Case Statement Question???

Hi

Can someone tell me, Is it possible to have a case statement without using a process?

P.S

A 'case' is exclusively for sequential code.
For combinatorial code there is the simular WHEN or WITH you could use.

yeh i looked through my notes again and the process is required.

Marcel,

A case statement is just a mux. It can be used in a sequential or combinatorial process.

Radix

It is used in sequential statements description only.
--
Amr Ali

Digit0001 said:

Hi

Can someone tell me, Is it possible to have a case statement without using a process?

P.S

Click to expand...

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;



entity mux is
Port ( i : in STD_LOGIC_VECTOR (3 downto 0);
s : in STD_LOGIC_VECTOR (1 downto 0);
y : out STD_LOGIC);
end mux;

architecture Behavioral of mux is

begin


using if statement

--process (i,s)
--begin
--(if s="00" then y<=i(0);
--elsif s="01"then y<=i(1);
--elsif s="10"then y<=i(2);
--end if; )
--end process;

-- with statement act same as case statement outside process

--with s select

-- y<=i(0) when "00",
-- i(1) when "01",
-- i(2) when "10",
-- i(3) when "11",
-- 'Z' when others;




-- when statement

-- y<=i(0) when s="00"else
-- i(1) when s="01"else
-- i(2) when s="10"else
--i(3) ;

-- case statement with in process


process(s,i)
begin
case s is

when "00"=> y<=i(0);
when "01"=> y<=i(1);
when "10"=> y<=i(2);
when "11"=> y<=i(3);
when others=> null;

end case;
end process;



end Behavioral;

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so if want to write a case statement outside process , use with select statement both are equl