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。-P0.0/AD0-P0.7/AD7 with AT89S51 microcontroller port connected digital tube a-h-side, 8-bit digital control of the S1-S8 through 74LS138 Decoder Y0-Y7 to control the strobe tube each digital The bit select. 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."　Can be smoothed to see the curtain effect.