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:
Jan. 12, 1999
Filed:
May. 15, 1995
Motorola, Inc., Schaumburg, IL (US);
Abstract
A data processing system (20) has a display controller (28) that uses bus arbitration and data bursting to supply display data for refreshing an LCD screen (49), utilizing a system memory (30) instead of a separate video RAM. A screen DMA (58) fills a line buffer (60) with display data from the system memory (30) in bursts of a predetermined number of words. The screen DMA (58) receives a faster clocking signal than is used by the CPU (22). This allows the screen DMA (58) to run faster than the CPU (22) to reduce bandwidth needed to retrieve the display data. In addition, if the CPU (22) clock frequency is changed for power management purposes, the LCD screen (49) is not affected since it uses a different clock. By using the system memory (30) for storing display data, pin count, packaging costs, and board space are reduced.