# NuttX

# NuttX RTOS

Last Updated: August 25, 2012

# 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.

- 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 separtely 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.

- NXFLAT. A new binary format call NXFLAT that can be used to execute separately linked programs in place in a file system.

| 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`, 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 Library

- Fully integrated into the OS.

| Networking

- TCP/IP, UDP, ICMP, IGMPv2 (client) stacks.

- SLIP

- 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 NXFLAT to provide true, embedded CGI.

| 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-6.21 Release Notes

The 88th release of NuttX, Version 6.21, was made on August 25, 2012, and is available for download from the SourceForge website. Note that the release consists of two tarballs: `nuttx-6.21.tar.gz` and `apps-6.21.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: r5052

Additional new features and extended functionality

- Core
  - Add support for multiple registered `atexit()` functions.
  - Syslog extended: Now any character driver may be used for the debug logging device. Mountpoint traversal logic.
- Common Drivers
  - Added support for the TI PGA112-7 amplifier/multiplexor.
- NXP LPC43XX
  - Added clock ramp-up logic to run at 204 MHz.
- NXP LPC43XX Drivers
  - SPIFI block driver
  - RS-485 support
  - Minimal termios support
  - Framework for USB0 device controller driver.
- NXP LPC17XX Drivers
  - Minimal termios support
- STM32
  - Support for STM32 F1 "Value Line" (contributed by Mike Smith).
  - Add support for STM32 F107 "Connectivity Line" (contributed by Max Holtzberg).
  - Clock restart logic needed for recovery from low power modes.
- STM32 Drivers
  - RTC alarm support. Usable for wakeup from sleep mode.
  - Minimal serial termios support.
  - USB OTG FS host driver (alpha).
- STM32 Boards
  - Add power management hooks for the STM32F4Discovery
  - Add support for the Olimex STM32-P107 (contributed by Max Holtzberg)
- PIC32
  - Add support for the Pinguino MIPS toolchain
- PIC32 Drivers
  - GPIO driver now supports F1 analog regiaters (ANSEL)
- PIC32 Boards
  - Add support for the PGA117 on the Mirtoo module
- Calypso
  - Add support for the SSD1783 LCD on the Compal E99
- Library
  - `cfsetispeed()`, `cfsetospeed()`, `tcflush()`, `memchr()`, and `memccpy()`.
- Applications
  - Port of freemodbus-v1.5.0.
  - Add support for testing devices with multiple ADC, PWM, and QE devices.
  - NSH `mount` command (with no arguments) will now show mounted volumes.
  - Added new NSH `df` command to show file system usage.
  - Extended NSH 'help' support.
  - NSH now catches the return value from spawned applications (provided by Mike Smith).
- Build System
  - `mkconfig` will not define `CONFIG_DRAM_END`.
  - A lot of progress has been made on the automated NuttX configuration logic (Thanks go to Richard Cochran).
- Documentation
  - Document ways to customize the behavior of NSH

Bugfixes (see the change log for details):

- Serial drivers (all)
  - Fix `ioctl()` return value.
  - Common "upper half" serial driver will now return with `EINTR` if a serial wait is interrupted by a signal.
- FAT
  - Fix statfs() file name length
- NXP LPC43xx
  - Clock configuration
- STM32
  - Pinmap fixes
  - SPI driver re-initialization
- STM32 Boards
  - Correct and lower SDIO frequency for F2 and f4 boards
- AVR
  - C++ build issues
- Power Management (PM)
  - Fix a place where interrupts were not be re-enabled
- Applications
  - Fix NSH application start-up race condition
- Library
  - Fieldwidth and justification for `%s` format.
  - Fixed several issues with presenting floating point numbers.
  - NULL definition for C++

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 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-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, Alan Carvalho de Assis, and Stefan Richter. Calypso support first appeared in NuttX-6.17.

NXP LPC214x. Support is provided for the NXP LPC214x family of processors. In particular, support is provided for the mcu123.com lpc214x evaluation board (LPC2148). This port also used the GNU arm-elf toolchain* under Linux or Cygwin.

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 with Cygwin GNU toolchain, or 3) Cygwin with Windows native toolchain (CodeSourcery or devkitARM). A DIY toolchain for Linux or Cygwin is provided by the NuttX 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-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-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 ENC29J60 Ethernet driver for add-on hardware is under development and should be available in the NuttX 5.5 release.

Development Environments: 1) Linux with native Linux GNU toolchain, 2) Cygwin with Cygwin GNU toolchain, or 3) Cygwin with Windows native toolchain (CodeSourcery or devkitARM). A DIY toolchain for Linux or Cygwin is provided by the NuttX buildroot package.

| ARM920T.

Freescale MC9328MX1 or i.MX1. This port uses the Freescale MX1ADS development board with a GNU arm-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-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-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-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 with Cygwin GNU toolchain, or 3) Cygwin with Windows native toolchain (CodeSourcery or devkitARM). A DIY toolchain for Linux or Cygwin is provided by the NuttX buildroot package.

Luminary/TI Stellaris LM3S6965. This port uses the Stellaris LM3S6965 Ethernet Evalution Kit with a GNU arm-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-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. However, there is no specific board support for this chip families in the NuttX source tree.

STMicro STM32F103x. Support for four MCUs and three board configurations are available. MCU support includes: STM32F103ZET6, STM32F103RET6, and STM32F103VCT. Boards supported include:

1. A port for the STMicro STM3210E-EVAL development board that features the STM32F103ZET6 MCU.
2. The ISOTEL NetClamps VSN V1.2 ready2go sensor network platform based on the STMicro STM32F103RET6. Contributed by Uros Platise.
3. A port for the HY-Mini STM32v board. This board is based on the STM32F103VCT chip. Contributed by Laurent Latil.

These ports uses a GNU arm-elf toolchain* under either Linux or Cygwin (with native Windows GNU tools or Cygwin-based GNU tools).

STATUS:

- 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.
- 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 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.

Development Environments: 1) Linux with native Linux GNU toolchain, 2) Cygwin with Cygwin GNU toolchain, or 3) Cygwin with Windows native toolchain (RIDE7, CodeSourcery or devkitARM). 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 and users have reported that they have successful brought up NuttX on there proprietary boards using this logic. Support for the Olimex STM32-P107 was contributed by Max Holtzberg and first appeared in NuttX-6.21.

STATUS: Configurations for the basic OS test and NSH are available and verified.

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-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 with Cygwin GNU toolchain, or 3) Cygwin with Windows native toolchain (CodeSourcery or devkitARM). A DIY toolchain for Linux or Cygwin is provided by the NuttX 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-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.

1. 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).

2. 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`).

3. 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.

4. 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.

5. 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 with Cygwin GNU toolchain, or 3) Cygwin with Windows native toolchain (CodeSourcery devkitARM or Code Red). 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 with Cygwin GNU Cortex-M3 or 4toolchain, or 3) Cygwin with Windows native GNU Cortex-M3 or M4 toolchain (CodeSourcery or devkitARM). 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:

1. 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,
2. 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 with Cygwin GNU toolchain, or 3) Cygwin with Windows native toolchain. 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-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:

1. The LITE version of the PIC32MX toolchain available for download from the MicroChip website, or
2. 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-elf-ld` link fails with the following message:

`m32c-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 Cygwin under WinXP.

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 Cygwin under WinXP.

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 Cygwin under WinXP.

STATUS: This release has been verified only on the ZiLOG ZDS-II Z8Encore! chip simulation as of nuttx-0.3.9.

| 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

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
| 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.
| Cygwin + GNU `make` + GCC/binutils
| 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.
| Cygwin + GNU `make` + SDCC
| I have never tried this combination, but it would probably work just fine.
| 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/winlink.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`. Dependencies can be enabled for the Windows native GCC compilers by setting `MKDEPS` to point to `$(TOPDIR)/tools/mkdeps.sh --winpaths $(TOPDIR)`.

Supported Windows Native Toolchains. At present, only the Zilog Z16F, z8Encore, and eZ80Acclaim ports use a non-GCC native Windows toolchain(the Zilog ZDS-II toolchain). Support for Windows native GCC toolchains (CodeSourcery and devkitARM) is currently implemented for the NXP LPC214x, STMicro STR71x, and Luminary LMS6918 ARM ports. (but could easily be extended to any other GCC-based platform with a small effort).

| 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? Windows Native `make` + Windows Native Toolchain?

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.

GNUWin32. For example, with suitable make system changes, it should be possible to use native GNU tools (such as those from GNUWin32) to build NuttX. However, that environment has not been used as of this writing.

NOTE: One of the members on the NuttX forum reported that they successful built NuttX using such a GNUWin32-based, Windows native environment. They reported that the only necessary change was to the use the NTFS mklink command to create links (see `tools/winlink.sh` script).

# 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-6.21 2012-08-25 Gregory Nutt <gnutt@nuttx.org>

        * configs/lpc4330-xplorer/up_nsh.c:  Add support for a basic SPIFI block
          driver for use by NSH.  Does not work!  Crashes on first SPIFI write.
        * configs/lpc4330-xplorer/*/defconfig: Calibrate delay loops (this is
          based on the current "slow" 72MHz M4 clock and will need to be
          re-calibrated when this is increased).
        * configs/stm3220g-eval/include/board.h and configs/stm3240g-eval/include/board.h:
          The SDIOCLK frequency in the F2 and F4 derives for PLL48CLK and not HCLK
          so that the SDIOCLK input frequency should always be 48MHz.
        * sched/os_internal.h, sched_setupidlefiles.c, sched_setuptaskfiles.c, and
          sched_setupidlefiles.c:  Detangle some conditional compilation.  Allow for
          a perverse configuration that has socket descriptors and streams but no file
          descriptors (sure, why not?).
        * sched/: Stylistic clean-up of all files.  Some of these files are pretty old
          and do not follow current NuttX coding standards in detail.
        * fs/: More stylistic file clean-up.
        * mm/: More stylistic file clean-up.
        * drivers/ and drivers/serial/: More stylistic file clean-up.
        * arch/arm/src/lpc43xx/lpc43_clockconfig.c:  Fix PLL1 bit manipulation logic.
          Critical bugfix! This would often cause the LPC43xx to fail to boot.
        * arch/arm/src/lpc43xx/lpc43_rgu.c:  The soft reset logic called from the
          beginning of __start seems cause problems.  A magic delay seems to improve
          the logic some.  But I suspect that real fix is to get rid of all of the
          soft reset logic.  This would also be a critical bugfix if I believed
          that it really fixed all of the issues.
        * arch/arm/src/lpc43xx/chip/lpc43_cgu.h:  Fix a bit mask in the PLL1
          control register.  Critical bugfix.
        * arch/arm/src/lpc43xx/lpc43_clockconfig.c and configs/lpc4330-xplorer/include/board.h:
          Implement PLL1 ramp-up logic; Now the LPC43xx is running at 204MHz.
        * configs/lpc4330-xplorer/*/defconfig:  Re-calibrated delay loops using
          the 204MHz clock.  The LPC43xx ripping rips!  This calibration was performed
          with symbols enabled and all optimization disabled.  It will need to be
          better recalibrated again down the road.
        * arch/arm/src/stm32/stm32_exti.c:  Renamed to rch/arm/src/stm32/stm32_exti_gpio.c
          to make a little room in the file name space.
        * arch/arm/src/stm32/stm32_exti_alarm.c:  Add initial logic to attached the
          RTC alarm EXTI interrupt.  This is work be performed mostly by Diego Sanchez.
        * include/: More stylistic file clean-up.
        * arch/arm/src/lpc43xx/lpc43_spifi.c, lpc43_spifi.h, and chip/lpc43_spifi.h:  Add
          logic to configure and initialize the SPIFI device (does not yet work).
        * configs/lpc4330-xplorer/include/board.h:  Reduce SPI SCLK value.
        * arch/arm/src/lpc43xx/lpc43_spifi.c, lpc43_spifi.h, and chip/lpc43_spifi.h:
          Logic completely redesigned.  It now creates an MTD driver to access SPIFI...
          but the driver still does not work.
        * arch/arm/src/stm32 and arch/arm/include/stm32: Make name of RTC ALARM interrupt
          common on STM32 F1,2,4
        * arch/arm/src/stm32 and arch/arm/include/stm32: Add support for the
          STM32F100x "Value Line" devices. This includes changes to stm32F10xx_rcc.c that
          add the ability to run the chip off the internal oscillator.  There is no open
          board configuration for this part yet (the STM32VLDiscovery would be a candidate).
          Contributed by Mike Smith.
        * arch/arm/src/stm32: Fixed typos in conditional compilation in the CAN and DMA
          and some pin configuration.  This would have caused problems for STM32 F107xx.
          Typos noted by Mike Smith.
        * arch/arm/src/lpc43xx/lpc43_serial.c:  Add support for certain RS-485 features
        * lib/termios/lib_cfsetispeed.c, lib_cfsetospeed.c, lib_tcflush.c:  Add
          simple implementations of cfsetispeed(), cfsetospeed(), and tcflush().
        * include/sys/str_tty.h, lib/lib_setspeed.c, lib_getspeed.c, and lib_resetspeed.c:
          Add APIs to support setting non-standard BAUD values not supported by POSIX
          termios.  These are non-standard interfaces but have a precedence:  There are
          similar interfaces in AIX.
        * include/sys/str_tty.h, lib/lib_setspeed.c, lib_getspeed.c, and lib_resetspeed.c:
          Sigh... removed.  We don't need any more almost standard interfaces!  (SVN
          revision 4968 if you want the short-lived code).
        * include/termios.h and lib/termios/*:  Open the existing, standard termios
          interfaces to permit some non-standard baud settings.  The new termios definitions
          still supports the POSIX standard except that it does not strictly enforce
          baud rate settings, permitting some non-portable, but useful baud rate settings
          (this is what the short-lived AIX-like interfaces would have accomplished as well).
        * include/termios.h and lib/termios/*:  Redesigned yet again (this is getting
          painful.  NuttX now supports the BOTHER baud setting just as Linux does.  termios
          Bxxx definitions are again encoded; cf[set|get][o|i]speed now deal with only the
          encoded values.  If the encoded baud is set to BOTHER, then the values in the (non-
          standard) c_ispeed and c_ospeed baud values may be accessed directly.
        * arch/arm/src/stm32/stm32_serial.c:  Add minimal termios support for the STM32
          (BOTHER style baud settings only).  Contributed by Mike Smith.
        * configs/lpc4343-xplorer/src:  Clean up SPIFI-library based build to that it
          actually works.
        * arch/arm/src/lpc43xx/lpc43_spifi.c:  Add support for verification to writes.
          Add debug option to dump buffers.  Several bugfixes... almost works.
        * include/termios.h, lib/termios/*, and arch/arm/src/stm32/stm32_serial.c: :
          BOTHER is gone again.
        * arch/arm/src/stm32/stm32_sdio.c and chip/stm32f20xx_pinmap.h:  STM32 F2 SDIO
          fixes from Gary Teravskis and Scott Rondestvedt.
        * include/termios.h and lib/termios/*:  Replace cfsetispeed and cfsetospeed with
          cfsetspeed (with definitions for the input/outputs in termios.h).
        * configs/stm32f4discovery/src and configs/stm32f4discovery/pm:  Add a power
          management configuration for the STM32F4Discovery and supporting logic.  This
          check-in also includes some fixes for the F4 RTC alarm logic.
        * drivers/input/pga11x.c and include/nuttx/input/pga11x.h:  Add support for the
          TI PGA112/3/6/7 amplifier/multiplexer parts.
        * configs/mirtoo/README.txt, nsh/defconfig, and nxffs/defconfig:  Add support
          for the PGA117 on the Mirtoo module.
        * drivers/analog/pga11x.c and include/nuttx/analog/pga11x.h:  These belong in
          the analog subdirectories, not input.
        * configs/compal_e99/src/ssd1783.c and /ssd1783.h:  Drivers for the SSD1783
          LCD found in the Motorola C155 telephone.  The driver is specific to the C155
          because it uses the uwire transport.  Contributed by Denis Carilki and
          Alan Carvalho de Assis.
        * drivers/power/pm_changestate.c.  Correct a case where interrupts were not
          being re-enabled.  Found by Diego Sanchez.
        * configs/mirtoo/nxffs/defconfig:  This Mirtoo NXFFS configuration now uses the
          open Pinguino toolchain by default.  This is necessary because the free C32
          toolchain does not support any optimization and the unoptimized NXFFS image
          hits the PIC32MX2 FLASH size (128K).  There is plenty of room to grow using
          the Pinguino toolchain with -O2 optimization.
        * configs/mirtoo/src/up_adc.c.  This is just a stub for now, but this is
          where Mirtoo ADC logic will eventually need to go.
        * arch/mips/src/pic32mx/pic32mx-gpio.c:  Now supports the PIC32MX1/2 ANSEL
          IOPORT register.
        * lib/string/lib_memchr.c:  Add support for memchr() (contributed by Mike Smith)
        * lib/string/lib_memccpy.c:  Add support for memccpy()
        * arch/arm/src/lpc17xx/lpc17_serial.c:  Now supports ioctl commands to change
          the baud using tcsetattr() (contributed by Chris Taglia).
        * arch/*/src/*_serial.c: Fix ioctl method return values.  These methods
          should return a negated errno value; they should not set the errno
          variable.
        * sched/on_exit.c, sched/task_exithook.c, and include/nuttx/sched.c:  Add
          support for multiple registered on_exit() functions if CONFIG_SCHED_ONEXIT_MAX
          is defined.
        * drivers/syslog/ramlog.c: Move the RAM SYSLOG device into drivers/syslog
          so that it will be in the same directory as some new SYSLOGing devices
          in the works.
        * include/nuttx/syslog.h and drivers/syslog/ramlog.c:  The SYSLOG putc function
          now has a common name that is independent of the device that provides the
          SYSLOG.
        * include/nuttx/syslog.h and drivers/syslog/syslog.c:  This is a new, generic
          SYSLOG device that can redirect debug output to any character device or file.
          So you can log debug output to a file or you can put the console on /dev/ttyS0
          and the debug output on /dev/ttyS1.
        * arch/arm/src/lpc43xxl/lpc43_spifi.c: Correct an addressing error in the LPC43
          SPIFI MTD driver
        * drivers/syslog/syslog.c and fs/fs_syslog.c:  Moved the generic syslog logic
          from drivers/syslog to fs/ where is belongs.  Especially after realizing that
          the syslog logic is going to have to some internal FS operations in order
          to realize a totally thread-independent SYSLOG interface.
        * arch/arm/src/stm32/stm32*_rcc.c and .h:  If CONFIG_PM is defined, add a
          function called stm32_clockenable() that can be used by PM logic to re-start
          the PLL after re-awakening from deep sleep modes.
        * fs/fs_foreachinode.c and fs/fs_foreachmountpoint.c:  Add logic to traverse
          inodes and mountpoints in the NuttX pseudo-file system.
        * fs/fat/fs_fat32.c: Max. filename length reported by statfs() was wrong
          if FAT long file names were enabled.
        * lib/stdio/lib_libvsprintf.c:  Fieldwidth and justification were not
          supported for the %s format.  As a result, %s, %12s, and %-12s all
          produced the same output.
        * lib/stdio/lib_libdtoa.c:  Fix several issues with presenting floating
          point numbers (conversions are fine, but presentation was bad).  This
          is a critical bug fix if you use printf or sprintf to deal with floating
          point numbers.
        * lib/stdio/lib_libdtoa.c and lib_libvsprintf.c:  Correct some floating
          point options.
        * arch/arm/lpc43xx/lpc32_usb0dev.c:  Add framework for development of
          an USB0, device-side driver for the LPC43XX.  The initial check-in,
          however, is simply for the LPC31xx driver with name changes.  The
          LPC31xx has the same USB IP, but will require some additional initialization
          (and lots of testing) before it can be used with the LPC43xx.
        * nuttx/Documentation/NuttShell.html:  Added a section covering ways to
          customize the behavior of NSH.
        * arch/arm/src/stm32/chip/stm32f1*_pinmap.h: STM32 CAN TX/RX pins reversed;
          inconsistent conditional compilation.  Reported by Max Holtzberg.
        * arch/arm/*/stm32:  Add support for STM32 F107 "Connectivity Line"
          Ethernet (contributed by Max Holtzberg).
        * configs/olimex-stm32-p107:  Add board support for the Olimiex STM32-P107
           board (contributed by Max Holtzberg).
        * arch/arm/src/stm32/stm32f2xx_dma.c, stm32f4xx_dma.c, stm32_serial.c, and
          stm32_spic.c:  DMA priority was getting zeroed by STM32 F2/F4 DMA drivers
          so that all DMAs ran at the lowest priority.
        * configs/stm3240g-eval/include/board.h and configs/stm3220:  Drop SD card
          frequency from 24 to 16 MHz.  Apparently 24 MHz is too fast for the board.
          This (plus the change to the STM32 DMA (above) fixes SDIO DMA on the
          STM3240G-EVAL (and probably STM3220G-EVAL -- untested).
        * arch/arm/src/stm32/stm32f2xx_dma.c and stm32f4xx_dma.c: Backed out the
          DMA priority change just above.  The reduced SD card frequency was
          necessary and sufficient to resolve the problem.
        * drivers/serial/serial.c:  open, read, write, and poll methods may now
          abort return EINTR (or a short transfer size) if a signal is received
          while waiting to receive or send serial data.  This behavior is required
          by POSIX.
        * include/sys/types.h:  Define NULL to be (0) if __cplusplus is defined.
          (contributed by Mike Smith)
        * include/ctype.h: Remove a stray semi-colon in a definitions (Thanks
          Mike Smith).
        * configs/.../Make.defs.  Fix C++ include path set-up in Make.defs file
          for all 8-bit AVR platforms (Thanks Richard Cochran).
        * lib/stdio/lib_*stream.c:  Revised to handle new error return values from
          serial.c.
        * arch/arm/src/stm32/stm32_spi.c:  SPI driver can now service re-
          initialization (Mike Smith).
        * tools/mkconfig.c:  If CONFIG_DRAM_END is not specified, this tool
          will provide default definition of (CONFIG_DRAM_START + CONFIG_DRAM_SIZE)
        * arch/arm/src/stm32/stm32_otgfshost.c:  Renamed from stm32_usbhost.c.
          This is nearly code complete and, with any luck, will be available
          in NuttX-6.21.
        * configs/*/defconfig:  Update all defconfig files to remove syntax
          that is incompatible with the mconf configuration tool.
        * arch/arm/src/stm32/stm32_otgfshost.c:  This driver now appears to be
          functional (although more testing is necesary).

    apps-6.21 2012-08-25 Gregory Nutt <gnutt@nuttx.org>

        * apps/include/: Stylistic clean-up of all header files.
        * apps/modbus and apps/include/modbus:  A port of freemodbus-v1.5.0
          has been added to the NuttX apps/ source tree.
        * apps/examples/modbus:  A port of the freemodbus-v1.5.0 "demo"
          program that will be used to verify the FreeModBus port
        * apps/modbus:  Don't use strerror().  It is just too big.
        * apps/modbus:  Add CONFIG_MB_TERMIOS.  If the driver doesn't support
          termios ioctls, then don't bother trying to configure the baud, parity
          etc.
        * apps/nshlib:  If waitpid() is supported, then NSH now catches the
          return value from spawned applications (provided by Mike Smith)
        * apps/nshlib:  Lock the scheduler while starting built-in applications
          in order to eliminate race conditions (also from Mike Smith).
        * apps/examples/adc, pwm, and qencoder:  Add support for testing
          devices with multiple ADC, PWM, and QE devices.
        * apps/nshlib/nsh_mntcmds.c:  Separated mount-related commands out of
          nsh_fscmds.c.  Extended to the mount command so that if no arguments
          are provided, then the current mountpoints are enumerated.
        * apps/nshlib/nsh_mntcmds.c:  Add an NSH df command to list the
          properties of mounted file systems.
        * apps/nshlib/nsh_parse.c:  Extend help command options.  'help' with
          no arguments outputs a short list of commands.  With -v lists all
          command line details.  A command name can be added to just get
          help on one command.
        * system/readline.c:  If character input/output is interrupted by a
          signal, then readline() will try the read/write again.
        * apps/*/Make.defs:  Numerous fixes needed to use the automated
          configuration (from Richard Cochran).

    NxWidgets-1.2 2012-06-15 Gregory Nutt <gnutt@nuttx.org>

        * NXWidgets::CCallback: callback arguement is now type CCallback and not
          CWidgetControl;  Added a method to redirect keyboard contacts to either
          the widgets in the window (via CWidgetControl) or to an NxConsole (via
          nxcon_kbdin()).
        * NXWidgets::INxWindow, CBgWindow, CNxTkWindow, CNxToolbar, CNxWindow:
          Now pass the CCallback intances as the callback argument instead of
          the CWidgetControl instance.  New method redirectNxConsole() will
          support redirection of any window keyboard input to the NxConsole
          (via CCallback).
        * NxWM:CNxConsole:  Configures the NxConsole window to redirection keyboard
          input to the NxConsole; redirects standard input to the NxConsole
          device driver.
        * NxWM:CKeyboard:  Add a new class that implements a keyboard listener
          thread.  This thread reads from /dev/console and injects the keyboard
          input into NX.  NX will determine which window is at the top of the
          heirarchy and re-direct the keyboard input to only that top window.
          This solves an important problem with, for example, running multiple
          copies of the NxConsole:  On the copy of the NxConsole at the top of
          the heirarchy should get the keyboard input.
        * UnitTests/nxwm/main.cxx: Now starts the keyboard thread if
          CONFIG_NXWM_KEYBOARD is defined.
        * NxWM::CTaskbar:  After drawing the task bar, need to raise the
          application window otherwise the taskbar will be on the top and
          keyboard input will not be received by the top application.
        * NxWM::CTaskbar:  Bugfix... previous window should not be minimized
          when a new window is started.  It should stay in a maximized state
          so that it will re-appear with the window above it is closed or
          minimized.
        * NxWM::CHexCalculator:  Add a hexadecimal/decimal calculator
          example.
        * NXWidgets::CNxTkWindow:  Back out height adjustment in the getSize()
          method.  The code was correct as it was before.
        * NXWidgets::CButtonArray and NXWidgets::CGraphicsPort:  There is
          a kludge in there to handle the case where we cannot read the
          background data because the LCD does not support read operations.
          In that case, we just use the default background color.  However,
          that doesn't work either for the case where the background color
          changes when the widget is selected.  Then the background color
          in the font is wrong.  Fixed in CButtonArrary, but the problem
          probably exists in other places as well.
        * NxWM:  Increase default spacing of icons on the Start Window.
        * NxWM::CHexCalculator:  Fix some non-standard calculator behavior
          after = is pressed.  Use upper case hex.  Increase font size.
        * nxwm/Makefile:  Fix error that creapt in during some other
          recent check-ins.

    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.

    buildroot-1.10 2011-05-06 <gnutt@nuttx.org>

        * Add patch submitted by Dimiter Georgiev to work around problems in building
          GDB 6.8 with versions of Cygwin > 1.7.
        * configs/i486-defconfig-4.3.3 - Builds an i486 cross development toolchain
          using gcc 4.3.3.  Why wouldyou want such a thing?  On Linux, of course,
          such a thing is not needed because you can use the installed GCC to build
          i486 ELF binaries.  But that will not work under Cygwin!  The Cygwin
          toolchain (and probably MinGW), build DOS MZ format executables (i.e.,
          .exe files).  That is probably not usable for most NuttX targets.
          Instead, you should use this i486-elf-gcc to generate true ELF binaries
          under Cygwin.
        * Makefile - Alter copy arguments to avoid permissions problems when
          copying NuttX header files.
        * toolchain/nxflat/nxflat.mk and Makefile - Fix include paths.
        * toolchain/gcc/3.3.6 - Added a patch to fixed compilation error on Ubuntu
          9.10.
        * toolchain/nxflat/Makefile - Correct static library link order.
        * configs/arm920t-defconfig-4.3.3 - Enable support for NXFLAT tools.
        * toolchain/binutils/2.21 and toolchain/gcc/4.5.2 - Add support for GCC
          4.5.2 with binutils 2.21.
        * configs/arm920t-eabi-defconfig-4.5.2 - Add a configuration to build a
          GCC 4.5.2 EABI ARM toolchain for the ARM920t.

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)
| 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.