Template:FAQ/Questions/suitable jtag debugger for

What is a suitable JTAG debugger for the gumstix?
Doug Sutherland has a list of JTAG adapters. (BrokenLink as of 2007-07-18)

He adds: &quot;It is possible to use a cheap parallel port adapter (ie Olimex) even home made, but it seems many people have problems with this setup. Sometimes it's due to strange parallel port behavior or port configuration, sometimes it involves the wiring of the signals to proto boards (wires must be short, solder joints must be good etc). And the parallel adapters are slow. But you can program flash and connect to debuggers etc. Quite a few people seem to like the amontec chameleon pod, they have a package for 159 euro.

Most people are looking for USB adapters though, since laptops generally don't have parallel ports anymore, and USB is a lot faster. I can't speak from experience but Rowley's CrossConnect? looks decent for 99 euro, and I see a linux driver there.

Cross Connect.

On the topic of JTAG, these TI chips sure look interesting. They have JTAG masters with 8-bit microcontroller interfaces. They take care of all necessary buffering, and they have a multiplexing protocol that allows chaining many on a passive backplane.

Rocky at digikey download.

Mate that with a USB microcontroller (ie LPC2148) and it would make a nice test/debug environment. The controlled/buffered chaining would also allow some system level debugging (connect to multiple processors on one board or even multiple boards).

Another interesting chip is the old FTDI USB-Serial in a new version with a special bus (MPSSE) that includes interfacing JTAG and SPI.

FT2232C.

FTDI also has a JTAG DLL. (BrokenLink as of 2007-07-18)

— Doug Sutherland

(for lots of details on JTAG, see the Open JTAG wiki http://openjtag.net/)