The many faces of the JTAG interface port

For many the term “JTAG” is still a point of confusion; for some engineers it is a device-programming port while for others it is for plugging in a microprocessor emulator or debugger, whereas, in fact, it was originally devised for neither. JTAG is an acronym of “Joint Test Action Group”, and initially the aim was to provide an alternative system to aid circuit board assembly testing, i.e. for detecting and diagnosing assembly errors such as solder shorts, lifted pins and missing/badly-placed components. The Group in JTAG refers to a small number of test professionals who met over a period of four to five years from 1985, to devise a scheme to embed test circuitry into digital devices with the aim of assisting in the structural test of PCBA(s). Similar schemes had been developed unilaterally by device manufacturers, such as IBM’s LSSD, but at that point there was no interoperability standard that all vendors could comply to. By 1990, the JTAG system, also known as “boundary-scan”, was officially an IEEE standard number 1149.1.

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Faster repair – Testing of electronics in the era of miniaturization

The test plan for a product should cover the whole product life-cycle and include: prototype debugging, manufacturing tests and field service repairs. The tools that can be used to locate a problem on a failing Printed Circuit Board Assembly (PCBA) depend on whether design data of the board is available or not, and whether test programs for the board already exist.

But conventional structural testing requires probing of device pins. With miniaturization, probing is no longer possible, and thus structural testing using external probes becomes impossible. With boundary-scan external probing is no longer needed.

In production testing is too often considered as a ‘no value-added’ proposition. However, this viewpoint ignores the real and substantial savings that can be realized with a well-conceived test strategy. High quality assembly and inspection equipment minimizes the chance for assembly errors. Test equipment is still needed to help detect remaining errors efficiently.

The challenge is to generate the best test strategy and choose the right tools to use in the production phase.

What can be done to shorten repair times?

Watch the video and download the free white paper:

‘Faster repair in the era of miniaturization’

Оставайтесь в курсе событий JTAG

Top 10 Test and Measurement Solution Companies – 2019

Test engineers in industries ranging from aerospace and defense to consumer electronics are facing the challenge of testing increasingly complicated designs with shrinking timelines and budgets. To address these issues, engineers and scientists are incorporating new test and measurement technologies that are capable of meeting complex design requirements without raising costs. One issue facing test engineers is that test instrumentation is not updated as rapidly as the devices being tested. The functionality of these complex devices is being defined by the software embedded in them, such as most smartphones, which gives design engineers the ability to add features faster than ever before. This is increasingly challenging for many test engineers because most stand-alone instruments often lack the measurement capabilities of the most recent standards due to the fixed user interface and firmware that must be developed and embedded in them. 

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Компания Миландр поставляет проверенные BSDL-описания для микросхем с поддержкой периферийного сканирования

Компания «Миландр» первой на территории России закупила уникальный программно-аппаратный комплекс BSDL Verifier производства JTAG Technologies. Устройство является профессиональным инструментом, позволяющим проверять BSDL-файлы на реальной микросхеме. Причем, обнаруживает оно не только синтаксические и семантические ошибки, но и несоответствие содержимого BSDL-файла самому кристаллу.

Все новые и разрабатываемые цифровые микросхемы ПКК «Миландр» поддерживают технологию периферийного сканирования. Регистры сканирования описываются в виде BSDL-файлов, которые затем, при тестировании собранных плат, автоматически обрабатываются тестовыми системами JTAG. Использование устройства BSDL Verifier позволит компании и её клиентам быть уверенными в точном соответствии JTAG-инфраструктуры микросхем её описанию.

ПКК «Миландр» использует периферийное сканирование во всех сферах своей деятельности: тестирование микросборок, микросхем и собранных печатных плат.