The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 19, 1994
Filed:
Jun. 24, 1993
Najmi T Jarwala, Lawrenceville, NJ (US);
Chi W Yau, Holland, PA (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
Both the input/output connections (16) of a circuit board (10) and the boundary scan devices (12.sub.1 -12.sub.n) thereon can be tested simultaneously by boundary scan techniques using a Serial Test Extension Module (STEM) (28) which mates with the circuit board. The STEM (28) contains at least one boundary scan register (36) which makes an electrical connection with a separate circuit board input/output connection (16) when the STEM mates with the board. The boundary scan registers (36) within the STEM (28) are serially connected in a chain, that is, connected in series with a chain of serially connected boundary scan registers (20) within the boundary scan devices (12.sub.1 -12.sub.n). By launching a known bit stream into the chain of boundary scan registers (20) and (36) and thereafter shifting out the bits and comparing them to a reference bit stream, representing a defect-free condition, faults in the input/output connections (16) and/or in the devices (12.sub.1 -12.sub.n) can be detected.