Add 'si_ack' to DDS Reader

Previously the simaple info data was valid for exectly 1 clock cycle,
in which the user had to pull the 'get_data' signal if he wanted the
associated payload.
This change allows the user to control how long the sample info data is
shown.

src/Tests/Level_0/L0_dds_reader_test1_abzkriu.vhd

@@ -205,6 +205,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test1_arzkriu.vhd

@@ -204,6 +204,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test1_arzksiu.vhd

@@ -204,6 +204,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test1_arznriu.vhd

@@ -183,6 +183,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test1_lbzkriu.vhd

@@ -205,6 +205,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test1_lrzkriu.vhd

@@ -205,6 +205,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test2_arpkriu.vhd

@@ -158,6 +158,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test3_arzkrio.vhd

@@ -198,6 +198,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test3_arzkriu.vhd

@@ -198,6 +198,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test3_arzkrto.vhd

@@ -198,6 +198,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test3_arzkrtu.vhd

@@ -198,6 +198,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test3_arzksto.vhd

@@ -199,6 +199,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test3_arznriu.vhd

@@ -179,6 +179,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test4_arzkriu.vhd

@@ -158,6 +158,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test4_arznriu.vhd

@@ -158,6 +158,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test5_arzkriu.vhd

@@ -158,6 +158,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test6_arzkriu.vhd

@@ -158,6 +158,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/Tests/Level_0/L0_dds_reader_test7_arzkriu.vhd

@@ -158,6 +158,7 @@ begin
             si_absolute_generation_rank     => si_absolute_generation_rank,
             si_valid_data                   => si_valid_data,
             si_valid                        => si_valid,
+            si_ack                          => '1',
             eoc                             => eoc,
             status                          => status
         );

src/dds_reader.vhd

@@ -84,6 +84,7 @@ entity dds_reader is
         si_absolute_generation_rank     : out std_logic_vector(ABSOLUTE_GENERATION_COUNT_WIDTH-1 downto 0);
         si_valid_data                   : out std_logic;
         si_valid                        : out std_logic;
+        si_ack                          : in std_logic;
         eoc                             : out std_logic;
         -- Communication Status
         status                          : out std_logic_vector(STATUS_KIND_WIDTH-1 downto 0)
@@ -647,8 +648,8 @@ begin
     -- GET_KEY_HASH                         Fetch the calculated key hash from the Key Hash Generator
     -- INITIATE_INSTANCE_SEARCH             Initiate Instance Search Memory Operation. This state is used to start the Search operation as soon as the required data is available
     -- FILTER_STAGE                         This state decides if the RTPS Cache Change is accepted, dropped, or rejected. It also decides what sample (if any) has to be removed.
-    -- UPDATE_INSTANCE                      Update the Data of the Instance of the received saample (Cache Change)
-    -- FINALIZE_PAYLOAD                     Finalize the payload addition (Update pointers).
+    -- UPDATE_INSTANCE                      Update the Data of the Instance of the received sample (Cache Change)
+    -- FINALIZE_PAYLOAD                     Finalize the payload addition (Update pointers)
     -- PRE_SAMPLE_FINALIZE                  Store Sample Info based on Instance Data
     -- FIND_POS                             Find Sample List position based on DESTINATION_ORDER_QOS
     -- FIX_POINTERS                         Update the List Pointers of the inserted Sample neighbours (First Step of Sample Addition Finalization)
@@ -3975,6 +3976,8 @@ begin
                         -- Reset Data Available Status
                         status_sig_next <= status_sig and (not DATA_AVAILABLE_STATUS);
                         
+                        -- Wait on User
+                        if (si_ack = '1') then
                             -- Sample Data Request
                             if (get_data_dds = '1') then
                                 stage_next  <= GET_PAYLOAD;
@@ -3984,6 +3987,7 @@ begin
                                 -- Invalidate Data
                                 si_valid_sig_next   <= '0';
                             end if;
+                        end if;
                     -- Post-Present Data
                     when 2 =>
                         -- Memory Operation Guard