Juan,

To identify one out of 128 SW's might be possible with a matrix
structure. I have seen it used in several keypads.
Make a structure with rows and colums with the SW's at their
intersections. By selecting one colum at the time and reading the
rows. One can identify wich SW's are open or closed.

There might be a few problems with this in your application.
1 the amount of inputs and outputs needed
   you probebly need some extra latches
2 the polling part
   you probebly want an interrupt first and then start polling
  this might work by selecting all colums and or-ing the rows
  for the interrupt


greetings,

Paul
Paul E. Kamphuis
Wilhelminastraat 9
5121 WR Rijen

0161-222362