I'm getting some antenna errors in my flow. What are typical causes of this or what does this usually indicate?

Are you using rc3 (master)?

Yes

You shouldn't be seeing many antenna violations though; how large is the design you're running?

Maybe I'm looking at the antenna report wrong. At the bottom of reports/routing/antenna.rpt, it has "Number of pins violated: 64" "Number of nets violated: 61" "Total number of unspecial nets: 47510" In terms of how big the design is, results/placement/<design>.placement.def shows a die area of 1595680 1606400. If there's another metric that would be more helpful for me to provide, let me know. Thanks for the responses.

How many cells is that design? You can also check how badly the antenna rule ratios are violated in the report. If most violations aren't very bad, usually there is not much to worry about.

Yosys.log reports 45402 cells. What am I looking for in the antenna report? I ask because the report is over 100MB in size (over 3,000,000 lines).

@Matt A: you're looking for values that exceed the ratio (search for

*

).

In one of the exceedance cases (had a *), the PAR is 10694.67 and the Ratio is 3130.28 (S.Area). Not sure what this means.

@Matt A: this means that you need to insert some diodes or segment the wire that is connected to this pin, or there will be a possibility (just a possibility) that this wire will act as an antenna during the manufacturing process and damage the chip as it's being made. (or that's my understanding at least.) But, if you're asking about the exact meaning of the numbers. I guess @mehdi is the best person to answer your question as he's the one who implemented the Antenna Rule Checker.