Monday, June 18, 2018
Publication Date: 02/1/2010
Archive >  February 2010 Issue >  Electronic Mfg. Products > 

JTAG Free-for-Life Tool Cracks PCB Debug Challenge
Eindhoven, Netherlands — With the breakthrough product family, JTAG Live, debugging boards that are too crowded for traditional probing becomes much easier. JTAG Live is suitable for electronics engineers and technicians to use in checking PCBs for basic continuity and correct operation. The product family consists of three products — Buzz, Clip, and Script — each targeted at different aspects of the debugging process.

Buzz provides the ability to quickly check direct and indirect connections between devices that support boundary-scan. Clip offers ways to verify cluster logic using vector-based cluster tests. Script enables users to adopt a functional, device-oriented test approach to take control of a design through on-board JTAG/boundary-scan compliant devices.

To support easy access and quick start-up, Buzz is available free of charge from the JTAG Live website. Clip and Script are downloads available for a nominal charge. JTAG Live capitalizes on the boundary-scan circuitry found on today's high-end boards. There is no need for a netlist; the tools use device BSDL files, available from the IC vendors, to identify inputs and outputs for driving and sensing. Users are able to easily define up to two boundary-scan chains and quickly verify chain integrity.

The Watch window in Buzz shows the current logic state (hi-low or toggling) of any selected boundary-scan pin. Buzz also gives hardware design engineers a practical way to check continuity between two pins on a prototype board, mimicking the familiar DMM buzz measurement but without probes. Within the "Measure" window of Buzz, a user selects a pin to be driven, sets it high or low, and reads the resulting value on the sense pin. Going beyond the functionality of a DMM, Buzz also shows multi-pin nets. Users can easily drive from one pin to many to check for correct fan-out connectivity or from multiple pins to one or more sense pins to perform a test on bus lines or to verify a simple cluster of one or more logic gates.

Clip, the second member of the JTAG Live family, allows engineers to debug more complex clusters using vector-based cluster test sequences. Each vector in a sequence contains a set of input values for device or cluster inputs and a set of expected cluster output values. The Clip user interface offers a logic analyzer/pattern generator-style state and timing display mode for defining vectors and observing test results. Tests created within Clip can be saved and recalled for testing multiple boards of the same type. Script provides a powerful API to manipulate and sense cluster I/Os. Script is especially suitable for users wanting a functional, device-oriented test approach for mixed-signal device testing, operations that require user intervention, and test pattern looping for setting up device registers. Within Script, users employ the open-source programming language Python to check interconnects and verify operation of non-boundary-scan clusters. Through high-level routines embedded in a Python program, Script drives and senses values on pins or groups of pins. The built-in Python editor facilitates preparation of the sequences to perform tests and collect results.

Contact: JTAG Technologies, 1006 Butterworth Ct., Stevensville, MD 21666 877-367-5824 fax: 410-604-2108 Web:

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