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[on:]

Hi all:

Can anybody recommend me a cheap JTAG adapter in order to debug with the Arduino Due?

Preferrably, it should come with a 1.27 mm pin header adapter, so I can use the small JTAG connector on the Arduino Due.

I tried with a cheap USB-Blaster clone and got no joy, see here:

  http://sourceforge.net/mailarchive/forum.php?thread_name=1361806114.60806.YahooMailNeo%40web171203.mail.ir2.yahoo.com&forum_name=openocd-user

If the link does not work, search for [Error "unable to get latency timer" with a cheap USB-Blaster clone] in the openocd-user @ lists.sourceforge.net mailing list.

I already searched in this forum, and there were some pointers, but the devices were relatively expensive or not fully tested yet. I am hoping that the situation is better now.

Thanks,
  rdiez

[Reply #1 on:]

I've not found any cheap JTAG adapters to be very reliable, and usually take a good deal of effort to work at all. For some combinations of OS, software, drivers and hardware they can work well, but it seems pretty hit and miss.

The professional level JTAG adapters are usually pretty reliable, some are better than others, but to get that quality for a specialist product inevitably costs money. It depends on how you value your time, but I do a lot of embedded programming so I prefer spending the money for the ease of use.

With Atmel, we are in luck, because there is an Atmel version of the Segger J-Link, which are pretty good and widely supported, and the Atmel version is considerably cheaper than the full Segger J-Link. I believe they work with OpenOCD and Atmel studio. There is an "educational" version of Segger J-Link as well which is cheaper than the full version.

For the 20 to 10 pin adapter, these can be got from ebay for a few $, Olimex also do one for €5.

[Reply #2 on:]

The Model I bought is the Segger Jtag-EDU  for educational purpose:  http://www.segger.com/j-link-edu.html
The price should be arround 50Euro.
It will give you a profesional supported product that should be usefull for many years.  There are many ARM based uControllers out there these days.

The offer includes free use of Unlimited Flash Breakpoints. The only limitation is that it may not be used to develop a product.
 The J-Link EDU is natively supported by IAR EWARM, KEIL µVision, Rowley Crossworks, and CodeSourcery G++.  Via GDB-Server, the supported tool-chains also include Atollic TrueStudio, Yagarto, and other GDB based or compatible development environments.
J-Link EDU is sold to private persons, colleges, schools, universities and NPOs (Non Profit Organizations) for educational purposes only. It is not sold to companies.

I bought it from Farnell, but Digikey, mouser also have them.
I works fine in Atmel Studio 6 after an update of the J-Link firmware. 
I use if for jtag based Programming and Debugging.  I have not tried SWD and SWO yet.