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:
Oct. 13, 1992
Filed:
Oct. 09, 1990
Najmi T Jarwala, Plainsboro, NJ (US);
Chi W Yau, Holland, PA (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
A scheme is provided for efficient transfer of N separate L-bit segments of data (where N and L are integers) to or from an L-bit register (14) in a device under test (10) serially coupled with at least one other register in a device (10') in a scan chain. To carry out such data transfer, a stream of N L-bit segments of interest is first concatenated to, and ahead of, a packet of L.sub.1 filler bits, where L.sub.1 is the cumulative number of register cells in the chain of devices (10') upstream of the L-bit register (14) in the device under test (10). The stream of L.sub.1 +NL bits is applied to the chain by shifting the first L.sub.1 bits of the block of NL bits through the chain to flush the previous data stored in the registers upstream of the L-bit register in the device under test (10). The remaining bits in the stream of L.sub.1 +NL bits are then shifted through the chain of devices (10 and 10' ) until the L.sub.1 filler bits have been shifted into the data registers of the devices (10') upstream of the device under test. An alternate data transfer scheme is also provided.