Design Of Synchronous Control System For Large LED Screen Based On FPGA

With the development of modern information technology,semiconductor technology and image processing technology,LED full-color screen industry has developed rapidly.As a semi-customized circuit,FPGA has the advantages of short design cycle,flexible development,powerful real-time signal processing and system control capabilities.A design scheme of synchronous control system for large LED screen based on FPGA technology is given in this thesis.The scheme has the characteristics of wide adaptability and high cost performance.Firstly,the display control principle of full-color LED screen is analyzed in this thesis.In view of the difficulty of high screen refresh rate in high gray level,the concept of sub-field is introduced,the mathematical model of the relationship between high gray level and high screen refresh rate is given,and the solution is also proposed.Combining with the pulse scattering algorithm,the screen flicker phenomenon at high gray level is also improved.Secondly,according to the design requirements of the control system,the hardware scheme of the full-color screen synchronous control system is given in this thesis.On the premise of guaranteeing performance,system cost is effectively reduced.Thirdly,the communication protocol of the transmission system is redesigned in this thesis,and the interconnection communication mode between the boards is given.By removing unnecessary data headers,the transmission efficiency of effective data is significantly improved;by introducing command frames,the real-time configuration of receiving card parameters is realized;by introducing line-field synchronization frames,video information synchronization and frame type recognition functions,the problem of bandwidth waste and low synchronization of small screen display is also solved.Finally,the sending and receiving systems are redesigned separately in this thesis to achieve higher performance with fewer logical resources.In the transmission system,according to the characteristics of data reading and writing,SDRAM controller is redesigned.By removing the gap between burst reading and writing,the throughput efficiency of data is significantly improved.By combining the working principle of full-color screen,the adaptive address allocation scheme is proposed,which takes less logical resources,requires lower performance of hardware and has higher reliability.In the receiving system,the comprehensive adjustment of multi-screen display parameters is realized by using the look-up table method;combined with the display characteristics of full-color screen,the complete reconstruction of data is completed,and the higher refresh rate under high gray level is also realized.The overall cost performance of the control system has been significantly improved and the maintenance cost has been reduced.