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:
Nov. 28, 1989
Filed:
Jun. 29, 1987
John B Keys, Cambridge, OH (US);
David A Rieker, Cambridge, OH (US);
NCR Corporation, Dayton, OH (US);
Abstract
A semiconductor memory controller chip associated with a remote DMA device, a multispeed microprocessor and a DRAM memory requiring refreshing periodically includes refresh circuits for generating refresh signals for controlling refreshing of the memory during transparent and contention refresh operations. When a conflict occurs between the DMA device requesting access to the memory and the occurrence of a transparent refresh operation, control signals are generated to allow the memory to be refreshed prior to the time the DMA device is given access to the memory, thereby eliminating the need for a contention refresh operation. Control signals are also generated in accordance with the speed of the microprocessor for synchronizing the operation of the microprocessor with the operation of the DMA device.