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The-OpenROAD-Project / OpenROAD-flow-scripts

OpenROAD's scripts implementing an RTL-to-GDS Flow. Documentation at https://openroad-flow-scripts.readthedocs.io/en/latest/
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Questions about cell selection and padding. #2011

Open chros098 opened 1 month ago

chros098 commented 1 month ago

Subject

[Flow] for any util, flow Makefile, or flow script issues.

Describe the bug

In the configuration of the platform, only one synthesis buff cell and one CTS buff cell are written. May I ask if I write all the buff cells, will the tool add them based on actual needs, such as the first or last one. In addition, will the spacing between cells be strictly maintained according to the spacing specified in the song value set at CELL-PAD-IN_SITES-DETAIL-PLACEMENT? Thank you.

Expected Behavior

In the configuration of the platform, only one synthesis buff cell and one CTS buff cell are written. May I ask if I write all the buff cells, will the tool add them based on actual needs, such as the first or last one. In addition, will the spacing between cells be strictly maintained according to the spacing specified in the song value set at CELL-PAD-IN_SITES-DETAIL-PLACEMENT? Thank you.

Environment

In the configuration of the platform, only one synthesis buff cell and one CTS buff cell are written. May I ask if I write all the buff cells, will the tool add them based on actual needs, such as the first or last one. In addition, will the spacing between cells be strictly maintained according to the spacing specified in the song value set at CELL-PAD-IN_SITES-DETAIL-PLACEMENT? Thank you.

To Reproduce

In the configuration of the platform, only one synthesis buff cell and one CTS buff cell are written. May I ask if I write all the buff cells, will the tool add them based on actual needs, such as the first or last one. In addition, will the spacing between cells be strictly maintained according to the spacing specified in the song value set at CELL-PAD-IN_SITES-DETAIL-PLACEMENT? Thank you.

Relevant log output

No response

Screenshots

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Additional Context

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maliberty commented 1 month ago

What is "the platform" you are referring to - a public PDK or some private setup?

In general we will use the available cells and not just one size. Padding should be obeyed.

maliberty commented 1 month ago

This seems more like a discussion than an issue as no particular problem needs resolving.

chros098 commented 1 month ago

This is a private craft, and I found that I have set multiple BUFFs in the config "CTS-BUF-CELL", such as BUFF1, BUFF2, BUFF4, and BUFF8. Actually, I will choose BUFF8, but when I mentioned setting BUFF1, BUFF2, and BUFF4, I will actually choose BUFF4. Will the tool default to the last BUFF I have set? Also, I noticed that there is an S in "FILL_CELLS" that can be set to multiple, and there is no S after "CTS-BUF-CELL", so only one is effective.

maliberty commented 1 month ago

There is no config CTS-BUF-CELL - where do you see this in ORFS?

chros098 commented 1 month ago
fe8bd1409d0e5a492b44629ece7b09e

Here, flow/platforms/nangate45/config.mk, line 74

chros098 commented 1 month ago
fe8bd1409d0e5a492b44629ece7b09e
maliberty commented 1 month ago

That's just a leftover and isn't connected to anything in scripts/. I'll remove it.

maliberty commented 1 month ago

removed in https://github.com/The-OpenROAD-Project/OpenROAD-flow-scripts/pull/2029