Hi everyone, I'm stuck on routing congestion for our final user_project_wrapper build. I really can'...

Ellen Wood

10/30/2023, 1:10 PM

Hi everyone, I'm stuck on routing congestion for our final user_project_wrapper build. I really can't understand the way in which the router is behaving. The ports its having trouble with appear to be just those along the bottom edge of the macro. I've brought these right out to the edge, and they are few and far between (only about 60 ports spanning a 1200um edge) but its still having trouble with congestion. It seems to be sending all the wires up a narrow corridor to the left of the macro, and then across and down, why? There's loads of empty space below it!

Ellen Wood

10/30/2023, 1:44 PM

Ok, figured out the problem, leaving it here incase it helps anyone else.. there was a tiny piece of metal 2 between each port and the very edge of the macro which I hadn't noticed - seems that was enough for the router to keep out of the whole area! Clearing it away so only the ports touched the very edge solved it

👍 1

Matt Liberty

10/30/2023, 10:58 PM

Routing through that tiny piece is a short and the router avoids shorts

steven darker

10/31/2023, 1:04 AM

I also encountered this error, but I haven't found a way to open the GUI to view routing and layout density. Can you show me how to open the GUI and share your config.json file after you've fixed the error for reference?

Matt Liberty

10/31/2023, 3:14 AM

see https://openlane.readthedocs.io/en/latest/reference/gui.html

Ellen Wood

10/31/2023, 10:19 AM

I didn't have to make any changes to the config for it to work, only to delete some M2 from the edges of the ports in the layout

Ellen Wood

10/31/2023, 10:19 AM

The way I run the GUI to see congestion is to:

Ellen Wood

10/31/2023, 10:20 AM

1. Change into /issue_reproducible directory 2. Open terminal 3. Run the following commands one by one: 4.

openroad

source run.tcl

gui::show

Ellen Wood

10/31/2023, 10:21 AM

Which shows the congestion even if Global Routing doesn't complete (as usually the .odb file won't get populated with heatmap data if this step doesn't finish). Then you can load the

/tmp/routing/resizer-routing-design-congestion.rpt

in the DRC viewer on the right hand side, which will show the white stars

Ellen Wood

10/31/2023, 10:22 AM

I think you have to have OpenRoad installed to do the above steps, but not 100% sure on that

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