Defender: remove redundant dac

Arcade_MiST/Williams 6809 rev.1 Hardware/rtl/dac.vhd

@@ -1,48 +0,0 @@
--------------------------------------------------------------------------------
---
--- Delta-Sigma DAC
---
--- Refer to Xilinx Application Note XAPP154.
---
--- This DAC requires an external RC low-pass filter:
---
---   dac_o 0---XXXXX---+---0 analog audio
---              3k3    |
---                    === 4n7
---                     |
---                    GND
---
--------------------------------------------------------------------------------
-
-library ieee;
-	use ieee.std_logic_1164.all;
-	use ieee.numeric_std.all;
-
-entity dac is
-	generic (
-		C_bits  : integer := 10
-	);
-	port (
-		clk_i   : in  std_logic;
-		res_n_i : in  std_logic;
-		dac_i   : in  std_logic_vector(C_bits-1 downto 0);
-		dac_o   : out std_logic
-	);
-end dac;
-
-architecture rtl of dac is
-	signal sig_in: unsigned(C_bits downto 0);
-begin
-	seq: process(clk_i, res_n_i)
-	begin
-		if res_n_i = '0' then
-			sig_in <= to_unsigned(2**C_bits, sig_in'length);
-			dac_o  <= '0';
-		elsif rising_edge(clk_i) then
-		        -- not dac_i(C_bits-1) effectively adds 0x8..0 to dac_i
-			--sig_in <= sig_in + unsigned(sig_in(C_bits) & (not dac_i(C_bits-1)) & dac_i(C_bits-2 downto 0));
-			sig_in <= sig_in + unsigned(sig_in(C_bits) & dac_i);
-			dac_o  <= sig_in(C_bits);
-		end if;
-	end process seq;
-end rtl;