This paper presents a link layer design of DisplayPort interface with a state machine based on packet processing. The DisplayPort link layer provides isochronous video/audio transport service, link service, and device service. The merged video, audio main link, and AUX channel controller are implemented with 7,648 LUTs(Loop Up Tables), 6020 register, and 821,760 of block memory bits synthesized using a FPGA board and it operates at 203.32MHz.