hi;
pramod try this if you want to interface a
single 8255:
1.connect A15 to to CS/CE of 8255.
2.connect a0/a1 (from demultiplexing latch)
to a0/a1 of 8255.
3.connect ad0-ad7 to d0-d7.
4.now all accesses that have A15=0 shall selct your 8255.it gets mapped for range 00 to 03h to 07fc to 07ff with 8k images!.don't put any other device in this range.
4.if you need less/no image then go for elaborate decoding scheme using more address lines.
regards
pranav