用AT89S51单片机的P0.0/AD0－P0.7/AD7端口接数码管的a－h端，8位数码管的S1－S8通过74LS138译码器的Y0－Y7来控制选通每个数码管的位选端。AT89S51单片机的P1.0－P1.2控制74LS138的A，B，C端子。在8位数码管上从右向左循环显示“12345678”。能够比较平滑地看到拉幕的效果。-AT89S51 MCU with P0.0/AD0-P0.7/AD7 port access digital tube side of the a-h, 8-bit digital control of the S1-S8 through the 74LS138 decoder to control the Y0-Y7 each gating bit digital tube end election. AT89S51 MCU P1.0-P1.2 control 74LS138 of A, B, C terminal. In the 8-bit digital tube display from right to left circle, " 12345678."　Able to smooth Curtain to see results.