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Creating Device Definitions

We have assumed that the Device Library is full of definitions ready to use to create devices, but  this is far from truth. On the contrary, there is a need for definitions and here you have a great opportunity to contribute in terms of data entry.

Before creating the new definition, make sure it does not exist already.

Hit the [Library] button in the Toolbar. Select your device type in the "Dev Type" list box (for example, "FS" for Frame Sync). Examine the list to see if your device is already there. If not, proceed as following to create it:

Hit the [Add] button to get to the "Add New device to the Library" form. Fill in the form as appropriate and hit [Save]. This will take you back to the list where the new definition should be now.

Select your just created definition from the list to get into the "Device Definition" View. This is the most important task: adding ports, which we will explain in details next.

Once in the Device Definition View, hit the [Add Ports] button to get to the "Add Port" form.

A ports can be either Input or Output. You establish this by selecting the proper value from the "Port Type" list box. Continue to fill in the up to the "QTY" field; if you are adding just one port, leave it with the default value (1). Press the [Add] button to save. You will be taken back to the "Device Definition" view, now showing the newly added port.

You can add multiple ports at once; this is useful in many cases, for example, DA outputs. To do that, fill in the form as described but now set the "QTY" field to the desired number of ports.

Optionally, multiple ports can be enumerated automatically. For example, to get outputs labeled "OT-1" to "OT-8", fill in the form as following:

    Label       : OT-
    QTY         : 8
    Append Enum : (checked)
    Starting at : 1

If you commit a mistake, or change your mind, you can always Edit a port to make the necessary corrections, even converting an Input to Output or vice versa.

It is not entirely true that a port can only be Input or Output. Some ports are "bidirectional" (duplex) which is the case of Ethernet, RS-232 and others. Green Book concerns about "Bidirectional Signals"; ports are kept into the Inputs/Outputs set.

When you add a port which Signal Type is bidirectional, you are free to define that port type as Input or Output. As a convention, we suggest to define Ethernet Switches ports as Outputs and computers NIC ports as Inputs.

It is very common in real-life devices to use multi-pins connectors such as DB25 to deliver linear signals like Analog Audio, usually via breakout panels or cumbersome hanging cables.

The problem with this is that, in Green Book, you cannot connect multiple wires to a single port, because the same is represented with a single table row.

The solution to this situation is the following:

A single multi-pins connector is represented by multiple rows in the Definition: as many rows as wires can be connected. For example, if you have a DB25 connector exposing 8 input audio channels, you define it with 8 Input Ports which connector type is "DB25".

When you define a device of type FRAME, you get an extra field in the form: "Slots Count". Fill this with the appropriate value.

That will suffice in most cases, but some frames present ports that belong to the frame itself. In those rare cases, you hit the [Add Ports] button and proceed as explained previously.

Remember that a Definition is a template from which devices will be created. This implies that the definition must be complete, it must contain all ports available in the real-life device including those of little or rare use in practice.

This fact encourage us to make our device definitions based on trust able data. Our recommendation is to always make device definitions from the device manual or datasheet.