Overview of Single Chip Microcomputer System Production

Single-chip microcomputer is a very practical course (it is half soft and half hard), so it is necessary to combine theory with practice. I have tried many teaching methods, but I still think that the "task teaching method" created by Teacher Pingfan is the most effective. At the same time, I have also been exposed to the most advanced teaching method in Germany: action-oriented teaching method. Therefore, my course will be written according to the teaching idea of ​​action-oriented teaching method, project teaching method and "task teaching method". It is written completely in accordance with the laws of human cognition, focusing on the cultivation of scholars' abilities. This is what I mentioned, "Learning knowledge is not as important as the ability to learn knowledge."
Single-chip microcomputer is something that many people want to learn, but it is difficult to learn single-chip microcomputer without the necessary conditions. I suggest that you need to prepare the following conditions to learn single-chip microcomputer:

1. You need a computer, preferably 586 or above, P2, P3 and P4 are better.
2. You need a programmer to write the compiled program into the ROM of the microcontroller, and insert the written chip into the test board for testing. Professional ones cost more than 1,000 yuan, medium ones cost 400 to 800 yuan, low-end ones cost about 150 yuan, and some miscellaneous ones sold online cost about 80 to 100 yuan.
4. You need a hardware microcontroller test board as the peripheral circuit part of the microcontroller test. Commercial ones generally cost 200 to 500 yuan, and complex ones are even more expensive.
5. You need several microcontroller chips for testing, such as the widely used 89C51, 89S51, 89S52, etc. The general market retail price ranges from 7 to 9 yuan. If you buy 2 pieces, it will be about 20 yuan.
Our school has prepared all the above for you, please feel free to study, and let's talk about the relevant content of learning.

1. Teaching objectives:
1. Understand the MCU development process
2. Learn to make and develop MCU systems

2. Teaching focus: MCU system production process

3. Teaching aids: a set of single chip microcomputer system kit (parts) experimental system

4. Teaching method: Task-based teaching

5. Teaching steps

1. Determine the task
of developing a single-chip microcomputer minimum system
2. Task analysis:
The system has the following functions:
(1) It has a 4-digit LED digital tube display function.
(2) Eight-way light-emitting diodes display various running lights.
(3) It can complete various sound-generating experiments such as playing music and alarms.
(4) Reset function
3. Knowledge preparation
(1) The external structure of the single-chip microcomputer (pin function)
(2) The display principle of light-emitting diodes and digital tubes
(3) Relevant knowledge of other peripheral devices, such as transistors, buzzers, voice/music discs, resistors, and crystal oscillators.
(4) Single-chip microcomputer working conditions
(5) Instruction code
(6) Delay program
(7) Program coding
(8) How to use the KEIL C51 development platform.
(9) Software simulation and hardware simulation
(10) Debugging method of single-chip microcomputer system
4. Preparation of tools and materials
(1) Programmer using AE integrated system
(2) Single-chip microcomputer minimum system kit
(3) Electric soldering iron, multimeter, multi-purpose board, etc.
(4) Computer and Keil software [page]
5. Production process
(1) Clean up the production kit
(2) Design the schematic diagram according to the task function
(3) Convert the schematic diagram into a circuit diagram and draw it on the multi-purpose board
(4) Solder components and check the circuit
(5) Program design
(6) Software simulation
(7) Use the programmer to input the program into the single-chip microcomputer
(8) Power on and view the results
(9) Self-evaluation of the product
(10) Comprehensive comments from the teacher

By the way, let me introduce the working conditions of the microcontroller. AT89S51 is suitable for all 51 series

For the microcontroller to work properly, the following working conditions must be met:
1. Power supply VCC +5V 40 pin
2. Ground GND 20 pin
3. Reset circuit: The RES pin must maintain a high level for no less than 24 oscillation cycles, and the microcontroller remains in the reset state (clock cycle = 12 × oscillation cycle, oscillation cycle = 1/f).
4. Clock circuit: The microcontroller works under a unified clock, so a clock circuit is necessary.
5. Memory control circuit: EA terminal on pin 31. When the EA input terminal is input at a high level, the CPU can access the 4KB address range of the on-chip program memory. If the PC value exceeds the 4KB range, it will automatically turn to access the off-chip program memory. When the EA input is low, only the off-chip program memory can be accessed, regardless of whether there is a program memory on the chip. Based on this, we generally let the EA terminal be connected to a high level when designing.
6. The microcontroller must have a corresponding program inside.

In summary, the microcontroller must have at least the following circuits: