Shulou(Shulou.com)06/01 Report--

In this issue, Xiaobian will bring you about how to understand the embedded real-time operating system RT-Thread. The article is rich in content and analyzed and described from a professional perspective. After reading this article, I hope you can gain something.

A brief introduction to RT-Thread series operating systems.

1.RT-Thread Overview

RT-Thread, the full name is Real Time-Thread, as its name implies, it is an embedded real-time multithreaded operating system, one of the basic attributes is to support multitasking, allowing multiple tasks to run simultaneously does not mean that the processor really executes multiple tasks at the same time. In fact, a processor core can only run one task at a time, because the execution time of each task is very short, and the task scheduler switches between tasks very quickly (the scheduler determines the task to be executed at the moment according to the priority), giving people the illusion that multiple tasks are running at the same time. In RT-Thread systems, tasks are implemented by threads, and the thread scheduler in RT-Thread is also the task scheduler mentioned above.

RT-Thread is mainly written in C language, easy to understand and easy to transplant. It applies object-oriented design method to real-time system design, which makes code style elegant, architecture clear, system modularity and tailoring very good. For resource-constrained microcontroller (MCU) systems, NANO versions requiring only 3KB Flash and 1.2 KB RAM can be tailored through easy-to-use tools (NANO is a minimalist kernel officially released by RT-Thread in July 2017); For resource-rich IoT devices, RT-Thread can also use online software package management tools, cooperate with system configuration tools to achieve intuitive and rapid modular cutting, seamlessly import rich software function packages, and realize complex functions such as Android graphical interface, touch sliding effect, intelligent voice interaction effect, etc.

Compared with Linux operating system, RT-Thread is small in size, low in cost, low in power consumption and fast in startup. In addition, RT-Thread also has the characteristics of high real-time performance and small resource occupation, which is very suitable for various resource-limited occasions (such as cost and power consumption restrictions). Although 32-bit MCUs are its primary operating platform, in fact many application processors with MMU, ARM9, ARM11 and even Cortex-A series CPUs are suitable for RT-Thread in certain applications.

1.1 license agreement

RT-Thread is completely open source, with versions 3.1.0 and earlier licensed under the GPL V2 + open source license. Versions from 3.1.0 onwards follow the Apache License 2.0 open source license, which is free to use in commercial products and does not require public private code.

1.2 Structure of RT-Thread

In recent years, the concept of Internet Of Things (IoT) has been widely popularized, the Internet of Things market has developed rapidly, and the networking of embedded devices has become a general trend. The networking of terminals has greatly increased the complexity of software, and the traditional RTOS kernel has become increasingly difficult to meet the needs of the market. In this case, the concept of Internet of Things Operating System (IoT OS) has emerged. IoT operating system refers to a software platform based on the operating system kernel (which can be RTOS, Linux, etc.), including relatively complete middleware components such as file system and graphics library, with low power consumption, security, communication protocol support and cloud connectivity capabilities. RT-Thread is an IoT OS.

One of the main differences between RT-Thread and many other RTOS such as FreeRTOS and uC/OS is that it is not only a real-time kernel, but also has rich middle-layer components.

2.RT-Thread Classification 2.1 RT-Thread Full Version

It contains many components and can be cut freely. It is suitable for scenarios that require the use of rich functions of RT-Thread, such as various peripherals, IoT components, software packages, etc.

2.2 RT-Thread Nano Edition

RT-Thread Nano is a minimalist hard real-time kernel, developed by C language, object-oriented programming thinking, with good code style, is a scalable, preemptive real-time multitasking RTOS. Its memory resources are very small, and its functions include relatively complete real-time operating system features such as task processing, software timer, semaphore, mailbox and real-time scheduling. Suitable for home appliances, consumer electronics, medical equipment, industrial control and other fields of extensive use of 32-bit ARM entry-level MCU occasions.

The following figure is a software block diagram of RT-Thread Nano, including supported CPU architecture and kernel source code, as well as removable FinSH components.

Support architecture: ARM: Cortex M0/ M3/ M4/ M7, RISC-V and others.

Function: thread management, synchronization and communication between threads, clock management, interrupt management, memory management.

2.3 RT-Thread Smart

RT-Thread Smart (referred to as rt-smart) is a new branch derived from RT-Thread operating system, which is oriented to chips with MMU and high-end applications, such as ARM Cortex-A series chips, MIPS chips, RISC-V chips with MMU, etc. rt-smart enables independent, complete processes on top of RT-Thread operating systems while executing in hybrid microkernel mode.

The above is how to understand the embedded real-time operating system RT-Thread shared by Xiaobian. If there is a similar doubt, please refer to the above analysis for understanding. If you want to know more about it, please pay attention to the industry information channel.

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