The adequacy and necessity of circuit design
The circuit design includes two specific work categories: the schematic diagram and the circuit board diagram, and the 2 categories are highly unified and distinct. It can be done by a professional engineer and can be divided into 2 professional engineers. The problem of the schematic diagram is to grasp the requirement analysis and verify the design scheme. The input is the task book (or the derived hardware design requirements) and the hardware design scheme. Its output is a schematic diagram that can guide the work of a circuit board. This work, as its name implies, focuses on the content of the principle. The problem of the PCB engineers is closer to the reality, and can see the model. It is closely related to device characteristics, layout, specification of circuit board and so on.
Most of the structural designs are closely related to the built-in circuit boards, such as the dimensions, mounting and fixing, external interfaces, device placement, circuit layout, external radiation, external radiation resistance, etc. Many factors are not understood by structural design professionals. Most of all, in many cases, users are not professional, so our company is forced to have some hardware research and development capabilities. Look at the needs of the user to determine how much the user can do in hardware research and development.
In the process of the actual product design of this project, the author's personal experience is summed up into two aspects of sufficiency and necessity. These 2 aspects are closely related to the actual project. The main purpose is to ensure that the design meets the requirements first, and the second is to ensure the optimal scheme.
The main meaning of the adequacy is to fully guarantee the design requirements and meet the requirements of various indicators and performance. The necessity is to consider whether the scheme is optimal, involving cost, craft, maintenance and so on. The two organic combination, the product designed to be qualified.
In addition to meeting customer needs, the adequacy needs to be met with some potential needs. In particular, it is a reasonable margin, and the possibility of future escalation is considered. It is also important to avoid the future redesign in order to increase a IO port. The reasonable margin is hard to assess. For example, the input bandwidth requirement is 5M. Is it reasonable to design 8M or is 10M reasonable? This is considered by the director and is generally written in the plan. If a chip, 8M and 20M basically a price, that of course, with the 20M, the margin is big.
The necessity is to examine the design plan in turn, whether it is necessary to design it, whether there is a cost to pay for a demand, etc., and also directly examine whether the overall hardware scheme is optimized, and whether there is better solution. If a chip is out of production, it is necessary to replace another chip with a better vision. In a word, consideration should be taken and the target is far away.
Then talk about the cost of the problem, say more, and the cost is the core content. The more large and large products, the more the cost is considered. The author took over a job in about 04 years, and gave me 20 thousand at that time. At that time, I was very happy. The activity is to optimize a pic program from 4.3K to less than 4K, no source code, and only burn code. I didn't know why I did that. It took a week, a period of optimization, and finally optimized to 3.7K. The function is completely maintained. Pure statement optimization is possible.