diff --git a/libraries/base/dp/hdllib.cfg b/libraries/base/dp/hdllib.cfg
index 1d3533b137fdbd8d27f60afb547b4febd902487b..26e882b63228ecd4ab4c86bd1150e28e84695f03 100644
--- a/libraries/base/dp/hdllib.cfg
+++ b/libraries/base/dp/hdllib.cfg
@@ -110,6 +110,7 @@ synth_files =
src/vhdl/dp_bsn_align.vhd
src/vhdl/dp_bsn_align_reg.vhd
src/vhdl/mms_dp_bsn_align.vhd
+ src/vhdl/dp_bsn_align_buffer.vhd
src/vhdl/dp_bsn_align_v2.vhd
src/vhdl/mmp_dp_bsn_align_v2.vhd
src/vhdl/dp_frame_rd.vhd
diff --git a/libraries/base/dp/src/vhdl/dp_bsn_align_buffer.vhd b/libraries/base/dp/src/vhdl/dp_bsn_align_buffer.vhd
new file mode 100644
index 0000000000000000000000000000000000000000..3bff0bcf7e754abce1f79298d09c9c021ce7f742
--- /dev/null
+++ b/libraries/base/dp/src/vhdl/dp_bsn_align_buffer.vhd
@@ -0,0 +1,114 @@
+-------------------------------------------------------------------------------
+--
+-- Copyright (C) 2024
+-- ASTRON (Netherlands Institute for Radio Astronomy) <http://www.astron.nl/>
+-- P.O.Box 2, 7990 AA Dwingeloo, The Netherlands
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program. If not, see <http://www.gnu.org/licenses/>.
+--
+-------------------------------------------------------------------------------
+
+-- Author: E. Kooistra
+-- Purpose: Circular buffer for dp_bsn_align_v2
+-- Description:
+-- . Default use same buffer size for all streams.
+-- . Optionally use reduced size for the remote stream to save block RAM. The
+-- reduced size is possible when there is only one remote input (so
+-- g_nof_streams = 2) and that input has been passed along a series of
+-- bsn aligners (so g_nof_aligners_max > 1). The local input requires the
+-- default buffer size (= g_ram_buf), but the remote input then can use a
+-- reduced buffer size (g_remote_ram_buf).
+-- . The buffer sizes have to be a power of two number of blocks.
+
+library IEEE, common_lib;
+use IEEE.std_logic_1164.all;
+use common_lib.common_mem_pkg.all;
+
+entity dp_bsn_align_buffer is
+ generic (
+ g_nof_streams : natural;
+ g_nof_aligners_max : natural := 1;
+ -- Default RAM buffer size for all streams
+ g_ram_buf : t_c_mem;
+ -- Optional smaller size for remote stream when c_use_reduced_remote_buffer = true
+ g_remote_ram_buf : t_c_mem := c_mem_ram
+ );
+ port (
+ dp_rst : in std_logic := '0';
+ dp_clk : in std_logic;
+ wr_copi_arr : in t_mem_copi_arr(g_nof_streams - 1 downto 0);
+ rd_copi : in t_mem_copi;
+ rd_cipo_arr : out t_mem_cipo_arr(g_nof_streams - 1 downto 0)
+ );
+end dp_bsn_align_buffer;
+
+architecture str of dp_bsn_align_buffer is
+ constant c_use_reduced_remote_buffer : boolean := g_nof_streams = 2 and g_nof_aligners_max > 1;
+begin
+ use_uniform_data_buffer : if c_use_reduced_remote_buffer = false generate
+ gen_data_buffer : for I in 0 to g_nof_streams - 1 generate
+ u_data_buffer : entity common_lib.common_ram_r_w
+ generic map (
+ g_ram => g_ram_buf
+ )
+ port map (
+ rst => dp_rst,
+ clk => dp_clk,
+ wr_en => wr_copi_arr(I).wr,
+ wr_adr => wr_copi_arr(I).address(g_ram_buf.adr_w - 1 downto 0),
+ wr_dat => wr_copi_arr(I).wrdata(g_ram_buf.dat_w - 1 downto 0),
+ rd_en => rd_copi.rd,
+ rd_adr => rd_copi.address(g_ram_buf.adr_w - 1 downto 0),
+ rd_dat => rd_cipo_arr(I).rddata(g_ram_buf.dat_w - 1 downto 0),
+ rd_val => rd_cipo_arr(I).rdval
+ );
+ end generate;
+ end generate;
+
+ use_reduced_data_buffer : if c_use_reduced_remote_buffer = true generate
+ -- Local data buffer has default size
+ u_local_data_buffer : entity common_lib.common_ram_r_w
+ generic map (
+ g_ram => g_ram_buf
+ )
+ port map (
+ rst => dp_rst,
+ clk => dp_clk,
+ wr_en => wr_copi_arr(0).wr,
+ wr_adr => wr_copi_arr(0).address(g_ram_buf.adr_w - 1 downto 0),
+ wr_dat => wr_copi_arr(0).wrdata(g_ram_buf.dat_w - 1 downto 0),
+ rd_en => rd_copi.rd,
+ rd_adr => rd_copi.address(g_ram_buf.adr_w - 1 downto 0),
+ rd_dat => rd_cipo_arr(0).rddata(g_ram_buf.dat_w - 1 downto 0),
+ rd_val => rd_cipo_arr(0).rdval
+ );
+
+ -- Remote data buffer has reduced size, to save block RAM
+ u_remote_data_buffer : entity common_lib.common_ram_r_w
+ generic map (
+ g_ram => g_remote_ram_buf
+ )
+ port map (
+ rst => dp_rst,
+ clk => dp_clk,
+ wr_en => wr_copi_arr(1).wr,
+ wr_adr => wr_copi_arr(1).address(g_remote_ram_buf.adr_w - 1 downto 0),
+ wr_dat => wr_copi_arr(1).wrdata(g_remote_ram_buf.dat_w - 1 downto 0),
+ rd_en => rd_copi.rd,
+ rd_adr => rd_copi.address(g_remote_ram_buf.adr_w - 1 downto 0),
+ rd_dat => rd_cipo_arr(1).rddata(g_remote_ram_buf.dat_w - 1 downto 0),
+ rd_val => rd_cipo_arr(1).rdval
+ );
+ end generate;
+end str;
diff --git a/libraries/base/dp/src/vhdl/dp_bsn_align_v2.vhd b/libraries/base/dp/src/vhdl/dp_bsn_align_v2.vhd
index 61db3174e6f4f846ff445cecef3a07421177f3b2..1db302c2c260d6961ad03118b44550c0afb7e6fd 100644
--- a/libraries/base/dp/src/vhdl/dp_bsn_align_v2.vhd
+++ b/libraries/base/dp/src/vhdl/dp_bsn_align_v2.vhd
@@ -168,6 +168,7 @@ end dp_bsn_align_v2;
architecture rtl of dp_bsn_align_v2 is
-- Circular buffer per stream, size is next power of two that fits
+ -- . default buffer size for uniform buffer
constant c_buffer_nof_blocks : natural := sel_a_b(g_nof_aligners_max = 1,
true_log_pow2(1 + g_bsn_latency_max),
true_log_pow2(1 + g_bsn_latency_max * (g_nof_aligners_max - 1) + g_bsn_latency_first_node));
@@ -179,6 +180,15 @@ architecture rtl of dp_bsn_align_v2 is
nof_dat => c_ram_size,
init_sl => '0');
+ -- . reduced buffer size for remote input
+ constant c_remote_buffer_nof_blocks : natural := true_log_pow2(1 + g_bsn_latency_max);
+ constant c_remote_ram_size : natural := c_remote_buffer_nof_blocks * g_block_size;
+ constant c_remote_ram_buf : t_c_mem := (latency => 1,
+ adr_w => ceil_log2(c_remote_ram_size),
+ dat_w => g_data_w,
+ nof_dat => c_remote_ram_size,
+ init_sl => '0');
+
-- Use +1 to ensure that g_block_size that is power of two also fits in c_block_size_slv
constant c_block_size_w : natural := ceil_log2(g_block_size + 1);
constant c_block_size_slv : std_logic_vector(c_block_size_w - 1 downto 0) := TO_UVEC(g_block_size, c_block_size_w);
@@ -500,23 +510,22 @@ begin
-- Circular buffers
------------------------------------------------------------------------------
- gen_data_buffer : for I in 0 to g_nof_streams - 1 generate
- u_data_buffer : entity common_lib.common_ram_r_w
- generic map (
- g_ram => c_ram_buf
- )
- port map (
- rst => dp_rst,
- clk => dp_clk,
- wr_en => r.wr_copi_arr(I).wr,
- wr_adr => r.wr_copi_arr(I).address(c_ram_buf.adr_w - 1 downto 0),
- wr_dat => r.wr_copi_arr(I).wrdata(c_ram_buf.dat_w - 1 downto 0),
- rd_en => rd_copi.rd,
- rd_adr => rd_copi.address(c_ram_buf.adr_w - 1 downto 0),
- rd_dat => rd_cipo_arr(I).rddata(c_ram_buf.dat_w - 1 downto 0),
- rd_val => rd_cipo_arr(I).rdval
- );
- end generate;
+ u_circular_buffer : entity work.dp_bsn_align_buffer
+ generic map (
+ g_nof_streams => g_nof_streams,
+ g_nof_aligners_max => g_nof_aligners_max,
+ -- Default RAM buffer size for all streams
+ g_ram_buf => c_ram_buf,
+ -- Optional smaller size for remote stream when g_nof_streams = 2 and g_nof_aligners_max > 1
+ g_remote_ram_buf => c_remote_ram_buf
+ )
+ port map (
+ dp_rst => dp_rst,
+ dp_clk => dp_clk,
+ wr_copi_arr => r.wr_copi_arr,
+ rd_copi => rd_copi,
+ rd_cipo_arr => rd_cipo_arr
+ );
------------------------------------------------------------------------------
-- MM to streaming DP