Goals. Nuttx is a real timed embedded operating system (RTOS). Its goals are:
Usable in all but the tightest micro-controller environments, The focus is on the tiny-to-small, deeply embedded environment.
The goal is to provide most standard POSIX OS interfaces to support a rich multi-threaded development environment.
NON-GOALS: (1) It is not a goal to provide OS subsystems such as network or USB (but these could obviously be added). (2) There is no MMU-based support for processes. At present, NuttX assumes a flat address space.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.
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 functionaly 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.
Fully pre-emptible, fixed priority and round-robin scheduling.
Non-restrictive BSD license.
The initial release of NuttX (nuttx-0.1.0) is avalable for download from the SourceForge website.
A user-mode port of NuttX to the x86 Linux platform is available. The purpose of this port is primarily to support OS feature developement.
STATUS: Does not support interrupts but is otherwise fully functional.
NuttX operates on the ARM7 of this dual core processor. This port uses the Spectrum Digital evaluation board with a GNU arm-elf toolchain*.
STATUS: This port is complete, verified, and included in the initial NuttX release.
This port uses the PJRC 87C52 development system and the SDCC toolchain.
STATUS: This port will require a few more weeks before it is ready for prime time.
There are partial ports for the TI TMS320DM270 and for MIPS.
* A highly modified buildroot is available that be used to build a NuttX-compatible arm-elf toolchain.
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
87C52 A reduced functionality OS test for the 8051 target requires only about 18Kb (see spreadsheet for details).
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.