Add testbench for the seconds display

NOTE: This doesn't actually compile yet, but it should once changes to
the seconds display are pushed

design/display_converter.sv

@@ -1,60 +0,0 @@
-/**
-* display_converter.sv - decodes a 5 bit digit input into its seven segment
-*                        display equivalent using a lookup table. Display can
-*                        do 0 - 9, A - F, individual segmentsm and special
-*                        characters.  
-* @author: Dilanthi Prentice, Waylon Cude
-* @date: [not sure when its due yet]
-*
-*
-****/
-module display_converter(
-    input logic [4:0] digit, 
-    output logic [6:0] segment
-);
-
-localparam ROM_SIZE=32;
-
-//ROM lookup table for seven segment display
-localparam logic [6:0] segment_rom [0:ROM_SIZE-1] = '{
-    7'b1111110, //0
-    7'b0000110, //1
-    7'b1101101, //2
-    7'b1111001, //3
-    7'b1011011, //4
-    7'b1011011, //5
-    7'b1011111, //6
-    7'b1110000, //7
-    7'b1111111, //8
-    7'b1111011, //9
-
-    7'b1110111, //A
-    7'b0011111, //B
-    7'b1001110, //C
-    7'b0111101, //D
-    7'b1001111, //E
-    7'b1000111, //F
-
-    7'b1000000, //segment a
-    7'b0100000, //segment b
-    7'b0010000, //segment c
-    7'b0001000, //segment d
-    7'b0000100, //segment e
-    7'b0000001, //segment f
-
-    7'b0110111, //H
-    7'b0001110, //L
-    7'b1110111, //R
-    7'b0000110, //l 
-    7'b0000101, //r
-
-    7'b0000000, //blank
-    7'b0000000, //blank
-    7'b0000000, //blank
-    7'b0000000, //blank
-    7'b0000000  //blank
-};
-//use digit input to index segment_rom lookup table.
-assign segment = segment_rom[digit];
-
-endmodule

design/seconds_display.sv

@@ -1,29 +1,10 @@
-/***
+module seconds_display(
-* seconds_display.sv - convert a seconds counter to a seven segement display.
+    input logic clk, 
-*
+    input logic reset, 
-* @author: Dilanthi Prentice, Waylon Cude
+    input [$clog2(60)-1:0] counter,
-* @date:[unsure of due date]
+    output [7:0] display_tens,
-*
+    output [7:0] display_ones
-*/
-module seconds_display
-(
-    input [$clog2(60)-1:0] seconds,
-    output [6:0] display_tens,      
-    output [6:0] display_ones       
 );
 
-logic [4:0] ones_digit; 
-logic [4:0] tens_digit;
-
-always_comb
-begin
-    ones_digit = seconds % 10;
-    tens_digit = seconds / 10;
-end
-
-//instantiate the display_converter to convert the counter
-//to a seven segment display number
-display_converter ones (ones_digit, display_ones);
-display_converter tens (tens_digit, display_tens);
 
 endmodule

verification/seconds_display_tb.sv

@@ -0,0 +1,51 @@
+module seconds_display_tb;
+int errors = 0;
+logic [5:0] seconds;
+wire [6:0] display_tens;
+wire [6:0] display_ones;
+
+logic [6:0] expected_tens;
+logic [6:0] expected_ones;
+
+seconds_display Dut(.*);
+initial begin
+    $display("Testing seconds_display");
+    for (seconds=0; seconds<60; seconds++) begin
+        expected_ones = encode_number(seconds % 10);
+        expected_tens = encode_number(seconds /10);
+        #1
+        if (display_ones !== expected_ones) begin
+            errors++;
+            $display("Failed ones test case, displayed = %b, expected = %b",
+                     display_ones,
+                     expected_ones);
+        end
+        else
+        if (display_tens !== expected_tens) begin
+            errors++;
+            $display("Failed tens test case, displayed = %b, expected = %b",
+                     display_tens,
+                     expected_tens);
+        end
+    end
+
+    if (errors == 0)
+        $display("All tests passing");
+end
+
+endmodule
+
+function automatic logic [6:0] encode_number(logic [5:0] num);
+    case (num)
+        0: return 7'b1111110;
+        1: return 7'b0000110;
+        2: return 7'b1101101;
+        3: return 7'b1111001;
+        4: return 7'b0110011;
+        5: return 7'b1011011;
+        6: return 7'b1011111;
+        7: return 7'b1110000;
+        8: return 7'b1111111;
+        9: return 7'b1111011;
+    endcase
+endfunction