SV Day 21 — UVM Introduction

What Is UVM?

UVM = reusable library of classes that structure testbenches. Instead of writing everything from scratch, inherit from UVM base classes.

✅ Agents: Stimulus drivers + monitors (reusable)
✅ Sequences: Scenarios (inherit and compose)
✅ Scoreboards: Automated checking
✅ Config database: Parameter passing (no hardcodes)
✅ Phase system: Structured execution (build → connect → run → check)

UVM Hierarchy

// Inherit from uvm_component (testbench building block)
class my_driver extends uvm_driver;
  function new(string name, uvm_component parent);
    super.new(name, parent);
  endfunction

  virtual task run_phase(uvm_phase phase);
    // Generate stimulus
  endtask
endclass

// Inherit from uvm_test (top-level test)
class my_test extends uvm_test;
  function new(string name, uvm_component parent);
    super.new(name, parent);
  endfunction

  virtual function void build_phase(uvm_phase phase);
    super.build_phase(phase);
    // Create testbench components
  endfunction
endclass

UVM Phases

Execution order:
1. build_phase: Create components
2. connect_phase: Wire them together
3. run_phase: Execute stimulus/check
4. extract_phase: Gather metrics
5. check_phase: Final verification
6. report_phase: Print results

Key Takeaways

✅ UVM = standardized class hierarchy
✅ Reduces code, increases reusability
✅ Phase system = deterministic execution order
✅ All major simulators support UVM

Day 22: UVM components (drivers, monitors, agents).