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:
Jun. 09, 1992
Filed:
Dec. 20, 1989
Robert J Russell, South Boston, MA (US);
Bull HN Information Systems Inc., Billerica, MA (US);
Abstract
A system provides for the testing of components which connect to one or more of programmable logic devices (PLDs), each of which is organized in a predetermined manner. Each PLD includes a plurality of programmable logic sections, each of which connect to I/O pins through driver and receiver circuits. An available section includes programmed means for causing its driver circuit to force the I/O pin to a first logic level when made operational. The other sections each include programmed means for connecting their associated driver circuits to be controlled by signals applied to the receiver circuit of the available section. During testing, means are externally applied to the I/O pin of the available section which drive the pin from the first logic level to a second logic level. This causes the receiver circuit to apply signals which inhibit the driver circuits of the remaining sections from applying signals to their I/O pins thereby enabling the testing of components which connect to these I/O pins without interference.