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:
Aug. 23, 1983
Filed:
Dec. 30, 1980
Douglas W Broyles, San Jose, CA (US);
Ronald S Palmer, Sunnyvale, CA (US);
International Memories, Inc., Cupertino, CA (US);
Abstract
The method and apparatus in a microprocessor-based data processing system which allows direct access to main memory associated with a central processing unit from peripheral intelligent devices such as mass storage and special processors. Main memory space is allocated in contiguous zones of actual memory and 'phantom' memory. An address decoder in connection with a bus buffer separates the peripheral from the CPU or the CPU from the peripheral whenever particular instructions are generated or address space is selected. During direct memory access, the CPU is placed in an idle state without disturbing CPU registers so that secondary functions of the CPU can be continued. The method and apparatus eliminates need for a conventional direct memory access device with its undesirably high overhead and support requirements.