At 2/07/2007 10:01 AM a message was posted to a thread you were tracking. -- RE: Using the Forum by hubertxCan I force or probe a signal in vhdl module from verilog top testbench?I heard some simulator has its own way to do that easily, can you give me a example code to do that with ncsim?
Hi Hubert,from a VHDL module you can probe/force any VHDL or Verilog signal using ncmirror and ncforce, refer to the following documentation: http://sourcelink.cadence.com/docs/files/Release_Info/Docs/ncvhdl/ncvhdl5.83/applications.html#1044121There is no mechanic to access a VHDL object from a Verilog module today. As a workaround you may instantiate a VHDL Mirror component inside your Verilog module. Inside this VHDL component you can use the ncmirror and ncforce functions as described above and connect the probed/force signals through the ports to local Verilog signals.F.
Actually you can access a VHDL object from a Verilog testbench using the $nc_force or $nc_mirror routines. They're relatively new to NC-Verilog. I just looked them up and I see that they're documented in Chapter 19 of the NC-Verilog Simulator Help manual.
Thank you very much, I'll try that.
Hi,we are facing a similar isue. We need to check connectivity between a source signal which is instantiated in a VHDL module and a destination signal which is instantiated in a Verilog noe. It is not clear if and how to use $nc_force command, which requires a value ('0|1)) iwith Formal Verification tool. Does soembody have ever tried that?
In response to forcing signals in Formal, this cannot be done. To check connectivity, you would write a property to ensure the two signals are always the same like:// psl verify_signals : assert always (siga == sigb);If the source of the signal is a port of a module you can blackbox the module driving the signal or just use [b]cutpoint[/b] to free the driven signal from being driven by the design. Now IFV will drive this signal as a free input signal and allow you to verify the connectivity to the destination. Does this explaination make sense to you?
Related to the last couple of posts, there was a paper presented at CDNLive in SJ last year regarding connectivity checking. Session 1.8: Formal Analysis of Padring Mux-Logic Using IFV (Incisive Formal Verifier)It talks about using Formal Analysis and assertions as a much more efficient way to solve the connectivity problem. You might find it useful. It can be found at:http://www.cdnusers.org/CDNLive/SiliconValley2006Proceedings/tabid/366/Default.aspx?topic=Functional%20verification