AR# 53245: Vivado: a netlist generated for timing simulation looks to be the UNISIM-based netlist
AR# 53245
Vivado: a netlist generated for timing simulation looks to be the UNISIM-based netlist
Description
After implementation, running "write_verilog -mode timesim" writes out a Verilog netlist used for timing simulation.
However, it is based on UNISIM components.
Why is this the case as the SIMPRIM library is referenced in timing simulation?
Solution
In Vivado, Verilog SIMPRIM and UNISIM library components are replaced by a single UNISIM component set with additional blocks specifically for timing annotation.
This is enabled by `ifdef XIL_TIMING in the UNISIM source code.
SIMPRIMS_VER is the logical library name to which the Verilog SIMPRIM is mapped.
In ISE, the SIMPRIM library components have separate names (with prefix X_ ) to the UNISIM components.