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:
Jul. 22, 1997
Filed:
Jun. 26, 1992
Robert Bailey, San Jose, CA (US);
Brian D Howard, Menlo Park, CA (US);
Michael D Johnson, Campbell, CA (US);
Apple Computer, Inc., Cupertino, CA (US);
Abstract
A method and apparatus for eliminating unnecessary address transitions on an DRAM address bus and DRAM write enable line. In a known DRAM controller and DRAM array, all address transitions on the CPU address bus are mirrored by address transitions on the DRAM address bus. The present invention eliminates all address transitions not associated with an actual DRAM access cycle by eliminating the DRAM controller's address multiplexer and replacing it with a multiplexing driver circuit and a bus holder circuit. In a similar fashion, a DRAM write enable circuit eliminates all transitions on the DRAM write enable line that are not associated with actual DRAM access cycles. Although specifically discussed in terms of a DRAM array and its associated circuitry, the portion of the present invention that reduces address transitions on the DRAM address lines could be used in any device currently using a multiplexer.