为了减少8位显示信号的接口连接线，实验箱中的数码显示采用扫描 显示工作模式。即8位数码管的七段译码输入（a,b,c,d,e,f,g）是并联在 一起的，而每一个数码管是通过一个3位选择sel[2..0]来选定 的。-In order to reduce the 8-bit display signal interface cable, digital display in the experimental box scan display mode of operation. I.e. the seven segment decoder 8-bit digital input (a, b, c, d, e, f, g) is connected in parallel with each digital tube is selected by a 3-bit SEL [2 .. 0] to be selected.