Developed by XJTAG, the free software for the Mentor Xpedition Designer product promises to significantly increase the design for test and debug capabilities of the schematic capture and PCB design environment. Printed circuit boards (PCBs) are becoming more densely populated and access to pins under many packages, such as Ball Grid Array (BGA), is virtually impossible. JTAG was designed to solve the problem of access and so it is now vitally important to get the JTAG chain right at the design stage. Failure to identify and fix design errors at an early stage can result in a board re-spin and a costly delay to a project. XJTAG DFT Assistant helps validate correct JTAG chain connectivity, through full integration with the Xpedition schematic capture environment.
The XJTAG DFT Assistant comprises of two key elements: the XJTAG Chain Checker, and the XJTAG Access Viewer. XJTAG Chain Checker identifies common errors in a JTAG scan chain, such as incorrectly connected Test Access Ports (TAPs). A single connection error would inhibit an entire scan chain from working. XJTAG Chain Checker identifies connection errors and reports them to the developer during the design process. Incorrectly terminated TAPs are also identified.
XJTAG Access Viewer overlays the extent of boundary scan access onto the schematic diagram, allowing users to instantly see which components are accessible using boundary scan, and where test coverage could be further extended. Engineers can highlight the nets individually to show read, write, power/ground and the nets that do not have any JTAG access on the schematic.
While the first prototype is being manufactured, XJTAG DFT Assistant allows engineers to export a preliminary XJTAG project from the Xpedition schematic capture environment to the XJTAG development software, where additional tests can be developed. These can then be used to test real hardware, as soon as it is available. This provides a vital new capability to electronic engineers everywhere.
This software is free of charge for Xpedition users of VX.2.1 or higher and can be downloaded from JTAG.