1. ghdl -a key_expansion.vhd key_expansion_tb.vhd
  2. key_expansion.vhd:81:7: signal interface "sbox_in" has no association in entity "key_expansion"
  3. key_expansion.vhd:81:7: signal interface "sbox_out" has no association in entity "key_expansion"
  4. ghdl: compilation error
  5. make: *** [makefile:2: key_expansion_tb] Error 1