intent/exposure-declared

Remedy ¶

Correct the ref-des in the declaration, or remove the entry. A declaration naming no connector on the board leaves every connector checked as external, which is the opposite of what it was written to say.

What it means ¶

A design’s intent can declare a connector internal, which tells the exposure rules (esd-protection, esd-clamp-not-tvs, input-protection and reverse-blocking-absent) that the connector joins this board to another inside the same product and faces nothing a user touches. This rule checks each such declaration against the design. It fails when the declared ref-des is not a component of the design, or when the component is not a connector.

intent:
  components:
    J1:  {exposure: internal}   # the module connector
    J18: {exposure: internal}   # the expansion mezzanine

Why engineers want it ¶

Exposure is a fact about one product rather than about the part. The same board-to-board connector is the module socket on one carrier and the cable entry on another, and its part number and footprint rarely say which. So the declaration has to come from the people who know the enclosure. If a declaration names the wrong ref-des, it changes nothing at all. Without this rule it would still read as a declaration that took effect.

Impact ¶

A declaration can be misspelled or stale. Then the connector it meant to name is still checked as external. The exposure rules then keep reporting it, or, if the ref-des now names a different connector, stop reporting one that does face the field.

Scope note ¶

An undeclared connector is external, so a design with no components: section checks every connector exactly as before. external can be written to state the default explicitly, and this rule checks it the same way.