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module testbench;
localparam integer PERIOD = 12000000 / 9600;
// reg clk = 0;
// initial #10 forever #5 clk = ~clk;
reg clk;
always #5 clk = (clk === 1'b0);
reg RX = 1;
wire TX;
wire LED1;
wire LED2;
wire LED3;
wire LED4;
wire LED5;
top uut (
.clk (clk ),
.RX (RX ),
.TX (TX ),
.LED1(LED1),
.LED2(LED2),
.LED3(LED3),
.LED4(LED4),
.LED5(LED5)
);
task send_byte;
input [7:0] c;
integer i;
begin
RX <= 0;
repeat (PERIOD) @(posedge clk);
for (i = 0; i < 8; i = i+1) begin
RX <= c[i];
repeat (PERIOD) @(posedge clk);
end
RX <= 1;
repeat (PERIOD) @(posedge clk);
end
endtask
reg [4095:0] vcdfile;
initial begin
if ($value$plusargs("vcd=%s", vcdfile)) begin
$dumpfile(vcdfile);
$dumpvars(0, testbench);
end
repeat (10 * PERIOD) @(posedge clk);
// turn all LEDs off
send_byte("1");
send_byte("3");
send_byte("5");
// turn all LEDs on
send_byte("1");
send_byte("2");
send_byte("3");
send_byte("4");
send_byte("5");
// turn all LEDs off
send_byte("1");
send_byte("2");
send_byte("3");
send_byte("4");
send_byte("5");
repeat (10 * PERIOD) @(posedge clk);
$finish;
end
endmodule
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