JTAG is a common standard for communicating with modern electronic devices like FPGAs and microcontrollers. A JTAG connection will allow you to do in-circuit debugging in a bewildering variety of ways and will generally allow you to program your device. The standard, apparently, defines five connections for this purpose. Add in power and ground and you have a minimum of 7 connections needed to implement JTAG. The trick is getting them delivered to your board or device…
