Embedded devices usually need to handle real-time tasks, which are usually time-bound and need to be completed within a specified time. When dealing with real-time tasks, embedded devices usually use a real-time operating system (Real-Time Operating System, RTOS), these operating systems can ensure that tasks are executed according to predetermined time constraints, and provide many useful functions, such as task scheduling, Memory management, file system, etc.
Following are some steps for an embedded device to handle real-time tasks:
- task definition
First, you need to define tasks, including task requirements, priorities, time constraints, and more. These tasks are usually sorted using a priority so that the operating system can execute the tasks according to the priority.
- task scheduling
The operating system will use a task scheduling algorithm to allocate processor time to each task. Commonly used task scheduling algorithms include preemptive scheduling and cooperative scheduling. Preemptive scheduling periodically interrupts the current task according to task priority and time constraints to execute higher priority tasks. Cooperative scheduling allows tasks to manage their own time slices and decide whether to give up processor time.
- task execution
Once a task is scheduled to execute on the processor, the operating system will provide various services, such as memory management, file system, etc., to help the task complete. During task execution, the operating system manages interrupts and exceptions to ensure the normal execution of the task.
- mission completed
When a task is complete, the OS removes it from the processor and starts executing the next task. A task that has completed a task will wait for the next dispatch to be executed again.
In short, embedded devices need to use a real-time operating system to process real-time tasks, and use task scheduling algorithms to allocate processor time to ensure that tasks are completed within a specified time. At the same time, the operating system also needs to provide various services to help task execution, and manage interrupts and exceptions to ensure the normal execution of tasks.