用二个16:1 取样 http://www.nxp.com/documents/data_sheet/74HC_HCT4067.pdf 接二个电压表. 记数器,产生控制信号 http://www.onsemi.com/pub_link/Collateral/MC74HC4060A-D.PDF 也可以用用二个16:1 取样反接 2x16个LED来代替1个2X7段通道LED.