Integrated Circuits Used 74LS90 Procedure Connect VCC Port to Pin-5 (VCC) of ICBase-1 (74LS90).Connect VCC Port to Pin-5 (VCC) of ICBase-2 (74LS90).Add IC 74LS90 into ICBase-1 (74LS90).Add IC 74LS90 into ICBase-2 (74LS90).