Category: Embedded Diagnostics

This past week, I did a webinar in collaboration with the UEFI Forum on JTAG-based UEFI Debug and Trace. This reviewed some of the often-used tools for low-level triage of difficult-to-diagnose, intermittent bugs. Near the end, I demonstrated the usage of technology running directly down on a BMC to perform low-level functions not achievable with firmware or OS-based applications.
Today, February 15th, 2020, marks the official 30th Anniversary of JTAG. What a wild ride it has been – from its humble beginnings for detecting short and open circuits, it has evolved to be, in some ways, the most powerful and feared technology on the planet. How did we get here?
In my spare time, I was doing some OpenBMC Yocto builds on my Linux machines, and decided I wanted to copy these files over to my Windows PC. Little did I know how complicated this could be.
In a prior blog, I wrote about the JTAG specification’s upcoming 30th anniversary, and reflected on how it has evolved over the years, and the powerful use cases it can be put to. This week, we look at how to secure the JTAG interface, to prevent its abuse by bad actors.
JTAG is coming up on its 30th anniversary. And some would say it’s older than that. As I prepared for doing an introductory presentation on this amazing technology, I got a chance to reflect on how useful it has become, and what the next 30 years might be like.
In my last article, I outlined a short embedded JTAG-based ‘C’ routine to dump machine check errors in the event of a system crash or hang. In today’s blog, I look at this in the larger context of diagnosing the root cause of system wedges, and what embedded ITP techniques can be used to gather as much forensics data as possible.
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