ID 683804
Date 9/26/2022
Public

## 1.4.1. Fast Sim Model for FGT Variants

To provide a reduction in a real-time simulation duration, you can utilize a Fast Sim model in your design example testbench. Available for the FGT variants only, the model is enabled by a macro in the simulation run script.
To enable the Fast Sim model, add the following macro to your simulation run script:
+define+IP7581SERDES_UX_SIMSPEED
The design example simulation script enables the macro by default for all variants with the exception of variants with enabled PTP or auto-negotiation and link training.
• In PTP variants, the macro is not enabled by default as it affects the timestamp accuracy in simulation. If you want to perform a general functionality check, you can enable the macro in your PTP simulation scripts.
• The macro is not available for designs with enabled auto-negotiation and link training.