Testable latch self checker

Details Testable latch self checker Testable latch self checker

1991-03-27

1992-07-14

Hudspeth, David

Electrical transmission or interconnection systems

Nonlinear reactor systems

Parametrons

364787, 307451, H03K 1921

Patent

active

051305755

ABSTRACT:
The present invention operates by verifying correct latch operation in a digital circuit. After a value has been stored in a latch, electronic circuitry can verify that the value has been stored correctly. The electronic circuitry that performs this verification can be tested to insure that it is operating properly. Several latches can be wired into a scan chain and tested with relative ease. Operation of the present invention is illustrated by an enhanced master-slave latch system. In this system, two comparators are used. A first comparator is used to determine if the internal state of the master latch is identical to the signal which has been applied to this latch's data input terminal. A second comparator is used to determine if the state transfer between the master and slave latches occurs properly. Each comparator consists of an EXCLUSIVE-OR function. By placing known logic levels on each input terminal of the comparison circuitry, the output terminal of the comparison circuitry can be examined for an expected logic level to verify that it is operating properly. By placing several latches into a scan chain, a single latch can be loaded with data which will cause an expected signal to appear on the output terminal of this latch's comparison circuitry. This allows for simplified testing of a multiple latch system.

REFERENCES:
patent: 4493077 (1985-01-01), Agrawal
patent: 4513418 (1985-04-01), Bardell
patent: 4554664 (1975-11-01), Schultz
patent: 4730266 (1988-03-01), van Meerbergen et al.
patent: 4761760 (1988-08-01), Tomoji
patent: 4968903 (1990-11-01), Smith et al.
patent: 4982117 (1991-01-01), Matsuzaki et al.
A CMOS LSSD test generation system, D. Leet et al., IBM J. Res. Develop. Sep. 1984, pp. 625-635.

Affiliated with

Also associated with

Rating

Testable latch self checker does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Testable latch self checker, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Testable latch self checker will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-336814