diff --git a/libraries/dsp/fft/src/vhdl/fft_lfsr.vhd b/libraries/dsp/fft/src/vhdl/fft_lfsr.vhd
index 56f5b5e453f9a2e009a05c2418f6890ee6aa22e3..7f53b0a398f8dddef39cc056eb7225767d53362b 100644
--- a/libraries/dsp/fft/src/vhdl/fft_lfsr.vhd
+++ b/libraries/dsp/fft/src/vhdl/fft_lfsr.vhd
@@ -21,12 +21,20 @@
-- Author: ported by E. Kooistra, original 2004 by W. Lubberhuizen / W. Poeisz
-- Purpose: Scramble quantization noise crosstalk between two real inputs
-- Description: Ported from LOFAR1, see readme_lofar1.txt
--- Remark: Copy from applications/lofar1/RSP/pft2/src/vhdl/pft_lfsr.vhd
+-- Remark:
+-- . Copy from applications/lofar1/RSP/pft2/src/vhdl/pft_lfsr.vhd
+-- . The g_seed must be > 0 for LFSR period is 2**c_fft_lfsr_len - 1. Value
+-- g_seed = 0 causes the LFSR to remain stuck at 0.
LIBRARY IEEE;
USE IEEE.std_logic_1164.ALL;
+USE work.fft_pkg.ALL;
ENTITY fft_lfsr IS
+ GENERIC (
+ g_seed1 : STD_LOGIC_VECTOR(c_fft_lfsr_len-1 DOWNTO 0) := c_fft_switch_seed1;
+ g_seed2 : STD_LOGIC_VECTOR(c_fft_lfsr_len-1 DOWNTO 0) := c_fft_switch_seed2
+ );
PORT (
in_en : IN STD_LOGIC;
out_bit1 : OUT STD_LOGIC;
@@ -43,23 +51,23 @@ ARCHITECTURE rtl OF fft_lfsr IS
-- x^41 + x^20 + 1 and x^41 + x^3 + 1
-- see XAPP217
- CONSTANT c_max : NATURAL := 41;
+ CONSTANT c_len : NATURAL := c_fft_lfsr_len; -- = 41, same for both trinomials
CONSTANT c1 : NATURAL := 20;
CONSTANT c2 : NATURAL := 3;
- SIGNAL s1 : STD_LOGIC_VECTOR(c_max-1 DOWNTO 0);
- SIGNAL nxt_s1 : STD_LOGIC_VECTOR(c_max-1 DOWNTO 0);
-
- SIGNAL s2 : STD_LOGIC_VECTOR(c_max-1 DOWNTO 0);
- SIGNAL nxt_s2 : STD_LOGIC_VECTOR(c_max-1 DOWNTO 0);
-
+ SIGNAL s1 : STD_LOGIC_VECTOR(c_len-1 DOWNTO 0);
+ SIGNAL nxt_s1 : STD_LOGIC_VECTOR(c_len-1 DOWNTO 0);
+ SIGNAL s2 : STD_LOGIC_VECTOR(c_len-1 DOWNTO 0);
+ SIGNAL nxt_s2 : STD_LOGIC_VECTOR(c_len-1 DOWNTO 0);
+
BEGIN
+
p_reg : PROCESS(rst,clk)
BEGIN
IF rst='1' THEN
- s1 <= "01000101011101110101001011111000101100001";
- s2 <= "11011001000101001011011001110101100101100";
+ s1 <= g_seed1;
+ s2 <= g_seed2;
ELSIF rising_edge(clk) THEN
s1 <= nxt_s1;
s2 <= nxt_s2;
@@ -69,22 +77,22 @@ BEGIN
out_bit1 <= s1(s1'HIGH);
out_bit2 <= s2(s2'HIGH);
- p_seed : PROCESS(in_en,s1,s2)
+ p_seed : PROCESS(in_en, s1, s2)
BEGIN
nxt_s1 <= s1;
nxt_s2 <= s2;
- IF in_en='1' THEN
+ IF in_en = '1' THEN
-- shift
- nxt_s1(c_max-1 DOWNTO 1) <= s1(c_max-2 DOWNTO 0);
- nxt_s2(c_max-1 DOWNTO 1) <= s2(c_max-2 DOWNTO 0);
+ nxt_s1(c_len-1 DOWNTO 1) <= s1(c_len-2 DOWNTO 0);
+ nxt_s2(c_len-1 DOWNTO 1) <= s2(c_len-2 DOWNTO 0);
-- feedback 1
- nxt_s1(0) <= s1(c_max-1);
- nxt_s2(0) <= s2(c_max-1);
+ nxt_s1(0) <= s1(c_len-1);
+ nxt_s2(0) <= s2(c_len-1);
-- feedback 2
- nxt_s1(c1) <= s1(c_max-1) xor s1(c1-1);
- nxt_s2(c2) <= s2(c_max-1) xor s2(c2-1);
+ nxt_s1(c1) <= s1(c_len-1) xor s1(c1-1);
+ nxt_s2(c2) <= s2(c_len-1) xor s2(c2-1);
END IF;
END PROCESS;
diff --git a/libraries/dsp/fft/src/vhdl/fft_pkg.vhd b/libraries/dsp/fft/src/vhdl/fft_pkg.vhd
index 4b4a00f80ba00c619efabaf1b8c5be9995588636..05eaa1ffb226920d9127c5d69ea56bdd2ecacefe 100644
--- a/libraries/dsp/fft/src/vhdl/fft_pkg.vhd
+++ b/libraries/dsp/fft/src/vhdl/fft_pkg.vhd
@@ -25,6 +25,13 @@ use common_lib.common_pkg.all;
package fft_pkg is
+ -- Default FFT switch and unswitch seeds from LOFAR1
+ constant c_fft_lfsr_len : natural := 41;
+ constant c_fft_switch_seed1 : std_logic_vector(c_fft_lfsr_len-1 DOWNTO 0) := "01000101011101110101001011111000101100001";
+ constant c_fft_switch_seed2 : std_logic_vector(c_fft_lfsr_len-1 DOWNTO 0) := "11011001000101001011011001110101100101100";
+
+ function fft_switch_new_seed(seed : std_logic_vector; offset : natural) return std_logic_vector;
+
-- FFT parameters for pipelined FFT (fft_pipe), parallel FFT (fft_par) and wideband FFT (fft_wide)
type t_fft is record
use_reorder : boolean; -- = false for bit-reversed output, true for normal output
@@ -68,6 +75,11 @@ end package fft_pkg;
package body fft_pkg is
+ function fft_switch_new_seed(seed : std_logic_vector; offset : natural) return std_logic_vector is
+ begin
+ return INCR_UVEC(seed, offset); -- make new unique seed
+ end;
+
function fft_r2_parameter_asserts(g_fft : t_fft) return boolean is
begin
-- nof_points
diff --git a/libraries/dsp/fft/src/vhdl/fft_r2_pipe.vhd b/libraries/dsp/fft/src/vhdl/fft_r2_pipe.vhd
index c9ed7f72c558ac588935c3670265363a810f4b5f..00c2007bd8a4bb7bafb6ca126bf1a11b5f602755 100644
--- a/libraries/dsp/fft/src/vhdl/fft_r2_pipe.vhd
+++ b/libraries/dsp/fft/src/vhdl/fft_r2_pipe.vhd
@@ -66,6 +66,7 @@ use work.fft_pkg.all;
entity fft_r2_pipe is
generic (
+ g_instance_index : natural := 0; -- used for FFT switch seed
g_fft : t_fft := c_fft; -- generics for the FFT
g_pipeline : t_fft_pipeline := c_fft_pipeline; -- generics for pipelining in each stage, defined in rTwoSDF_lib.rTwoSDFPkg
g_dont_flip_channels : boolean := false; -- generic to prevent re-ordering of the channels
@@ -92,6 +93,8 @@ architecture str of fft_r2_pipe is
constant c_switch_sz_w : natural := ceil_log2(g_fft.nof_points) + g_fft.nof_chan;
constant c_switch_dat_w : natural := g_fft.in_dat_w + 1; -- add 1 extra bit to fit negation of most negative value per real input switch function
constant c_unswitch_dat_w : natural := g_fft.out_dat_w; -- no need for extra bit, because most negative value cannot occur in output
+ constant c_switch_seed1 : STD_LOGIC_VECTOR(c_fft_lfsr_len-1 DOWNTO 0) := fft_switch_new_seed(c_fft_switch_seed1, g_instance_index);
+ constant c_switch_seed2 : STD_LOGIC_VECTOR(c_fft_lfsr_len-1 DOWNTO 0) := fft_switch_new_seed(c_fft_switch_seed2, g_instance_index);
constant c_nof_stages : natural := ceil_log2(g_fft.nof_points);
constant c_stage_offset : natural := true_log2(g_fft.wb_factor); -- Stage offset is required for twiddle generation in wideband fft
constant c_in_scale_w : natural := g_fft.stage_dat_w - g_fft.in_dat_w - sel_a_b(g_fft.guard_enable, g_fft.guard_w, 0);
@@ -143,6 +146,8 @@ begin
u_switch : ENTITY work.fft_switch
GENERIC MAP (
g_switch_en => c_switch_en,
+ g_seed1 => c_switch_seed1,
+ g_seed2 => c_switch_seed2,
g_fft_sz_w => c_switch_sz_w,
g_dat_w => c_switch_dat_w
)
@@ -303,6 +308,8 @@ begin
u_unswitch : ENTITY work.fft_unswitch
GENERIC MAP (
g_switch_en => c_switch_en,
+ g_seed1 => c_switch_seed1,
+ g_seed2 => c_switch_seed2,
g_fft_sz_w => c_switch_sz_w,
g_dat_w => c_unswitch_dat_w
)
diff --git a/libraries/dsp/fft/src/vhdl/fft_switch.vhd b/libraries/dsp/fft/src/vhdl/fft_switch.vhd
index cad57405ab3b2c03ed84834171fab082b2ed6b51..9da13b566ede8834d55739437b8515417fac3bf5 100644
--- a/libraries/dsp/fft/src/vhdl/fft_switch.vhd
+++ b/libraries/dsp/fft/src/vhdl/fft_switch.vhd
@@ -46,10 +46,13 @@
LIBRARY IEEE, common_lib;
USE IEEE.std_logic_1164.ALL;
USE common_lib.common_pkg.ALL;
+USE work.fft_pkg.ALL;
ENTITY fft_switch IS
GENERIC (
g_switch_en : BOOLEAN := FALSE;
+ g_seed1 : STD_LOGIC_VECTOR(c_fft_lfsr_len-1 DOWNTO 0) := c_fft_switch_seed1;
+ g_seed2 : STD_LOGIC_VECTOR(c_fft_lfsr_len-1 DOWNTO 0) := c_fft_switch_seed2;
g_fft_sz_w : NATURAL;
g_dat_w : NATURAL
);
@@ -156,6 +159,10 @@ BEGIN
END PROCESS;
u_fft_lfsr: ENTITY work.fft_lfsr
+ GENERIC MAP (
+ g_seed1 => g_seed1,
+ g_seed2 => g_seed2
+ )
PORT MAP (
clk => clk,
rst => rst,
diff --git a/libraries/dsp/fft/src/vhdl/fft_unswitch.vhd b/libraries/dsp/fft/src/vhdl/fft_unswitch.vhd
index 6d9f561a15e7ca184f70c418810bd85f9b1ac6d6..f94f12e7f0954a3b6af011504a33052e471bef90 100644
--- a/libraries/dsp/fft/src/vhdl/fft_unswitch.vhd
+++ b/libraries/dsp/fft/src/vhdl/fft_unswitch.vhd
@@ -31,10 +31,13 @@
LIBRARY IEEE, common_lib;
USE IEEE.std_logic_1164.ALL;
USE common_lib.common_pkg.ALL;
+USE work.fft_pkg.ALL;
ENTITY fft_unswitch IS
GENERIC (
g_switch_en : BOOLEAN := FALSE;
+ g_seed1 : STD_LOGIC_VECTOR(c_fft_lfsr_len-1 DOWNTO 0) := c_fft_switch_seed1;
+ g_seed2 : STD_LOGIC_VECTOR(c_fft_lfsr_len-1 DOWNTO 0) := c_fft_switch_seed2;
g_fft_sz_w : NATURAL;
g_dat_w : NATURAL
);
@@ -147,6 +150,10 @@ BEGIN
END PROCESS;
u_fft_lfsr: ENTITY work.fft_lfsr
+ GENERIC MAP (
+ g_seed1 => g_seed1,
+ g_seed2 => g_seed2
+ )
PORT MAP (
clk => clk,
rst => rst,
diff --git a/libraries/dsp/fft/tb/vhdl/tb_fft_switch.vhd b/libraries/dsp/fft/tb/vhdl/tb_fft_switch.vhd
index 08d04ee3e9bae1ffaea762e535be0d38d97395f6..981f017da2af2a9125e6155283168f6e17d83542 100644
--- a/libraries/dsp/fft/tb/vhdl/tb_fft_switch.vhd
+++ b/libraries/dsp/fft/tb/vhdl/tb_fft_switch.vhd
@@ -52,9 +52,11 @@ LIBRARY IEEE, common_lib;
USE IEEE.std_logic_1164.ALL;
USE common_lib.common_pkg.ALL;
USE common_lib.tb_common_pkg.ALL;
+USE work.fft_pkg.ALL;
ENTITY tb_fft_switch IS
GENERIC (
+ g_instance_index : NATURAL := 0;
g_switch_en : BOOLEAN := TRUE;
g_in_val_gaps : BOOLEAN := TRUE;
g_increment_at_val : BOOLEAN := TRUE;
@@ -66,9 +68,9 @@ END tb_fft_switch;
ARCHITECTURE tb OF tb_fft_switch IS
- CONSTANT clk_period : TIME := 10 ns;
+ CONSTANT clk_period : TIME := 10 ns;
- CONSTANT c_dat_w : NATURAL := 16;
+ CONSTANT c_dat_w : NATURAL := 16;
CONSTANT c_nof_clk_per_block : NATURAL := 2**g_fft_size_w;
CONSTANT c_nof_block_per_sync_max : NATURAL := ceil_div(g_nof_clk_per_sync, c_nof_clk_per_block);
@@ -76,6 +78,9 @@ ARCHITECTURE tb OF tb_fft_switch IS
CONSTANT c_dly : NATURAL := 4; -- pipeling in fft_switch, mux, fft_unswitch and demux
+ constant c_switch_seed1 : STD_LOGIC_VECTOR(c_fft_lfsr_len-1 DOWNTO 0) := fft_switch_new_seed(c_fft_switch_seed1, g_instance_index);
+ constant c_switch_seed2 : STD_LOGIC_VECTOR(c_fft_lfsr_len-1 DOWNTO 0) := fft_switch_new_seed(c_fft_switch_seed2, g_instance_index);
+
SIGNAL tb_end : STD_LOGIC := '0';
SIGNAL rst : STD_LOGIC := '1';
SIGNAL clk : STD_LOGIC := '0';
@@ -185,6 +190,8 @@ BEGIN
u_fft_switch : ENTITY work.fft_switch
GENERIC MAP (
g_switch_en => g_switch_en,
+ g_seed1 => c_switch_seed1,
+ g_seed2 => c_switch_seed2,
g_fft_sz_w => g_fft_size_w,
g_dat_w => c_dat_w
)
@@ -227,6 +234,8 @@ BEGIN
u_fft_unswitch : ENTITY work.fft_unswitch
GENERIC MAP (
g_switch_en => g_switch_en,
+ g_seed1 => c_switch_seed1,
+ g_seed2 => c_switch_seed2,
g_fft_sz_w => g_fft_size_w,
g_dat_w => c_dat_w
)
diff --git a/libraries/dsp/wpfb/src/vhdl/wpfb_unit_dev.vhd b/libraries/dsp/wpfb/src/vhdl/wpfb_unit_dev.vhd
index 158f3cb747fb60b86fb13e8ba917f330920df0d1..c12d89665762e8451ba9e6e337e367d3bb72f11f 100644
--- a/libraries/dsp/wpfb/src/vhdl/wpfb_unit_dev.vhd
+++ b/libraries/dsp/wpfb/src/vhdl/wpfb_unit_dev.vhd
@@ -597,6 +597,7 @@ begin
gen_fft_r2_pipe_streams: for S in 0 to g_wpfb.nof_wb_streams-1 generate
u_fft_r2_pipe : entity fft_lib.fft_r2_pipe
generic map(
+ g_instance_index => S,
g_fft => c_fft,
g_pipeline => g_wpfb.fft_pipeline,
g_dont_flip_channels => g_dont_flip_channels,