How to Send a Sequence of Commands and Wait for Responses Using a State Machine?

Sending a Sequence of Commands and Waiting for Response

This code sample demonstrates how to send a sequence of commands and wait for the desired response using a state machine approach. The original query involves updating firmware and settings on a device connected via a serial port, where each step requires sending a command and waiting for a specific keyword in the response to indicate completion.

StatefulObject Class

A helpful class, StatefulObject, manages a state machine and provides signals for monitoring progress.

Simplified State Transition Generator

The addTransition function is used to guard state transitions based on specified conditions. This makes it easier to manage transitions and improves readability of the code.

Action Generators

Various action generators, such as send, expect, and delay, facilitate the creation of state transitions and actions associated with them.

Device and Programmer State Machines

Two StatefulObject instances represent the device and the programmer, each with defined states and transitions. The device emulates expected behavior by responding to specific commands and providing appropriate feedback. The programmer transitions through states based on received responses.

Visual Representation

A graphical user interface (GUI) provides a visual representation of the communication, displaying sent and received data and the current state of the device and programmer.

Key Points

• State machines provide a structured and asynchronous way to handle sequential commands and responses.
• Custom state transition generators allow for cleaner and more maintainable code.
• The waitForKeyword function effectively scans lines until the desired keyword is found or a timeout occurs.
• The QIODevice abstraction used for communication can represent either a real serial port or an emulated device like AppPipe.
• A text browser in the GUI visualizes the flow of data for debugging and monitoring purposes.

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