Aldec Active-HDL vs Modelsim PE state of play.
Started by 5 years ago●3 replies●latest reply 3 years ago●734 viewsA long-time ModelSim user is evaluating alternatives like Aldec Active-HDL due to the high cost of dual-language upgrades and a lack of significant feature improvements in ModelSim. The discussion compares these tools against Xilinx Vivado's XSIM, weighing factors like cost, simulation speed, and compatibility with encrypted Xilinx IP.
While XSIM is recommended for its cost-effectiveness and SystemVerilog support, users noted performance trade-offs and specific limitations when simulating complex components like UltraScale HBM.
- ModelSim PE dual-language upgrades are perceived as prohibitively expensive compared to modern alternatives.
- Xilinx XSIM is a viable free alternative that supports VHDL, Verilog, and SystemVerilog, though it lacks VHDL variable viewing and code coverage.
- Users reported that XSIM can be significantly slower than ModelSim PE for certain simulation workloads.
- For specific high-end components like UltraScale HBM, Xilinx may recommend QuestaSIM over their own XSIM tool.
- ModelSim remains reliable for handling encrypted Xilinx IP when using correctly compiled libraries.
What's the state of play here in 2021 ? I have had a Modelsim PE seat in maintenance for 16 years. Modelsim has not changed, improved any done anything in that time. Zippo. nothing. The dual language upgrade cost for Modelsim is about USD$10k , insane !!! then extra 500/year which is probably OK.
I only stay in Modelsim Maintenance because Xilinx keep changing compressed and encrypted file formats for IP which when modelsim gets a couple of years old it will not recognize the Xilinx changes..
I only do VHDL simulation to waveform all from my own scripts.... test-benches etc, I do no post place-and-route simulation, no need for source code step and debugging.... The is a coming need for Verilog though, alot of the XIlinx IP is moving to Verilog only , so far I have just not used them and written my own IP to get around my lack of ability to simulate Xilinx IP written in Verilog..
-glen
I've used Modelsim, Active HDL and Xilinx Vivado XSIM.
I have a version of Modelsim available at work but I still prefer XSIM because it's free and has most if the features I could ever want.
My simulations are fairly complex. They are self checking, written in Systemverilog (it supports all the HDL's), post-synth, some randomization and class based. It also supports UVM which I haven't used yet. The only things it lacks so far is ability to view VHDL variables and code coverage. Although it supports functional coverage.
....Steve
The fun fact I recently discovered with XSIM, that Xilinx did not recomend to use it together with a simulation where an UltraScale HBM was involved and pointed to QuestaSIM.
Generally ModelSIM accepts all Xilinx IP so far, even the Altera Version is capeable of simulating several encrypted IPs, when using the self compiled libraries.
