
QP™ Real-Time Embedded Frameworks (RTEFs)
Real-Time Embedded Frameworks for MCUs
The most important difference between a toolkit (e.g., RTOS) and a framework (e.g., QP RTEF) is the inversion of control. When you use a traditional RTOS, you write the main body of each thread and you call the code from the RTOS (such as a semaphore, time delay, etc.) In contrast, when you use a framework, you reuse the whole architecture and write the code that it calls. This inversion of control is the main mechanism for the architectural-reuse and enforcement of the policies of the framework.

QP™ Highlights
Lightweight
Hard Real-Time
Market Leadership
Support for Modern State Machines
Standalone (Bare-Metal) Operation
You do not need to use a traditional RTOS just to achieve preemptive multitasking with QP. The built-in, preemptive QK and QXK kernels, support preemptive priority-based multitasking that is fully compatible with Rate Monotonic Scheduling to achieve guaranteed, hard real-time performance. These preemptive kernels perfectly match the run-to-completion execution semantics of active objects, yet are simpler, faster, and more efficient than the traditional blocking RTOS kernels.
Example Evaluation Boards
Traditional RTOS Support

The QP™ RTEFs can also work with many traditional third-party RTOSes. QP ports and ready-to-use examples are provided for several RTOSes (such as FreeRTOS, embOS, ThreadX, MicroC/OS, etc.)
The most important reason why you might consider using a traditional RTOS kernel for executing event-driven QP™ applications is compatibility with the existing software. For example, many communication stacks (TCP/IP, USB, CAN, etc.) are designed for a traditional blocking kernel. In addition, a lot of legacy code requires blocking mechanisms, such as semaphores or time-delays. A traditional RTOS allows you to run the existing software components as regular “blocking” threads in parallel to the event-driven QP™ active objects.
General Purpose OS Support
The QP™ RTEFs can also work with general purpose OSes, such as Linux (POSIX), Windows, and macOS.
The QP™ ports to the general purpose operating systems are interesting in their own right. For example, the QP port to POSIX supports real-time extensions and works with embedded Linux, and POSIX subsystems of such RTOSes as QNX, INTEGRITY, VxWorks, etc. Similarly, QP port to Windows can work with Windows IoT or Windows Embedded Compact.
But the OS support can be also interesting for developing of deeply embedded code on the desktop workstations, which is called “dual-targeting”.

QP/C and QP/C++ Feature Comparison
Feature | QP/C | QP/C++ |
---|---|---|
Most Recent Version (Revision History) Latest Release Date | 6.9.2 2021-01-18 | 6.9.2 2021-01-18 |
Intended target systems (Representative hardware) | 32-bit/16-bit MCUs (ARM Cortex-M) | 32-bit/16-bit MCUs (ARM Cortex-M) |
Supported by the free QM™ Model-Based Design tool | ||
Maximum number of active objects | 64 | 64 |
Dynamic events with arbitrary parameters | ||
Automatic event recycling | ||
Direct event posting (FIFO) | ||
Direct event posting (LIFO) | ||
Publish-Subscribe event delivery | ||
Event deferral | ||
Number of system clock tick rates | configurable (0..15) | configurable (0..15) |
Number of time events per active object | Unlimited | Unlimited |
----------------------------------------------- State Machines ----------------------------------------------- | ||
Hierarchical State Machines (QHsm-strategy) | ||
Hierarchical State Machines (QMsm-strategy) | ||
Sub-machines and sub-machine states | ||
----------------------------------------------- Built-in Kernels ----------------------------------------------- | ||
Preemptive non-blocking kernel (QK) | ||
Preemptive blocking dual-mode kernel (QXK) | ||
----------------------------------------------- 3rd-Party RTOS/OS ----------------------------------------------- | ||
Portable to 3rd-party RTOS kernels | ||
Available port to POSIX (Linux, QNX, INTEGRITY, etc.) | ||
Available port to Windows | ||
----------------------------------------------- Testing/Profiling ----------------------------------------------- | ||
QP/Spy™ software tracing | ||
QUTest™ Unit Testing Harness | ||
MISRA compliance | MISRA-C:2004 | |
AUTOSAR-C++ compliance | AUTOSAR-C++ 14 | |
PC-Lint-Plus support package | ||
-----------------------------------------------Licensing ----------------------------------------------- | ||
Open Source Licensing (GPL) | ||
Closed Source (Commercial) Licensing |

Legacy QP™ Development Kits (QDKs)
Why "Legacy"?
Starting with QP release 5.4.0, all officially supported ports and examples are bundled into the QP downloads, as opposed to being distributed as separate QP Development Kits (QDKs). The QDKs released for earlier QP versions are called “legacy-QDKs” and are available for download from SourceForge.
The "legacy-QDKs" are not recommended for new projects. The "legacy-QDKs" do not come with commercial support from Quantum Leaps, although questions about "legacy-QDKs" are welcome on the Free QP Support Forum
How to Find QDK You Want?
All “legacy QDKs” are distributed in ZIP archives named according to the following general convention:
qdkxxx_<cpu/rtos>-<toolset>-<board>_<version>.zip
qdkxxx
denotes the QP framework type, whereasqdkc
stands for QDK for QP/C,qdkcpp
for QP/C++, andqdkn
for QP-nano<cpu>
denotes a QDK for standalone QP for the given embedded CPU type, such as AVR, M16C, R8C, etc.<rtos>
denotes a QDK for QP running on top of a given RTOS, such as eCos, VxWorks, etc.<toolset>
denotes a port to specific toolset, such a IAR, GNU, Renesas, etc.<board>
denotes that the examples are for the specified boards, such as SKP3607, YRDKRX62N, etc.<version>
denotes the compatible version of the QP framework.
All QDKs have been developed and tested with the specified <version>
of the QP framework. A QDK might work with the newer QP version as well, but might require some modifications.
QDK Installation
The installation procedure for most “legacy QDKs” is as follows:
- Download the QDK that you like and check its
<version>
number. - Download and install (unzip) the corresponding QP
<version>
. For example, if your QDK file starts withqdkcpp_
and ends with_4.5.02
, you should download and install QP/C++ version 4.5.02. - Unzip the QDK to a temporary directory.
- Copy the contents of the QDK directory to the QP installation directory. For example, if your QDK unzipped into directory
qdkcpp_avr-iar_4.5.02
, you should copy the content of this directory inside the QP/C++ installation folder (typically, insideC:/qp/qpcpp/
). Note that you will need to give your consent to overwrite the already existing directoriesexamples/
andports/
.
QDK Documentation
Every “legacy QDK” contains the “QDK Manual” in PDF in the main directory of the ZIP archive.