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:
Nov. 16, 1999
Filed:
Jul. 10, 1997
Andrew Thomson, Austin, TX (US);
National Instruments Coporation, Austin, TX (US);
Abstract
An apparatus and method is provided for caching data in a universal serial bus (USB) system. In one embodiment, the present invention employs a host computer coupled to an I/O device via a USB. The host computer includes a data cache for storing data retrieved from the I/O device. The data cache allows data to be returned to the host computer upon request without accessing the I/O device via a USB transaction. A cacheability look-up table and cache table are provided to ensure the integrity of data returned to the host computer. Requested data is returned from the I/O device if the cacheability look-up table indicates the requested data is noncacheable. Data is returned from the data cache if the cache table indicates the requested data is available in the cache as valid data. If the cache table indicates the requested data is not available in the cache as valid data, the requested data is returned from the I/O device along with data stored in predetermined I/O device addresses. The additional data is stored in the cache for subsequent access by the host computer. By returning data from the cache, the present invention reduces the response time and reduces the traffic over the USB between the host computer and I/O device.