nc-pin-connected

Remedy ¶

Disconnect the pin and mark it no-connect. Where the connection is deliberate (a factory test pad, a vendor-documented exception), cite the datasheet section that allows it in a schematic note.

What it means ¶

A pin whose electrical type is NO_CONNECT (the symbol author’s “leave this alone”) sits on a net that connects it to at least one other pin.

Why engineers want it ¶

It is the no-connect column of every ERC connection matrix (KiCad reports it as “connected NC pin”, an error). NC pins exist because vendors reserve pads: internal test points, factory-trim pins, pads with no bond wire. A wire landing on one is usually a misplaced connection, and occasionally a genuine misuse of the part.

Impact ¶

Best case, a signal routed to a dead pad silently does nothing (a missing connection in disguise). Worst case, the net disturbs an internal node the datasheet says to leave floating.

Scope note ¶

Fires only when the net has two or more members: a lone NC pin on its own stub net is the intentional case (single-pin-net skips it for the same reason). Cross-sheet (external) nets are skipped. The pairing is NC ↔ anything, so one flagged net reports once, on the net.

Query structure ¶

select multi-member nets carrying a NO_CONNECT-typed pin.

select N in nets where count(N.connections) >= 2
  and exists P in N.connections where pin_dir(P) == no_connect

Reads: net.attributes, net.pin_count, on_net, pin.electrical_type. Tier R.