UVM Top Testbench

top testbench在top_tb中包含进所有的文件，将DUT放在top_tb中（例化DUT），连接好各个端口，提供clk时钟和rst_n复位信号。最主要的是要给组件中的虚接口设置接口，一般是给driver和monitor的虚接口例化接口。初始化run_test()使其自动启动UVM仿真。用config机制配置内部变量。如例：

`timescale 1ns/1ps
`include "uvm_macros.svh"

import uvm_pkg::*;
`include "my_if.sv"
`include "my_transaction.sv"
`include "my_sequencer.sv"
`include "my_driver.sv"
`include "my_monitor.sv"
`include "my_agent.sv"
`include "my_model.sv"
`include "my_scoreboard.sv"
`include "my_sequence.sv"
`include "my_env.sv"
`include "base_test.sv"

module top_tb;

reg clk;
reg rst_n;
reg[7:0] rxd;
reg rx_dv;
wire[7:0] txd;
wire tx_en;

my_if input_if(clk, rst_n);
my_if output_if(clk, rst_n);

dut my_dut(.clk(clk),
           .rst_n(rst_n),
           .rxd(input_if.data),
           .rx_dv(input_if.valid),
           .txd(output_if.data),
           .tx_en(output_if.valid));

initial begin
   clk = 0;
   forever begin
      #100 clk = ~clk;
   end
end

initial begin
   rst_n = 1'b0;
   #1000;
   rst_n = 1'b1;
end

initial begin
   run_test("base_test");
end

initial begin
   uvm_config_db#(virtual my_if)::set(null, "uvm_test_top.env.i_agt.drv", "vif", input_if);
   uvm_config_db#(virtual my_if)::set(null, "uvm_test_top.env.i_agt.mon", "vif", input_if);
   uvm_config_db#(virtual my_if)::set(null, "uvm_test_top.env.o_agt.mon", "vif", output_if);
end

endmodule

参考文献：

[1] 测试平台说明. http://www.asicdv.com/uvm_scan.asp?id=39.

[2] 张强. UVM实战. 机械工业出版社. 2014.07.