Integrated Circuits Used 74LS90 74LS21 74LS08 Procedure Add IC 74LS90 into ICBase-1 (74LS90).Add IC 74LS21 into ICBase-2 (74LS21).Add IC 74LS08 into ICBase-3 (74LS08).Add IC 74LS90 into ICBase-4 (74LS90).Add IC 74LS90 into ICBase-5 (74LS90).
