intent/io-map-net-absent

Remedy ¶

Add the missing net, or amend the IO map. Check for a misspelling first: a net present under a slightly different name is a different fix from one that was never drawn.

What it checks ¶

The IO map declares a net and the netlist does not have it.

The rule gives one verdict per declared NET rather than per row. It is ordinary for a map to name one net on several rows. Repeating an absence per row would inflate the count, and a reader uses that count to judge how bad the disagreement is.

For hardware engineers ¶

This and an incomplete map are opposite defects, and they get confused constantly:

• A net the map declares and the netlist does not have is usually a real disconnection. Something was meant to be drawn and was not.
• A net the netlist has and the map does not declare is usually an incomplete map. The design is fine and the document is behind.

This rule reports the first. The second is a coverage question, and intent/io-map-coverage reports it. There the interesting number is how much of the netlist the map covers at all, rather than a failure count. Imagine a design with sixteen hundred nets and a map declaring two hundred. Two hundred nets are checked and fourteen hundred are UNEXAMINED, and that is not the same as clean.

A misspelling is not a disconnection ¶

When no net carries the declared name but one differs from it only by spelling, the verdict is inconclusive and names the net it found, rather than failing.

Imagine a net that is present, under a name that differs by one invisible character pasted out of a spreadsheet. Sending a reviewer to look for it as missing costs more than the finding is worth. We measured a shipped checker of this kind against a large production board. Every warning it produced was a comparison artifact of exactly this family.

The shared identifier comparison forgives case, invisible characters, and zero-padded and bracketed indices, and spelling here means those differences. It does not mean a fuzzy match, since dropping a token from a net name names a different net.

Declaring it ¶

Declare the same io_map section that intent/io-map-pin-mismatch reads. This rule uses the net field alone.

Fixing a finding ¶

Check for a misspelling before drawing anything. If a net is present under a slightly different name, the fix is one character in whichever document is wrong. If a net was never drawn, the fix is a schematic edit. The finding tells you which, because a suspected misspelling reports as inconclusive and names its candidate.