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:
Jun. 23, 2009
Filed:
Sep. 30, 2005
Applicants:
Hidenori Takahashi, Kawasaki, JP;
Yuichi Ogawa, Kawasaki, JP;
Terumasa Haneda, Kawasaki, JP;
Inventors:
Assignee:
Fujitsu Limited, Kawasaki, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F 3/00 (2006.01); G06F 13/28 (2006.01);
U.S. Cl.
CPC ...
Abstract
A DMA circuit prevents an erroneous data transfer by a descriptor due to an address failure of memory. When a descriptor is created, the data processing unit writes a pointer, for storing the descriptor, in a predetermined part of the descriptor, and stores the descriptor in memory, and when a DMA engine reads the descriptor from the memory, the DMA engine confirms whether the value is correct, and judges whether a DMA transfer of the data in the memory is possible. For both reading and writing of a descriptor, data corruption due to an address failure can be prevented.