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:
Apr. 04, 1995
Filed:
Mar. 22, 1993
Compaq Computer Corporation, Houston, TX (US);
Abstract
Filtering logic coupled between the microprocessor and the host bus to decode illegal special cycles executed by the processor to prevent these cycles from appearing on the host bus, which would otherwise be misinterpreted by logic coupled to the host bus. In the preferred embodiment, a modularized computer system based primarily on the 80386 or i486 microprocessors by Intel is upgraded to the new P5 or Pentium processor, also by Intel. The host and I/O buses are not modified and operate at the same speed and data width as in the previous systems. A processor board is upgraded with the P5 processor and includes the filtering logic according to the present invention. The P5 processor includes 8 byte enable bits as compared to the 4 byte enable bits used by the microprocessors 80386 and i486. Two new special cycles supported by the P5 processor are not supported by the previous host bus and would cause erroneous operation if allowed to be executed on the host bus. The filtering logic detects the two new cycles and prevents the cycles from being passed to the host bus.