The Development of a JTAG Boundary Scan Structure for VLSI Chips

Many techniques have been developed to simplify the testing of device after production. One technic is called "boundary scan" or sometimes referred to as "JTAG" (Joint Test Action Group). Each device that complies with the standard, which was accepted by the IEEE, includes 5 dedicated pins for testing only (AKA TAP – Test Access Port).
In this project the students will take an existing logic project, preferably their own VLSI lab project, and will make all the required changes to add the TAP, and the boundary scan.

Every VLSI manufacturing process is susceptible to defects. When a manufacturer is going to sell its devices, it is required to test each device for functionality, and make sure that each device is fully functional.

One of the requirements is to test the I/O pins, during production of the chip, and also after it is soldered on a board. The technique enables verifying that the I/O pins can write/read data, and also that it can talk to other devices soldered on the same board. (Check that the soldering is OK)

Many techniques have been developed to simplify the testing of device after production. One technic is called “boundary scan” or sometimes referred to as “JTAG” (Joint Test Action Group). Each device that complies with the standard, which was accepted by the IEEE, includes 5 dedicated pins for testing only (AKA TAP – Test Access Port). These pins control and access an internal block “JTAG block” which can enable a wide set of self-testing.

One test is called BS (Boundary Scan). Every I/O buffer is replaced with the BS enables I/O buffer, that can be used for testing.

One of the features of the TAP, is for the tester, to read the device name and version, and verify that the correct device was soldered on the board.

In this project the students will take an existing logic project, preferably their own VLSI lab project, and will make all the required changes to add the TAP, and the boundary scan. Then will run and test it on a simulator.

This technology is a must for every logic device that goes to high volume manufacturing. It is used by all the big players on the market. It is a “must have” requirement by the PC manufacturers.

Prerequisite:  Digital Systems and Computer Structure – 044252

Supervisor : Gabi Leobl