Signals with no Driver

Parent category: Violations Associated with Nets

Default report mode:

Summary

This violation occurs when a pin (with I/O Type Input or IO) or a sheet entry (with I/O Type Input or Bidirectional) is not connected to a driving pin or a port on the schematic sheet.

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:

Signal <SignalName> has no driver

where:

• SignalName is the name of the affected signal.

Recommendation for Resolution

This error can sometimes be caused by the offending pin/sheet entry not being wired to the intended net in the circuit. If this is the case, an additional error stating that the affected signal pin/sheet entry is unconnected will also appear in the Messages panel. With the violation selected in the Messages panel, use the Details region of the panel to cross-probe to the affected signal pin/sheet entry. Trace the wiring from the pin/sheet entry to ensure it is connected as required and modify if it is not.

If the 'signal has no driver' message appears on its own, look for the component output pin to which the input pin/sheet entry is directly connected. Once identified, you can check/edit the output pin's electrical type from the Component Pin Editor dialog. Access this dialog from the Pins section on the Pins tab of the Properties panel (when browsing the properties of a selected component) by clicking the  button.

Tips

1. This violation type will only be displayed when compiling a free schematic document.
2. 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).