add solutions

zz-solutions/04-Lissajous/Board/hdl/DFF_sim.vhd

@@ -0,0 +1,14 @@
+ARCHITECTURE sim OF DFF IS
+BEGIN
+
+  process(clk, clr)
+  begin
+    if clr = '1' then
+      q <= '0';
+    elsif rising_edge(clk) then
+      q <= d;
+    end if;
+  end process;
+
+END ARCHITECTURE sim;
+