Abstract: In today's highly developed information age, the traditional mobile garage door display control system can no longer meet people's demand for information display. At present, LED display screens related to electronic circuits, integrated circuits, information image processing, information transmission and electronic product installation projects are particularly active in the information field, and their application and popularization in various industries have made great progress.
This paper designs a simple LED display screen based on AT89S5 1 MCU. The display screen system adopts the upper and lower computer mode composed of PC and single chip microcomputer. Among them, PC is used to update information data, single chip microcomputer is used to control hardware scanning and display circuit, and RS-232 communication standard is adopted between upper and lower computers. The system software consists of PC control and communication software written by C++ Builder and display control software written by C language. The hardware processor is AT89S5 1. The display screen can display 1 16× 16 dot matrix Chinese characters, and the display mode includes moving up and down, left and right, and replacement.
Keywords: single chip microcomputer; LED lattice; RS-232；
Design of display screen control system for mobile garage door
Abstract: With the rapid development of social communication, the traditional mobile garage door display system can no longer meet people's demand for information display. Nowadays, LED large screen integrates many technologies such as electronic circuit, integrated circuit, image processing, information transmission and electronic manufacturing, and its application and promotion in the information field is becoming more and more active.
This paper designs a simple LED display system scheme based on AT89S5 1 single chip microcomputer. The display system is mainly composed of PC and single chip microcomputer. The PC updates communication data, and the single chip microcomputer controls hardware scanning circuit and display circuit. Communication is based on RS232C interface standard. The software of the system consists of two parts, one is control and communication based on C++ Builder language, and the other is display control based on C language. The hardware is based on AT89S5 1. The display screen can display Chinese characters with the dot matrix of 16× 16. Display modes include up, down, left, right and replacement.
Keywords: single chip microcomputer, LED dot matrix, RS-232
catalogue
Chapter 1 Thread Theory 1
Project background and significance 1. 1 1
1. 1. 1 project background 1
1. 1.2 Purpose and significance of the project 1
1.2 research status and development trend at home and abroad 1
1.2. 1 foreign research status 1
1.2.2 Domestic research status II
1.2.3 development trend 2
1.3 main contents of the paper 3
Chapter II Principle of LED Display System 4
2. Working principle of1LED device 4
2. Basic principle of1.1led4
2.1.2 driving of led devices 4
2.2 Composition of large screen display system based on LED display screen 5
2.2. 1 Composition of large-screen LED display system 5
2.2.2 Function introduction of main components 6
2.3 Hardware composition of simple LED display system 7
2.4 Software system of simple LED system 9
Chapter III System Hardware Design 10
3. 1 overall design analysis 10
3.2 Introduction to the principle and function of processor selection 1 1
3.2. 1 chip selection principle 1 1
3.2.2 Introduction of processor system functions 1 1
3.3 Line Drive Circuit Design 14
3.4 Design of Column Driving Circuit 15
3.4. 1 Comparison of train drive schemes 15
3.4.2 The column driving mode is 17.
3.5 Data Memory Interface Design 18
3.5. 1 introduction of data storage chip 18
3.5.2 Data storage interface connection 19
3.6 serial interface circuit 20
The fourth chapter system software design 22
4. 1 PC system software design 22
4.2 Lower computer system software design 23
4.2. 1 Design of display control software 24
4.2.2 LED dynamic scanning program design 24
4.3 Special Effect Display Program Design 25
4.3. 1 Up mode display 26
Down mode display 26
4.3.3 Left shift mode display 27
4.3.4 Right Shift Mode Display 28
4.4. Chinese character extraction program design 29 pages
The fifth chapter system debugging 3 1
5. 1 hardware debugging 3 1
5. 1. 1 LED display debugging 3 1
5. Debugging of1.2 Driving Circuit 3 1
5. 1.3 serial communication circuit debugging 32
5.2 Software debugging 32
5.2. 1 Lower computer software debugging 32
5.2.2 PC software debugging 33
Conclusion 34
Thanks 35
Reference 36
Appendix 1 System Physical Diagram 37
Appendix 2 Hardware Circuit Diagram 38
Appendix 3 Program Code 39
Chapter 65438 +0 thread theory
Background and significance of the project 1. 1
Project background 1. 1. 1
Electronic display screen is a high-brightness display device which uses light-emitting diodes as display materials and combines computer control technology and image processing technology. Light-emitting diode (LED) is the abbreviation of light-emitting diode, which uses the electroluminescent principle of semiconductor P-N junction to produce red, green, blue and other colors. LED has the advantages of high brightness, bright colors, good stability, low power consumption, high luminous efficiency and long life.
As the "fifth largest media" after TV, radio, newspapers and magazines, LED electronic display screen is widely used in various places because of its advantages compared with TV wall, plasma display screen, magnetic flip board, neon lights and other media. Early LEDs were only red or green, so they were only monochrome or double primary colors. 1993, NICHIA developed mixed-color high-brightness light-emitting diodes, and the display screen began to enter the full-color era [1].
LED display screen has bright colors, strong stereoscopic impression, static as oil painting and moving like a movie, and is widely used in public places such as stations, docks, airports, shopping malls, hospitals, hotels, banks, securities markets, construction markets, auction houses and industrial enterprise management.
Therefore, LED display screen has a very strong market space and prospect, and now many companies at home and abroad are also vigorously developing and producing LED display screens.
The purpose and significance of 1. 1.2 project
The main purpose of this paper is to design a simple LED display screen based on 5 1 single chip microcomputer, which can realize the up, down, left, right and static display of Chinese characters. Through this topic, we can learn about 5 1 single chip microcomputer, LED display screen, serial communication and so on. Understand the industry trend and development trend of LED display screen. It can improve hands-on ability, programming ability and self-study ability. At the same time, through the specific graduation project, it is also a good opportunity to test the knowledge of university learning.
1.2 research status and development trend at home and abroad
1.2. 1 research status abroad
In March 2007, at CeBIT 2007 in Hanover, Germany, Samsung officially displayed a brand-new 30-inch LED display. The color gamut of this Samsung SyncMaster XL30 LED display is as high as 1.23%, making it the best color flat panel display in the world.
Ordinary flat panel displays use CCFL (cold cathode fluorescent lamp) as backlight. Due to the limitation of physical characteristics, the color gamut value is usually difficult to exceed 100%. However, this Samsung XL30 uses LED as backlight, and the wavelength of light meets the requirements of displaying purer and truer colors, so it can display a more natural color gamut, so its color gamut value is also the largest, especially it can display a wider range of green, red and purer black.
Adobe RGB color standard has become the industry standard of digital photography and digital printing. Most liquid crystal displays cannot display the complete sRGB color space. In contrast, the performance of Samsung XL30 LED display has completely covered and surpassed the color space of sRGB and Adobe RGB.
Samsung XL30LED display has built-in Samsung professional "FPGA" processing chip, which can perfectly reproduce high-speed 14BIT images. Randomly configured natural color expert software allows users to change the settings of the display as needed, and calibration software can provide uniform standards among the settings, gamma value, color temperature and white balance of digital devices, so that the displayed color is completely equal to the real color [1].
1.2.2 Domestic research status
Since the 1990s, the scale of LED display industry in China has developed rapidly, and at the same time, the product technology has been constantly innovated, and it has always maintained a relatively leading level in this field. As early as the early 1990s, the domestic LED display screen had mature 16 gray scale, 256-color video control technology and wireless remote control, which represented the international advanced technology at that time. In recent years, domestic enterprises have advanced products in full-color LED display screen, 256-level gray video control technology, trunking wireless control and multi-level group control technology.
These products are widely used in traffic police, cars, stations, docks, sports, advertising, banks, securities, shopping malls, post and telecommunications, government agencies and other fields, and have good income prospects [2].
1.2.3 development trend
(1) High brightness and full color
Since the appearance of blue-green ultra-high brightness LED products, the cost has been rapidly reduced year by year, which has reduced the cost of LED full-color display products and accelerated the promotion speed. At the same time, with the development of control technology and the improvement of screen stability, the brightness, color and white balance of full-color LED display screen have achieved ideal results, which can fully meet the requirements of all-weather outdoor environmental conditions.
(2) diversification of product structure
With the formation of information society, the information field is more and more extensive, and the application prospect of LED display screen is broader. It is predicted that the situation that large or super-large LED displays are the mainstream products will change, the small LED displays suitable for service industry characteristics and professional requirements will be greatly improved, the product categories and variety systems of LED displays facing the information service field will be more abundant, and some potential market demands and application fields will be broken through, such as public transportation, parking lots, hospitals and other comprehensive services will be greatly improved, and large-scale and miniaturized standard system LED displays will occupy a place in the entire LED display market.
1.3 main contents of the paper
Based on the design idea of LED large screen display system, a design scheme of LED dot matrix simple display screen based on 5 1 single chip microcomputer is proposed. The hardware design principle of simple LED display screen, the scanning driving principle of LED display screen, the software design method of single chip microcomputer control circuit, the design of PC upper computer control and communication software and the design method of special effect display mode software are discussed in detail.