Integrated Circuits Used 74HC191 74LS191 74LS139 Procedure Add IC 74HC191 into ICBase-1 (74HC191).Add IC 74LS191 into ICBase-2 (74LS191).Add IC 74LS191 into ICBase-3 (74LS191).Add IC 74LS139 into ICBase-4 (74LS139).