[ARM] what is JTAG & how to use it.

[v.s.n.kumar]

Hi,
can any body tell what is J-TAG in LPC2148 & how to use it with lpc2148. for using it, is there any software required for it. please tell in brief

 

[embpic]

JTAG means Joint Test Action Group which is used for in circuit debugging. and for LPC2148 Keil provides ULINK2 for debugging.
in circuit debugging means monitor the hardware behaviour while running code step by step.

 

[macein]

JTAG or Joint Test Action Group is a IEEE 1149.1 architecture for testing VLSI chips. It provides a mechanism for controlling the pins of the device under test (DUT) and also monitoring the outputs.
VLSI Test Principles and Architecture is one of the books that provides a good idea about what JTAG is, the different JTAG instructions that are present and what the mean, which may help you to debug the failure.
For debugging make sure which IEEE standard you are using. IEEE 1149.6 is for high-speed networks(which also have ac-differential pair inputs and outputs).