Linux Advanced embedded system design and development process

Article title: design and development of advanced embedded systems for Linux. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.

Embedded System Design process

According to the conventional engineering design method, the design of the embedded system can be divided into three stages: analysis, design and implementation. The analysis stage is to determine the problems to be solved and the objectives to be completed, also known as the demand stage. the design stage mainly addresses how to fulfill user requirements under given constraints; the implementation phase focuses on how to coordinate the entire software and hardware system based on the selected hardware and software. After the analysis stage, developers usually face a difficult problem, namely the selection of the hardware platform and software platform, because its quality directly affects the completion of current tasks.

Generally, hardware and software options include processors, hardware components, operating systems, programming languages, software development tools, hardware debugging tools, and software components. In the above selection, the processor is often the most important, and the operating system and programming language are also critical. The selection of processors often limits the selection of operating systems, and the selection of operating systems also limits the selection of development tools.

Hardware platform selection

Processor selection

The core component of the embedded system is various types of embedded processors. According to incomplete statistics, the total number of embedded processors worldwide has exceeded more than 1000, with more than 30 popular systems. However, unlike the global PC market. No microprocessor or microprocessor company can lead an embedded system. there are more than 100 types of embedded microprocessor for 32-bit CPUs. The design of embedded systems varies greatly, so the selection is diversified. ARM is an influential microprocessor architecture in embedded systems in recent years. its design is very suitable for small embedded devices.

When selecting a processor, designers should consider the following main factors:

① Processing performance. The performance of a processor depends on multiple factors, such as clock frequency, internal register size, and whether the command processes all the registers in a peering manner. For many embedded systems that require processors, the goal is not to select the fastest processor, but to select the processor and I/O subsystem that can complete the job. For high-performance application designs, we recommend that you consider some new processors at a relatively low price, such as IBM and Motorola Power PC.

② Technical indicators. At present, many embedded processors integrate the functions of peripheral devices, reducing the number of chips and the development cost of the entire system. The first consideration for developers is whether the hardware required by the system can be connected to the processor without the need for too much Glue Logic (GL, Glue Logic. The second is to consider some supporting chips of the processor, such as DMA controller, memory manager, interrupt controller, serial device, clock, and so on.

③ Power consumption. The largest and fastest growing market for embedded microprocessors is handheld devices, electronic notebooks, PDAs, mobile phones, GPS navigators, smart appliances, and other consumer electronic products. Among these products, the microprocessor is typically characterized by high performance and low power consumption. Many CPU manufacturers have already entered this field. Today, users can buy an embedded microprocessor, which is as fast as the Pentium in a notebook, and it is only powered by a common battery, and the price is very low. If it is used for industrial control, the consideration for this aspect is weak.

④ Software support tools. Only one processor does not support good software development tools. Therefore, selecting appropriate software development tools will play a very good role in system implementation.

⑤ Whether the debugging tool is built in. If the processor has built-in debugging tools, the debugging cycle can be greatly reduced to reduce the debugging difficulty.

⑥ Whether the supplier provides the evaluation board. Many processor vendors can provide evaluation boards to verify that theories are correct and decisions are appropriate.

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