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Code generation tool written in Python for C++ hierarchical state machines. Code generation tool for C++ hierarchical state machines It’s worth noting that you’re already coding state machines, except that they’re hidden in the code. It’s also applicable for single-threaded and synchronous applications, but it might not be the most efficient option. HSMCPP is a C++ library providing implementation of state machine design pattern (also known as statecharts).
Use your existing favourite modelling tool and generate code from your created model with an easy-to-use command line tool. SinelaboreRT generates production quality source code from state diagrams created with many different UML tools. Nowadays several affordable UML modeling tools are available supporting the efficient design of state machines in a graphical way.
However, when the underlying QP Framework is licensed commercially, the Licensee receives a QP License Certificate file, which can be registered with QM by means of the Code Generation License Dialog Box. It is free to download and free to use for any purpose, including commercial projects, but is not open source. Instead QM uses higher-level primitives of initial-transition and choice-segment, respectively. In this respect, the tool is innovative and might work differently from other graphical state machine tools on the market. All actions executed by state machines are entered into the model directly in C or C++. That said, if it simplifies things and makes the code neater, it can’t hurt, right?
In low power system designs a key design goal is to keep the processor as long as possible in low power mode and only wake it up if something needs to be processed. In this design an endless loop — typically the main function — calls one or more state machines after each other. Others more relevant for developers having not so tight resource constraints. There are different ways how to integrate state machines in a specific system design.
It suggests to generate source code based on a spread sheet table. In the past different μC manufacturers have published application notes about the benefit of using state machines for the design of embedded software. There is a .puml file for viewing in PlantUml and a .txt file that is used for FloHsm. A second file sm.puml only contains the following lines and is used to render the diagram in PlantUml Here are some examples of valid FloHsm transitions. This notation enables you to attach internal transitions and/or regular state transitions to a single choice point— something that comes up very often in practice and was never addressed well in the UML standard.
In this design each state machine usually runs in the context of an own task. Prefixes for the header and the C file can be specified separately. The example below shows an interrupt service routine with the compiler specific extensions as required by mspgcc
QWeave weaves together models, events, and code — from design to embedded execution. Sinelabore enables developers to effectively combine event-driven architecture, hierarchical state machines, model-based design and automatic code generation. QWeave is designed as a modern, open replacement for proprietary state-machine modeling tools,with the goals of language neutrality, extensibility, and reproducible code generation. The primary design objective in QM was to respect your design decisions as much as possible and leave you in control, not only in the physical design of the generated code, but down to the exact details of arranging your states and routing your transitions. Open the .puml file in plantuml and have a look at the test for using the generated code in C++
If no UML tool is already in place take a look at the built in state machine diagram editor. Read the sections related to your UML tool and the language backend you want to use. To get an impression of the powerful capabilities of the tool download the demo version.
An example is the application note SLAA402 from Texas Instruments (TI). The StateSmith-examples repo has a growing list of examples showcasing different application uses. I love generating fully working code from the documentation. Documentation trust issues arise and as designs get larger, the effort to ensure the diagram is accurate starts to become quite punishing. Urgent client requests come in and you update the code, but do you and your team always remember to update the drawing? They are incredibly helpful for certain applications.
Apart from selecting the superclass (base class) in the Class Property Sheet, the constructor of the application-level state machine must call the appropriate base class constructor. Generate the state machine files and run the tests. You need to write them yourself in your state machine class. The solution is to write the state machine description in a text file sm.txt. For now, FloHsm does not parse the @startuml and @enduml keywords that are required by PlantUml. Transition triggerd by event E1, but only if boolean guard expression G1 evaluates to true
It is still one of the most common ways of designing small embedded systems. The code generator does not dictate how you design your system. The SinelaboreRT code generator supports you in the creation of the state based control logic. Some design principles are more applicable for developers of deeply embedded systems. Sinelabore avoids the error-prone and tedious hand-coding by generating high-quality source code directly from the state machine design document. Configuration is stored in a plain text file which allows customisation of generated code to exactly your needs.
Based on the current state, conditions derived from boolean signals are used to trigger state transitions. Alternatively transitions are triggered by boolean conditions. Only if an event is present a transition is taken (e.g. evDoorClosed, evButtonPressed). chicken road game money This design can be realized with every real-time operating system.
Anything I come up with seems to be very complicated at the least (if not even an external code processor to scan the C++ code and generate some kind of annotation a la Qt’s MOC). The idea is that, upon calling this command, the HSM must transition to the innermost default state (it is only possible for the HSM to actually be in a leaf, i.e. not further inherited, state, which then implies being also in all the states further up the hierarchy from it as well). And when I noticed how messy my old GUI code was and then found this pattern, I thought of giving it a shot. I’ve been toying with this for the past couple of days but am not sure what the best way to design it is – particularly in regard to the top-level interface. In this case the state machine runs without receiving a dedicated event.
It does not use an internet connection and will never collect nor submit data, code, statistics, analytics, or any other information from your system over any channel. Developers spend a lot of their time coding state machines by hand. Avoid bugs that can waste countless hours of developer and end-user time before they are found. Typical examples are control-logic-oriented applications such as metering, monitoring, workflows and control applications. Many systems are likely candidates for implementation as finite state machines. SinelaboreRT focus is on generation of readable and maintainable code from flat or hierarchical UML state machine diagrams.
The basic idea is to design your state machine graphically in PlantUml and then use the PlantUml input file also as an input file for FloHsm.py to generate C++ code. Nothing is more frustrating than a tool that suddenly changes the arrangement of your diagrams, after you spent hours arranging the states and routing the transitions. Also, QM provides mechanisms to quickly go back and forth between the model and the generated code so that any changes can be conveniently applied directly to the model rather than the code. This unique approach gives you the ultimate flexibility and control over the source code structure and mitigates the needs to make manual changes to the generated code in order to combine it with hand-written code or existing 3rd-party code. This is because such a framework provides well-defined “framework extension points” designed for customizing the framework into applications, which in turn provide well-defined rules for generating code.
Events might be stored in the event queue from various sources. In case one or more new events are available the RTOS wakes up the task. The tasks wait for new events to be processed from the state machine. For code generation some considerations are necessary. Using state machines in an interrupt handler can be useful in any system design. Sometimes state dependent interrupt handling is required.
For more information on how to use state-machines in low-power embedded systems see here and here. The following temperature transmitter using a MSP430F1232 header board with just 256 bytes of RAM and 8K of program memory is based on this design principle. The timer service for the small runtime framework is handled in the timer interrupt. The main difference is that the main loop runs not all time but only in case an event has happened. But the state machine receives its events from an event queue. The benefits of this design are no need for a runtime framework and only little RAM requirements.
