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. 15, 1997
Filed:
Feb. 06, 1996
L Randall Mote, Jr, Laguna Hills, CA (US);
AST Research, Inc., Irvine, CA (US);
Abstract
A method for toggling the output pins of a IC chip to satisfy an ASIC manufacturer's output toggle test requirements parallel loads data from an IC tester into the IC's JTAG boundary scan data shift register, so that the parallel loaded data is an alternating high and low data bits. The test pattern of alternating data bits is then latched to the JTAG data latch register and driven onto the output pins of the IC chip. The bidirectional buffers connected to the output pins are then enabled for output while the IC tester tri-states its alternating data test pattern. The test pattern is then shifted by one bit within the IC's JTAG shift register and parallel loaded into the JTAG latch register on the next clock cycle. In this manner, the complement of a test pattern driven onto the output pins by the external test circuit is driven out from the IC chip. The process is then repeated once more to provide an alternating transition for each of the output pins so that a toggle from high to low and also from low to high is satisfied for each of the output pins on the IC chip.