The Semiconductor Multi Test and the Semiconductor Action steps examine the pin map to determine which sites to synchronize. Steps can also specify required pins or pin groups and relays, relay groups, or relay configurations for a code module. For example, if you connect a pin to a shared instrument but a code module does not require the pin, you might be able to execute the code in parallel. After determining the sites to synchronize, the Semiconductor Multi Test and the Semiconductor Action steps wait until those sites reach the synchronization point or become disabled. The step then calls a LabVIEW or .NET code module and passes a SemiconductorModuleContext object that contains the information about the sites for the code module.

A subsystem is a part of the test system that can operate independently. TSM defines subsystems dynamically based on the active sites, the flow of each test socket, and the instrumentation required to conduct a test.

The following figure illustrates the connections between four DUTs/sites, two NI-HSDIO instruments, and one power supply. Each NI-HSDIO instrument requires that the channels for that instrument operate together but the power supply can operate four independent channels. Each DUT has an A, B, and C pin. Each pin A and pin B connects to an NI-HSDIO instrument, and each pin C connects to the power supply.

The two subsystems illustrated in the figure can operate independently. If a test uses pin A or B, you can break the test up into two subsystems. If a test uses only pin C, you can break the test setup into four subsystems—one for each site.

By default, the Semiconductor Multi Test and Semiconductor Action steps assume that a code module uses every DUT pin and no site relays. Improve the performance of the tester by specifying only the pins that the code module uses.



The following figure illustrates a similar situation as the previous figure but replaces the two NI-HSDIO instruments with two NI-Digital Pattern instruments that are grouped together. By default, TSM groups all NI-Digital Pattern instruments together.

The figure shows a single subsystem for test steps that use only pins A or B. TSM executes the test code module in a single TestStand test socket because all NI-Digital Pattern channels must operate together. The NI-Digital Pattern driver performs some operations on the channels in parallel to achieve improved performance. As in the previous example, if a test uses only pin C, you can break the test setup into four subsystems.