MicroMaster: Extend Test Coverage

Extend your test coverage using MicroMaster, based on processor emulation from International Test Technologies.

MicroMaster can be used to extend the test coverage of Boundary Scan Testers (BST or JTAG), In-Circuit Testers (ICT) and Manufacturing Defects Analyzers (MDA). MicroMaster overcomes test access problems in structural test and adds fast functional test.

A summary of how MicroMaster can extend ICT/MDA and JTAG coverage is shown in the diagram below.

Extended JTAG Coverage

While JTAG testers are becoming one of the preferred methods of structurally testing today's PCBAs, there are still gaps in test coverage because some ICs are not JTAG enabled. Sometimes PCBAs don't implement JTAG, even though the components used on them are JTAG enabled.

JTAG tests the interconnections between ICs and other components - it doesn't test the core logic of the ICs to verify their function. At-speed testing of buses is not possible.

MicroMaster testing combines CPU Emulation and JTAG test methods to get the best of both worlds.

MicroMaster's CPU Emulation is different from JTAG. While it accesses the board via the same JTAG port, it only uses this port to transfer CPU commands and data. MicroMaster instructs the CPU to set up ICs and test them in a similar way to the board's boot code and device drivers. This allows at-speed testing of buses and ICs, including non-JTAG-enabled devices. MicroMaster is a perfect compliment to JTAG testers, overcoming any coverage shortfalls. MicroMaster can also run JTAG tests itself, using SVF format test vector files.

ICT/MDA plus MicroMaster

The greatest problem for ICT and MDA testers is the lack of access for bed-of-nails probes to test points on today's PCBAs. Multi-layered boards with hidden VIAs, miniaturized components, and components with concealed contacts, such as BGA's, all cause problems for these testers.

In addition to access problems, the functional testing of complex IC's is impractical due to the vast amount of vectors that need to be injected to fully test the core logic.

MicroMaster requires only 5-6 test points to access the whole board. The functional testing of complex ICs is also easily carried out by MicroMaster. Combining MicroMaster with ICT or MDA testers provides additional benefits, such as at-speed testing of bus terminations and differential buses.