MCU programmer's interview experience and suggestions

Single chip microcomputer STM32L151CCU6

1206RGB (single)

0201 package SLP0603 ESD electrostatic diode 5V one-way ESD

Mobile phone crystal 3.2*2.5mm 3225 26M (26.000MHZ) 7.5PF 10PPM 20PPM 30PPM

What skills do you need to master?

● Need to understand and use several common microcontrollers.

● Need to be familiar with common hardware interfaces such as UART, SPI, I2C

● Need to know some sensor related knowledge, such as sound, light, magnetic, temperature, inertial devices

● Need to be able to understand the datasheet to understand the operating specifications of the chip, is to use the code to configure the sensor's registers

● Can read the schematic and understand the PCB

● Will use the oscilloscope, will analyze the circuit

What is the actual interview?

● C language basic knowledge, algorithm water problem

● Chat, chat items, how to achieve

What is actually used in the work?

The chances of my interview success are all from the companies that mainly do MCUs, and they are all small companies. The teams that enter are also small, and the things they do are what two or three people can do. Although I think that writing a program is OK, but every time I answer the algorithm, I can't answer the question. I am really depressed. Although I have already added a lot of relevant knowledge recently, I still feel that if I have been doing these embedded devices. Project, I may never use these algorithm knowledge.

I knew this very long ago, and the computer data structure and algorithm for the development of single-chip programs is the water moon mirror. In another sense, the algorithm is very practical. For example, I bought a copy of the commonly used algorithm in the design of embedded system software before I graduated. This is a very useful tool, many methods. In the actual embedded software development is very effective, I classify this type of algorithm as DSP, that is, digital signal processing, to process the data in the single-chip microcomputer are digital signal data, to analyze and summarize these data, after processing Information from the sensor, then use the controller or communicator to feedback the outside world

a little bit of insight

I have been engaged in the development of single-chip microcomputers. These years, I have done a little bit of unreliable projects with these technologies. Now I think I have been honing my technology and then I have not used it in the molded products. What is the use of these in the past? The power detection device that was previously used with PIC microcontrollers may have been produced in small quantities, but it has not become a product worthy of my pride. Every time I am looking for a company, in fact, how much effort do I really put on these products? Every time I do these things just as a job, although my technology is constantly improving. It is more and more convenient to deal with some technical difficulties, but I have already lost the enthusiasm when I was at school. I started to learn some other techniques in my spare time. I only thought of the work I did in my hand as a living job. I felt that I didn’t have any technical content, and some things were slowly polished. I might as well swear. Nowadays, I am ready to join a richer technology ocean. Over time, the original red heart was long gone, and I became just a constant job of chasing wage growth. And the experience of embedded Linux in the past year has indeed taught me a lot of skills in programming under the operating system. I have been exposed to file programming, network programming, and computer algorithms that I have not used before. Now I found out that Many of the technologies that I am eager to use under the microcontroller are just that. Remember that I used to want to build a real-time operating system myself. Want to achieve multi-threading or coroutine under the microcontroller, with the operating system these are simple, no previous program is complicated to write. And these simple implementations of the complexities of the previous on the microcontroller, there are new and complex things. With multi-threaded programming, the issues of synchronization and mutual exclusion that are of concern are not as simple as doing a lot of things at the same time.

There is also the streaming of video and audio, buffering of buffers, and careful handling. MCU development needs to pay more attention to the various characteristics of the physical world and the electrical world. It is necessary to turn the continuous signal of the simulation into digital discrete data, with a real-time and simple sequence structure.

a little advice

● Still recognize that you are the most important. Don't be bound by the technology that you used to do. In fact, I now see that many people who have used software before are also trying to program the hardware of the microcontroller. The feedback directly to the physical world is a wonderful feeling. Compared to the abstraction of dealing with database information, dealing with real-world data may be more interesting in a sense, giving people a sense of solidity.

● Everyone can continue to learn new things. As a kind of work that has been popular in human society for nearly two decades, we have too many things to learn and explore. There are few engineers who work for 20 years. This industry has not yet fully developed, so it is absolutely not to be fooled by the nonsense of other people's software technology. Being a person who insists on learning is worthy of respect.

● MCU programmers are also a kind of software engineers. The things they do are just as useful and interesting. They can earn a good salary when they are done. In other software programmers, they may be regarded as hardware and do the underlying. But the difference I understand may be about the same as writing java and python. Anyway, there are no software engineers who don't grow up and don't learn for a lifetime, unless they go to do "high-end" positions like "management."