What should I do if the MCU system does not work properly?

Recently, I have finally had enough time to learn the principles of computer composition and the principle of single-chip microcomputers, and simply talk about my feelings about these two courses.

1. First of all, the two major branches of the computer: general-purpose computers, microcontrollers. It is two different development directions. We know that a computer has five major components, the operator controller memory input device input device.

The single chip microcomputer is integrated on an IC chip, and the arithmetic chip controller and the IO interface are integrated on the IC chip, which is equivalent to a computer system. The general purpose computer is a sub-module, such as a memory stick, a CPU, a graphics card, and these devices are connected into a computer system through a system bus. Therefore, it can be seen that the single-chip microcomputer is a microcomputer system, which is very suitable for use in an embedded system because of its small size and low price. Of course, the function of the microcontroller is not as powerful as the function of a general-purpose computer.

2. Let me talk about the principle of computer composition. The principle of computer composition is to introduce the basic principles of computers. It does not involve specific models, such as intel 8086. It is not introduced and explained by specific models. The course of microcomputer principle and interface technology is based on 8086. Of course, when introducing the computer principle, you can also introduce a specific model as an example, but if it is too specific for a certain model, it cannot reflect the basics of the principle of the computer.

3. The principle of single-chip microcomputer, some of the single-chip principle books I have read are all explained by MCS-51 single-chip microcomputer, because the 51-core single-chip microcomputer is very simple and easy to learn, and it is widely used. Arm is also a kind of single-chip microcomputer, which is a 32-microcontroller. The 51 MCU is an 8-bit microcontroller.

4. Computer composition principle Assembly language microcomputer principle and interface technology computer architecture This is a professional course in computer science and technology. Of course, if you can learn these courses, you will have a deeper understanding of the computer, because the content of a single course is limited.

5. I have to say that today's courses are just as general, and it is really not suitable for oneself to learn. It’s hard all the way. In the future, we will learn some aspects of industrial control, PLC ARM.

If the MCU system does not work properly, you can check the following steps:

1. Look at the reset output of the dog. If possible, add an LED to the board and pull it down. This seems more convenient; if the watchdog reset signal is there, go down.

2. Check the MCU to see if there is any problem with the pin; the general programmer can write the program, indicating that the MCU is good; it is best to prepare a verified MCU on hand, there is a simple program inside, for example, in a certain A square wave with a duty cycle of 1 second is output on the port line, and can be measured with a multimeter.

Add one sentence: When designing the product, it should be in the key places: power supply, serial port, watchdog output and input, I/O port, etc. with different color LED indications for easy debugging; as a large batch product, some LEDs can be removed. On the one hand, it is to reduce costs, on the other hand, the process is confidential.

3. Check the magnetic capacitor, and some ceramic capacitors can't be used. Simply change it. By the way, it is better to use the soldering strip to replace the tin in the solder pad and then pull out the device. The via hole in the damage pad; when the new ceramic capacitor is soldered up, it is good to re-weld with a multimeter.

4. If there is no problem in the above three points, then only the crystal oscillator will be changed at the end; when changing the crystal oscillator, it is necessary to remember to buy a good crystal oscillator. Some brands have better quality.

5. When the above steps are detected, the extraneous peripheral chips are removed; because some of the peripheral devices are faulty, the MCU minimum system does not work.