I created a simple multiplexer which feeds different input into output depending on statemachine. Now there are states when I do not need the output so I usually set it to 0.
INST <= "01" WHEN fsm_state = read_first_half OR fsm_state = read_second_half OR fsm_state = next_r ELSE "10" WHEN fsm_state = write_first_half OR fsm_state = write_second_half OR fsm_state = next_w ELSE "00";
As far as I remember there was a third syntetisable value 'Z'. I far as I remember it's floating value with high impedance. When do I use it and is it safe to use? Will it be syntetisable on all FPGAs?