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:
Jan. 21, 1997
Filed:
Aug. 04, 1995
Philippe Klein, Newton, MA (US);
David W Maruska, Hopkinton, MA (US);
Kevin W Ludlam, Stow, MA (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
An apparatus for providing data to an I/O bus at the maximum I/O bus bandwidth comprises an exerciser unit coupled to the I/O device. The exerciser unit includes DMA circuitry for providing a constant stream of transactions to the I/O bus. Each transaction provides a plurality of data quadwords to the I/O bus which are parity protected. The exerciser unit includes a memory device for storing data to be provided for each transaction, and a parity circuit for calculating and providing parity for the data stored in the memory. The exerciser unit further includes a data generation device for providing both data having predictable parity and the parity to the bus for each bus cycle while bypassing the parity generation logic to provide data at maximum bandwidth. The data generation device provides a sequence of different data bytes using a modified Gray-code algorithm, which facilitates parity generation for each byte in the sequence of bytes.