a modular tester architecture allows end - users to mix - and - match scan chain modules and clock driver modules . modules are interconnected via a synchronization bus allowing the test modules to synchronize with each other so that each can perform its portion of the overall test at the proper time in relation to the testing performed by other modules . the modules can include a bist driver module , a data acquisition module , networking interface modules , a controller module , a current measurement module , and a dc parametrics module , among others .