Express Logic ThreadX – The fastest & smallest Kernel engine for SoC/VLSI

For more information:

Zvika Almog


ThreadX is Express Logic’s advanced Real-Time Operating System (RTOS) designed specifically for deeply embedded applications. ThreadX has many advanced features, including its picokernel™ architecture, preemption-threshold,™ event-chaining,™ and a rich set of system services. Combined with its superior ease-of-use, ThreadX is the ideal choice for the most demanding of embedded applications.
Major Cores Support list
  • ARC
  • ARM7,9,11/Cortex-M3, M4, R4, R5, A8, A9
  • MIPS
  • Xilinx MicroBlaze& Zynq (Cortex-A9)
  • MIPS
  • Altera Cyclone V Cortex-A9 & Nios II
  • Power PC Architecture
  • Tensilica – Xtensa/Diamond
  • and more…
Major MCUs list
  • Freescale i.MX Family
  • Freescale Kinetis
  • Atmel AVR32
  • TI Luminary Micro’s Stellaris
  • STMicroelectronics STM32
  • NXP LPC13XX/17XX

ThreadX is Fast!

Boot Time:
300 cycles
Context Switch Time:
20 cycles
Semaphore Get:
30 cycles
Minimal RAM requirement:
500 bytes
Minimal ROM requirement:
2K bytes

ThreadX is Small!

Minimal Kernel Size
Under 2K bytes
Queue Services
900 bytes
Semaphore Services
450 bytes
Mutex Services
1200 bytes
Block Memory Services
550 bytes



FileX is Express Logic’s high-performance MS-DOS compatible file system. It is fully integrated with ThreadX and is available for all supported processors. Like ThreadX, FileX is designed to have a small footprint and high-performance, making it ideal for today’s deeply embedded applications that require file operations.


NetX is Express Logic’s high-performance implementation of TCP/IP protocol standards. It is fully integrated with ThreadX and is available for all supported processors. NetX has a unique Piconet™ architecture. Combined with a zero-copy API, it makes it a perfect fit for today’s deeply embedded applications that require network connectivity.



The PegX (Portable Embedded GUI for ThreadX) development package is a professional quality graphical user interface package created to meet the needs of embedded systems developers. Unlike the alternatives, PegX is small, fast, and easily ported to virtually any hardware configuration capable of supporting graphical output. PegX also delivers exceptional visual appeal and an intuitive and powerful API for application-level user interface development.



USBX™ is Express Logic’s high-performance USB host, device, and On-The-Go (OTG) embedded stack. It is fully integrated with ThreadX and is available for all ThreadX supported processors. Like ThreadX, USBX is designed to have a small footprint and high-performance, making it ideal for today’s deeply embedded applications that require to interface with USB devices or be connected with a Windows/Apple/Linux desktop over USB.



TraceX™ is Express Logic’s host-based system event analysis tool. TraceX provides developers with a graphical view of real-time system events. TraceX enables embedded developers to visualize and better understand the behavior of their real-time systems.



StackX™ is a new development tool that helps developers avoid stack overflow problems that traditionally have plagued embedded systems. StackX performs a comprehensive analysis of a complete application at the executable code level, computing the worst-case stack usage the application can experience. Express Logic is the only RTOS company that can identify how large a stack customers need for each application thread and automatically alerts them if they fail to allocate sufficient memory!

No Mysteries

ThreadX is delivered with complete C and assembly source code so you can see exactly how ThreadX operates. If you are used to in-house kernels or had bad experiences with “black box” commercial RTOS products, this should be most comforting.

Complete Multitasking Facilities

ThreadX provides a complete set of multitasking facilities, including:

  • Threads
  • Application Timers
  • Message Queues
  • Counting Semaphores
  • Mutexes
  • Event Flags
  • Block Memory Pools
  • Byte Memory Pools

Advanced Technology

The following are highlights of the advanced technology in ThreadX:

  • Small, fast picokernel™ architecture
  • Automatic scaling (small footprint)
  • Deterministic processing
  • Fast real-time performance
  • Preemptive and cooperative scheduling
  • Flexible thread priority support (32 – 1024 priority levels)
  • Dynamic system object creation
  • Unlimited number of system objects
  • Optimized interrupt handling
  • Preemption-threshold™
  • Priority inheritance
  • Event-chaining™
  • Fast software timers
  • Flexible memory utilization
  • Run-time performance metrics
  • Run-time stack analysis
  • Built-in system trace
  • Vast processor support
  • Vast development tool support
  • Completely endian neutral

Dynamic Creation

ThreadX allows you to create system resources dynamically. There are no predetermined limits on the number of ThreadX resources you can use. Furthermore, the number of system objects does not have any impact on performance.

Preemption-Threshold ™

ThreadX’s preemption-threshold technology is a unique addition to the priority based, preemptive scheduling algorithm. Preemption-threshold allows the application to disable preemption over ranges of priorities instead of disabling preemption of the entire system. Applications can take advantage of ThreadX’s preemption-threshold to eliminate excessive context switching, un-deterministic priority inversion, and enhance responsiveness.

Priority Inheritance

Another tool for battling un-deterministic priority inversion is the priority inheritance feature found in the ThreadX Mutex object.

Event-Chaining ™

ThreadX’s event-chaining technology allows the application to “chain together” various system objects. With the ThreadX event-chaining technology it is very easy for a single thread to block on any number and/or type of system objects. For example, it is very easy for a single thread to suspend waiting for activity on any number of queues, semaphores, etc. Hence, complex system events are much easier to manage and by using less threads – saving both space and CPU cycles.

Fast Software Timers

ThreadX application timers are available in one-shot or periodic operation. ThreadX manages activation and expiration without linear searching. This greatly reduces the amount of overhead in timer-centric applications like communications and process control.

Flexible Memory Utilization

ThreadX control blocks and memory areas associated with thread stacks, message queues, and memory pools can be easily located (during run-time) in any address space on your hardware. For example, ThreadX makes it easy to boost the performance of a high-priority thread by placing its stack in a fast memory area.

Run-time Performance Metrics

ThreadX provides optional run-time performance information. This information is available on a per-object basis as well as over an entire object class. For example, if performance information is enabled for thread objects, ThreadX keeps track of thread resumptions, suspensions, preemptions, priority inversions, time-slices, timeouts, and much more for each thread and for all threads collectively. This kind of information is essential for tuning an application as well as helping debug various problems like thread starvation.

Run-time Stack Analysis

ThreadX provides optional run-time stack analysis. If enabled, the ThreadX run-time stack analysis examines thread stack parameters before the thread is scheduled, which helps avoid going off into the weeds caused by typical stack overflow situations. In addition, ThreadX run-time stack analysis keeps track of the stack usage of each thread, which can then be used to tune the thread stack requirements.

Dedicated ISR Stack

ThreadX utilizes a dedicated stack for all ISR processing, thus keeping the thread stack requirements as small as possible.

Built-in System Trace

ThreadX provides an optional system trace capability. If enabled, ThreadX stores event information in a circular buffer that can be viewed with host-based viewing tools from Express Logic. The size, location, and contents of the trace are under complete application control. The application can also insert custom events into the trace buffer by simply calling an API service.

Vast Processor Support

ThreadX currently supports most popular CISC, RISC, and DSP processors. Because of its portable design, ThreadX can be ported to an entirely new processor family within four weeks. Both of these facts help ensure your product’s migration path.

Vast Development Tool Support

ThreadX currently supports most of the popular development tools on each processor supported. In addition, ThreadX kernel awareness is available for most popular debuggers, including ARM RealView, Wind River Workbench, IAR C-SPY, Freescale CodeWarrior, Lauterbach, Eclipse, Analog VisualDSP, and GHS MULTI.

ThreadX is Field Proven!

With over 400 million deployments, ThreadX is industry proven and ready for your most demanding requirements.

Express Logic Gets You to Market First

Express Logic products are designed for ease-of-use. Everything from well thought out APIs to simple startup procedures help you get up and running in a matter of hours! This coupled with advanced debugger integration, make our products the easy choice to win the race to market.


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For more information: Zvika Almog 054-2101400