For some simple device models (i.e. nets and bus connectors), all that is editable are the name of the device in the library, and the EDIF name. For all functional devices, the title of the device, which appears above the device picture, may be edited in this dialog. Also, propagation delays may be edited for each pin capable of output. Power dissipation [[parameters]], including Icc, the static current dissipated, and the dynamic [[parameters]] Cpd and Cin, are available. [[Parameters]] for fan-out violations, Iol, Ioh, Iil, and Iih are available here. For dynamic devices, the additional [[parameters]] of set-up and hold time and maximum clock frequency are available.
All digital devices in the circuit have unique models. For example, if you place two 7404 inverters in the circuit and change tplh for one of them, the other will still have its old tplh value. There is no way to share models in the digital mode of [[B2RF.Spice A/D]]. However, if you use mixed mode in [[B2 RF.Spice A/D]], then you can share models and changing one 7404 inverter's delays will change the delays for all 7404 inverters in the circuit unless you specify through the Edit->Options menu that all devices are unique.
The most obvious cause of an unknown output value is an unknown input. You should probe the inputs to the device to find which of its inputs if any is unknown, and continue backtracking to the source of the problem. The possible causes of unknown output values are unknown input values, set-up time violations, and hold-time violations. For example, if you are using a 7474 D flip-flop, and d changes at time 10, then the clock changes at time 25ns, the output will soon change to unknown because the 7474's set-up time requirement is 20ns. Edit the model for a register or flip flop to view its set up and hold time requirements.