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:
Oct. 20, 1998
Filed:
Feb. 10, 1997
Jianhua Pang, Arlington, TX (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A direct memory access (DMA) controller having memory to memory data transfer capability, a programmable fixed priority scheme, a programmable wait state, a buffer chaining mode data transfer capability, a cascade-master mode, separate channels for internal and external devices, and a programmable 8 or 16 bit requester bus size. The DMA controller includes a channel circuit connected to transfer data to and from a port, a CPU interface, a bus connected to the channel circuit and to the CPU interface to transfer data therebetween, a state machine which generates a clock signal that is used for transferring data from the channel circuit across the bus to the CPU interface, the state machine having a programmable wait state which delays the transfer of data for a preprogrammed number of clock cycles, and a data mode register which is used for setting the preprogrammed number of clock cycles.