The Quartus II software Chip Planner displays an error message if you attempt to create an atom by right-clicking a COMB node of an ALM

In the Chip Planner, if you attempt to create an atom in a design that targets an Arria GX, Arria II GX, Arria II GZ, Stratix II, Stratix II GX, Stratix III, or Stratix IV device by right-clicking a COMB node of an ALM and selecting Create Atom, the Chip Planner displays

Can’t create node. Click the System tab on the Messages window for details. However, the Messages window does not contain any details.

To create an atom for a COMB node of an ALM:

1. Select and right-click an empty FF of an ALM and then click Create Atom.
2. In the Create Atom dialog box, name the atom you created in step 1.
3. Select and right-click an empty COMB node of the same ALM and then click Create Atom.
4. In the Create Atom dialog box, name and specify the type of atom you created in step 3.
5. In the Change Manager window of the Chip Planner, select and right-click the atom you created in step 1, and then click Restore Selected Change.

You can proceed to run Check and Save all Netlist Changes to verify these engineering changes.