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Thread: Constant inputs in SDC

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Category: ℹ️ - Information Parent channel: #⁉️-questions Thread ID: 1436125469295513752

Messages: 2

message-1436125469295513752

2025-11-06T22:49:53.801+00:00 — Tholin (@tholin)

Content

So, this would be more of a "nice to have" for my project to make the results of top-level timing analysis look a bit neater, but my die is a multi-project die, with 5 input-only pins providing project selection through a multiplexer. However, during top-level timing analysis, STA considers changes on the project select inputs in-between clock ticks. As the chip is designed to have those pads permanently bonded/wired to power or ground according to the desired selection, they should be considered constants for the purpose of timing analysis. But how do I codify this in my .sdc file?
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message-1436229763269263403

2025-11-07T05:44:19.422+00:00 — Leo Moser (mole99) (@mole99)

Content

You can ignore a timing path using `set_false_path`.
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