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JTAG Boundary-Scan Benefits FAQ

Learn some facts on how you can benefit from JTAG and JET technology.

• Why use JTAG?

• What are the benefits and advantages of JTAG?

• What are the benefits and advantages of JET?

• What fault coverage does JTAG and JET provide?

Why use JTAG?

There is an increased demand for JTAG due to some of the following:

• PC boards are becoming more complex

  • Loss of physical/electrical access decreases
    effectiveness of Bed of Nails test technologie

  • Smaller, multilayer, internal vias, dual-sided placement, BGAs, more complex devices

• Product life cycles are becoming shorter

  • Minimize time from design to volume manufacturing

• Device packaging density and lack of access makes physical access

  • Expensive

  • Unreliable

  • Impossible

• Increased Board Density

• In-System Programming

What are the benefits and advantages of JTAG?

• JTAG provides the capability to test interconnects on a PC-board without physical test probes or test fixtures

• Does not require the board to be in a bootable state for fault diagnostics

• JTAG allows In-System Programming of devices such as Flash, CPLDs, FPGAs and Serial EEPROMs

• Automated test development for DSP initialization, memory and flash

• Device level diagnostics

• Customized diagnostic messages

• JET rigorously exercises all external memory locations before execution of any boot code

• Test vectors can be reused in production

What are the benefits and advantages of JET?

• Does not require the board to be in a bootable state for fault diagnostics

• Embedded tests are downloaded and run from on-chip DSP memory at-speed

• Provides testability on all DSP addressable components by exercising their functionality

• In-system programming at theoretical speeds reduces time waiting for code to download

• Automated test development for DSP initialization, memory and flash

• Device level diagnostics

• Customized diagnostic messages

• JET rigorously exercises all external memory locations before execution of any boot code

• Test vectors can be reused in production

What fault coverage does JTAG and JET provide?

• JTAG Pin Connectivity; Noisy Signals

• Opens, Shorts & Stuck-At Conditions

• DSP Initialization

• Component Discovery and Identification

• Bad Memory Locations

• Flash Communication Problems

• Timing Problems

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