top_tb: keep grey box approach & read tmds values directly, fixes #7

Author: sameer

test/top_tb/top_tb.sv

@@ -3,24 +3,10 @@
 module top_tb();
 
 initial begin
-  $dumpvars(0, top_tb);
-  // #36036000000ps $finish; // Terminate simulation after ~2 frames are generated
   #20ms $finish;
 end
 
-logic clk_original = 0;
-logic [2:0] tmds_p;
-logic tmds_clock_p;
-logic [2:0] tmds_n;
-logic tmds_clock_n;
-
-top top (
-    .clk_original(clk_original),
-    .tmds_p(tmds_p),
-    .tmds_clock_p(tmds_clock_p),
-    .tmds_n(tmds_n),
-    .tmds_clock_n(tmds_clock_n)
-);
+top top ();
 
 logic [9:0] cx = 858 - 4;
 logic [9:0] cy = 524;
@@ -62,27 +48,11 @@ generate
   end
 endgenerate
 
-logic [3:0] counter = 0;
-always @(posedge top.clk_pixel_x10)
+always @(posedge top.clk_pixel)
 begin
-  assert (counter == top.hdmi.tmds_counter) else $fatal("Shift-out counter doesn't match decoder counter");
-  if (counter == 9)
-  begin
-    counter <= 0;
-  end
-  else
-    counter <= counter + 1'd1;
-
-  tmds_values[0][counter] <= tmds_p[0];
-  tmds_values[1][counter] <= tmds_p[1];
-  tmds_values[2][counter] <= tmds_p[2];
-
-  if (counter == 0)
-  begin
-    tmds_values[0][9:1] <= 9'dX;
-    tmds_values[1][9:1] <= 9'dX;
-    tmds_values[2][9:1] <= 9'dX;
-  end
+  tmds_values[0] <= top.hdmi.tmds[0];
+  tmds_values[1] <= top.hdmi.tmds[1];
+  tmds_values[2] <= top.hdmi.tmds[2];
 end
 
 logic [4:0] data_counter = 0;

top/pll.v

@@ -3,7 +3,6 @@
 `timescale 1 ns / 100 ps
 
 module pll (
-	input wire inclk0,
 	output reg c0 = 0,
 	output reg c1 = 1,
 	output reg c2 = 0

top/top.sv

@@ -1,17 +1,14 @@
-module top (
-    input logic clk_original,
-
-    output logic [2:0] tmds_p,
-    output logic tmds_clock_p,
-    output logic [2:0] tmds_n,
-    output logic tmds_clock_n
-);
+module top ();
+logic [2:0] tmds_p;
+logic tmds_clock_p;
+logic [2:0] tmds_n;
+logic tmds_clock_n;
 
 logic clk_pixel;
 logic clk_pixel_x10;
 logic clk_audio;
 
-pll pll(.inclk0(clk_original), .c0(clk_pixel_x10), .c1(clk_pixel), .c2(clk_audio));
+pll pll(.c0(clk_pixel_x10), .c1(clk_pixel), .c2(clk_audio));
 
 logic signed [15:0] audio_sample_word = 16'sd0; // Since the L-PCM audio is 2-channel by default, this is mono audio.
 always @(posedge clk_audio) // Sawtooth wave generator