Hi Andy,

>However, the problem with this method, it incurred
>a lot of logic gates like AND, NOT, OR and etc.
>A14 (Eprom) = A15*/A13 + A14*A13
>A13 (Eprom) = /A13 * (A14 + A15)
>A12 (Eprom) = A12 * (A15 + /A15)
>CS (Eprom) = A15*A14 + A15*A13 + A15*A14*/A13 - mistake

It can be done very simply for the single 32 KB EPROM:
A14 (Eprom) = A13*A14 + A15
A13 (Eprom) = /A13
A12 (Eprom) = A12 * (A15 + /A15) = A12*1 = A12 - do nothing
CS (Eprom) = A13 + A14 + A15 - it works

Regards,
George