This paper presents an experimental case for digital system design, based on the Xilinx Nexys4 DDR Artix-7 FPGA development board and the ov2640 camera. The experimental case uses a top-down design approach to divide the system into subsystems, and then design the subsystems and controllers separately, and finally implement the entire system function. This experiment can guide students to master digital system design methods, develop students' intelligence and improve their practical ability.