How to make process to execute when S'active?

[PeggyYao]

I'd like to execute one process whenever the signal S is active (that is, a new value is assigned to S, but not necessary to be different from the old value of S). How to make that?

If just put S in the process sensitive list, the process will only be executed when S has an event (that is, S gets a different value from the old one)...

Then, how shall I write? Thank you!

 

[DigilogDesigner]

synched update process


signal Value: STD_LOGIC_VECTOR(7 dowhnto 0);
signal S: STD_LOGIC_VECTOR(7 dowhnto 0);
signal S_Active:STD_LOGIC;
signal S_Read: STD_LOGIC_VECTOR(7 dowhnto 0);
signal S_NotActive:STD_LOGIC;

-----------------------------
---- S Update process -------
-----------------------------
S_Writer: Process(CLK)
if (CLK = 1 AND CLK'event) then
if (however you know you have a 'Value' wanted?)then
S <=Value;-- update with value
S_Active <= NOT S_Active;-- mark as active
end if;
endif;
end process;

-----------------------------
---- s read process ---------
-----------------------------
S_Reader: Process(CLK)
if (CLK = 1 AND CLK'event) then
if S_NotActive /= S_Active then
S_Read <=S;
S_NotActive <= S_Active then
endif;
endif;
end process;