JTAG NT for PPC, and/or boundary scan?

JTAG software bug report.
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NathanA
Junior Member
Posts: 3
Joined: Sat Mar 05, 2011 3:22 am

JTAG NT for PPC, and/or boundary scan?

Post by NathanA »

I own a USBJTAG NT from several years back. I now have a need to un-brick a device with a Freescale QorIQ P3041 SoC, which has a PowerPC e500mc core (x4). The board has a 16-pin JTAG/COP header on it.

I understand that USBJTAG NT software does not support the PowerPC COP debugging interface. From what I can tell, on these CPUs, JTAG is only usable for boundary scan, and CPU registers/RAM/memory-mapped flash access and breakpoint debugging are all only available through the extra COP pins. Furthermore, the specifications for the COP interface are a closely guarded secret by IBM & Freescale, protected by NDA. As a result, USBJTAG NT is very unlikely to ever gain support for this, and there are very few reasonably-priced JTAG solutions for these platforms...generally a JTAG emulator box with PPC COP support runs north of $3,000.

So unless I want to spend thousands of $ for a commercial solution, I am limited to boundary scan flash methods. But USBJTAG NT software does not support this, either.

There are other software solutions for this; for example, TopJTAG. TopJTAG Flash Programmer supports "many popular JTAG cables" but USBJTAG NT is not one of them. Is USBJTAG NT a clone of any of the cables on their supported cable list (http://www.topjtag.com/flash-programmer/) or is it an original design?

I do understand I would need to supply the BSDL file for the SoC, but for the sake of argument let's say that's not an issue. It would be nice if either USBJTAG NT supported boundary scan (slow) programming methods for parallel NOR memory, or if third-party software like TopJTAG supported the USBJTAG NT. If the TopJTAG developers asked for design details about USBJTAG NT for the purposes of implementing compatibility with it, would you be open to providing them the info they would need?

It seems stupid that I already own a perfectly good JTAG cable, but that I'd have to go out and buy another one simply to un-brick this one board.

-- Nathan
usbbdm
Junior Member
Posts: 8962
Joined: Mon Jul 18, 2005 9:33 pm

Re: JTAG NT for PPC, and/or boundary scan?

Post by usbbdm »

USB JTAG NT is a ground up project initially started for MIPS core.
It does have some capability to program PPC device. http://www.usbjtag.com/jtagnt/ird/dm500.php
https://www.youtube.com/watch?v=hyz95Z_eIQQ
Boundary scan is slow and should be possible to do in the future.
However I would rater "Talk" to the CPU and let CPU do the work for you to get super fast speed reading and writing flash.
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