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 d4242feaebc959a9d0e792e2416a2f3cb1ec3c88..27447448cb25d3e196dfb262c3f0f332e86be09e 100644
--- a/libraries/base/dp/src/vhdl/dp_bsn_align_v2.vhd
+++ b/libraries/base/dp/src/vhdl/dp_bsn_align_v2.vhd
@@ -20,36 +20,36 @@
-- Purpose :
-- Align frames from multiple input streams
-- Description:
--- The aligner uses a circular buffer to capture the blocks that arrive at
--- the input streams. The blocks have a block sequence number (BSN) that
--- is used to align the inputs. The input stream 0 is treated as local
--- input stream that is ahead of the other remote input streams. After a
--- certain number of blocks on input 0, the same block on all remote
--- inputs should also have arrived. If not then they are replaced by
--- replacement data. The output streams are paced by the block rate of
--- input 0. The user has to read the block within the block period.
+-- Aligner:
+-- . The aligner uses a circular buffer to capture the blocks that arrive at
+-- the input streams. The blocks have a block sequence number (BSN) that
+-- is used to align the inputs. The input stream 0 is treated as local
+-- input stream that is ahead of the other remote input streams. After a
+-- certain number of blocks on input 0, the same block on all remote
+-- inputs should also have arrived. If not then they are replaced by
+-- replacement data. The output streams are paced by the block rate of
+-- input 0. The user has to read the block within the block period.
+-- . The aligner can align g_nof_streams that all arrive within a latency
+-- of g_bsn_latency_max after the local stream at index 0. The aligner
+-- can also be used in a chain of aligners, whereby each aligner typically
+-- has the local input and one remote input and the remote input is the
+-- output of an upstream aligner. Then the latency on the last node in
+-- the chain will be within g_nof_aligners_max * g_bsn_latency_max.
--
--- The aligner can align g_nof_streams that all arrive within a latency
--- of g_bsn_latency_max after the local stream at index 0. The aligner
--- can also be used in a chain of aligners, whereby each aligner typically
--- has the local input and one remote input and the remote input is the
--- output of an upstream aligner. Then the latency on the last node in
--- the chain will be within g_nof_aligners_max * g_bsn_latency_max.
---
--- The size of the circular buffer is c_buffer_nof_blocks and depends on the
--- maximum latency. The c_buffer_nof_blocks has to a power of two to ease
--- the control of the circular buffer. The lowest bits of the input block
--- sequence number (BSN) are used as write block index into the circular
--- buffer. The g_bsn_latency_first_node can be useful to reduce the
--- required circular buffer size just enough, such that the next power of two
--- is only a feq blocks larger, instead of almost a factor two larger. This
--- then may save a significant amount of block RAM.
---
--- In case of a chain of aligners then the circular buffer size depends on
--- the latency of local input. The most remote input will only use a
--- fraction of the buffer. Therefore more block RAM can be saved by using
--- a smaller circular buffer size for signal inputs that are from more
--- remote (i.e. that have passed through more upstream aligners).
+-- Circular buffer:
+-- . The size of the circular buffer is c_buffer_nof_blocks and depends on
+-- the maximum latency. The c_buffer_nof_blocks has to a power of two to
+-- ease the control of the circular buffer. The lowest bits of the input
+-- block sequence number (BSN) are used as write block index into the
+-- circular buffer. The g_bsn_latency_first_node can be useful to reduce
+-- the required circular buffer size just enough, such that the next power
+-- of two is only a few blocks larger, instead of almost a factor two
+-- larger. This then can save a significant amount of block RAM.
+-- . In case of a chain of aligners then the circular buffer size depends on
+-- the latency of local input. The most remote input will only use a
+-- fraction of the buffer. Therefore more block RAM can be saved by using
+-- a smaller circular buffer size for signal inputs that are from more
+-- remote (i.e. that have passed through more upstream aligners).
--
-- Features:
-- . The g_block_size <= block period, so supports input blocks arriving
@@ -213,7 +213,7 @@ architecture rtl of dp_bsn_align_v2 is
-- . For unique representation as signal wire, the p_comb should assign each
-- field in t_comb only once to a variable. It is allowed to reasign a
-- t_comb variable in p_comb, but then only the last assignment value will
- -- be visible via the signal dbg_wires in the Wave window.
+ -- be visible via the signal w_comb in the Wave window.
type t_comb is record
blk_pointer_slv : std_logic_vector(c_blk_pointer_w - 1 downto 0);
product_slv : std_logic_vector(c_product_w - 1 downto 0);
@@ -248,7 +248,7 @@ architecture rtl of dp_bsn_align_v2 is
signal nxt_r : t_reg;
-- Memoryless signals in p_comb (wires used as local variables)
- signal dbg_wires : t_comb;
+ signal w_comb : t_comb;
-- Structural signals (wires used to connect components and IO)
signal dp_done : std_logic;
@@ -333,11 +333,11 @@ begin
-- p_control, all at sop of local reference input 0
---------------------------------------------------------------------------
v.ref_sosi := in_sosi_arr_p(0);
- -- Use r.ref_sosi.sop, that occurs one cycle after in_sosi_arr_p(I).sop,
- -- to support immediate aligner output when g_use_aligner_at_first_node =
- -- false. While the local block of chain_node_index = 0 is written into
- -- the circular buffer, then it can already be read from the circular
- -- buffer one dp_clk cycle later.
+ -- Use v.ref_sosi.sop instead of r.ref_sosi.sop, to support alignment of
+ -- streams that have no data valid gap between blocks, so when
+ -- g_block_size is equal to the block period or when shorter blocks have
+ -- jitter in arrival time that could cause two blocks to arrive without a
+ -- gap.
if v.ref_sosi.sop = '1' then
-- . write sync & bsn buffer
v.wr_blk_pointer := TO_UINT(v.ref_sosi.bsn(c_blk_pointer_w - 1 downto 0));
@@ -365,6 +365,10 @@ begin
v.rd_offset := RESIZE_UVEC(w.product_slv, c_ram_buf.adr_w);
-- . issue mm_sosi, if there is output ready to be read, indicated by filled reference block
+ -- - can use 'if r.filled_arr(0)' instead of 'if v.filled_arr(0)',
+ -- because input stream 0 arrives first, so is already filled
+ -- - need to use 'not v.filled_arr(I)' for w.lost_data_flags_arr(I),
+ -- because last input I = g_nof_streams - 1 may just got filled.
if r.filled_arr(0)(v.rd_blk_pointer) = '1' then
v.mm_sosi.sop := '1';
v.mm_sosi.eop := '1';
@@ -413,7 +417,7 @@ begin
-- Do the output via the MM interface
--------------------------------------------------------------------------
-- . adjust the rd address to the current buffer output block
- -- sum yields c_ram_buf.adr_w bits, because left operand in ADD_UVECdetermines width
+ -- sum yields c_ram_buf.adr_w bits, because left operand in ADD_UVEC determines width
v.rd_copi := mm_copi;
v.rd_copi.address := RESIZE_MEM_ADDRESS(ADD_UVEC(r.rd_offset, mm_copi.address));
@@ -427,7 +431,7 @@ begin
-- Do the output via the DP streaming interface
--------------------------------------------------------------------------
-- . adjust the rd address
- -- sum yields c_ram_buf.adr_w bits, because left operand in ADD_UVECdetermines width
+ -- sum yields c_ram_buf.adr_w bits, because left operand in ADD_UVEC determines width
v.rd_copi := dp_copi;
v.rd_copi.address := RESIZE_MEM_ADDRESS(ADD_UVEC(r.rd_offset, dp_copi.address));
@@ -475,7 +479,7 @@ begin
nxt_r <= v;
-- local wires, only for view in wave window
- dbg_wires <= w;
+ w_comb <= w;
end process;
------------------------------------------------------------------------------