Connection Test Errors

When tests are run on a circuit, one of the first steps is usually to run a connection test. This automatically generated test checks all the connections it can between devices in the circuit to ensure that the Unit Under Test (UUT) matches the circuit described in the project and netlist. XJTAG's connection test includes checking for short-circuit and open-circuit faults, testing of pull resistors, and testing of discrete logic between JTAG devices. After running the connection test, the test system will typically move on to run more tests which use the functionality of non-JTAG devices, such as loading data into RAM or checking clock signals, in order to fill in gaps in the test coverage.

If there's a problem with the UUT, the connection test can display a number of different errors. Connection test errors show which nets are affected and right-clicking on an error will allow you to show the problem area in the Layout Viewer and Schematic Viewer. Clicking the + next to Net Detail will expand that section, showing all the pins on the affected nets.

Click to expand

Figure 1: A connection test error

In this user guide section you can find:

• A summary of broken chain issues which might cause the connection test to exit without completing its tests.
• A list of all the possible connection test error types and explanations of what they mean, followed by how to investigate and solve them.