On 2/12/2010 11:44 PM, John Kent wrote: > signal HDBDOS : std_logic := X; Should be: signal HDBDOS : std_logic := 'L'; ie. if you don't know, then you probably don't! :) Regards, -- | Mark McDougall | "Electrical Engineers do it | <http://members.iinet.net.au/~msmcdoug> | with less resistance!"