Clarify g_nof_destinations_max design revision parameter and package constants...

Clarify g_nof_destinations_max design revision parameter and package constants c_sdp_bdo_mm_nof_destinations_max = 32 and c_sdp_bdo_reorder_nof_blocks_max = 16.

Closes L2SDP-964

applications/lofar2/libraries/sdp/src/vhdl/sdp_beamformer_output.vhd

@@ -319,34 +319,36 @@ begin
     -----------------------------------------------------------------------------
     -- Register output info dependent on DN and DI to ease timing closure
     p_reg : process(dp_clk)
-      variable v_DN : natural;  -- number of destinations
       variable v_DI : natural;  -- destination index
     begin
       if rising_edge(dp_clk) then
-        v_DN := multi_destinations_info.nof_destinations_act;
-        v_DI := to_uint(dp_fifo_data_src_out.channel);
-
-        s_DN <= v_DN;
-        s_DI <= v_DI;
-
-        -- Variable values that depend on DN set via MM and/or on current DI
-        -- from dp_packet_unmerged that is passed on via
-        -- dp_fifo_data_src_out.channel.
-        -- . Use s_DN to ease timing closure. Use v_DI to ensure that the mdi
-        --   values are valid at dp_pipeline_data_src_out.sop
-        mdi_eth_dst_mac  <= multi_destinations_info.eth_destination_mac_arr(v_DI);
-        mdi_ip_dst_addr  <= multi_destinations_info.ip_destination_address_arr(v_DI);
-        mdi_udp_dst_port <= multi_destinations_info.udp_destination_port_arr(v_DI);
-
-        -- . Account for beamset offset in beamlet index
-        mdi_beamlet_index_per_destination <= c_beamset_beamlet_index + c_beamlet_index_per_destination_mat(s_DN, v_DI);
-        -- . In total there are S_sub_bf = 488 beamlets for nof_destinations.
-        --   The packet for last destination contains the same number of
-        --   beamlets as the first destinations, or less beamlets.
-        if v_DI < s_DN - 1 then
-          mdi_nof_beamlets_per_block_per_destination <= mdi_nof_beamlets_per_block_first_destinations;
-        else
-          mdi_nof_beamlets_per_block_per_destination <= mdi_nof_beamlets_per_block_last_destination;
+        -- Register number of destinations (DN)
+        s_DN <= multi_destinations_info.nof_destinations_act;
+
+        -- Capture destination index (DI) from channel field, valid at sop
+        if dp_fifo_data_src_out.sop = '1' then
+          v_DI := to_uint(dp_fifo_data_src_out.channel);
+          s_DI <= v_DI;  -- for view in Wave window
+
+          -- Variable values that depend on DN set via MM and/or on current DI
+          -- from dp_packet_unmerged that is passed on via
+          -- dp_fifo_data_src_out.channel.
+          -- . Use s_DN to ease timing closure. Use v_DI to ensure that the mdi
+          --   values are valid at dp_pipeline_data_src_out.sop
+          mdi_eth_dst_mac  <= multi_destinations_info.eth_destination_mac_arr(v_DI);
+          mdi_ip_dst_addr  <= multi_destinations_info.ip_destination_address_arr(v_DI);
+          mdi_udp_dst_port <= multi_destinations_info.udp_destination_port_arr(v_DI);
+
+          -- . Account for beamset offset in beamlet index
+          mdi_beamlet_index_per_destination <= c_beamset_beamlet_index + c_beamlet_index_per_destination_mat(s_DN, v_DI);
+          -- . In total there are S_sub_bf = 488 beamlets for nof_destinations.
+          --   The packet for last destination contains the same number of
+          --   beamlets as the first destinations, or less beamlets.
+          if v_DI < s_DN - 1 then
+            mdi_nof_beamlets_per_block_per_destination <= mdi_nof_beamlets_per_block_first_destinations;
+          else
+            mdi_nof_beamlets_per_block_per_destination <= mdi_nof_beamlets_per_block_last_destination;
+          end if;
         end if;
       end if;
     end process;
@@ -408,15 +410,25 @@ begin
   );
 
   -- FIFO: to store and align payload error bit from eop to sop
-  -- Simple fifo to store the payload error bit at eop of FIFO input to be used
-  -- at sop of FIFO output, so that payload_err can then be used in the packet
-  -- header. Typically the u_dp_fifo_data will store between 0 and
-  -- c_sdp_N_beamsets = 2 packets. Choose g_nof_words > c_sdp_N_beamsets to
-  -- have some margin compared to c_fifo_size of the data FIFO.
+  -- . The payload error bit is set when dp_packet_merge detects an BSN
+  --   increment error. The dual page mechanism in reorder_col_select makes
+  --   that the sosi.err bit will be valid during the entire output packet,
+  --   so that it can be passed on at the sop via the application header.
+  --   For g_nof_destinations > 1 each destination packet will have its
+  --   payload error bit set as well, because dp_packet_unmerge applies the
+  --   input sosi.err at the sop to all unmerged output packets.
+  -- . Simple fifo to store the payload error bit at eop of FIFO input to be
+  --   used at sop of FIFO output, so that payload_err can then be used in
+  --   the packet header. Typically the u_dp_fifo_data will store between 0
+  --   and c_sdp_N_beamsets = 2 packets. Choose g_nof_words > c_sdp_N_beamsets
+  --   to have some margin compared to c_fifo_size of the data FIFO.
+  -- . No need to account for g_nof_destinations_max > 1 in FIFO g_nof_words,
+  --   because the BDO packets are multiplexed round-robin with fair chance
+  --   per beamset by the dp_mux in sdp_station.vhd
   u_common_fifo_err : entity common_lib.common_fifo_sc
   generic map (
     g_dat_w => 1,
-    g_nof_words => g_nof_destinations_max * c_sdp_N_beamsets + 2
+    g_nof_words => c_sdp_N_beamsets + 2
   )
   port map (
     rst    => dp_rst,