Add testbench for top_ultrasonic_led module

- Created a new testbench file `top_ultrasonic_led_tb.vvp` to simulate the `top_ultrasonic_led` module.
- Defined the necessary signals and events for testing the ultrasonic sensor functionality.
- Implemented the main test sequence including triggering the ultrasonic sensor and monitoring the output LEDs based on distance measurements.
- Included timing and state management for accurate simulation of the ultrasonic sensor behavior.

Semaine 1/Capteur_recule/Ultrasonic/tb_ultrasonic_fpga.v

@@ -0,0 +1,73 @@
+`timescale 1ns/1ps
+
+module tb_ultrasonic_fpga;
+
+    reg clk = 0;
+    reg rst = 1;
+    reg start = 0;
+    reg echo = 0;
+    wire trig_out;
+    wire [8:0] distance;
+
+    time t_start, t_end;
+
+    // Clock 27MHz => periode = 37ns
+    always #18 clk = ~clk;
+
+    ultrasonic_fpga uut (
+        .clk(clk),
+        .rst(rst),
+        .start(start),
+        .echo(echo),
+        .trig_out(trig_out),
+        .distance(distance)
+    );
+
+    initial begin
+        $dumpfile("ultrasonic.vcd");
+        $dumpvars(0, tb_ultrasonic_fpga);
+
+        // Reset
+        #100;
+        rst = 0;
+
+        // Start
+        #100;
+        start = 1;
+        #40;
+        start = 0;
+
+        wait (trig_out == 1);
+        t_start = $time;
+
+        // Attendre qu'il redescende
+        wait (trig_out == 0);
+        t_end = $time;
+
+        $display("Trig HIGH duration: %0dns", t_end - t_start);
+
+        if ((t_end - t_start) >= 9500 && (t_end - t_start) <= 10500) begin
+            $display("Trigger signal is high for 10us.");
+
+            #10;
+            echo = 1;
+
+            #5800;// Echo dure 5800ns (≈ 100 cycles @ 27MHz => ≈ 100 cm aller-retour)
+            echo = 0;
+        end else begin
+            $display("Trigger signal is NOT high for 10us.");
+        end
+
+        #500;
+
+        // Affiche la distance
+        if (distance > 0) begin
+            $display("Distance measured: %d cm", distance);
+        end else begin
+            $display("No distance measured.");
+        end
+
+        $finish;
+    end
+
+endmodule