Convert NCD to VCD

Understanding ncd and vcd file formats

NCD (Native Circuit Description) files are used primarily by Xilinx ISE software to store synthesized netlist data for FPGA designs. These files contain detailed information about the logical structure and connectivity of digital circuits, optimized for implementation on Xilinx FPGAs.

VCD (Value Change Dump) files are a standard format in the EDA (Electronic Design Automation) industry for recording signal changes during digital simulation. VCD files are widely used for debugging and analyzing digital designs, as they capture the transitions of signals over time.

Why convert ncd to vcd?

Converting an NCD file to a VCD file allows engineers to simulate and analyze the behavior of their FPGA designs. The VCD format is compatible with many waveform viewers and simulation tools, making it easier to debug and verify digital circuits.

How to convert ncd to vcd

Direct conversion from NCD to VCD is not typically supported, as NCD files are not simulation data but netlists. However, you can generate a VCD file from your design by following these steps:

1. Use Xilinx ISE or Vivado to synthesize your design and generate the NCD file.
2. Run a simulation of your design using a supported simulator (such as ModelSim or Xilinx ISim).
3. During simulation, enable VCD output. In most simulators, you can do this by adding a command or using the GUI to export signal changes to a VCD file.
4. For example, in ModelSim, use the command: vcd file output.vcd and vcd add -r /* before running the simulation.
5. After simulation, the VCD file will be available for waveform analysis.

Best software for ncd to vcd conversion

The recommended approach is to use Xilinx Vivado or Xilinx ISE for synthesis, and ModelSim or Xilinx ISim for simulation and VCD export. These tools provide robust support for FPGA design and simulation workflows.

• Xilinx Vivado: Synthesize and implement your design, then export simulation data.
• ModelSim: Simulate your design and export VCD files via File → Export → VCD or simulation commands.

Summary

While you cannot directly convert an NCD file to a VCD file, you can simulate your FPGA design and export signal changes to a VCD file using industry-standard tools like Xilinx Vivado and ModelSim. This process enables effective debugging and verification of digital circuits.