Design Of Full-color Outdoor LED Large Screen Control System Based On FPGA

LED large screen display system is an integrated system of optoelectronics, Semiconductor devices, digital circuits and control technology, which has been widely used in many areas and with the features such as high luminous efficiency, long using life, rich colors etc. LED displays has been experiencing rapid development ever since its birth. Until now, full-color LED display has become an important product in flat panel display filed.In the current thesis, a large outdoor full-color LED screen control system based on FPGA was designed. On the basis of the structure of the large screen display system and the principle of gray realization, gamma correction, the overall design was proposed, with DVI interfaces as the data source, Gigabit Ethernet as the transmission medium, FPGA as the master chip. The main contents are as follows:1. On the basis of the timing characteristics of the DVI interface output and the structure of LED screen, video source with resolution 1024×768 and refresh rate 60Hz was taking as the research object. Adopting the verilog hardware description language, the serial communication and DVI data receiving module, SDRAM controller, as well as the RAM read and write cache module were designed, thereby the video data receiving and sending based on FPGA has been implemented. Modelsim simulation and download board reviewed that the system functions had meet the design requirement, and with real time and system stability etc.2. After analyzing the organizational structure and the storage methods of the video pixel data in the system, the SDRAM memory control module was designed. According to the timing of SDRAM operation, the SDRAM controller was designed using verilog hardware description language, so that other modules could control the reading and writing operations of the SDRAM. The controller had stronger flexibility and scalability, which not only meet the current system requirements, but also could apply to other high-speed data acquisition system.3. On the analysis of the advantages and disadvantages about the existing long-distance high-speed data transmission, the distance transmission systems with medium of Gigabit Ethernet was designed to meet the high-speed data transmission requirements. Actual results revealed that the system can guarantee real-time, accurate and stable data transmission. 4. On the basis of LED display driver circuit structure, gray realization principle and multi-line scanning principle, the scanning control module to drive the LED screen was designed. Since the LED screen is a linear display system, while video source is a nonlinear system, the raw data was corrected by anti-gamma correction in order to truly restore the original image; Aftering discussing the causes of brightness uniformity and the advantages and disadvantages of different solutions accordingly, the dynamic correction method based on FPGA and SDRAM was proposed, which could finally reduced the system cost.The designed LED screen control system, the simulation and the test results show that the system supports multi-line scanning, adjustable resolution and gray scale, and the non-uniform luminance can be corrected and it has the high market value.