otherwise work well. NOTE: In this environment, it should be possible to use the NTFS `mklink` command to create links. This should only require a minor modification to the build scripts (see `tools/copydir.sh` script). Dependencies NuttX uses the GCC compiler's `-M` option to generate make dependencies. These dependencies are retained in files called `Make.deps` throughout the system. For compilers other than GCC, there is no support for making dependencies in this way. For Windows native GCC compilers, the generated dependencies are windows paths and not directly usable in the Cygwin make. By default, dependencies are surpressed for these compilers as well. NOTE: dependencies are suppress by setting the make variable `MKDEPS` to point to the do-nothing dependency script, `tools/mknulldeps.sh`. Supported Windows Native Toolchains. At present, the following Windows native toolchains are in use: GCC built for Windows (such as CodeSourcery, Atollic, devkitARM, etc.), SDCC built for Windows, the ZiLOG XDS-II toolchain for Z16F, z8Encore, and eZ80Acclaim parts.
| Windows Native (`CMD.exe`) + GNUWin32 (including GNU `make`) + MinGW Host GCC compiler + Windows Native Toolchain
|  | Build support has been added to support building natively in a Windows console rather than in a POSIX-like environment. This build: Uses all Windows style paths Uses primarily Windows batch commands from cmd.exe, with A few extensions from GNUWin32 This capability first appeared in NuttX-6.24 and should still be considered a work in progress because: (1) it has not been verfied on all targets and tools, and (2) still lacks some of the creature-comforts of the more mature environments. The windows native build logic initiatiated if `CONFIG_WINDOWS_NATIVE=y` is defined in the NuttX configuration file: At present, this build environment also requires: Windows Console. The build must be performed in a Windows console window. This may be using the standard `CMD.exe` terminal that comes with Windows. I prefer the ConEmu terminal which can be downloaded from: http://code.google.com/p/conemu-maximus5/ GNUWin32. The build still relies on some Unix-like commands. I usethe GNUWin32 tools that can be downloaded from http://gnuwin32.sourceforge.net/. See the top-level `nuttx/README.txt` file for some download, build, and installation notes. MinGW-GCC. MinGW-GCC is used to compiler the C tools in the `nuttx/tools` directory that are neede by the build. MinGW-GCC can be downloaded from http://www.mingw.org/. If you are using GNUWin32, then it is recommendedthe you not install the optional MSYS components as there may be conflicts.
| Wine + GNU `make` + Windows Native Toolchain
> | I've never tried this one, but I off the following reported by an ez80 user using the ZiLOG ZDS-II Windows-native toolchain: "I've installed ZDS-II 5.1.1 (IDE for ez80-based boards) on wine (windows emulator for UNIX) and to my surprise, not many changes were needed to make SVN snapshot of NuttX buildable... I've tried nsh profile and build process completed successfully. One remark is necessary: NuttX makefiles for ez80 are referencing `cygpath` utility. Wine provides similar thing called `winepath` which is compatible and offers compatible syntax. To use that, `winepath` (which itself is a shell script) has to be copied as `cygpath` somewhere in `$PATH`, and edited as in following patch:
>     # diff -u `which winepath` `which cygpath`
>     --- /usr/bin/winepath 2011-05-02 16:00:40.000000000 +0200
>     +++ /usr/bin/cygpath 2011-06-22 20:57:27.199351255 +0200
>     @@ -20,7 +20,7 @@
>     #

>     # determine the app Winelib library name
>     -appname=`basename "$0" .exe`.exe
>     +appname=winepath.exe

>     # first try explicit WINELOADER
>     if [ -x "$WINELOADER" ]; then exec "$WINELOADER" "$appname" "$@"; fi
"Better solution would be replacing all `cygpath` references in `Makefiles` with `$(CONVPATH)` (or `${CONVPATH}` in shell scripts) and setting `CONVPATH` to `cygpath` or `winepath` regarding to currently used environment.
| Other Environments?
| Environment Dependencies. The primary environmental dependency of NuttX are (1) GNU make, (2) bash scripting, and (3) Linux utilities (such as cat, sed, etc.). If you have other platforms that support GNU make or make utilities that are compatible with GNU make, then it is very likely that NuttX would work in that environment as well (with some porting effort). If GNU make is not supported, then some significant modification of the Make system would be required. MSYS. I have not used MSYS but what I gather from talking with NuttX users is that MSYS can be used as an alternative to Cygwin in any of the above Cygwin environments. This is not surprising since MSYS is based on an older version of Cygwin (cygwin-1.3). MSYS has been modified, however, to interoperate in the Windows environment better than Cygwin and that may be of value to some users. MSYS, however, cannot be used with the native Windows NuttX build because it will invoke the MSYS bash shell instead of the `CMD.exe` shell. Use GNUWin32 in the native Windows build envionment.

# Memory Footprint

C5471 (ARM7) The build for this ARM7 target that includes most of the OS features and a broad range of OS tests. The size of this executable as given by the Linux `size` command is (3/9/07):

       text    data     bss     dec     hex filename
      53272     428    3568   57268    dfb4 nuttx

DM320 (ARM9) This build for the ARM9 target includes a significant subset of OS features, a filesystem, Ethernet driver, full TCP/IP, UDP and (minimal) ICMP stacks (via uIP) and a small network test application: (11/8/07, configuration netconfig, apps/examples/nettest)

       text    data     bss     dec     hex filename
      49472     296    3972   53740    d1ec nuttx

Another build for the ARM9 target includes a minimal OS feature set, Ethernet driver, full TCP/IP and (minimal) ICMP stacks, and a small webserver: (11/20/07, configuration uipconfig, apps/examples/uip)

       text    data     bss     dec     hex filename
      52040      72    4148   56260    dbc4 nuttx

87C52 A reduced functionality OS test for the 8052 target requires only about 18-19K:

    Stack starts at: 0x21 (sp set to 0x20) with 223 bytes available.

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

# Licensing

NuttX is available under the highly permissive BSD license. Other than some fine print that you agree to respect the copyright you should feel absolutely free to use NuttX in any environment and without any concern for jeopardizing any proprietary software that you may link with it.

# Release History

ChangeLog snapshots associated with the previous, current, and future release are available below.

| Change logs for previous NuttX releases
| ChangeLog for the current NuttX releases
| Unreleased changes

ChangeLog for the Current Release

    nuttx-6.24 2012-12-20 Gregory Nutt <gnutt@nuttx.org>

        * arch/arm/src/stm32:  Support for STM32F100 high density chips
          added by Freddie Chopin.
        * configs/stm32f100_generic:  Support for generic STM32F100RC board
          contributed by Freddie Chopin.
        * arch/arm/src/stm32_otgfsdev.c:  Partial fix from Petteri Aimonen.
        * drivers/lcd/ug-2864ambag01.c and include/nuttx/lcd/ug_2864ambag01.h:
          LCD driver for the Univision OLED of the same name (untested on
          initial check-in).
        * configs/stm32f4discovery/nxlines:  Configure to use mconf/Kconfig
          tool.
        * configs/stm32f4discovery/src/up_ug2864ambag01.c:  Board-specific
          initialization for UG-2864AMBAG01 OLED connecte to STM32F4Disovery.
        * libxx/libxx_stdthrow.cxx:  Exception stubs from Petteri Aimonen.
        * configs/stm32f4discovery/src/up_ug2864ambag01.c: Driver has been
          verified on the STM32F4Discovery platform.  Some tuning of the
          configuration could improve the presentation.  Lower resolution displays
          are also more subject to the "fat, flat line bug" that I need to fix
          someday.  See http://www.nuttx.org/doku.php?id=wiki:graphics:nxgraphics
          for a description of the fat, flat line bug.
        * libc:  Renamed nuttx/lib to nuttx/libc to make space for a true lib/
          directory that will be forthcoming.  Also rename libraries:  liblib.a -> libc.a,
          libulib.a -> libuc.a, libklib.a -> libkc.a, liblibxx.a ->libcxx.a.
          (I will probably, eventually rename libxx to libcxx for consistency)
        * Makefile, lib/: A new, empty directory that will hold generated libraries.
          This simplifies the library patch calculations and lets me get rid of some
          bash logic.  The change is functional, but only partially complete;
          additional logic is needed in the arch/*/src/Makefile's as well.  Right
          now that logic generate multiple library paths, all pointing to the lib/
          directory.
        * arch/*/src/Makefile:  Now uses only the libraries in lib/
          Replace bash fragments that test for board/Makefile.
        * Makefile.win:  The beginnings of a Windows-native build.  This is just
          the beginning and not yet ready for prime time use.
        * configs/stm32f4discovery/winbuild:  This is a version of the standard
          NuttX OS test, but configured to build natively on Windows.  Its only
          real purpose is to very the native Windows build logic.
        * tools/mkdeps.bat and tools/mkdeps.c:  mkdeps.bat is a failed attempt
          to leverage mkdeps.sh to CMD.exe.  It fails because the are certain
          critical CFLAG values that cannot be passed on the CMD.exe command line
          (like '=').  mkdeps.c is a work in progress that will, hopefully,
          replace both mkdeps.sh and mkdeps.bat.
        * tools/Config.mk:  Centralize the definition of the script that will be
          used to generated header file include paths for the compiler.  This
          needs to be centralized in order to support the Windows native build.
        * tools/incdir.bat:  A replacement for tools/incdir.sh for use with the
          the Windows native build.
        * Makefile.unix:  The existing top-level Makefile has been renamed
          Makefile.unix.
        * Makefile:  This is a new top-level Makefile that just includes
          either Makefile.unix or Makefile.win
        * configs/stm3240g-eval/src:  Qencoder fixes from Ryan Sundberg.
        * arch/arm/src/stm32/stm32_qencoder.c: TIM3 bug fix from Ryan Sundberg.
        * tools/mkromfsimg.sh: Correct typo in an error message (Ryan Sundberg)
        * arch/*/src/Makefile:  Remove tftboot install and creation of System.map
          for Windows native build.  The first is a necessary change, the second
          just needs re-implemented.
        * configs/mirtoo: Update Mirtoo pin definitions for Release 2.  Provided
          by Konstantin Dimitrov.
        * Fixed an uninitialized variable in the file system that can cause
          assertions if DEBUG on (contributed by Lorenz Meier).
        * Config.mk:  Defined DELIM to be either / or \, depending upon
          CONFIG_WINDOWS_NATIVE.  This will allow me to eliminate a lot of
          conditional logic elsewhere.
        * nuttx/graphics: One a mouse button is pressed, continue to report all
          mouse button events to the first window that received the the initial
          button down event, even if the mouse attempts to drag outside the
          window. From Petteri Aimonen.
        * nuttx/graphics/nxmu/nx_block.c:  One more fix to the NX block message
          logic from Petteri Aimonen.
        * include/nuttx/wqueue.h: Some basic definitions to support a user-
          space work queue (someday in the future).
        * graphics/nxmu:  Add semaphores so buffers messages that send buffers
          will block until the buffer data has been acted upon.
        * graphics/nxmw:  Extended the blocked messages to cover mouse movement
          and redraw events.  These will also cause problems if sent to a window
          while it is closing.
        * arch/several:  Change UARTs are enabled for i.MX, LM3S, ez80, and M16C to
          match how they are enabled for other architectures.
        * configs/ez80f910200kitg:  Convert to use mconf configuration.
        * sched/pause.c:  Implements the POSIX pause() function.
        * ez80: Lots of changes to ez80 configurations and build logic as I
          struggle to get a clean Windows build (still not working).
        * configs/cloudctrl:   Darcy Gong's CloudController board.  This is a
          small network relay development board. Based on the Shenzhou IV development
          board design.  It is based on the STM32F107VC MCU.
        * arch/arm/src/stm32_serial.c and stm32_lowputc.c:  Added optional RS-485
          direction bit control. From Freddie Chopin.
        * Lots of build files:  ARMv7-M and MIPS32 Make.defs now include a common
          Toolchain.defs file that can be used to manage toolchains in a more
          configurable way.  Contributed by Mike Smith
        * configs/stm32f4discovery/winbuild and configs/cloudctrl:  Adapted to use
          Mike's Toolchain.defs.
        * tools/configure.sh:  Adapted to handle paths and setenv.bat files correctly
          for native Windows builds.
        * More of build files:  AVR and AVR32 Make.defs now include a common
          Toolchain.defs file that can be used to manage toolchains in a more
          configurable way.  Contributed by Mike Smith
        * tools/incdir.sh and incdir.bat: Add -s option to generate system header
          file paths.
        * nuttx/arch/arm/src/arm/Toolchain.defs: Add support for more ARM toolchains
          (from Mike Smith).
        * arch/arm/src/stm32/stm32f40xxx_rcc.c:  Enabled FLASH prefetch (from Petteri
          Aimonen).
        * graphics/nxtk/nxtk_filltrapwindow.c:  Correct an offset problem (from
          Peterri Aimonen).
        * graphics/nxglib/nxglib_splitline.c:  Fix error in drawing of near horizontal
          lines (from Peterri Aimonen).
        * sched/task_exithook.c:  Missing right bracket with certain conditional
          compilation (thanks James Goppert).
        * arch/arm/srch/stm32/stm32_otgfshost.c:  Replace timeout handling; use
          system tick instead of frame counter.  The frame counter gets reset to
          zero at 0x3fff making it error prone.
        * arch/arm/src/stm32/stm32f20xx_rcc.c and stm32f40xx_rcc.c: Added option
          CONFIG_STM32_FLASH_PREFETCH.  FLASH prefetch will now only be enabled
          if this option is selected.
        * confgs/ez80f910200zco/ostest:  Now uses Kconfig/mconf configuration
          tool. Updated to build in native Windows environment.  Other ez80f910200zco
          build scripts also updated.
        * configs/z8f64200100kit/ostest: Update to same level as ez80 configurations.
        * nuttx/configs/z8f64200100kit/scripts/setenv.bat: Add support for native
          Windows build.
        * nuttx/arch/arm/src/lpc17xx/lpc17_i2c.c: Resources not being released when
          I2C is uninitialized.
        * cloudctrl/src/up_chipid.c and shenzhou/src/up_chipid.c:  Add functions to
          get chip ID.  Contributed by Darcy Gong.  These should not be board-dependent,
          but should be in arch/arm/src/stm32 where they can be used from any board.
        * sched/work_thread.c: Fix backward conditional compilation.  This might
          has caused a memory leak.  From Freddie Chopin.
        * configs/<many>/Make.defs:  Fix typo -wstrict-prototypes should be
          -Wstrict-prototypes (From Denis Carilki).
        * arch/arm/src/calapyso/calypso_keypad.c:  Add Calypso keypad driver.  From
          Denis Carilki.
        * z8encore000zco/ostest and z8f64200100kit/ostest:  Converted to use Kconfig/
          mconf configuration tool.
        * arch/arm/src/armv7-m/up_exception.S: missing curly braces for push/pop
          From Freddie Chopin.
        * z8encore000zco/ostest and z8f64200100kit/ostest:  Can now be modified to
          support the Windows native builds (see corresponding README.txt files).
        * configs/z16f2800100zcog - All configurations updated to use the ZDS-II
          5.0.1 toolchain.
        * configs/z16f2800100zcog - All configurations updated to use Kconfig/mconf
          configuration tools.
        * configs/z16f2800100zcog/ostest - Now supports a native Windows build
          (other ZNEO configs may also support the native build, but this has not
          been verfiied).
        * include/nuttx/input/keypad.h, arch/arm/src/calypso/calypso_keypad.c, and
          configs/compal_e99/nsh_highram: First cut at a standard keypad interface
          definition.  Contributed by Denis Carikli.
        * libc/stdlib/lib_rand.c:  Always add one to result congruential generators
          to avoid the value zero.  Suggested by Freddie Chopin.
        * tools/b16.c:  Fixed precision math conversion utility.
        * graphics/nxglib/nxglib_splitline.c:  Fix the "fat, flat line bug"
        * arch/z80/src/*/Toolchain.defs:  Add dummy Toolchain.defs files for the
          z80 family.
        * configs/z80sim/ostest:  Converted to build with the Kconfig/mconf tool.
          Current configuration failed to build for me (Ubuntu 12.10, SDCC 3.2.0
          pre-built for Linux) due to a glibc memory corruptionerror in SDCC.
        * configs/z80sim/ostest: Default is now the Windows native build.  See
          configs/z80sim/README.txt for instructions to convert back to a Linux or
          or Cygwin build.
        * arch/z80/src/Makefile.sdccw:  Renamed makefiles with extensions zdiil,
          zdiiw, sdccl, and sdccw for the ZDS-II vs SDCC compilers and for the
          POSIX vs Windows native builds.
        * nuttx/drivers/mtd/ftl.c:  Fix for the flash translation layer. Short
          unaligned writes were buggy.  From Petteri Aimonen.
        * nuttx/libc/math/lib_round*.c:  Add rounding functions to the math
          library.  Contributed by Petteri Aimonen.
        * include/cxx/cstdlib:  Add stroul().  From Petteri Aimonen.
        * arch/*/include/limits.h:  Change signed minimum values from, for example,
          (-128) to (-127 - 1) to avoid overflows under certain conditions.  From
          Peterri Aimonen.
        * graphics/nxtk/nxtk_subwindowmove.c: Previously it was very difficult to
          do e.g. "scroll by dx, dy". When given the full window area, nxtk_subwindowmove
          would clip the offset always to 0,0. It makes more sense for it to clip the
          source area and not modify the offset.  From Petteri Aimonen.
        * graphics/nxtk/nxtk_getwindow.c: Clipping would change the offset of returned
          data, and caller has no way to know what the new offset would be. This messes
          up font drawing when the text is partially out of window, e.g. when scrolling.
          Also from Petteri Aimonen.
        * include/stdbool.h: Can now be disabled for C++ files if CONFIG_C99_BOOL8 is
          defined.  CONFIG_C99_BOOL8 indicates (1) that the sizeof(_Bool) is one in both
          C and C++, and (2) the the C compiler is C99 and supports the _Bool intrinsic
          type. Requested by Freddie Chopin.
        * include/stdlib/lib_rand.c:  Various additional changes so that the integer
          value zero can be returned.  Requested by Freddie Chopin.
        * arch/z80/src/Makefile.sdcc*, z80/up_mem.h:  Redesign Z80 build so that it
          no longer depends on Bash scripts.
        * configs/z80sim/nsh and pashello:  Converted to (1) use the kconfig-frontends
          configuration tool, and (2) to build natively under Windows.  The NSH
          configuration is verified; the pashello configuration needs a more TLC.
        * tools/copydir.sh:  Rename tools/winlink.sh to tools/copydir.sh
        * tools/link.bat, unlink.bat, and copydir.bat:  Add Windows counterparts
          to the link.sh, unlink.sh, and copydir.sh Bash scripts.
        * configs/z80sim/pashello:  Now builds correctly.
        * configs/xtrs/ostest, nsh, and pashello:  Converted to (1) use the kconfig-
          frontends configuration tool, and (2) to build natively under Windows.
        * drivers/serial/Kconfig and sched/Kconfig:  Two names for same configuration:
          CONFIG_LOWLEVEL_CONSOLE is bogus and CONFIG_DEV_LOWCONSOLE is in the wrong
          Kconfig file.  Moved to drivers/serial/Kconfig replacing CONFIG_LOWLEVEL_CONSOLE.
        * arch/z80/include/z180:  Add header files for z180 chips.  Initial versions
          are just clones of z80 header files.
        * arch/z80/src/z180:  Add source files for z180 chips.  Initial versions
          are just clones of z80 source files.
        * include/nuttx/arch.h:  Add address environment control interfaces (for use
          with CPUs the provide MCUs and support process-like address environments).
        * arch/z80/src/z180/z180_mmu.*:  Add MMU support for z180 tasks.
        * configs/p112:  Add very basic board support and an examples/ostest
          configuration for the venerable P112 board.
        * sched/os_bringup.c: If CONFIG_PATH_INITIAL is defined, then the initial
          environment of the task started by os_bringup() will have the PATH
          environment variable defined to be that string.
        * binfmt/binfmt_exepath.c:  If CONFIG_BINFMT_EXEPATH is defined, then this
          file will be built.  It contains logic to search for regular files at
          the absolutes paths found in the current PATH environment variable
          setting.  This is untested and not yet hooked into the binfmt exec()
          logic on initial check-in
        * binfmt/binfmt_loadmodule.c: load_module() will now traverse the PATH
          variable to locate files from their relative path.
        * include/nuttx/arch.h and arch/z80/src/z180/z180_mmu.c:  Restructure the
          address environment interfaces so that they will better integrate with
          binfmt/.
        * binfmt/libelf/*, binfmt/libnxflat/* and other files:  Integrate the
          address environment interfaces.  If CONFIG_ADDRENV=y, then binfmt/
          will now create an address environment for new tasks (instead of
          just malloc'ing the task memory).
        * configs/stm32f4discovery/elf:  Enable support/test of the PATH
          to find executables using a relative path.

    apps-6.24 2012-12-20 Gregory Nutt <gnutt@nuttx.org>

        * apps/examples/ostest/roundrobin.c:  Replace large tables with
          algorithmic prime number generation.  This allows the roundrobin
          test to run on platforms with minimal SRAM (Freddie Chopin).
        * apps/nshlib/nsh_dbgcmds.c:  Add hexdump command to dump the contents
          of a file (or character device) to the console  Contributed by Petteri
          Aimonen.
        * apps/examples/modbus:  Fixes from Freddie Chopin
        * apps/examples/modbus/Kconfig: Kconfig logic for FreeModBus contributed
          by Freddie Chopin.
        * Makefile, */Makefile:  Various fixes for Windows native build.  Now uses
          make foreach loops instead of shell loops.
        * apps/examples/elf/test/*/Makefile: OSX doesn't support install -D, use
          mkdir -p then install without the -D.  From Mike Smith.
        * apps/examples/relays/Makefile: Reduced stack requirement (Darcy Gong).
        * apps/nshlib and apps/netutils/dhcpc:  Extend the NSH ifconfig command plus
          various DHCPC improvements(Darcy Gong).
        * apps/nshlib/nsh_apps.c: Fix compilation errors when CONFIG_NSH_DISABLEBG=y.
          From Freddie Chopin.
        * Rename CONFIG_PCODE and CONFIG_FICL as CONFIG_INTERPRETERS_PCODE and
          CONFIG_INTERPRETERS_FICL for consistency with other configuration naming.
        * apps/examples/keypadtest:  A keypad test example contributed by Denis
          Carikli.
        * apps/examples/elf and nxflat:  If CONFIG_BINFMT_EXEPATH is defined, these
          tests will now use a relative path to the program and expect the binfmt/
          logic to find the absolute path to the program using the PATH variable.

    NxWidgets-1.4 2012-12-20 Gregory Nutt <gnutt@nuttx.org>

        * libnxwidgets/Makefile, NxWidgets/nxwm/Makefile, and
          NxWidgets/UnitTests/nxwm/Makefile:  Makefile improvements from
          submitted by Petteri Aimonen.  Other Makefiles in the UnitTests
          directory probably also need these changes.
        * libnxwidgets/src/ccallback.cxx: Fix misplaced #endif.  Provided
          by Petteri Aimonen.
        * libnxwidgets/src/cnxserver.cxx:  Reduce delay to allow NX server
          to start.  One second was un-necessarily long.  Reduced to 50 MS.
          Reduction suggested by Petteri Aimonen.
        * tools/bitmap_converter.py:  This script converts from any image type
          supported by Python imaging library to the RLE-encoded format used by
          NxWidgets.
        * NxWidgets/nxwm/src/capplicationwindow.cxx: If the "desktop" is empty,
          users have no need to minimize any windows. If the buttons are small,
          it's easy to hit minimize button accidentally when trying to close an
          application.  Contributed by Petteri Aimonen.
        * NxWidgets/nxwm/src/ctaskbar.cxx:  Add an option to eliminate the
          background image.  Contributed by Petteri Aimonen.
        * NxWidgets/nxwm/src/chexcalculator.cxx and NxWidgets/nxwm/src/cstartwindow.cxx:
          The config settings CONFIG_NXWM_STARTWINDOW_ICON and CONFIG_NXWM_HEXCALCULATOR_ICON
          allow changing the icons used for these applications. However, to declare symbols
          for these icons user would need to modify NxWidgets header files.
          This commit adds a simple forward declaration to the relevant files, based on the
          configured icon. If the icon does not exist, linker will give an error about it.
          Contributed by Petteri Aimonen.
        * NxWidgets::CTaskBar: Highlight the current window in the task bar.
          Contributed by Petteri Aimonen.
        * NxWidgets/libnxwidgets/src/glyph_cycle.cxx:  Width of glyph_cycle was wrong;
          Destructor needs to by public.  From Petteri Aimonen.
        * NxWidgets::CNumericEdit.  This is basically a label with plus and minus buttons.
          Contributed by Petteri, Aimonen.
        * NxWM::CStartWindow:  Fix mq_receive error handling with signal is recieved.
          From Petteri Aimonen.
        * NxWidgets::CNxTimer:  Replace the original (apparently non-functional) signal-
          based solution with a work queue-based solution.  This raises some isses about
          using the internal work queues from user space.  I have decided to implemented
          user-space work queues (someday) in order to accomplish that functionaliy.
          Submitted by Petteri Aimonen.
        * NxWidgets:CText and NxWidgets:CNumericEdite:  Fix some memory freeing bugs
          (from Petteri Aimonen).
        * NxWidgets::CScrollingPanel:  Usability improvements.  It is borderless for now,
          because there was no easy way to redraw only the required part of the border.
          Contributed by Petteri Aimonen.
        * NxWidgets::CNxWidgets and NxWM::CStartWindow: Small changes to make sub-
          classing easier (from Petteri Aimonen).

    uClibc++-1.0 2011-11-05 <gnutt@nuttx.org>

        * The initial release of the uClibc++ implementation of the standard
          C++ library for NuttX.  This package was contributed ay Qiang Yu and
          David for the RGMP team.

    buildroot-1.11 2011-11-05 <gnutt@nuttx.org>

        * configs/avr-defconfig-4.3.3 - Added --enable-long-long as a GCC
          option.
        * configs/avr-defconfig-4.5.2 - New configuration.
        * Config.in and almost all configurations in configs/ - Changed the
          default nuttx path to $(TOPDIR)/../../nuttx
        * Misc files.  Patch provided by Gerd v. Egidy that solves the following
          problems
          - binutils 2.21 is not available on the gnu servers anymore, they replaced
            it with 2.21.1
          - there is some assembler error when compiling gcc for arm, gcc bugzilla
            43999
          - you can't build nuttx for cortex m3/m4 because of a missing instruction
            in the assembler, binutils bugzilla 12296
        * Add support for binutils 2.22 and GCC 4.6.3.
        * Change name of all tools from xxx-elf to xxx-nuttx-elf
        * Added an ARM EABI GCC 4.6.3 configuration (tool name is arm-nuttx-eabi-).
        * ldnxflat: Add support for the R_ARM_REL32 relocation.  This relocation
          type was not generated by GCC/LD prior to gcc-4.6.3
        * R_ARM_REL32 logic is conditionally disabled because it has not been
          tested.
        * ldnxflat: Correct a memory allocation error that could cause written
          past the end of allocated memory.  Partial restoration of R_ARM_REL32
          logic.  There are lots of issues that I still do not understand here.

    pascal-3.0 2011-05-15 Gregory Nutt <gnutt@nuttx.org>

        * nuttx/:  The Pascal add-on module now installs and builds under the
          apps/interpreters directory.  This means that the pascal-2.1 module is
          incompatible with will all releases of NuttX prior to nuttx-6.0 where the
          apps/ module was introduced.

Unreleased Changes

- nuttx-6.18. The ChangeLog for the not-yet-released version 6.18 is available at the bottom of the ChangeLog file that can viewed in the SourceForge SVN.
- apps-6.18. The ChangeLog for the not-yet-released version 6.18 is available at the bottom of the ChangeLog file that can viewed in the SourceForge SVN.
- NxWidgets-1.1. The ChangeLog for the not-yet-released version 1.1 is available at the bottom of the ChangeLog file that can viewed in the SourceForge SVN.
- pascal-1.1. The ChangeLog for the not-yet-released version 1.1 is available at the bottom of the ChangeLog file that can viewed in the SourceForge SVN.
- buildroot-1.11. The ChangeLog for the not-yet-released version 1.11 is available at the bottom of the ChangeLog file that can viewed in the SourceForge SVN.

# Bugs, Issues, Things-To-Do

The current list of NuttX Things-To-Do in SVN here. A snapshot of the To-Do list associated with the current release are available here.

# Other Documentation

| Getting Started
| User Guide
| Porting Guide
| NuttShell (NSH)
| NuttX Binary Loader
| NXFLAT Binary Format
| NX Graphics Subsystem
| NxWidgets
| Demand Paging
| NuttX README Files
| Change Log
| To-Do List
| USB Device Driver Tracing

# Trademarks

- ARM, ARM7 ARM7TDMI, ARM9, ARM920T, ARM926EJS Cortex-M3 are trademarks of Advanced RISC Machines, Limited.
- Cygwin is a trademark of Red Hat, Incorporated.
- Linux is a registered trademark of Linus Torvalds.
- Eagle-100 is a trademark of Micromint USA, LLC.
- LPC2148 is a trademark of NXP Semiconductors.
- TI is a tradename of Texas Instruments Incorporated.
- UNIX is a registered trademark of The Open Group.
- VxWorks is a registered trademark of Wind River Systems, Incorporated.
- ZDS, ZNEO, Z16F, Z80, and Zilog are a registered trademark of Zilog, Inc.

NOTE: NuttX is not licensed to use the POSIX trademark. NuttX uses the POSIX standard as a development guideline only.