I do not see a way to assign bidirectional signals in StateCAD. Is this possible?
StateCAD does not directly support bidirectional.
One possible way to work around this is to create two 3-state signals/vectors that get tied together (input<=>output), with a control signal generated by StateCAD. The control signal enables the 3-state signal of one and disables the other.
A better approach would be to use StateCAD to generate a separate input and output signal and the control logic, and to feed all three signals into an external bidirectional module.