elsif call(1) = '1' then control <= DN2; en <= '1'; else control <= CL2; en <= '1'; end if; else control <= CL2; en <= '1'; end if; when OP2 => if cout = '1' then -- 开门已完毕 if call(2) = '1' then control <= OP2; en <= '1'; else control <= CL2; en <= '0'; end if; else control <= OP2; en <= '1'; end if; when others => control <= CL1; end case; end if; end process; end behav;
问题3，根据图b所示升降平台模块图，写出升降平台控制器ELEV_TOP的VHDL顶层描述：