3vhdl简单程序设计；4,8-3优先编码器5,3-8译码器；6,6d锁存器；7，数码管扫描显示；8，四位二进制加法计数器-3vhdl simple programming 4,8-3 5,3-8 priority encoder decoder 6,6 d latch 7, the digital scan 8, four binary up counter