- ARC
- ARM/Thumb
- AVR32
- BlackFin
- ColdFire/68K
- Hitachi H8/300H
- Leon3
- Luminary Micro’s Stellaris®
- M-CORE
- MicroBlaze
- Microchip PIC24/dsPIC
- Microchip PIC32
- MIPS
- NEC V8xx
- Nios II
- Power Architecture
- Renesas SH
- SHARC
- StarCore
- STMicroelectronics STM32
- StrongARM
- TMS320C54x
- TMS320C6x
- Under Development
- Win32
- x86/x386
- XScale
- Xtensa/Diamond
ThreadX
ThreadX
- Preemptive, Priority-based, Multithreading RTOS
- Supports all popular 32-bit Architectures
- Wide choice of development tools
- Small-footprint, deterministic, fast, easy-to-use, preemptive scheduling, message passing
- Low Overhead
- Small, Fast, Easy to Use
- Full Source Code
- Royalty-Free
- Deployed in over 750 million Devices
ThreadX is Field Proven!
With over 750 million deployments, ThreadX is industry proven and ready for your most demanding requirements.
Small Footprint
ThreadX is implemented as a C library. Only the features used by the application are brought into the final image. The minimal footprint of ThreadX is under 2KB on Microcontrollers.
Fast Response
ThreadX helps your application respond to external events faster than ever before. ThreadX is also deterministic. A high priority thread starts responding to an external event on the order of the time it takes to perform a highly optimized ThreadX context switch.
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
* timing based on ThreadX V5.1, configured for maximum performance and minimal size.
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
* Measurements based on ThreadX V5.1, configured for minimal size
Instant On
ThreadX requires as little as 300 cycles to initialize and start scheduling application threads. This is hugely important for consumer and medical devices that simply can't afford a long boot time.
Easy To Use
ThreadX is very easy to use. The ThreadX API is both intuitive and highly functional. In addition, the API names are made of real words and not the “alphabet soup” names that are common to other RTOS products. Building a ThreadX application is also easy. Simply include the TX_API.H file in the application software and link the application objects with the ThreadX library. The resulting image is ready for execution – it’s that simple!
ThreadX also boasts the very best documentation. Please review our ThreadX User Guide and see for yourself!
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.
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.

