Initial import

git-svn-id: http://moon:8086/svn/vhdl/trunk@5 cc03376c-175c-47c8-b038-4cd826a8556b

lib/radio/nco/src/waverom_dual.vhd

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+--------------------------------------------------------------------------------
+-- Company: 
+-- Engineer:
+--
+-- Create Date:    12:16:14 10/02/05
+-- Design Name:    
+-- Module Name:    cordic_stage - Behavioral
+-- Project Name:   
+-- Target Device:  
+-- Tool versions:  
+-- Description:
+--
+-- Dependencies:
+-- 
+-- Revision:
+-- Revision 0.01 - File Created
+-- Additional Comments:
+-- 
+--------------------------------------------------------------------------------
+library IEEE;
+use IEEE.STD_LOGIC_1164.ALL;
+use IEEE.MATH_REAL.ALL;
+USE ieee.numeric_std.ALL;
+use work.fixed_pkg.all;
+use work.nco_pkg.all;
+
+---- Uncomment the following library declaration if instantiating
+---- any Xilinx primitives in this code.
+--library UNISIM;
+--use UNISIM.VComponents.all;
+
+entity waverom_dual is
+Generic
+(
+	nbits_wave		: integer := 12;
+	nbits_wave_frac	: integer := 12;
+	nbits_rom_depth	: integer := 12
+);
+Port
+(
+	clk			: in std_logic;
+	addr_i		: in unsigned(nbits_rom_depth-1 downto 0);
+	addr_q		: in unsigned(nbits_rom_depth-1 downto 0);
+	wave_i_out	: out sfixed;
+	wave_q_out	: out sfixed
+);
+end waverom_dual;
+
+architecture Behavioral of waverom_dual is
+
+-------------------------------------------------------------------------------
+constant rom_depth : integer := 2**nbits_rom_depth;
+type wave_mem_t is array (0 to rom_depth-1) of sfixed(sproto(nbits_wave, nbits_wave_frac)'high downto sproto(nbits_wave, nbits_wave_frac)'low);
+
+constant sfixed_proto : sfixed(sproto(nbits_wave, nbits_wave_frac)'high downto sproto(nbits_wave, nbits_wave_frac)'low) := (others => '0');
+
+-------------------------------------------------------------------------------
+function to_wave_mem(wave_real : real_array_t; len : integer; proto : sfixed) return wave_mem_t is
+variable res : wave_mem_t;
+begin
+	for i in 0 to len-1 loop
+		res(i) := to_sfixed(wave_real(i), proto, fixed_round, fixed_saturate);
+	end loop;
+
+	return res;
+end to_wave_mem;	
+
+-------------------------------------------------------------------------------
+-- Create ROM
+constant real_wave_tbl : real_array_t(0 to rom_depth-1) := cos_tbl(rom_depth, 0.25/real(rom_depth), 0.0);
+constant wave_tbl : wave_mem_t := to_wave_mem(real_wave_tbl, rom_depth, sfixed_proto);
+
+-------------------------------------------------------------------------------
+begin
+
+-------------------------------------------------------------------------------
+proc_wave: process(clk)
+	begin
+		if rising_edge(clk) then
+			wave_i_out <= wave_tbl(to_integer(addr_i));
+			wave_q_out <= wave_tbl(to_integer(addr_q));
+		end if;	
+	end process;
+
+------------------------------------------------------------
+end Behavioral;