How to IJTAG like a pro: convert BSDL files to ICL

By Tessent Solutions

The process of switching from traditional JTAG (IEEE 1149.1) boundary scan to a plug-and-play IJTAG (IEEE  1687) infrastructure can feel complex. Tessent IJTAG simplifies many of the tasks that get you to full IJTAG compliance, including converting legacy files to their IJTAG equivalents

Designing a modern product requires the integration of multiple IP blocks from both in-house and third party sources. The IEEE 1687 standard is designed to provide plug-and-play IP test and instrument integration. It standardizes a language for describing the IP interface and how IPs are interconnected with each other. It also introduces a language that defines how patterns that operate or test the IP are to be described. The ICL file, one of two new file types required for IJTAG, describes the interfaces and connectivity in your design.

IJTAG is quickly gaining ground with IP providers, chip designers, test integrators, and diagnosis/failure analysis engineers. Tessent IJTAG simplifies the process of connecting any number of IEEE 1687 compliant IP blocks into an integrated, hierarchical network and to transfer data to/from the cores from a single top-level access point. It provides a flow in which the user does not need to know the ins-and-outs of IEEE 1687, but can leave it up to Tessent IJTAG to find the best possible solution. As Mentor test expert Etienne Racine says, “IJTAG is like a GPS for test vectors; it moves test data by determining the quickest route to its destination.”

Mentor test expert Etienne Racine created a 5 minute video to demonstrate how to use the Tessent IJTAG tool to convert legacy boundary scan description language (BSDL) files to an Instrument Connectivity Language (ICL) file that is suitable for IJTAG usage. BSDL is a subset of VHDL that describes how JTAG is implemented in a device. In the how-to video, the assumption is that you only have a BSDL file to start with. This BSDL can be used to generate Verilog test benches or pattern files in standard tester formats. However, the BSDL-derived tests are limited to the standard 1149.1 and 1149.6 tests and thus exclude any non-standard test data registers (TDRs). Converting the BSDL to ICL preserves the custom TDR functions. It can be used to perform not only TAP-related tests, but also IJTAG-based access to on-chip instruments. After the conversion, Tessent IJTAG automatically generates test vectors to verify that the new ICL correctly matches the design.

Watch the video Converting Boundary-Scan Language Description

Leave a Reply

This article first appeared on the Siemens Digital Industries Software blog at