1.5. Simulation Versus Hardware Implementation
EMIF Simulation Models
This table compares the characteristics of the skip calibration and full calibration models.
|Skip Calibration||Full Calibration|
|System-level simulation focusing on user logic.||Memory interface simulation focusing on calibration.|
|Details of calibration are not captured.||Captures all stages of calibration.|
|Has ability to store and retrieve data.||Includes leveling, per-bit deskew, etc.|
|Represents accurate efficiency.|
|Does not consider board skew.|
RTL Simulation Versus Hardware Implementation
This table highlights key differences between EMIF simulation and hardware implementation.
|RTL Simulation||Hardware Implementation|
|Nios® initialization and calibration code execute in parallel.||Nios® initialization and calibration code execute sequentially.|
|Interfaces assert cal_done signal signal simultaneously in simulation.||Fitter operations determine the order of calibration, and interfaces do not assert cal_done simultaneously.|
You should run RTL simulations based on traffic patterns for your design's application. Note that RTL simulation does not model PCB trace delays which may cause a discrepancy in latency between RTL simulation and hardware implementation.