The development of the Internet of Things and artificial intelligence is inseparable from the embedded system, and the embedded operating system is an important part that cannot be ignored. The requirements of engineers are also improved from the simple and easy to use in the past to be simple and easy to use and safe. . There are so many embedded operating systems. Which one is suitable for the application of engineers at the time of design? In particular, several industry leaders were invited to share their views on this issue.

Industry voice

Which operating system you choose depends on your application

Silicon Labs Software Architect, founder of Micrium Jean J. Labrosse

In fact, there is currently no operating system on the market that can accommodate all types of embedded applications, although some are very close. Embedded systems range from simple 8-bit MCUs to highly complex 64-bit multi-core CPUs. In the kernel of most embedded operating systems, there is a real-time operating system (RTOS), which is software that manages CPU timing and other resources. In addition, some operating systems provide additional modules to handle communication protocols, data storage, user interfaces, and more. The figure below shows the CPU support of some popular embedded RTOS. So far, the RTOS that is very popular in China is μC/OS-II (OS2) and μC/OS-III (OS3) from Micrium (now acquired by Silicon Labs). These RTOSs are free to use in non-commercial applications, but require authorization for commercial use. OS2 and OS3 can cover almost all CPUs on the market, which is a very desirable feature because it helps protect your investment in software, and your application can easily migrate from one processor architecture to another. On a processor architecture.

If your application requires RTOS functionality for multitasking and resource sharing, FreeRTOS, the popular open source RTOS, may be another good choice. Similarly, if you use the Cortex-M processor, ARM will offer free RTX. However, if you are designing a commercial product, it is highly recommended that you use a commercial RTOS instead of an open source solution.

Now, the Internet of Things is a very hot topic, depending on what you are talking about. If you are designing a leaf node, chances are that you will need some form of wireless connection. There are many protocols to choose from, but most embedded operating system providers do not directly provide wireless protocol stacks, and you may have to use semiconductor manufacturers to provide these solutions. It turns out that only a handful of vendors can offer a complete combination of wireless chips and software.

However, Silicon Labs offers IoT solutions and wireless connectivity, providing a complete solution for the following protocols: Bluetooth, Bluetooth Mesh, ZigBee, Thread, WiFi, proprietary protocols (ie custom protocols). In fact, these protocols are pre-integrated in Silicon Labs' EFR32 multi-protocol Wireless Gecko SoC family. These chips not only include wireless protocols, but also integrate Micrium's embedded operating system. This makes it relatively easy to increase the functionality of the product without worrying about the complexity of the wireless technology.

More and more applications need to use multiple wireless protocols at the same time, and in order to reduce costs, the same chip needs to support these protocols at the same time. For example, you might want your customers to use Bluetooth to configure a ZigBee and Thread device. Once the configuration is successful, it is feasible to continue running both protocol stacks at the same time. Bluetooth can still serve as a beacon device to provide passers-by with additional information about the value-added features that your device can provide. This can be very useful for electronic shelf labels, restaurants, gas stations or other similar applications.

Another aspect is cloud connectivity. Your embedded device will most likely be part of a larger network of connected devices, connecting to Amazon Web Services, Microsoft Azure Cloud, IBM Bluemix or other platforms will no longer be an issue, and embedded operating system vendors are growing Cloud connectors and their protocol stacks are provided to support these services.

Of course, IoT solution providers must provide some features to ensure that these devices are secure, reliable, and field scalable. Designers need to consider security factors early in the development cycle, not after the fact. Customers are increasingly asking us to provide complete, end-to-end solutions. This is now possible, as part of Silicon Labs, we can not only provide an embedded operating system with additional modules and cloud connectivity, but also provide a complete wireless MCU and protocol stack, allowing engineers to concentrate more In terms of the uniqueness of product design.

For the development of IoT devices, how should the operating system be chosen?

He Xiaoqing, Secretary General of the Embedded Systems Association

Commercial embedded operating systems originated in the late 1970s and early 1980s and have undergone four stages of development: RTOS kernel, RTOS, general-purpose operating system embedded (such as embedded Linux and embedded Windows) and Android-represented Application-oriented embedded operating system. The development history of the embedded operating system is described in more detail in my book "Embedded Operating System".

At present, the new generation of embedded operating system is an operating system represented by IoT applications. When selecting engineers, engineers should consider the following factors: First, real-time requirements, first of all, depends on whether the projects are real-time. Requirements, and real-time is divided into hard real-time and soft real-time, μC/OS-III and VxWorks can provide hard real-time, embedded Linux can provide soft real-time; second, security considerations, according to the level of security requirements of the project Choice, if it is used for general consumer electronics, the safety requirements are lower. If it is used for high-speed rail and aircraft, the safety requirements are very high, so it is necessary to select the system that meets the requirements of safety regulations according to the needs; The open source operating system has an active community, rich ecological environment, and the software, hardware and standards are very complete. Therefore, when doing the Internet of Things design, developers like to choose an open source operating system. Fourth, the consideration of tools depends on whether the operating system has A large number of third-party tools (including development tools, performance analysis tools and test tools) support, the more tool support, the better Use, the shorter the development cycle; Fifth, cost considerations, the cost of purchasing commercial software, if you use the open source system, although the source code is free, but still need to invest a considerable amount of money when you actually use it, so open source may not be really free, when you choose Need to consider in advance.

Personally feel that if you do IoT device development, you can choose two ways: one is based on open source Linux and FreeRTOS, because open source, they have IoT protocol stack, can be connected to the cloud, there will be some IoT chip company developed Connection protocols and drivers, such as WiFi, Bluetooth, ZigBee, etc., through integration, can enable the open source operating system to support IoT development. From the current market, this solution is the most used; the other is to choose the Internet of Things operating system, which is a The station-based program is highly targeted, but the disadvantage is that the general-purpose type is weak. If the enterprise does not do the Internet of Things project in the future, the system cutting will be more troublesome. These IoT operating systems are more suitable for the IoT startup project, and the products can be listed as soon as possible. .

However, there is a need for developers to note that in the IoT era, more and more devices use MCUs. Because of the architecture, it can only choose to use RTOS, and it is not suitable for large operating systems such as Linux. Therefore, developers should be prepared to get familiar with the RTOS and master an RTOS technology as soon as possible, and make a good knowledge reserve, which will help future development. The cores of some IoT operating systems are also based on RTOS technology, such as Huawei Lite OS and Qingke Mico OS. For future IoT systems, RTOS will become a basic software platform.

When embedded engineers and makers choose operating systems for IoT device development, there will be some differences. Maker will like open source hardware such as Raspberry Pi and Arduino, and many of them are transferred from Internet development. Using high-level programming languages ​​(Python and Javascrpit), they don't know much about the underlying embedded layer, and they are better at connecting with the cloud, so there is a difference in the choice of embedded operating system.

Consider embedded operating systems in terms of product, ecology and technical services

Co-founder and Vice President of Shanghai Ruiside Electronic Technology Co., Ltd.

When engineers choose the embedded operating system, if they are learning for the purpose, mainly to see if the system is easy to get started and whether the data is rich, generally consider the mainstream open source embedded operating system; if it is for product development, then it can be from the product, Ecological and technical services consider the embedded operating system in three aspects.

First, the product side. First, maturity and stability are the basic requirements. The system that has been verified in the industry for at least 5 years and is widely used by various industries will be more secure. Second, choose a system that is easy to use, easy to develop, and focused on the developer experience. Clear architecture, succinct and complete API, extensive support for compiler tools, and easy debugging are essential for engineers' application development. Thirdly, the rise of the Internet of Things era and artificial intelligence has raised many new demands. Hardware fragmentation and product diversification are one of the main features. Product development will use different architectures, branded chip platforms, and high-end and low-end products span a very large span. Therefore, it is very important to choose a cross-chip architecture and a highly tailorable system. On the one hand , it can avoid a lot of extra work and instability caused by replacing the chip platform. On the other hand, an operating system is suitable for different grades of products. And it can achieve small resource occupation and light structure, which can greatly increase the reusability of software and improve development efficiency.

In addition, IoT applications put forward many requirements for connection, security, low power consumption, etc. Therefore, selecting a feature-rich system can greatly help product development, such as connection, security, low power consumption, and reliable storage. Even features such as lightweight GUI graphics interaction. Network connection is the core of IoT terminal development. If the operating system can support rich network protocols (such as MQTT, LWM2M, Web Socket, etc.), or even complete the docking of the mainstream IoT cloud platform, the development cycle of the IoT terminal will be greatly reduced. And risk.

Second, the ecological aspect. When engineers choose an embedded operating system, they need to pay attention to its ecosystem and developer community. Developers can acquire and share technical documents, software modules, third-party tools and other materials from a good ecosystem, and can also learn in the developer community. And exchange development experience, and even get ideas to solve problems, thus contributing to product development.

Third, technical services. Engineers generally face pressures on time to market and R&D costs during product development, especially in the development of IoT solutions. The system is complex and difficult. If you choose an embedded operating system that provides good technical services (including technical support, technical training, etc.) ), then it is very helpful to improve team research and development capabilities, reduce research and development costs, and speed up product launch.

In addition to the above three aspects, it is recommended that everyone pay attention to two major trends. First, paying attention to the open source open embedded operating system, the traditional closed embedded operating system is going down, the open source open embedded operating system is being used more and more widely, and the ecology is gradually improving. Second, focus on domestic independent embedded and IoT operating systems, because IoT is manufactured in China, IoT chips are in China, and IoT market is in China, so the IoT operating system must also be in China. For example, RT-Thread is a very high-quality, self-developed domestic operating system that is very friendly to developers. After 11 years of testing, it has high maturity, convenient development, good software ecological support, and is very compatible with the terminal software of the Internet of Things era. System requirements.

Editorial perspective

The variety of embedded system applications determines the variety of embedded operating systems. When designing, if you are designing a commercial product, try to choose a mature commercial product with good ecosystem. If it is a maker, you can give priority to emerging ones. Open source operating system. In particular, IoT applications are more diverse, and choosing the right operating system is more important!