Access Analyzer (AA) automates pre-layout testability analysis. AA tools are typically used after schematic capture and before CAD layout for assemblies that have a mix of scan and non-scan devices. AA generates two reports to help design and test engineers make the most effective use of physical and virtual access to the assembly-under-test.
The Virtual Interconnect Test report identifies all the pure scan nets and scan control nets (TDI/TDO interconnects) that can be fully tested by VIT
techniques, and where physical test points can be safely eliminated. The Virtual Component Test report identifies the nets where adding physical access would permit VCCT
testing of non-scan devices. For in-circuit test, these nets can be accessed by a bed-of-nails probe. For the edge-connector test, nets can be routed to an edge connector or to a test connector for access by ATE.
For the VIT report, AA sorts networks into four categories:
- Pure scan nets
- Scan control nets
- Partial scan nets
- Non-scan nets
Physical test-pad access can be safely eliminated from pure scan and scan control networks.
Virtual Interconnect Test Report sorts the nets on a board into four categories of boundary scan access: pure scan, scan control, partial scan and no access. Note: IC_1, IC_2, and IC_3 are scan devices. IC_4 and IC_5 are non-scan devices.