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Method to update and debug JTAG devices across multi node systems

IP.com Disclosure Number: IPCOM000225335D
Publication Date: 2013-Feb-11
Document File: 3 page(s) / 36K

Publishing Venue

The IP.com Prior Art Database


Disclosed is a method to update and debug JTAG devices across multi node systems.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 52% of the total text.

Page 01 of 3

Method to update and debug JTAG devices across multi node systems

When debugging multi-node systems, the more information available about the state of the systems before the failure the easier it is to find the root cause. One of the tools used to gather information about the state of the chips is the Joint Test Action Group (JTAG) Test Access Point (TAP), interface. JTAG has been standardized for some time and there are multiple tools available for debug, as well as programming the chips. JTAG can currently be placed sequentially into a long chain.

The problem is that when you try to tie together multiple nodes (or systems), every system has it's own JTAG chain. Tying the information together that is acquired from multiple JTAG chains currently requires multiple pieces of monitoring hardware and also requires synchronization of the information which is typically the hardest part. Synchronizing the data requires synchronizing system clocks and requires additional work in to synchronize events across the nodes. Having a method that provides a method to gather all the data in a multi-node system from a single access point, not only saves time and resources, it provides a level of synchronization not available by merging individual nodes.

The invention is to implement a configurable switched serial link such that JTAG can be linked across multiple nodes. There are several advantages to this:

1. Reduces the amount of attach systems needed for debug.

2. Reduces the amount of time interpolating the data from several independent systems to create a unified view.

3. Synchronization of the data is no longer a problem since all the data is available across the enhanced JTAG chain at one time.

4. Could be used to program the PLDs/FPGAs as one application running in one systems, instead of several independent applications.