各种FPGA初级入门程序（已调试通过），包括计数器、流水灯、7段数码管显示以及PS2键盘接口驱动，采用VHDL语言编写，适合初学者参考-Various FPGA primary entry procedures (already debugged), including the counter, water light, 7 segment LED display and PS2 keyboard interface driver, using VHDL language, suitable f