Any time an assembly is created, an assembly data source is also created. This data source provides access to how the data is to be rolled up from the given lower-level design into the upper-level assembly.
Assembly Data Sources cannot be created from within Data Source Administration, as they are automatically created when creating an assembly. The assembly data source panel appears as shown to the right:
Options available on this panel
Assembly File - identifies the name and location of the design file to which the assembly is linked. The Analyst can change the file to which the assembly is linked by clicking on the icon to the right of this field. This is often a better way to change an assembly than unlinking and re-linking (that is, converting the assembly into a component and then back to an assembly again) because more information is retained. For example, if the new design file closely matches the previous one (that is, it is a newer version, etc), then only those differences between the two will result in changes to the functions assigned on the assembly. In contrast, although converting an assembly to a component is fairly simple, converting the component back to an assembly will result in functions being recreated from scratch. This could disrupt other definitions in the model, such as input filters, coverage-based testdefinitions, etc.
Assembly Controls
- displays the abbreviation assigned to the associated assembly (this field is for reference only, it cannot be edited here).
Roll-Up Approach
- This field controls how information will be rolled up. The following choices are available:
Top-Down Only - Retains all ports currently on the assembly and tries to match them to I/O flags in the lower-level design. Mismatches are treated as design errors.
Bottom-Up Only - Ensures that ports on the assembly match the I/O flags in the lower-level design. Upper-level ports that are not found in the lower-level model (as I/O flags) are removed, and ports are added for any lower-level I/O flags that do not exist (as ports) on the assembly.
Mixed Top-Down and Bottom-Up - Allows the definition at the bottom to override only those ports on the assembly that have not been identified as top-down. Any port whose direction is changed from the way in which it is defined in the lower-level design is considered to be a top-down port. Otherwise, ports are treated as bottom-up and will continue to change to match the lower-level design.
Create New Ports as Needed - If "Mixed" mode is chosen, this checkbox specifies that the roll-up process is to create new ports should the lower-level design identify new inputs or outputs. If disabled, existing ports will be reconciled according to the mixed mode behavior, but no new ports will be created.
Update Interval
- The frequency at which eXpress will check if the file has changed and re-import the data if necessary. For hierarchical data sources, it is not recommended that this value be increased from the default of 10 seconds. Assembly data sources are very optimized in how they examine changes so as to not cause extra computation due simply to the file data changing, without any real data changing in a lower-level design.
