Error (10309): VHDL Interface Declaration error in keyboard.vhd(63): interface object "scan_code" of mode out cannot be read. Change object mode to bu

entity中定義為:
scan_code : out STD_LOGIC_VECTOR(15 DOWNTO 0);

architecture中說明:

scan_code(15 downto 8) <= scan_code(7 downto 0);
scan_code(7 downto 0) <= SHIFTIN(7 DOWNTO 0);

將OUT 改成 BUFFER 即可