拉幕式数码显示技术，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-Pull-screen digital display technology, with the AT89S51 microcontroller P0.0/AD0-P0.7/AD7 port connected to a-h digital side, 8-bit digital control of the S1-S8 through the 74LS138 decoder to Y0-Y7 LED strobe control bits of each selected terminal