An input/output byte control device using a nonvolatile ferroelectric
register can maintain compatibility with various memories by selectively
controlling bytes of input/output data. Since bytes of input/output data
are selectively activated, the compatibility can be maintained with SRAM
(Static Random Access Memory) having wide bytes and flash memory having
fixed input/output bytes. Additionally, programs can be changed in a
software system using a nonvolatile ferroelectric register.