The Open JTAG project is an Open Source

Open source

The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

 project released under GNU

GNU

GNU is a Unix-like computer operating system developed by the GNU project, ultimately aiming to be a "complete Unix-compatible software system"...

 License.

It is a complete hardware and software JTAG reference design, based on a simple hardware composed by a FTDI

FTDI

Future Technology Devices International, commonly known by its initialization, FTDI, is a Scottish privately traded semiconductor device company, specializing in Universal Serial Bus technology...

 FT245 USB front-end and an Altera

Altera

Altera Corporation is a Silicon Valley manufacturer of PLDs . The company offered its first programmable logic device in 1984. PLDs can be reprogrammed during the design cycle as well as in the field to perform multiple functions, and they support a fairly fast design process...

 EPM570 MAX II CPLD

CPLD

A complex programmable logic device is a programmable logic device with complexity between that of PALs and FPGAs, and architectural features of both. The building block of a CPLD is the macrocell, which contains logic implementing disjunctive normal form expressions and more specialized logic...

. The capabilities of this hardware configuration make the Open JTAG device able to output TCK signals at 24 MHz using macro-instructions sent from the host end.

The scope is to give the community a JTAG device not based on the PC parallel port: Open JTAG uses the USB channel to communicate with the internal CPLD, sending macro-instructions as fast as possible. The complete project (Beta version) is available at OpenCores.com and the Open JTAG project official site.