[rescue] Anyone recommend a JTAG probe for IXP42x?

Joshua Boyd jdboyd at jdboyd.net
Tue Apr 11 11:25:37 CDT 2006

On Tue, Apr 11, 2006 at 11:04:41AM -0500, Jonathan Sadler wrote:
> I'm looking to rescue a board that has an Intel IXP425 NPU (includes an 
> Xscale core), but don't want to spend big $$$ for a JTAG probe just to 
> do re-flashing.  Something like a Wiggler would work fine, but I can 
> only find schematics targeted to ARM processors.
> Anyone have a pointer to an appropriate Wiggler schematic?

I use a Xilinx parallel cable III.  They are darn simple to build, and
the jtag tool from the OpenWinCE project (a project for putting Linux on
all sorts of WinCE machines, often using JTAG to do the loading)
supports them.  I used that program to program SH3 devices, but the
program focuses more on StrongARM and Xscale than it does on Renasas

To build a compatible (but unbuffered) cable to the one I use, see this
specifically the first big picture.

The official Xilinx cables terminate at a 0.1" header (I forget how many
pins) so that you can make your own cables easily to go the last little
bit of distance, since when you build your own boards, you might not
follow the Xilinx pinout, or you might use a different type of connector
altogether.  For the boards with made, we used part of a PCI style
card edge for our programming connector (I'm not sure that was a good
idea since the PCI female pieces loose structural integrity when you cut
them up, and wear out quickly).  For a general use cable, I think the
way that Xilinx does it is probably best. 

It is really slow though.  However, I'm not aware of anything faster
that would have out of box support for what you want to do.  One of
these days I want to build a small microcontroller box to act as a high
speed SVF player.  However, there is also a lack of open tools for
turning ROM images into SVF files as well.

Joshua D. Boyd
jdboyd at jdboyd.net

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