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:
Aug. 17, 2004
Filed:
Aug. 31, 2000
Dilip K. Bhavsar, Shrewsbury, MA (US);
Steve Lang, Stow, MA (US);
Hewlett-Packard Development Company, L.P., Houston, TX (US);
Abstract
A system for scan testing a device under test (“DUT”) in which the clock speed of the DUT differs from test equipment. A plurality of scan-flops in the DUT form a scan-wheel, which defines a closed scan path. The Data bits in the scan path are shifted through a scan-wheel controller based on the DUT clock speed, so that a different bit passes through the scan-wheel controller on each clock cycle of the DUT. Test data is only loaded by replacing the data bit as it passes through the controller. The different clock rates of the DUT and the test equipment define a scan wheel ratio, which is used to determine the number of times that the scan-wheel must rotate before all old data bits are unloaded and replaced by newly loaded bits, and which also determines when data bits passing through the controller will be unloaded and replaced.