title: vhdl code for keypad interfacing
body: <pre><code> entity hex_kp is
      Port ( row : out  STD_LOGIC_VECTOR (3 downto 0);
             coloumn : in  STD_LOGIC_VECTOR (3 downto 0);
             sevenseg : out  STD_LOGIC_VECTOR (7 downto 0);
             ca : out  STD_LOGIC_VECTOR (3 downto 0));
  end hex_kp;
  
  architecture Behavioral of hex_kp is
  
  begin
  
   ca &lt;="0111";
  
   if(row = "0111") then
  
       if(coloumn = "0111") then sevenseg &lt;= "00000110" ;
      elsif (coloumn = "1011") then sevenseg &lt;= "01011011" ;
       elsif (coloumn = "1101") then sevenseg &lt;= "01001111" ;
       elsif (coloumn = "1110") then sevenseg &lt;= "01110001" ;
       end if;
  end if;
  </code></pre>
  
  <p>This my part of my vhdl code for 4x4 keypad scanner for Basys2. It gives an error to "if(row = "0111") then" statement. I couldn't find why help please.</p>