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Guidelines help smooth the implementation of new TopCAT features

TopCAT™ (Topology and Cluster Analysis Technology) is a new set of ScanWorks capabilities that dramatically reduces the time needed to achieve an acceptable level of test coverage. For example, TopCAT's test automation features reduced the test development time to less than a day for a complex printed circuit board with almost 9,000 nets, over 40,000 solder joints and approximately 6,000 components, including more than 60 memory clusters and over 40 logic clusters.

The following guidelines will help users implement TopCAT's features as effectively as possible.

1. Be consistent with device type names in all designs. This simplifies the creation of a library of models with matching names. Then, ScanWorks' TopCAT capabilities can match the appropriate model to a device name and automatically insert the correct model into test actions.
2. Use consistent names for power nets. This allows ScanWorks' TopCAT features to automatically determine the power nets during netlist translation. This is important because ScanWorks will be able to automatically detect the pull-up and pull-down resistors and identify the pins that are tied to power nets.
3. The naming conventions for JTAG TAP signals should be consistent among all designs. This will make it easier to describe the scan path to ScanWorks and enable automatic scan path discovery in future versions of ScanWorks.
4. Reference designators should be consistent throughout all designs. For example, ‘Ux” could refer to digital devices, while “Jx” and “Px” designated connectors, “Cx” capacitors, “Rx” resistors and so on. Designator consistency makes net list management and model assignment much easier.
5. Certain attributes of devices should be defined so that some sort of identifier can be added to the standard schematic symbols that identify a device as “special.” Examples are boundary-scan devices, memory devices, flash devices, programmable logic devices (PLDs), processors and others. Attributes also can be added to a device's schematic symbol to identify the programming source file. ScanWorks has access to all of this information through its design browser. In the future, enhancements to TopCAT technology will enable ScanWorks to automatically identify the device type and create the proper action to test or program it.
6. Limit the use of special characters in the names that are used during schematic capture. ScanWorks uses the path name as the name for specific models. As a result, a backslash (\) in a name could indicate a directory level to ScanWorks and this would make it difficult to find a model. In addition, dashes (-) are used as the separator between reference designator and pin number (for example, U1-1). Consequently, a dash in a name also can confuse the ScanWorks tools.
7. Create a master copy of the "usersettings.ini" file so that all ScanWorks stations are set up consistently. Also, use the same default settings for parameters such as default names for power and ground nets and limits during test generation.
8. Define a master cross reference list of Memory Access Verification (MAV) models that will be used with all designs. This will enable the auto-create MAV and MAV replicate features of TopCAT.
9. Create department- or company-wide libraries of models of all types of devices and make them available to all test developers across the entire organization. Developers will be able to reuse models previously verified by others, and duplication of model creation and validation effort will be avoided.
10. Use the model libraries provided by ASSET on the ASSET support web site as the first sources for new models. Thousands of models are available to ASSET maintenance customers for downloading. Models can easily be copied to a company library and renamed to match a design's device names.
11. Invest a little time in learning all you can about the new features of ScanWorks. A few minutes now could save hours on each ScanWorks project. ASSET provides a free web-based seminar on the new features of each release. The support web site, which is available through the ScanWorks user interface, lists the training schedule. Local application engineers can also provide this information.