GATE 2016 Electronics & Communication PYQ

Question

An 8 Kbyte ROM with an active low Chip Select input CS is to be used in an 8085
microprocessor based system. The ROM should occupy the address range 1000H to 2FFFH.
Theaddress lines are designated as A15 to A0, where A15is the most significant address
bit.Which one of the following logicexpressions will generate the correct $$\overline{CS}$$ signal for this
ROM?

Accepted Answer

$$A_{15}\;+\;A_{14}\;+\;(A_{13}.A_{12}+\overline{A_{13}}.\overline{A_{12}})$$

Answer

$$A_{15}.\;A_{14}.(A_{13}+A_{12})$$

Answer

$$\overline{A_{15}}.\;\overline{A_{14}}.(A_{13}.\overline{A_{12}}+\overline{A_{13}}.A_{12})$$

Answer

$$\overline{A_{15}}+\overline{A_{14}}+A_{13}A_{12}$$