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:
Feb. 16, 1999
Filed:
Jun. 30, 1997
Farideh Golshan, Mountain View, CA (US);
Marc E Levitt, Sunnyvale, CA (US);
Sun Microsystems, Inc., Palo Alto, CA (US);
Abstract
A method for coupling a linear impedance control (LIC) type output driver to IEEE 1149.1 boundary scan circuitry includes entering a boundary scan load mode to load a test pattern into a chain of boundary scan registers (BSRs). The test pattern includes values corresponding to output enable and data signals according to the IEEE 1149.1 standard. Then these data and output enable signals from the BSRs are converted into test 'q.sub.-- up' and 'q.sub.-- dn' signals meeting the requirements of the LIC driver. These test 'q.sub.-- up' and 'q.sub.-- dn' signals are selectively provided to the LIC driver during boundary scan testing of the LIC driver. In a further refinement, the method enters a boundary scan capture mode to capture the response (i.e., the functional q.sub.-- up and q.sub.-- dn signals) of the circuit under test to input test patterns shifted into the BSRs. The functional q.sub.-- up and q.sub.-- dn signals are converted into response data and oe signals complying with the IEEE 1149.1 specification, which are then captured in the BSRs. Thus, this method allows the widely used IEEE 1149.1 boundary scan standard to be used with LIC drivers. The resulting compatibility simplifies the testing and use of the LIC drivers, and provides a boundary scan standard for use with LIC drivers that is compliant with the IEEE 1149.1 standard.