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DeveloperGregory Nutt
Written inC, C++, assembly
OS familyReal-time operating systems
Working stateCurrent
Source modelOpen source
Latest release8.1 / September 14, 2019; 4 months ago (2019-09-14) [1]
Marketing targetEmbedded systems
PlatformsARM, AVR, AVR32, HCS12, LM32, MIPS, RISC-V, SuperH, Xtensa XL6, Z80
Kernel typeMicrokernel

NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 32-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSes (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply embedded environments – such as fork().

NuttX was first released in 2007 by Gregory Nutt under the permissive BSD license.


NuttX is written almost exclusively in C and uses Kconfig to configure and generate GNU makefiles for the system. The NuttX distribution combines the kernel itself and a substantial amount of middleware and board support/driver code. The kernel and much of the NuttX code was written by the original author, Gregory Nutt. The source is maintained exclusively by Gregory Nutt, and all community contributions must be approved by him.

Key features[edit]

  • Standards compliant
  • Core Task management
  • Modular Design
  • Fully preemptible
  • Naturally scalable
  • Highly configurable
  • Easily extensible to new processor architectures, SoC architecture, or board architectures.
  • FIFO and round-robin scheduling
  • Real-time, deterministic, with support for priority inheritance
  • Tickless operation
  • POSIX/ANSI-like task controls, named message queues, counting semaphores, clocks/timers, signals, pthreads, environment variables
  • Multiple filesystems
  • VxWorks-like task management and watchdog timers
  • BSD socket interface
  • Extensions to manage preemption
  • Optional tasks with address environments (processes)
  • Symmetric Multi-Processing (SMP)
  • Loadable kernel modules
  • Memory Configurations: (1) Flat embedded build, (2) Protected build with MPU, and (3) Kernel build with MMU
  • Memory Allocators: (1) standard heap memory allocation, (2) granule allocator, (3) shared memory, and (4) dynamically sized, per-process heaps
  • Thread Local Storage (TLS)
  • Inheritable “controlling terminals”, pseudo-terminals and I/O redirection
  • On-demand paging
  • System logging
  • May be built either as an open, flat embedded RTOS or as a separately built, secure kernel with a system call gate interface
  • Built-in, per-thread CPU load measurements
  • Custom NuttX C library

Supported platforms[edit]

  • ARM
    • ARM7TDMI (TI TMS320 C6571, Calypso, MoxART, NXP LPC214x, LPC2378, STMicro STR71x)
    • ARM920T (Freescale i.MX1)
    • ARM926EJS (TI DM320, NXP LPC31xx)
    • ARM Cortex-A5 (Atmel SAMA5D2, SAMA5D3, SAMA5D4)
    • ARM Cortex-A8 (Allwinner A10)
    • ARM Cortex-A9 (NXP/Freescale i.MX6)
    • ARM Cortex-R4/R4F (TI TMS570, Samsung Artik)
    • ARM Cortex-M0 (nuvoTon: NUC120, NXP: KL25Z, KL26Z, LPC11xx, Atmel: SAMD20/21, SAML21, ST Micro STM32 F0)
    • ARM Cortex-M3 (ST Micro STM32 F1/F2/L1, TI/Stellaris LM3S, NXP LPC17xx, Atmel SAM3U/3X, SiliconLabs EFM32)
    • ARM Cortex-M4 (with/without floating point unit: ST Micro STM32 F3/F4/L4/L4+, TI/Stellaris LM4F/TM4C, NXP LPC43xx/LPC54xx, Freescale Kinetis K20/K28/K40/60/64/66, Atmel SAM4C/4E/4S/4L, Infineon XMC4xxx, Nordic NRF52xxx, Sony CXD5602/Spresense[2])
    • ARM Cortex-M7 (Atmel SAMV71/SAME70, ST Micro STM32 F7/H7, NXP i.MX RT)
  • Atmel AVR
    • Atmel 8-bit AVR (AT90USB, ATmega)
    • AVR32
  • Freescale M68HCS12
  • Intel
  • MIPS
    • MicroChip PIC32MX (MIPS32 24Kc)
    • MicroChip PIC32MZ (MIPS32 M14k)
  • Misoc
    • LM32 (Qemu)
  • OpenRISC
    • mor1kx
  • Renesas/Hitachi
    • Renesas/Hitachi SuperH
    • Renesas M16C/26
  • RISC-V
    • NEXT RISC-V NR5Mxx (RV32IM)
    • GreenWaves GAP8 (RV32IM)
  • Xtensa LX6
    • Expressif ESP32
  • Zilog

File system[edit]

  • Tiny in-memory, root pseudo-file-system.
  • Virtual File System (VFS).
  • Mount-able volumes. Bind mountpoint, filesystem, and block device driver.
  • Generic system logging (SYSLOG) support.
  • FAT12/16/32 filesystem support.
  • NFS Client. Client side support for a Network File System (NFS, version 3, UDP).
  • NXFFS. The tiny NuttX wear-leveling FLASH file system.
  • SMART. FLASH file system from Ken Pettit.
  • Generic driver for SPI-based MMC/SD/SDHC cards.
  • Romfs filesystem support.
  • BINFS pseudo-file system support.
  • HOSTFS file system support (simulation only).
  • Union file system. Supports combining and overlaying file systems.
  • PROCFS (/proc) pseudo-file system.
  • 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.
  • File transfers via TFTP and FTP (get and put), HTML (wget), and Zmodem (sz and rz)
  • Intel HEX conversions.

Device drivers[edit]

  • VFS supports character and block drivers.
  • Asynchronous I/O (AIO).
  • Network, USB (host), USB (device), serial,I2C, I2S, NAND, CAN, ADC, DAC, PWM, Quadrature Encoder, and watchdog timer driver architectures.
  • RAMDISK, pipes, FIFO, /dev/null, /dev/zero 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.
  • Graphics Devices: framebuffer drivers, graphic and segment LCD drivers.
  • Audio Subsystem: CODECs, audio input and output drivers. Command line and graphic media player applications.
  • Cryptographic sub-system.
  • Input Devices: Touchscreen, USB keyboard, USB mouse, GPIO-based buttons and keypads.
  • Memory Technology Devices.
  • Analog Devices: Support for Analog-to-Digital conversion (ADC), Digital-to-Analog conversion (DAC), multiplexers, and amplifiers.
  • System Logging Devices.
  • Porting Guide.[3]

C/C++ library[edit]

  • Standard C library fully integrated into the OS
  • Includes floating point support via a Standard Math Library
  • Add-on uClibc++[4] module provides Standard C++ Library supporting iostreams, strings, STL, RTTI, exceptions, etc. (LGPL)


The network stack included with NuttX is derived from uIP (micro IP), originally developed by Adam Dunkels.

  • Multiple network interface support; multiple network link layer support
  • IPv4, IPv6,TCP/IP, UDP, ICMP, IGMPv2 (client) stacks.
  • Stream and datagram sockets.
  • Raw socket and local, Unix domain socket support.
  • DNS name resolution / NetDB.
  • IEEE 802.11 (WiFi) FullMac.
  • IEEE 802.15.4 MAC + 6loWPAN.
  • SLIP, TUN/PPP, local loopback devices.
  • A cJSON[5] port
  • 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, NTP client). Inheritable Telnet sessions (as “controlling terminal”). VNC server.
  • NFS Client. Client side support for a Network File System (NFS, version 3, UDP).
  • ICMPv6 autonomous auto-configuration.
  • A NuttX port of Jef Poskanzer's Thttpd HTTP server integrated with NXFLAT to provide embedded CGI.
  • PHY Link Status Management.
  • UDP Network Discovery, XML RPC Server.
  • XML RPC Server.
  • Support for network modules (such as the TI CC3000 WLAN module)

Flash support[edit]

  • MTD-inspired interface for Memory Technology Devices
  • FTL. Simple Flash Translation Layer support file systems on FLASH
  • NAND Support
  • NXFFS. the NuttX wear-leveling FLASH file system
  • Support for SPI-based FLASH devices

USB support[edit]

USB host support[edit]

  • USB host architecture for USB host controller drivers and device-dependent USB class drivers.
  • USB host controller drivers available for the Atmel SAMA5Dx, NXP LPC17xx, LPC31xx, and STmicro STM32.
  • Device-dependent USB class drivers available for USB mass storage and HID keyboard.
  • Seamless support for USB hubs.

USB device support[edit]

  • Gadget-like architecture for USB device controller drivers and device-dependent USB class drivers
  • USB device controller drivers available for the PIC32, Atmel AVR, SAM3, SAM4, and SAMA5Dx, NXP LPC17xx, LPC214x, LPC313x, and LPC43xx, Silicon Laboraties EFM32, STMicro STM32 F1, F2, F3, and F4, and TI DM320.
  • Device-dependent USB class drivers available for USB serial and for USB mass storage
  • Built-in USB trace functionality for USB debug

Graphics support[edit]

  • Framebuffer drivers
  • LCD drivers for both parallel and SPI LCDs and OLEDs
  • Segment LCD drivers
  • VNC Server
  • NX Graphics Subsystem: A graphics library, windowing system and font support that works with either framebuffer or LCD drivers
  • NuttX Widgets:[6] A graphical user interface written in conservative C++ that integrates with NX graphics
  • NuttX Window Manager:[7] A tiny window manager based on the NX graphics subsystem and NuttX widgets

Projects using NuttX[edit]

  • Thingsee IoT development device.[8]
  • Autopilot PX4 is using NuttX to control a variety of autonomous platforms.[9]
  • Pixhawk: An Advanced, User-Friendly Autopilot.[10]
  • Biffer Board supports NuttX besides many other RTOS.[11]
  • MP3 player implemented with NuttX.[12]
  • OsmocomBB is using NuttX to develop an operating system for cell phones.[13]
  • A homebrew steer-by-wire system implemented using NuttX.[14]
  • Video Performance Measurement Device.[15]
  • Low Power Embedded Software Optimization for the NuttX RTOS.[16]
  • Motorola Moto Z.[17][18]
  • Sony is using NuttX in their audio processors.[19]
  • Samsung announces TizenRT based on NuttX RTOS.[20]


  1. ^ "NuttX-8.1 Released". Retrieved 2019-09-14.
  2. ^ "Spresense combines multi-core and power efficiency". Retrieved September 5, 2019.
  3. ^ "Porting Guide". Retrieved 22 November 2012.
  4. ^ "uClibc++". Retrieved 22 November 2012.
  5. ^ "cJSON". Retrieved 22 November 2012.
  6. ^ "NuttX Widgets". Retrieved 22 November 2012.
  7. ^ "NxWM". Retrieved 22 November 2012.
  8. ^ "Thingsee". Retrieved 27 July 2015.
  9. ^ "Autopilot PX4". Retrieved 3 May 2013.
  10. ^ "Pixhawk". Retrieved 10 January 2014.
  11. ^ "Bifferboard". Retrieved 22 November 2012.
  12. ^ "Nuttx playing MP3 in Detron Board". Retrieved 22 November 2012.
  13. ^ "OsmocomBB". Retrieved 22 November 2012.
  14. ^ "A Homebrew Steer-by-Wire System". Retrieved 22 November 2012.
  15. ^ "Design of an Embedded System for Video Performance Measurements. Petteri Aimonen's Master Thesis" (PDF). Retrieved 22 July 2014.
  16. ^ "Low Power Embedded Software Optimization for the NuttX RTOS. Diego Sánchez López's Monograph of Electric Engineering Graduation" (PDF). Retrieved 12 July 2015.
  17. ^ "Moto Mods Firmware: Overview". Retrieved 28 December 2016.
  18. ^ "Modular Moto Z Android phone supports DIY and RPi HAT add-ons". Retrieved 22 August 2016.
  19. ^ "Developing Audio Products with Cortex-M3/NuttX/C++11" (PDF). Retrieved 20 January 2017.
  20. ^ "Tizen RT". Retrieved 21 February 2017.

External links[edit]