- new signal 'start' to trigger FIR process

use din_vld for data load. This permits decimation FIR filtering


git-svn-id: http://moon:8086/svn/vhdl/trunk@217 cc03376c-175c-47c8-b038-4cd826a8556b

lib/filter/src/fir_semi_parallel.vhd

@@ -58,6 +58,7 @@ Port
 	din_vld		: in std_logic;
 	din			: in sfixed;
 	dout_vld	: out std_logic;
+	start		: in std_logic;
 	rdy			: out std_logic;
 	dout		: out sfixed
 );
@@ -103,10 +104,11 @@ architecture Behavioral of fir_semi_parallel is
 	-------------------------------------------------------------------------------
 begin
 
+	assert nstages > 0 report "nstages  must be greater than 0!" severity failure;
 	assert ntaps_per_stage = NextPowerOfTwo(ntaps_per_stage) report "ntaps_per_stage must be of form 2**R!" severity failure;
 	assert ntaps_per_stage >= 4 report "ntaps_per_stage must be greater than 4" severity failure;
 
-	x(0)		<= resize(din_r, x(0));
+	x(0)		<= resize(din, x(0));
 	y(0)		<= to_sfixed(0.0, y(0));
 
 	accu_load	<= accu_ld_pipe(accu_ld_pipe'left);
@@ -168,7 +170,7 @@ counter:
 				end if;	
 			else
 				en	<= '0';
-				if din_vld = '1' then
+				if start = '1' then
 					en	<= '1';
 					cnt := 0;
 					ce0	<= '1';
@@ -256,10 +258,29 @@ gen_stages:
 	end generate;
 					
 
+inst_first_delay_line : entity work.delay_line(ram_based)
+	GENERIC MAP
+	(
+		nbits		=> nbits_stages,
+		nbits_frac	=> nbits_stages_frac,
+		ntaps		=> ntaps_per_stage,
+		delay_fix	=> 0
+	)
+	PORT MAP
+	(
+		rst			=> rst,
+		clk			=> clk,
+		ce			=> '1',
+		shift_en	=> din_vld,
+		delay		=> count_array(0),
+		din			=> x(0),
+		dout		=> x(1)
+	);
+
 gen_delays:
-	for i in 0 to nstages-1 generate
+	for i in 1 to nstages-1 generate
 	begin
-		inst_delay_line : entity work.delay_line(ram_based)
+		inst_delay_lines : entity work.delay_line(ram_based)
 		GENERIC MAP
 		(
 			nbits		=> nbits_stages,

lib/filter/src/tb_fir_semi_parallel.vhd

@@ -31,8 +31,8 @@ use work.PCK_FIO.all;
 ENTITY tb_fir_semi_parallel IS
 	Generic
 	(
-		ntaps_per_stage		: integer := 32;
+		ntaps_per_stage		: integer := 16;
-		nstages				: integer := 2;
+		nstages				: integer := 4;
 		nbits_in			: integer := 32;
 		nbits_in_frac		: integer := 30;
 		nbits_stages		: integer := 32;
@@ -47,7 +47,7 @@ ARCHITECTURE behavior OF tb_fir_semi_parallel IS
 	-------------------------------------------------------------------------------
 	--Constants
 	constant PERIOD : time := 10 ns;
-	constant zero_in : sfixed := to_sfixed(0, nbits_in, nbits_in_frac);
+	constant nsamples : integer := 32;
 
 	--Inputs
 	SIGNAL clk			: std_logic := '0';
@@ -57,6 +57,7 @@ ARCHITECTURE behavior OF tb_fir_semi_parallel IS
 	signal h_addr		: natural := 0;
 	SIGNAL h_we			: std_logic := '0';
 	SIGNAL h_in			: sfixed(shi(nbits_stages, nbits_stages_frac) downto slo(nbits_stages, nbits_stages_frac));
+	SIGNAL start		: std_logic := '0';
 
 	--Outputs
 	SIGNAL d_out		: sfixed(shi(nbits_out, nbits_out_frac) downto slo(nbits_out, nbits_out_frac));
@@ -87,6 +88,43 @@ ARCHITECTURE behavior OF tb_fir_semi_parallel IS
 	-- file I/O
 	subtype sample_t is integer range -32768 to 32767;
 	type file_t is file of sample_t;
+
+	signal x_input : real_array_t(0 to nsamples-1) :=
+	(
+		0.0,	
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.9999,
+		-0.0000,	
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0,		
+		0.0
+		
+	);
 	
 	-------------------------------------------------------------------------------
 BEGIN
@@ -102,7 +140,7 @@ BEGIN
 	(
 		ntaps_per_stage		=> ntaps_per_stage,
 		nstages				=> nstages,
-		mul_latency			=> 2,
+		mul_latency			=> 5,
 		nbits_in			=> nbits_in,
 		nbits_in_frac		=> nbits_in_frac,
 		nbits_stages		=> nbits_stages,
@@ -121,6 +159,7 @@ BEGIN
 		din			=> d_in,
 		dout_vld	=> dout_vld,
 		rdy			=> rdy,
+		start		=> start,
 		dout		=> d_out
 	);
 	
@@ -160,51 +199,39 @@ BEGIN
 		wait until rising_edge(clk);
 		h_we	<= '0';
 
-		d_in <= to_sfixed(0.0, d_in);
+		-- Write zeros
-		wait for 64*ntaps*PERIOD;
+		for i in 0 to ntaps_per_stage*nstages-1 loop
-		wait until rising_edge(clk);
-			
-		for i in 0 to 19 loop
 			wait until rising_edge(clk) and rdy = '1';
-			din_vld <= '1';
-			d_in <= to_sfixed(real(i)*0.01, d_in);
-			wait until rising_edge(clk);
-			din_vld <= '0';
-		end loop;
-		wait until rising_edge(clk) and rdy = '1';
-		------------------------------------------
-		din_vld <= '1';
-		d_in <= to_sfixed(0.0, d_in);
-		wait for 64*ntaps*PERIOD;
-		wait until rising_edge(clk);
-		din_vld <= '0';
-		
- 		wait for 64*ntaps*PERIOD;
-		
-		wait until rising_edge(clk) and rdy = '1';
-		din_vld <= '1';
-		d_in <= to_sfixed(1.0, d_in);
-		wait until rising_edge(clk);
-		din_vld <= '0';
-
- 		wait for 10*PERIOD;
-		wait until rising_edge(clk) and rdy = '1';
-		din_vld <= '1';
-		d_in <= to_sfixed(0.0, d_in);
-		wait until rising_edge(clk);
-		din_vld <= '0';
-
-		for i in 0 to 9999 loop
-	 		wait for 2*PERIOD;
-			wait until rising_edge(clk) and rdy = '1';
-			din_vld <= '1';
 			d_in <= to_sfixed(0.0, d_in);
+			din_vld <= '1';
+			start <= '1';
 			wait until rising_edge(clk);
 			din_vld <= '0';
-			
+			start <= '0';
+		end loop;
+
+		------------------------------------------
+		-- Write data
+		for i in 0 to nsamples-1 loop
+			wait until rising_edge(clk) and rdy = '1';
+			d_in <= to_sfixed(x_input(i), d_in);
+			din_vld <= '1';
+			start <= '1';
+			wait until rising_edge(clk);
+			din_vld <= '0';
+			start <= '0';
+		end loop;
+
+		-- Write zeros
+		for i in 0 to 99 loop
+			wait until rising_edge(clk) and rdy = '1';
+			d_in <= to_sfixed(0.0, d_in);
+			din_vld <= '1';
+			start <= '1';
+			wait until rising_edge(clk);
+			din_vld <= '0';
+			start <= '0';
 		end loop;
-		
-		wait for 40*PERIOD;
 
 		assert false report "Test finished" severity error;
 		wait;