Browse Prior Art Database

Tri-State Driver Testing

IP.com Disclosure Number: IPCOM000099730D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Carnell, CH: AUTHOR [+5]

Abstract

Disclosed is a method of testing a tri-state driver 10 connected at a Common Input-Output (CIO) node 13 with a receiver 12. A portion of a tester is shown including a driver circuit 14 and a level detector 16.

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Tri-State Driver Testing

       Disclosed is a method of testing a tri-state driver 10
connected at a Common Input-Output (CIO) node 13 with a receiver 12.
A portion of a tester is shown including a driver circuit 14 and a
level detector 16.

      The ability of driver 10 to produce a high impedance state (H)
as well as logic "1" and logic "0" presents a problem in testing.
The "H" states must be converted to "1" and "0" values by the level
detector 16 because the tester cannot handle "H" or indeterminate (X)
states.  In addition, these "1" and "0" levels must be valid levels
to the receiver 12 in order to prevent indeterminate states into the
product under test.

      The method developed to test driver 10 consists of applying a
tester "weak stimulation" to the tri-state driver CIO node 13.  When
tri-state driver 10 is in the high impedance state, the tester
dominates node 13 for either the stimulation of "1" or "0" receiver
12 values. Alternatively, when tri-state driver 10 is active for
either the drive "1" or drive "0" value, the tri-state driver
dominates node 13.  The results are shown in the State Table.