SV Day 23 — UVM Scoreboard

Automated Checking

Scoreboard collects transactions from monitor, predicts output, and compares actual.

class fifo_scoreboard extends uvm_scoreboard;
  uvm_analysis_export #(fifo_transaction) wr_port;
  uvm_analysis_export #(fifo_transaction) rd_port;

  int wr_count = 0, rd_count = 0;
  fifo_transaction wr_queue[$];

  function void build_phase(uvm_phase phase);
    super.build_phase(phase);
    wr_port = new("wr_port", this);
    rd_port = new("rd_port", this);
  endfunction

  function void connect_phase(uvm_phase phase);
    super.connect_phase(phase);
    wr_port.connect(write_imp.analysis_export);
    rd_port.connect(read_imp.analysis_export);
  endfunction

  virtual function void write_wr(fifo_transaction tr);
    wr_queue.push_back(tr);
    wr_count++;
  endfunction

  virtual function void write_rd(fifo_transaction tr);
    fifo_transaction pred;
    if(wr_queue.size() > 0) begin
      pred = wr_queue.pop_front();
      if(pred.data != tr.data) begin
        `uvm_error("FIFO", $sformatf("Mismatch: expected %0x, got %0x",
          pred.data, tr.data));
      end
    end
    rd_count++;
  endfunction
endclass

Key Takeaways

✅ Scoreboard = automated checker
✅ Multiple analysis ports = multiple streams
✅ Predict expected output, compare actual

Day 24: Config database and advanced UVM.