Simple question - What is a JTAG? What can it do?

[Communications_Engineer]

Simple question

Hi, I came across this term while reading a document on Software Defined Radio, this 'JTAG'. So what is a JTAG? What can it do? Is it with all DSPs?

 

[nareshgtr]

Re: Simple question

JTAG is an IEEE standard (1149.1) developed in the 1980s to solve electronic boards manufacturing issues. This is used for boundary scan testing. This will be there in controllers, processors and all most all ICs.

 

[sau_sol]

Re: Simple question

as told by nareshgtr JTAG is used for Boundary scan

but relating platform we can divide it in 2 categories...

1.......PCB testing
it is mainly developed for PCB testing pf SMD components.
like microcontroller
to test whwther all the pins are perfectly soldered hence connected

2.....Microcontrollers

in this section it is very powerful device for debugging
using JTAG we can debug the hardware in a runtime environment.
i.e. we can see the actual values of the registers inside the controller as we are looking in the simulator
through JTAG we can change the values of all the registers and the pins at runtime
it works as a simulator but on a real hardware

through JTAG we can also program the controller