Nets Containing Floating Input Pins

Parent category: Violations Associated with Nets

Default report mode:

Summary

This violation occurs when an input pin for a placed part within the design has been detected to be floating, i.e. not electrically connected to any other part of the circuit.

Notification

If compiler errors and warnings are enabled for display on the schematic (enabled on the Schematic - Compiler page of the Preferences dialog), an offending object will display a colored squiggle beneath it. Hovering over the object will display a pop-up hint that summarizes the violation. A notification is also displayed in the Messages panel in the following format:

Net <NetName> contains floating input pins (<PinList>)

where:

• NetName is the name of the offending net.
• PinList is the comma-separated list of pins in that net which are floating.

Recommendation for Resolution

This violation can arise in a number of situations. Consider the following when resolving a violation of this type:

• If the pin is not to be used within the design, either tie it to the appropriate power line (e.g., GND), or place a No ERC directive on it.
• Ensure that the wiring to the pin is making electrical contact, i.e. the wire or bus connects to the pin's electrical hot spot.
• Use the Navigator panel (compile the project first) to trace the connectivity of the parent net to which the offending pin is associated. Sometimes, a pin can be caused to 'float' when there is a break somewhere else in the net. For example, a pin might receive its signal from an input port on the sheet, which in turn is fed a signal from a linked sheet entry higher up in the design hierarchy. The input to this sheet entry may be disconnected. Fixing the connection to the sheet entry will resolve the floating input pin violation.
• Look for additional violation messages in the Messages panel that relate to the same parent net, especially those that mention unconnected objects. This can give an indication where the break in connectivity lies.

Tip

• Object hints will only appear provided the Enable Connectivity Insight option is enabled on the System - Design Insight page of the Preferences dialog. Use the controls associated with the Object Hints entry in the Connectivity Insight Options region of the page to determine the launch style for such hints (Mouse Hover and/or Alt+Double Click).