Verilog HDL - Installing and Testing Icarus Verilog + GTKWave

This is our first video on implementing digital logic circuits in Verilog, a Hardware Description Language (HDL). In this lesson we'll go through the installation (Windows) for Icarus and GTKWave and write a very simple, hello world, style module and testbench.

[@vevasam]

This is just beautiful. Simulation is synthesizing a test bench. Thank you.

[@abdulpangandaman]

How come you only have a very few subscriber. You are underrated man! I wish you'll keep going. Btw, thank you, just done watching the first episode. I'm a computer engineer and I sense that it is a worth watching series. :)

[@jeremyvidaurri]

Just a heads up, he is using the grave accent ` when he says apostrophe.

[@DarkLightning96]

Next time you make a video like this, add the links to the description, it would help. Thanks! :)

[@yubdr]

Very simple explanation with a good example. Thanks!!

[@abhiraj2005]

Thank you derek bhai love you.

[@ArpitDhamija]

Getting this error, how to fix it , pls tell
iverilog : The term 'iverilog' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the
spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ iverilog -o hello_tb.vvp hello.v hello_tb.v
+ ~~~~~~~~
+ CategoryInfo : ObjectNotFound: (iverilog:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException

[@yelhaus]

Hey Arpit! It looks like you may have made an error when you installed iverilog. This error is caused when the operating system doesn't have the 'iverilog' command in it's PATH variable.

[@M4comp]

@@yelhaus I'm having this same issue. Someone help please.

[@prateeksrivastava1269]

@@M4comp reinstall and while reinstalling, check mark both the download gtk and ADD PATH

[@dmo4657]

@@yelhaus How to fix this ? please help

[@ankitdhaker111]

ADD VERILOG BIN PATH TO ENVIRONMENT VARIABLES SECTION .

[@ashan8k]

one good suggestion: Don't record the full screen. It's too small to see on TH-cam. Or please increase the font size.
Thanks for this video :)

[@ihanick]

Hi Derek, Thank you for the clean and easy tutorial on Icarus Verilog! Are you going to cover coding style (like "Verilog Coding Standard"), Verilog-2001 features, fusesoc (libraries management, build tool), Verilator? It's really hard to find explanation how to use something more complex than MUX or 7-segment indicators.

[@bjrnbrodtkorb9288]

Thank you so much for explaining this!

[@bhonduakalmand9604]

Thanks for such a clear explanation

[@EternalNoobCoder]

Excellent tutorial. Thank You ❤️

[@benedicti309]

Someone help, I've got a problem. The vvp file isn't getting created. And it gives me the error "Unable to open input file". What do I do?!

[@devojyotichaki]

iverilog : The term 'iverilog' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify
that the path is correct and try again.
I'm having this problem , can you please help me with me it?

[@yipengtang957]

I installed iverilog and gtkWave on my Linux Mint. But it does not include VVP simulator. how everyone run simulation on the LInux?

[@WeasyK]

Big help, thank you!

[@monishmeher3901]

yeah true he's a god

[@pratiklomte]

@@monishmeher3901 its you Monish the real one?! I am a big fan of your vidoes!! Nice to meet you

[@alkac6654]

After instalation, when I enter in terminal "iverilog" I obtain: 'iverilog' is not recognized as an internal or external command,
operable program or batch file. OS is Windows 10. I tried different versions of the program. Did you met the same problem? Thanks for the answer.

[@costanzapizzo9454]

I was about to ask him the same question, have u found a solution?

[@alkac6654]

@@costanzapizzo9454 yes, in "environment variables" you need to add in path also path with \iverilog\bin . Drop me a massage on skype "zxz12m" for example if you need more help.

[@costanzapizzo9454]

@@alkac6654 oh okay thank you

[@luizastorga8066]

i was also getting the 'No top level modules, and no -s option." and i just forgot to save before compiling/running

[@kushgandhi503]

Same problem

[@basilpmathew9639]

It helped me a lot, Thank You

[@palzangnorgaygansarpa7367]

how do we fix "no top level modules and no -s option error" shown in terminal?

[@prateeksrivastava1269]

hey , did u resolve ?

[@supersultan7374]

@@prateeksrivastava1269 I had this problem too, it turns out I just forgot the "-o" in the command

[@ashmt1084]

@@supersultan7374 just save the code

[@ryoma8402]

Guys the vcd file is not created after running the vvp command. Any help?

[@josephhyatt]

Did you ever figure this out? I'm having the same problem..

[@ryoma8402]

@@josephhyatt No, I didn't. I ended up switching to ModelSim Student Edition. I got a licence key with a fake name and a disposable mobile phone and I managed to set it up. Good luck with ModelSim's hideous GUI btw. It's gonna take a lot of getting used to.

[@khangnp7850]

great video!

[@anurag_6363]

it's showing the error in terminal "No top level modules, and no -s option."

[@UddhavSurve]

check the folder in which you stored programs and then check whether its the same path shown in terminal

[@LordBeerus14]

Same Error

[@LordBeerus14]

@@UddhavSurve and yes, terminal is showing the folder where the programs are stored

[@amirhossein_1235]

great , thanks!

[@GenkiKuri]

Thank you!

[@joshuaduplaa9033]

Thank you master.

[@shadon_official2510]

amazing video

[@z.o.e3023]

It isnt creating the vcd file after the 'vvp hello_tb.vvp' step. Message not displayed either.
Can you kindly help here?

[@z.o.e3023]

In this line in the code
hello uut(A,B);
hello and uut arent blue like yours

[@eliasreyes4913]

nice video, helped my a lot

[@remzialtparmak9070]

Allah razı olsun abi

[@user-zs8rg8xh4h]

half_adder.vvp: Unable to open input file.
getting this error please help

[@dentakuweb]

How did you get the colour highlighting in your Powershell window?
I see you get iverilog in yellow and -o in grey for example.

[@kartikeyak3425]

did you add verilog to path?

[@eldararush]

how to run the terminal command you wrote automatically when I run the code via vscode?

[@subhraneelmukhopadhyay309]

what do I do when I get this "'iverilog' is not recognized as an internal or external command,
operable program or batch file."

[@subhraneelmukhopadhyay309]

I did all the steps till 1:08

[@bharaths2646]

Same error for me too

[@ahmedhassanibrahimhassan5039]

thank you very much❤❤❤

[@ravneet6648]

can we use it for .sv files?

[@prateekchauhan8531]

No such file or directory
No top level modules, and no -s option.
this problem is coming up
can anyone solve this

[@crazyTG_]

I am also getting the same problem, do you know how to resolve it. Help much appreciated

[@heyitsmea8883]

Iam getting error and Thouse vvp file is not created in verilog folder please anybody help me with this..

[@ArpitDhamija]

mine is not compiling

[@pranathikottakapu4813]

I'm getting an error saying "unknown module type" and error during elaboration during compilation time.

[@monishmeher3901]

yeah I had the same problem, feel you bud

[@abdulkhaleqsabeeh2128]

i cant find verilog in the explorer

[@Karga4430]

this command: iverilog -o hello_tb.vvp hello_tb.v
gives this in the next line:
No top level modules, and no -s option.
HELP

[@emilyzhang3589]

maybe try to declare your hello_tb.v path in the command

[@aviroxi]

thank you so much

[@Ochin2011]

Hi Derek, when I use the command "iverilog -o hello_tb.vvp hello_tb.v" im getting an error "No such file or directory. No top level modules, and no -s option"

[@ihanick]

Hi Ochin, The command you have used expects to find hello_tb.v and hello.v files to be in current directory. Use Set-Location -Path "put path to directory with .v files here" in PowerShell or cd "put path to directory with .v files here" in CMD.exe or OS X/Linux/BSD shells. VSCode opens workspace directory by default. In order to open a correct directory make a right-click on filename under "OPEN EDITORS" at left and select "Open in Terminal"

[@Ochin2011]

@@ihanick thank you for your response. I am on Windows and I did use CMD.exe to put my path directory (cd ilverilog\bin\). I started off with even a simpler tutorial provided here www.referencedesigner.com/tutorials/verilog/verilog_02.php where we just have to compile "iverilog hello.v" (i have tried with and without -o). what I have noticed is that when I use "iverilog hello.v.txt" then only the "a.out" file is generated and I can then output ""Learning Verilog is easy with referencedesigner.com tutorial"". I'm very confused on how to fix this as I'm a newbie. I really appreciate your help

[@ihanick]

@@Ochin2011 In order to use "iverilog" command you should put X:\Full Path\iverilog\bin\ to your %PATH%. -o filename instructs icarus to save vvp script to "filename". E.g. if you have installed icarus to C:\iverilog, add C:\iverilog\bin to path. alternatively you can run set PATH="%PATH%;C:\iverilog\bin\" after each cmd.exe restart and cd c:\hdl\lesson01 (assuming that you have hello.v and hello_tb.v in c:\hdl\lesson01 ). With windows 10 windows subsystem for linux you can also forget about all this program installation hell and install icarus with sudo apt install iverilog. and of course switch to right directory with your hello_tb.v with cd.

[@sanikachepe8489]

Hi, make sure you wrote the program correctly.. I had written input instead of output for B, in the hello.v file which was causing this error for me. Hope this helps :)

[@shandeeparya1618]

Can we able to work on Verilog pli in Icarus ?

[@revvisionvlogs]

Thanks!

[@nefertiti1456]

hello I've got an error saying "hello_tb.vvp: Unable to open input file." How can I solve it? Please help :(

[@smartoikra4315]

probably the file wasn't present in bin folder

[@rsubrahmanyam555]

I had given command
iverilog -o hello_tb.vpp hello_tb.v
Instead of
iverilog -o hello_tb.vvp hello_tb.v
After giving correct command the issue is resolved. Hope this might help you

[@jasperjohnjaso2720]

hello_tb.v:1: syntax error
I give up
I end up with this

[@yelhaus]

in your testbench, be sure to use apostrophe (`) not single quote (') for the timescale and include statements. This gets a lot of people the first time.

[@dailydose2019]

@@yelhaus still getting same error :/

[@mushyomens6885]

same error

[@neeleshranjan7827]

thank you

[@Bhuvan_cv]

My vcd file is not opening please help

[@aeroldmarougalela1605]

it didn't work on my laptop.

[@lauram.6285]

Thank you very much!

[@devegna_kanzariya]

Time 11:11

[@bharaths2646]

man u left one basic thing to explain that is how setup a verilog extension

[@chris_yt4115]

I get this error even tho I installed Verilog correctly following each step in the video
iverolog : The term 'iverolog' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the
name, or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ iverolog -o
+ ~~~~~~~~
+ CategoryInfo : ObjectNotFound: (iverolog:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException

[@tarunjangir8460]

I am facing the same issue. Did you get any solution?
PS, i tried editing environment variables

[@zhengliew169]

@@tarunjangir8460 bro how to edit environment variables?

[@francis.joseph]

what is the use of this of we have modesim

[@yelhaus]

Modelsim is proprietary whereas Icarus Verilog + GTKWave is Open Source.

[@someone-gl7oy]

Marshall from How I Met Your Mother

[@stubborn176]

"WORKING" tutorial.

[@abdulpangandaman]

How come you only have a very few subscriber. You are underrated man! I wish you'll keep going. Btw, thank you, just done watching the first episode. I'm a computer engineer and I sense that it is a worth watching series. :)