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. 27, 1999
Filed:
Oct. 20, 1997
Junji Nishikawa, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A data transfer apparatus for DMA-transferring stream data between a memory and each of n ports. The data transfer apparatus includes: an address counter for storing a start address of a memory area between which and a port a next piece of stream data is DMA-transferred; a data counter for storing a size of the next piece of stream data; n chain address counters each for storing an address of a memory area storing a certain command list; a port selecting unit for selecting one port; a command list transferring unit for, each time the port selecting unit selects a port, obtaining a command list according to a chain address counter corresponding to the selected port, transferring a start address in the command list to the address counter, transferring a size in the command list to the data counter, transferring the command to the port selecting unit, and updates the chain address counter; a stream data transferring unit for DMA-transferring a piece of stream data between the selected port and the memory area specified by the address counter. After the stream data transferring unit completes a DMA transfer, the port selecting unit, based on a predetermined order and the command, selects a new port or a current port. Each time the command list transferring unit transfers the size to the data counter, the stream data transferring unit DMA-transfers a piece of stream data between the selected port and the memory area specified by the address counter.