tb_vtu: add an observer to the vtu.

24fbd5e6 · Tristan Gingold · 348d36b8 · 24fbd5e6
Commit 24fbd5e6 authored Apr 21, 2020 by Tristan Gingold
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tb_vtu.vhd hdl/testbench/vtu/tb_vtu.vhd +76 -1

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--- a/hdl/testbench/vtu/tb_vtu.vhd
+++ b/hdl/testbench/vtu/tb_vtu.vhd
@@ -48,9 +48,27 @@ architecture arch of tb_vtu is
      end loop;
      return res;
    end to_string;
+
+    --  Command to be sent to the VTU observer: number of expected pulses.
+    type observer_type is record
+      count : natural;
+    end record;
+
+    signal observer_cmd : observer_type;
+
+    --  VTU observer state.
+    type obs_state_type is (IDLE, WORKING, OBS_DONE, OBS_ERR);
+    signal observer_state : obs_state_type := IDLE;
+    signal observer_period : time;
 begin
    --  System clock, 62.5 Mhz
-    clk_sys <= not clk_sys after 8 ns;
+    process
+    begin
+      clk_sys <= '0';
+      wait for 8 ns;
+      clk_sys <= '1';
+      wait for 8 ns;
+    end process;
    rst_sys <= '1', '0' after 16 ns;

    --  RF clock, ~200Mhz (5ns)
@@ -81,6 +99,49 @@ begin
        stop_i => stop
      );

+    --  VTU observer.
+    process (trig_p, observer_cmd)
+      variable count : natural;
+      variable last_ts : time;
+      variable this_period : time;
+    begin
+      if observer_cmd'event then
+        --  New command
+        case observer_state is
+          when IDLE | OBS_DONE | OBS_ERR =>
+            observer_state <= WORKING;
+            count := 0;
+            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);
+        case observer_state is
+          when IDLE =>
+            report "VTU observer: trigger before command" severity error;
+          when WORKING =>
+            this_period := now - last_ts;
+            if count = 1 then
+              observer_period <= this_period;
+            elsif count > 1 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_state <= OBS_DONE;
+            end if;
+          when OBS_DONE | OBS_ERR =>
+            null;
+        end case;
+      end if;
+    end process;
+
    process
        variable val : std_logic_vector(15 downto 0);
    begin
@@ -123,6 +184,8 @@ begin
        report "config online = " & to_string(val);
        assert val = x"0000" severity error;

+        observer_cmd <= (count => 64);
+
        --  Start pulse.
        start <= '1';
        wait for 40 ns;
@@ -179,6 +242,18 @@ begin
        read16_pl (clk_sys, wb_in, wb_out, ADDR_TRIGUNIT_REGS_BVALUEONLINE + 6, val);
        assert val = x"0020" severity error;

+        --  Wait until end of generation.
+        wait on observer_state;
+        --  Check observer status.
+        assert observer_state = OBS_DONE severity error;
+        assert observer_period = 8 * 5 ns;
+        --  Check VTU status.
+        read16_pl (clk_sys, wb_in, wb_out, ADDR_TRIGUNIT_REGS_STATUS, val);
+        report "status = " & to_string(val);
+        assert val (TRIGUNIT_REGS_STATUS_STARTREADY_OFFSET) = '1' severity error;
+        assert val (TRIGUNIT_REGS_STATUS_RUNNING_OFFSET) = '0' severity error;
+
+        report "end of tests";
        wait;
    end process;
 end arch;