Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

timing features don't work #20

Open
Devil-SX opened this issue Nov 1, 2024 · 6 comments
Open

timing features don't work #20

Devil-SX opened this issue Nov 1, 2024 · 6 comments

Comments

@Devil-SX
Copy link

Devil-SX commented Nov 1, 2024

use Verilator backend, timing argument

picker export ... -sim verilator -V --timing

I use some delay assignments in my RTL code. such as a <= #(10) b

Didn't see any delay on waveform. Verilator version 5.024 supports timing features.

@Makiras
Copy link
Contributor

Makiras commented Nov 1, 2024

Maybe we can check if the --timing argument has been successfully enabled for design at first? the building logs may show the status.

@Devil-SX
Copy link
Author

Devil-SX commented Nov 1, 2024

Thanks for you quick reply. I think argument has been successfully enabled because without argument compile process would fail and with argument it can be compiled successfully.

@Makiras
Copy link
Contributor

Makiras commented Nov 1, 2024

that's an unusual behavior, may I have your minimal code for reproduce?

@Devil-SX
Copy link
Author

Devil-SX commented Nov 3, 2024

This is a minimal example for reproducing.
delay.zip

If you run the current version or delete the timescale ... of Delay.v, you can't see any delay on the waveform.
If you change 1ps/1ps to 1ns/1ps, you can't see any change of output signal.

What is the default period of InitClock ?
I also tried add --timescale argument to verilator, but I didn't find correct form.

@Makiras
Copy link
Contributor

Makiras commented Nov 4, 2024

The default period for Verilator is 1ps/1ps. Each Step() will push the clock for 1ps by default (the last one, 1ns/1ps will be 1ps).
So if 1ns/1ps is changed, #10 will delay 10ns, which is 10000 ps and needs 10000 Step().

I will try to reproduce in the next few days, thanks for you artifacts.

@Makiras
Copy link
Contributor

Makiras commented Dec 2, 2024

I'm sorry, but I couldn't reproduce this situation in my environment. It would be appreciated if you could provide more details about your environment.
such as verilator, python, picker, gcc, linux, environment variable version

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

2 participants