ENTITY rf_out_buf_4 IS
PORT (
  nck    : in  BIT;
  xcks	 : out BIT;
  vdd	 : in  BIT;
  vss	 : in  BIT
);
END rf_out_buf_4;

ARCHITECTURE VBE OF rf_out_buf_4 IS

BEGIN
  ASSERT (vdd and not (vss))
  REPORT "power supply is missing on rf_out_buf_4"
  SEVERITY WARNING;

  xcks <= not nck;

END;