How to select components for products?

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How to select components for products? [Copy link]

I. Several principles for selecting components for products a. Universality principle: The selected components should be widely used and verified, and try to use less unpopular and niche chips to reduce development risks. b. Cost-effectiveness principle: When the functions, performance and usage rates are similar, try to choose components with better prices to reduce costs. c. Convenient procurement principle: Try to choose components that are easy to buy and have a short supply cycle. d. Sustainable development principle: Try to choose components that will not be discontinued in the foreseeable time. e. Substitutability principle: Try to choose components with more pin-to-pin compatible chip brands. f. Upward compatibility principle: Try to choose components that have been used in previous old products. g. Resource conservation principle: Try to use all the functions and pins of the components. The chip selection process is a compromise of considerations in various dimensions. II. Pay attention to chip properties throughout the entire process 1. When selecting, you need to consider the trial production situation and the situation during mass production. The price, supply cycle, and sample application for small-volume purchases; at the same time, we need to pay attention to the price and supply cycle after large-volume purchases. It is possible that after the batch becomes larger, the supply price has no advantage, or after the batch becomes larger, the production capacity is insufficient. In addition, according to your actual purchasing situation, find suppliers of corresponding quantities. For example, the original factory often does not supply directly, but needs to go through agents. Some agents have requirements for the supply volume. At the same time, since there are not many scenarios in which the chip is used in the entire industry, the price on Taobao is very expensive and cannot be accepted at all. At the same time, a friend who sells chips said that it is difficult to buy because of the large-scale use of drone manufacturers, which has led to some people speculating on the price of this chip. 2. Pay attention to the matching of the life cycle of the device itself and the life cycle of the product. For communication equipment, it is generally required that the devices we choose have a life cycle of more than 5 years and have a complete subsequent product development roadmap. For example, a new hardware platform was used at the time, and when the product was planned, it was used to replace a mature platform with a shipment volume of millions of single boards. Due to the long switching cycle, new products were gradually put into production 1 to 2 years after the development was completed. One of the DSP circuit boards has SDRAM as the peripheral storage. When the product was about to be mass-produced, several major memory chip manufacturers such as Micron announced that they would stop production. As a result, as soon as the product was put into mass production, they stockpiled a large number of chips and looked for small factories in Taiwan to replace the devices. Therefore, when selecting devices, it fully reflects the saying "If you don't think about the future, you will have immediate worries." 3. In addition to considering the function and laboratory environment, you also need to consider the scenario of the entire life cycle. Three, specific selection, processor selection To choose a good processor, there are many factors to consider, not just the pure hardware interface, but also the relevant operating system, supporting development tools, emulators, and the engineer's microprocessor experience and software support. Considerations for the selection of embedded microprocessors: In product development, the microprocessor as the core chip has its own functions, performance, and reliability, which are highly expected, because the richer its resources and the more powerful its built-in functions, the shorter the product development cycle and the higher the project success rate. However, no microprocessor can be perfect and meet the needs of every user, so this involves the issue of selection. 1. Application field Once the function and performance of a product are customized, its application field is also determined. The determination of the application field will narrow the scope of selection. For example, the working conditions of products in the industrial control field are usually harsh, so the working temperature of the chip is usually wide, so industrial-grade chips must be selected, and civilian-grade chips are excluded. At present, the more common application field classifications include aerospace, communications, computers, industrial control, medical systems, consumer electronics, automotive electronics, etc. 2. Built-in resources You often see or hear such questions: What is the main frequency? Is there a built-in Ethernet MAC? How many I/O ports are there? What interfaces are built-in? Does it support online simulation? Does it support OS, and which OS can it support? Is there an external storage interface? ... All of the above involve chip resource issues. What kind of resources the microprocessor brings is an important consideration in the selection. The closer the chip's built-in resources are to the product requirements, the simpler the product development will be. 3. Scalable resources The hardware platform must support OS, RAM and ROM, and the resource requirements are relatively high. Chips generally have built-in RAM and ROM, but their capacity is generally very small. A built-in 512KB is considered large, but the OS is generally above the megabyte level. This requires the chip to have expandable memory. 4. Power consumption "Power consumption" alone is a relatively abstract term. Low-power products are energy-saving and cost-saving, and can even reduce environmental pollution and increase reliability. It has so many advantages, so low power consumption has become an important indicator when selecting chips. 5. Package Common microprocessor chip packages are mainly QFP and BGA. BGA type package welding is more troublesome, and generally small companies will not weld, but the chip size of BGA package is much smaller. If the product does not have strict requirements on the chip size, it is best to choose QFP package when selecting. 6. Chip sustainability and technology inheritance At present, the speed of product replacement is very fast, so the chip upgradeability should be considered when selecting. If it is a chip of the same core series from the same manufacturer, its technology inheritance is better. You should consider well-known semiconductor companies, then check their related products, and then make a judgment. 7. Price and supply guarantee The price and supply of chips are also factors that must be considered. Many chips are currently in the sampling stage, and their prices and supply will be unstable, so try to choose chips that are in mass production when selecting. 8. Emulator The emulator is a tool used for debugging hardware and underlying software. If it is not available in the early stages of development, it will be difficult to proceed. Choosing a suitable emulator will bring many conveniences to development. For those who already have an emulator, consider whether it supports the selected chip during the selection process. 9. OS and development tools As a product development, when selecting a chip, you must consider its support for software, such as what kind of OS it supports. For those who already have an OS, consider whether the selected chip supports the OS during the selection process, or vice versa, whether the OS supports the chip. 10. Technical support The current trend is to buy services, that is, to buy technical support. The technical support capabilities of a good company are relatively guaranteed, so it is best to choose a well-known semiconductor company when selecting a chip. In addition, the maturity of the chip depends on the user's usage scale and usage. Choosing a chip that is widely used on the market will have more shared resources, which will bring many conveniences to development. Here is another point. Some manufacturers are good at simple MCU applications, while others are good at industrial control or more complex MCU and CPU applications, so each has its own advantages and disadvantages. CPUs are divided into four mainstream systems according to the instruction set architecture system: PowerPC, X86, MIPS, and ARM. X86 uses the CISC instruction set, while POWERPC, MIPS, and ARM use the RISC instruction set. RISC CPUs are mostly used in embedded systems. In the industry, PowerPC is mainly used in the network communication market, while X86 focuses on the PC and server markets. The target market for MIPS is embedded applications such as network and communication, as well as digital consumer applications. The target market for ARM is portable and handheld computing devices, multimedia, and digital consumer products. Among high-end processors, the x86 architecture dual-core processor and the MIPS architecture multi-core processor have different business positioning. The MIPS processor is easy to implement multi-core and multi-threaded computing, and performs well in data plane message forwarding, but the core structure of a single processor is simple, and it is obviously inferior to x86 and PowerPC in complex computing and message depth processing. Multi-core MIPS or NP is used for data processing, and PowerPC or embedded x86 is used for control applications. The industry ecosystem for ARM devices is relatively good, and there are many chip suppliers that can provide ARM devices. The selection must be based on multiple comparative analysis and competitive evaluation.