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  3. ncelab: segmentation of a signal

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ncelab: segmentation of a signal

konx
konx over 14 years ago

 Hello everyone.

I try to be specific:


- I wrote some Verilog modules for a design (counter, shift registers, etc..)

- Using RTL Compiler I do the synthesis of the design

- I load the desing in Encounter and I do P&R

- Send back the layout to Virtuoso using OpenAccess database

- Encounter produces a post-P&R verilog netlist: saveNetlist name_of_netlist.v -includePowerGround

- Import the post-P&R verilog netlist in Virtuoso using the Import->Verilog option you can find in the Virtuoso menu': this generates the schematic view for all the verilog blocks I wrote for this design

- Run DRC and LVS: during the LVS there is a mistake. One gate (NAND2) is supposed to have input A connected to VDD but Encounter did not make the connection. Ok, I do the connection by hand and LVS is clean.

- Now I want to run AMS-simulations. I setup everything, netlist is ok and compiler is ok, but when I arrive at the Elaboration I receive the following error:

ncelab: *E,CUVNAS (<my_path>/counter_12bit/schematic/verilog.vams,206|19): segmentation of  a signal
.VDD( VDD ), .A( VDD ), .B( reset ) );

Now, this is exactly the port that I connected by hand in Virtuoso and wasn't connected by Encounter (so, I guess there is something related here).

This connection has not been made by me, but it is the result of the synthesized netlist, so I guess that the synthesizer knew what it was doing when it connected the pin A of the NAND2 gate to VDD.

I assume this is some kind of "bug" or something that requires a workaround.

 

Any idea how to solve the problem or where the problem could come from?

 

Thanks

 

Francesco

 

PS: I hope this is the correct forum; sorry for any mistakes

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  • konx
    konx over 14 years ago

     

    diablo said:

    Are you using TIEHO and TIELO cells while synthesizing the verilog design? 

     

    Hi diablo,

    we are not using TIEHO and TIELO cells because they are not present in the library we are using. It seems indeed to be problem, but until now the only way to avoid it was to synthesize the design with different constraints, in order not to have such a connection.

    Thanks

     

    Konx

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  • konx
    konx over 14 years ago

     

    diablo said:

    Are you using TIEHO and TIELO cells while synthesizing the verilog design? 

     

    Hi diablo,

    we are not using TIEHO and TIELO cells because they are not present in the library we are using. It seems indeed to be problem, but until now the only way to avoid it was to synthesize the design with different constraints, in order not to have such a connection.

    Thanks

     

    Konx

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