// Test: Triple 3-input NAND gate module test; `TBASSERT_METHOD(tbassert) localparam BLOCKS = 5; localparam WIDTH_IN = 3; // DUT inputs reg [BLOCKS*WIDTH_IN-1:0] A; // DUT outputs wire [BLOCKS-1:0] Y; // DUT ttl_7410 #(.BLOCKS(BLOCKS), .WIDTH_IN(WIDTH_IN), .DELAY_RISE(5), .DELAY_FALL(3)) dut( .A_2D(A), .Y(Y) ); initial begin reg [WIDTH_IN-1:0] Block1; reg [WIDTH_IN-1:0] Block2; reg [WIDTH_IN-1:0] Block3; reg [WIDTH_IN-1:0] Block4; reg [WIDTH_IN-1:0] Block5; integer i; $dumpfile("7410-tb.vcd"); $dumpvars; // all ones -> 0 Block1 = {WIDTH_IN{1'b1}}; Block2 = {WIDTH_IN{1'b1}}; Block3 = {WIDTH_IN{1'b1}}; Block4 = {WIDTH_IN{1'b1}}; Block5 = {WIDTH_IN{1'b1}}; A = {Block5, Block4, Block3, Block2, Block1}; #10 for (i = 0; i < BLOCKS; i++) tbassert(Y[i] == 1'b0, "Test 1"); #0 // all zeroes -> 1 Block1 = {WIDTH_IN{1'b0}}; Block2 = {WIDTH_IN{1'b0}}; Block3 = {WIDTH_IN{1'b0}}; Block4 = {WIDTH_IN{1'b0}}; Block5 = {WIDTH_IN{1'b0}}; A = {Block5, Block4, Block3, Block2, Block1}; #10 for (i = 0; i < BLOCKS; i++) tbassert(Y[i] == 1'b1, "Test 2"); #0 // only a single bit causes -> 1 Block1 = 3'b110; Block2 = {WIDTH_IN{1'b1}}; Block3 = {WIDTH_IN{1'b1}}; Block4 = {WIDTH_IN{1'b1}}; Block5 = {WIDTH_IN{1'b1}}; A = {Block5, Block4, Block3, Block2, Block1}; #10 tbassert(Y == 5'b00001, "Test 3"); #0 // same on another input Block1 = 3'b011; Block2 = {WIDTH_IN{1'b1}}; Block3 = {WIDTH_IN{1'b1}}; Block4 = {WIDTH_IN{1'b1}}; Block5 = {WIDTH_IN{1'b1}}; A = {Block5, Block4, Block3, Block2, Block1}; #10 tbassert(Y == 5'b00001, "Test 4"); #0 // only a triplet of bits causes -> 0 Block1 = {WIDTH_IN{1'b0}}; Block2 = {WIDTH_IN{1'b0}}; Block3 = {WIDTH_IN{1'b0}}; Block4 = 3'b111; Block5 = {WIDTH_IN{1'b0}}; A = {Block5, Block4, Block3, Block2, Block1}; #10 tbassert(Y == 5'b10111, "Test 5"); #0 // zeroes anywhere causes -> 1 Block1 = 3'b110; Block2 = 3'b110; Block3 = 3'b110; Block4 = 3'b110; Block5 = 3'b110; A = {Block5, Block4, Block3, Block2, Block1}; #10 tbassert(Y == 5'b11111, "Test 6"); #0 // same on another input Block1 = 3'b101; Block2 = 3'b101; Block3 = 3'b101; Block4 = 3'b101; Block5 = 3'b101; A = {Block5, Block4, Block3, Block2, Block1}; #10 tbassert(Y == 5'b11111, "Test 7"); #0 // mixed bits causes both -> 0, 1 Block1 = 3'b100; Block2 = 3'b101; Block3 = 3'b000; Block4 = 3'b111; Block5 = 3'b110; A = {Block5, Block4, Block3, Block2, Block1}; #6 tbassert(Y == 5'b10111, "Test 8"); #0 // same on other inputs Block1 = 3'b010; Block2 = 3'b011; Block3 = 3'b000; Block4 = 3'b111; Block5 = 3'b110; A = {Block5, Block4, Block3, Block2, Block1}; #6 tbassert(Y == 5'b10111, "Test 9"); #0 // same with bits cycled differently Block1 = 3'b000; Block2 = 3'b111; Block3 = 3'b010; Block4 = 3'b101; Block5 = 3'b111; A = {Block5, Block4, Block3, Block2, Block1}; #6 tbassert(Y == 5'b01101, "Test 10"); #0 // all input bits transition from previous Block1 = 3'b111; Block2 = 3'b000; Block3 = 3'b101; Block4 = 3'b010; Block5 = 3'b000; A = {Block5, Block4, Block3, Block2, Block1}; #6 tbassert(Y == 5'b11110, "Test 11"); #0 // timing: clear inputs, then must wait for outputs to transition Block1 = {WIDTH_IN{1'bx}}; Block2 = {WIDTH_IN{1'bx}}; Block3 = {WIDTH_IN{1'bx}}; Block4 = {WIDTH_IN{1'bx}}; Block5 = {WIDTH_IN{1'bx}}; A = {Block5, Block4, Block3, Block2, Block1}; #10 Block1 = 3'b111; Block2 = 3'b000; Block3 = 3'b101; Block4 = 3'b010; Block5 = 3'b000; A = {Block5, Block4, Block3, Block2, Block1}; #3 tbassert(Y === 5'bxxxxx, "Test 12"); #7 tbassert(Y == 5'b11110, "Test 12"); #10 $finish; end endmodule