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u mean,u just want to make sure which package of FPGA u should choose, don't u?
or to design a protect ciucuit?
if package of FPGA, i suggest PLCC, well, u could use a chip carrie socket for PLCC.
in my design ,i use CPLD,EPM7128SLC84, for removing it expediently,i bought a PLCC socket.
and to design a demo board, i've used 4 headers for the io pins of CPLD,all io pins coludn't connect directly with their corresponding pins of other chips on the board.