Difference between revisions of "ESim/C4/Advanced-NgVeri/English"

• Add dependency files and folders
• Remove NgVeri models and
• Add and remove lint_off commands.

in Ngveri.

• Ubuntu OS v20.04
• eSim v2.2

The process demonstrated in this tutorial is similar in Windows OS also.

Prerequisites

https://spoken-tutorial.org

• Basic knowledge of eSim
• Familiarity with Verilog and Mixed Signal Simulation
• Basic knowledge of NgVeri feature

For pre-requisite eSim tutorials, please visit this website.

• The files used in this tutorial are provided in the Code files link.
• Please download and extract the files.
• Make a copy and then use them while practicing.

Example: Add Dependency Files

• For demonstration, we have taken the 8bit_vedic_multiplierproject.
• Note that the 8bit_vedic_multiplier is taken from opencores.org
• The same project folder is provided in the Code files link.

Now we will see how to add the dependency files.

Browse the full_adder.v file

Click on Open

Then select the full_adder.v file and click on the Open button.

The file gets loaded.

Switch to the NgVeri Tab

Click on Run Verilog to Ngspice Converter

To do so, click on the NgVeri Tab.

Then click on Run Verilog to Ngspice Converter.

Highlighting the error message in the Terminal

Let us scroll up to see why the error occurred.

Highlight another error in the Terminal

The message indicates that the half_adder dependency file is missing in the eSim interface.

So let us add the dependency file.

Click on the Add Other file option

The Add Other file option is used to add dependency files to the Verilog file.

Let us click on it.

Locate and select half_adder.v file

Click on Open

Highlight the message in the Terminal

Locate and select the verilog file half_adder.v from the Downloads folder.

Click on the Open button.

In the terminal we see that the dependency file half_adder.v has been added to eSim.

Click on the Clear Terminal Button

Click on Run Verilog to Ngspice Converter

Click on the Clear Terminal button to clear the terminal.

Now click on Run Verilog to Ngspice Converter.

Highlighting the message on the Terminal

This indicates that the previous error has been rectified.

Now the model can be used to create a Mixed-Signal schematic in eSim.Please refer to the earlier tutorials to do the same.

This is done when a user needs to add more files.

Click on Add Top Level Verilog File

Click on Downloads>>8bit_vedic_multiplier>>vedic8x8.v

Click on Open

Then click on Add Top Level Verilog File to add the vedic8x8.v verilog file..

Go to the Downloads Folder and then to 8bit_vedic_multiplier.

Select the vedic8x8.v file and click on the Open button.

Switch to the NgVeri Tab

Click on Run Verilog to Ngspice Converter

To do so, again click on the NgVeri tab.

Then click on Run Verilog to Ngspice Converter.

Scroll Up

Highlight another error message ‘Cannot find file containing module: 'vedic4x4’ in the Terminal

Let us scroll up to see why the error occurred.

We see another message Cannot find file containing module: 'vedic4x4'.

It indicates that the 'vedic4x4' and the other dependency files are missing.

So, we will now add all the files at once using the Add Folder Option.

Click on Add Folder

Click on Open

Locate and select the 8bit_vedic_multiplier folder.

Click on the Open button.

If we click on Yes, the only contents of the folder will be added.

If we click on No, the complete folder will be added.

Click on Yes

Highlight the message in the Terminal

We can see in the terminal that the dependency folder has been added.

Dependency filesor folders help us to divide a large Verilog file into submodules.

The user can make use of this option depending upon the requirement.

Click on Run Verilog to Ngspice Converter

Click on the Clear Terminal button to clear the terminal.

Now click on Run Verilog to Ngspice Converter.

Highlighting the message on the Terminal

About lint:

• Linting helps us to check programmatic or stylistic errors in a program.

• lint_off errors/warnings create a problem in compilation of NgVeri.

• To ignore these lint_off errors, lint_off commands need to be added or removed.

• To know more about lint_off commands, please refer this website: https://verilator.org/guide/latest/warnings.html#list-of-warnings

We see the list of all the lint_off commands.

The lint_off commands help to ignore lint_off warnings in Verilator compilation.

Select EOFNEWLINE from the drop-down menu.

EOFNEWLINE occurs when there is no empty line at the end of file.

We see that the command EOFNEWLINE is removed successfully.

Click on the Clear Terminal Button

Click on Run Verilog to Ngspice Converter

Click on the Clear Terminal button and then on Run Verilog to Ngspice Converter

Scroll Up

Highlight another error in the Terminal

Let us again scroll up to see why the error occurred.

We see another message Missing newline at end of file.

We can see a text box to the left of the Add Lint_off option.

Click on Add Lint_Off

Let us type EOFNEWLINE in the text box.

Then, click on the Add Lint_Off option.

Click on the Clear Terminal

Click on Run Verilog to Ngspice Converter

Click on the Clear Terminal button to clear the terminal.

Now click on Run Verilog to Ngspice Converter

Highlighting the message on the Terminal

The Edit modlst option is used to see all the models present in the NgVeri.

We see a list of models.

Removing NgVeri Model:

• While creating a model, sometimes we might get an error which can’t be resolved.
• The error creates problems in building NgVeri for future Verilog files also.
• In such a case, the error giving model must be removed by the Edit modlst option.
• The error model can be identified in the terminal.
• The Edit modlst option is useful to users to remove redundant models.
• It also reduces memory space

To do so, click on counter4bit from the drop-down.

Click on Edit modlst dropdown menu

Again click on the Edit modlst dropdown.

We see that the model counter4bit is removed successfully.

Let us summarize.

In this tutorial, we have

• Added dependency files and folders
• Removed NgVeri models and
• Added and removed lint_off commands

in NgVeri.

• Click on the Edit lint_off
• Check all the commands in the drop-down
• Remove the CASEX lint_off command
• Click on the Run Verilog to Ngspice Converter to generate the model again
• Check if there are errors.
• Add the CASEX command again using the Add lint_off option.
• Check whether it has been added by clicking on Edit lint_off drop-down.

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Acknowledgement

Thanks for joining.