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:
Apr. 21, 2009
Filed:
Mar. 21, 2007
Koji Kajita, Kanagawa-ken, JP;
Koji Kajita, Kanagawa-ken, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
When a plurality of sub-processors are daisy chained in a loop, for example, to a main processor by a one-way bus, a command packet from the main processor addressed to itself is transmitted to the one-way bus which form a return path back to the main processor so as to easily specify a fault portion. If the command packet is returned to the main processor within a predetermined time, it is determined that no fault exists within the electronic device. When a fault exists, a test signal is transmitted to sub-processors via a dedicated signal line, separate from the one-way bus, to trigger a test packet that will be routed through the one way bus. The faulty portion in the electronic device is specified based on whether the test packet transmitted via the one-way bus in accordance with the test packet from each sub-processor is received within a predetermined time.