QuantumLeaps/qpn
QP-nano real-time embedded framework/RTOS for embedded systems based on active objects (actors) and hierarchical state machines
What's New?
NOTE: QP-nano has been discontinued from active development
and support and is not recommended for new designs. This QP-nano
repository is preserved for the existing user base.
LICENSING: If you are interested in commercial licensing QP-nano,
please refer to section QP-nano Licensing.
QM Tool Compatibility: The last QM version that supports code
generation for QP-nano is
QM 5.2.3 released on 2022-11-18.
Newer QM versions no longer support QP-nano.
Documentation
The offline HTML documentation for this particular version of QP-nano
is located in the folder html/. To view the offline documentation, open
the file html/index.html in your web browser.
The online HTML documention for the latest version of QP-nano is located
at: https://www.state-machine.com/qpn/
About QP-nano
QP-nano (Quantum Platform Nano) is an ultra-lightweight, open source
Real-Time Embedded Framework (RTEF) for building modern embedded
software as systems of asynchronous, event-driven active objects
(actors). The QP-nano framework is a member of a larger QP family
consisting of QP/C, QP/C++, and QP-nano frameworks, which are all
strictly quality controlled, thoroughly documented, and commercially
licensable.
Safer Model of Concurrency
The QP framework family is based on the Active Object (actor)
design pattern, which inherently supports and automatically enforces the
following best practices of concurrent programming:
-
Keep data isolated and bound to active objects' threads. Threads should
hide (encapsulate) their private data and other resources, and not
share them with the rest of the system. -
Communicate among active object threads asynchronously via event
objects. Using asynchronous events keeps the threads running truly
independently, without blocking on each other. -
Active object threads should spend their lifetime responding to incoming
events, so their mainline should consist of an event-loop that handles
events one at a time (to completion), thus avoiding any concurrency hazards
within an active object thread itself.
This architecture is generally safer, more responsive and easier to
understand and maintain than the shared-state concurrency of a conventional
RTOS. It also provides higher level of abstraction and the correct
abstractions to effectively apply modeling and code generation to
deeply embedded real-time systems.
Hierarchical State Machines
The behavior of active objects is specified in QP-nano by means of
Hierarchical State Machines (UML statecharts). The framework
supports manual coding of UML state machines in C as well as automatic
code generation by means of the free QM modeling tool.
Built-in Real-Time Kernels
The QP-nano framework can run on bare-metal single-chip microcontrollers,
completely replacing a traditional "superloop" or an RTOS. The framework
contains a selection of built-in real-time kernels, such as the
cooperative QV-nano kernel and the preemptive non-blocking QK-nano kernel.
Native QP-nano ports and ready-to-use examples are provided for such CPUs
MSP430, AVRmega, and ARM Cortex-M (M0/M0+/M3/M4).
Maturity
With 60,000 downloads a year, the QP family is the most popular such
solution on the embedded software market. It provides a modern, reusable
architecture for embedded applications, which combines the active-object
model of concurrency with hierarchical state machines.
Getting Started with QP-nano
The QP-nano Reference Manual provides
instructions on how to download, install, and get started with QP-nano quickly.
The AppNote: "Getting Started with QP-nano" contains also a tutorial,
in which you build a simple "Blinky" application.
QP-nano Licensing
QP-nano is licensed under the
dual licensing model,
in which both the open source software distribution mechanism and
traditional closed source software distribution models are combined.
NOTE: Even though QP-nano has been discontinued, Quantum Leaps will
continue to provide commercial licenses for QP-nano to customers still
interested in deploying QP-nano in closed-source products. These commercial
licenses will NOT provide technical support and will be discounted accordingly.
QP-nano Documentation
The QP-nano Manual is located online at: https://www.state-machine.com/qpn
3rd-Party QP-nano Ports/Adaptations
QPN-PIC16 is an adaptation of the
QP-nano framework to the
Microchip PIC16
architecture as compiled by the MPALB-X IDE using the XC8 compiler (C90/C99).
It allows QP-nano models developed using the QM modeling tool to be integrated
with the QV-nano kernel to build
Active Object applications.
The very limited resources of the PIC16 family of MCUs, primarily the hardware
stack, required a special version of QP-nano and a QM-Modeler editing
post-processor, QM2HSM.exe, to effect.