tb_vtu: add a test for lowfreq mode.

7efea296 · Tristan Gingold · c1ebd73b · 7efea296
Commit 7efea296 authored Apr 24, 2020 by Tristan Gingold
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Showing with 74 additions and 13 deletions

tb_vtu.vhd hdl/testbench/vtu/tb_vtu.vhd +74 -13

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--- a/hdl/testbench/vtu/tb_vtu.vhd
+++ b/hdl/testbench/vtu/tb_vtu.vhd
@@ -51,7 +51,14 @@ architecture arch of tb_vtu is

    --  Command to be sent to the VTU observer: number of expected pulses.
    type observer_type is record
+      --  Number of expected pulses.
      count : natural;
+
+      --  True if can go beyond the number of pulses (infinite window).
+      infinite : boolean;
+
+      --  If True, expect square waves.  Check half-period.
+      square : boolean;
    end record;

    signal observer_cmd : observer_type;
@@ -59,6 +66,7 @@ architecture arch of tb_vtu is
    --  VTU observer state.
    type obs_state_type is (IDLE, WORKING, OBS_DONE, OBS_ERR);
    signal observer_state : obs_state_type := IDLE;
+    signal observer_count : natural;
    signal observer_period : time;
 begin
    --  System clock, 62.5 Mhz
@@ -101,7 +109,6 @@ begin

    --  VTU observer.
    process (trig_p, observer_cmd)
-      variable count : natural;
      variable last_ts : time;
      variable this_period : time;
    begin
@@ -110,38 +117,41 @@ begin
        case observer_state is
          when IDLE | OBS_DONE | OBS_ERR =>
            observer_state <= WORKING;
-            count := 0;
+            observer_count <= 1;
            last_ts := now;
          when WORKING =>
            report "VTU observer command overrides the previous one" severity error;
        end case;
      end if;

-      if trig_p'event and trig_p = '1' then
-        report "Trigger:" & Natural'image(count);
+      if trig_p'event and (observer_cmd.square or trig_p = '1') then
+        report "Trigger:" & Natural'image(observer_count);
        case observer_state is
          when IDLE =>
            report "VTU observer: trigger before command" severity error;
-          when WORKING =>
+          when WORKING | OBS_DONE =>
            this_period := now - last_ts;
-            if count = 1 then
+            if observer_count = 2 then
              observer_period <= this_period;
-            elsif count > 1 then
+            elsif observer_count > 2 then
               if this_period /= observer_period then
                 report "VTU observer: irregular period" severity error;
               end if;
            end if;
            last_ts := now;
-            count := count + 1;
-            if count = observer_cmd.count then
+            observer_count <= observer_count + 1;
+            if observer_count = observer_cmd.count then
              observer_state <= OBS_DONE;
+            elsif observer_count > observer_cmd.count and not observer_cmd.infinite then
+              report "VTU observer: too many pulses" severity error;
            end if;
-          when OBS_DONE | OBS_ERR =>
+          when OBS_ERR =>
            null;
        end case;
      end if;
    end process;

+    --  Test process.
    process
        --  Send a pulse on the start signal and wait until it is propagated to the VTU.
        procedure start_pulse is
@@ -162,7 +172,7 @@ begin
          sync <= '1';
          wait for 10 ns;
          sync <= '0';
-  
+
          --  Wait until the VTU get the sync pulse.
          for i in 1 to 3 loop
            wait until rising_edge(clk_vtu);
@@ -223,7 +233,7 @@ begin
        assert val = x"0000" severity error;

        --  Expect 64 syncs.
-        observer_cmd <= (count => 64);
+        observer_cmd <= (count => 64, infinite => False, square => False);

        --  Start pulse.
        start_pulse;
@@ -276,14 +286,65 @@ begin
        assert val (TRIGUNIT_REGS_STATUS_STARTREADY_OFFSET) = '1' severity error;
        assert val (TRIGUNIT_REGS_STATUS_RUNNING_OFFSET) = '0' severity error;

-        --  Second test: check that missing valid parameters is reported.
+        -------------------------------------------------------------------------------------------------
+
+        --  Test 2: check that missing valid parameters is reported.
        --  (A cycle has been finished, the start signal has to be ignored because
        --   parameters aren't set.)
+        report "test 2 - start";
        start_pulse;

        read_status(val);
        assert val (TRIGUNIT_REGS_STATUS_MISSVALID_OFFSET) = '1' severity error;

+        -------------------------------------------------------------------------------------------------
+
+        --  Test 3: Program the vtu
+        --  Delay between start and the first pulse.
+        write64be_pl (clk_sys, wb_in, wb_out, ADDR_TRIGUNIT_REGS_BVALUEOFFLINE, x"0000_0000_0000_0010");
+        --  Delay between the pulses.
+        write64be_pl (clk_sys, wb_in, wb_out, ADDR_TRIGUNIT_REGS_HTVALUEOFFLINE, x"0000_0000_0000_0011");
+        --  Number of pulses (unused).
+        write64be_pl (clk_sys, wb_in, wb_out, ADDR_TRIGUNIT_REGS_WVALUEOFFLINE, x"0000_0000_0000_0014");
+
+        --  Lowfreq generation, enable.
+        write16_pl (clk_sys, wb_in, wb_out, ADDR_TRIGUNIT_REGS_CONFIGOFFLINE, x"0041");
+
+        --  Expect 64 syncs.
+        observer_cmd <= (count => 20, infinite => true, square => true);
+
+        report "test 3 - start";
+        start_pulse;
+
+        read_status(val);
+        assert val (TRIGUNIT_REGS_STATUS_MISSVALID_OFFSET) = '0' severity error;
+
+        --  Sync pulse.
+        sync_pulse;
+
+        --  Check ...
+        read_status(val);
+        assert val (TRIGUNIT_REGS_STATUS_STARTREADY_OFFSET) = '1' severity error;
+        assert val (TRIGUNIT_REGS_STATUS_RUNNING_OFFSET) = '1' severity error;
+
+        --  Wait until end of generation.
+        wait on observer_state;
+        --  Check observer status.
+        assert observer_state = OBS_DONE severity error;
+        assert observer_period = 17 * 5 ns;
+
+        --  Stop counter.  Synchronize to
+        wait until rising_edge(clk_vtu);
+        stop <= '1';
+        wait for 40 ns;
+        stop <= '0';
+
+        --  Wait a little bit (2 full periods)
+        wait for 2 * 2 * observer_period;
+
+        --  We should have stopped after 20 periods.  There are some extra periods because of synchronizers.
+        assert observer_count = 23 severity error;
+
        report "end of tests";
        wait;
    end process;