Design Of Full Color LED Dot-Matrix Display Controller Based On FPGA

LED display screen is a kind of large-scale display system, which is composed ofLight Emitting Diode lattice modules. This display screen can dynamically display text,image, and video, which has some unique advantages such as long durability, highreliability, low power consumption, high brightness, abundant color and so on.Nowadays, LED display screen has been widely used in industry, transport, businessadvertisement, information release, physical match and other fields.The main reserch object in this paper is the controller of full color LED dot-matrixdisplay, and the paper proposes a system implementation based on FPGA by the meansof hardware and software combination. The entire controller is divided into four parts:Ethernet interface module, FPGA control module, DDR storage module and LEDdriving circuit module. The software on the PC loads in data including information fortext, image or video, then sends it to the controller with specified IP address throughEthernet cable. Afterwards, the Ethernet chip on the controller forwards the data frameto FPGA control module, FPGA control module decodes the data frame, provides aanti-γ correction operation to the data, separates the data bit by bit. DDR SDRAM isused to store data for FPGA. Finally, outputs RGB data and control signals to the LEDdriving circuit module for LED screen displaying.The design of FPGA control module is the main content for design of LED displayscreen controller. The FPGA control module will be divided into seven parts: GMIIcommunication module, anti-γ correction module, bit separating and recombiningmodule, gray scale generation module, DDR reading and writing control module, scanand driving control module and clock generation module.GMII communication module in this paper is designed to realize the communicationfor the GMII interface between Ethernet Chip and FPGA.As to anti-γ correction module, it adopts the means of look-up table mapping toachieve anti-γ correction for data. As the gray scan of the LED display is based onweights, the grayscale data after anti-γ correction must be separated and recombined.Horizontal writing and vertical reading is the way indeed in realizing process of bitseparation and recombination. Gray scale generation module is designed to realize the256gray level.DDR reading and writing control module includes three submodules such as readingaddress generation module, writing address generation module and reading and writingcontrol module. Reading address generation module generates reading addressaccording to color and weight, and writing address generation module generates writingaddress according to color data. Reading and writing control module is used to controlthe read and write operation for DDR.LED scan and driving control module is designed to gererate driving control signalsand send the image data to driving circuit.Clock module is used to generating clocksignals to relative modules. The paper describes the overall design of full-color LED dot matrix displaycontroller in detail, and analyzes the hardware and software design for every module.Test result shows the design is flexible and can achive a good result.