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:
Dec. 04, 1990
Filed:
Feb. 08, 1990
Shuichi Saito, Tachikawa, JP;
Mituru Hasegawa, Komae, JP;
Teac Corporation, Tokyo, JP;
Abstract
A microcomputer interfaced with an input/output (I/O) device comprises a central processor unit (CPU), a memory, and a direct memory access (DMA) controller, together with a bus system for interconnecting them. The DMA controller can cause the CPU either to be electrically coupled to the bus system for programmed CPU data transmission between the I/O device and the memory, or to be uncoupled therefrom for DMA data transmission therebetween. The CPU is periodically coupled to, and uncoupled from, the bus system for data transmission in a cycle steal mode, in which DMA transmission and programmed CPU transmission alternate at regular intervals, when the CPU is active. When the CPU is inactive, on the other hand, the CPU is held uncoupled from the bus system for data transmission in a sustained DMA mode. More efficient data transmission is thus possible than if data is transmitted in the cycle steal mode regardless of whether the CPU is active or inactive.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile