UVM RAL Interview Questions
Questions on UVM Register Abstraction Layer.
Beginner Level
What is the advantage of using RAL?
Abstraction. Tests can write `reg_model.CTRL.write(1)` instead of calculating address `0x400`.
Intermediate Level
Frontdoor vs Backdoor Access?
Frontdoor: Uses Bus Driver -> Takes simulation time -> Verifies path.
Backdoor: Uses VPI string path -> Zero time -> Bypasses logic.
Advanced Level
What is Auto-Prediction vs Passive-Prediction?
Auto: The `write()` method updates the mirror immediately, assuming success. Good for simple tests.
Passive: A predictor sits on the Monitor. It only updates the mirror when it sees the ACTUAL transaction on the bus. Required for systems where writes might be dropped or modified.