JTAG Mixed-signal IO Systems (MIOS) Redefine Benchtop ATE

Feature articles | March 31, 2016

By Julien Happich

Test and Measurement

However, accessing the JTAG feature in a reliable and repeatable manner has always been an aspect somewhat neglected by boundary-scan technology and programmable device vendors. Until recently it has been largely the responsibility of the end user to liaise with either the functional test system builder or maybe an In-Circuit Test (ICT) bureau to make sure that JTAG tester hardware is ‘production ready’.

Now though we see the co-incidence of two capabilities that can combine to make a powerful, adaptable and low-cost bench-top ATE (Automatic Test Equipment) system. With the introduction of multi-function JTAG testers such as the ‘MIOS’ series from JTAG Technologies you get a low-cost, compact (100mm x 100mm) JTAG-based tester complete with mixed signal IO channels (voltage, measure, source and frequency) that can be embedded directly in to one of several re-configurable test fixtures – complete with a bed-of-nails interface. Add a power supply and any other measurement resources you might require and your ATE hardware is complete.

However there remains the matter of software to program and control this novel ATE architecture. Fortunately in this area too there are a number of available options to suit all budgets. Thus to develop and execute high-integrity JTAG tests using the MIOS hardware (e.g. scan path infrastructure, interconnections, logic clusters & memory clusters), ISP (In-System Programming), ADC/DAC, PSU and clock tests you can choose from:

Python scripting language – a favourite among engineers and scientists that comes with a host of open-source libraries to control instruments (e.g. GPIB, USB), serial ports, JTAG controllers and more. Its flexibility allows easy construction of loops branches variable handling and file IO. You may have to undertake more coding than some other methods, however dozens of test modules already exist for devices and logic clusters accessed by JTAG/boundary-scan and there is even a VISA control library in existence.

LabVIEW – for scientists with a preference for graphical icon-based programming National Instruments LabVIEW has become a staple of the test world especially within functional mixed-signal testers. Control icons (VIs) exist for prepared test execution and also low-level control of JTAG device pins.

JTAG ProVision – for those with no desire to undertake coding (graphical or textual), then a high-level auto-generation system like JTAG ProVision simply ‘sucks in’ CAD data and device models from a supplied library featuring 10 000s or parts and exports a complete test program set. You can still augment these tests with scripted applications to get the ultimate in flexibility and fault coverage.

Furthermore there are also .NET, TestStand and ATEasy support, and other options depending on the current method of working or individual preferences.

For hardware interfacing (fixtures) the open architecture of the JTAG MIOS testers allow it to be added to almost any popular cassette based fixture. To date there have been successful applications created with ATX, DD Mechatronics, Ingun and MG hardware but it’s straightforward to marry this potent test capability with any local or international fixture supplier.