The wire_load_model is used to model the interconnect parasitics, which can be modeled with RLC model. Since L can be neglected for on-chip pre-layout analysis, it becomes an RC network. Base on the block size and fanout, wlm_light, wlm_conservative, and wlm_aggresive fall into a wire_load_model_selection_table that we can specify. For wire_load_model to model the interconnect parasitics, best_case rc tree, balanced rc tree and worst_case rc tree can be used to represent to above three models respectively. The wire_load_model_selection_table should be in the lib file a std cell lib, but I don't have it, I also don't know how to get it into .lib during characterization.
Can someone tell more about K? Something I don't quite agree is K-value is not used here to specify any wire_load_model, it is used to multiply the far-end capacitance for calculation of the effective capacitance when doing delay calculation. K should range within 0 and 1.
Thanks |