ENTITY rf_out_buf_2 IS PORT ( nck : in BIT; xcks : out BIT; vdd : in BIT; vss : in BIT ); END rf_out_buf_2; ARCHITECTURE VBE OF rf_out_buf_2 IS BEGIN ASSERT (vdd and not (vss)) REPORT "power supply is missing on rf_out_buf_2" SEVERITY WARNING; xcks <= not nck; END;