For my thesis I specified the parameters of the designed LED matrix display. Considering the available place, the pixel number and the budget a decision was made about the resolution of the LED display. The final resolution was 60 x80 pixel, which resulted in a 1.49 x 1.98 m display. According to the specifications, the display is monochrome and able to visualize caracters and graphics.
After cooperation with the firm’s consultant we defined the functional structure of the system. After considering some possibilities, we designed the main elements of the system, for examle the controller unit and the interfaces of communication. We chose a Raspberry Pi B+ model for embedded computer. This unit receives the information via Ethernet and sends itt to the Spartan 6 FPGA via SPI. The FPGA is modelled as a FIFO, which transmits the received data to the TLC 5955 LED driver IC-s. These are located on the LED panels. Each panel contains 4 LED drivers and 192 green LEDs. One panel is 297 x 396 mm and the whole display consists of 25 of them.
The inner structure of the FPGA is built up by moduls. This modular structure makes the system easily scalable. I designed 5 moduls, an SPI Master modul, an SPI Slave modul, an initialization modul, a central modul and a blokk RAM. These moduls are responsible for the communication between the embedded computer and the LED-driver ICs. I also made a software for the Raspberry Pi, which transmits data to the FPGA from a predefined buffer.