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, 1998
Filed:
Aug. 14, 1995
Vlad Bril, Campbell, CA (US);
Dwarka Partani, Fremont, CA (US);
Cirrus Logic, Inc., Fremont, CA (US);
Abstract
A VGA compatible graphics controller receives character data, attribute data and font data, each of which are stored in different planes of a display memory. The font data comprises bit maps of at least two character fonts, which may be user fonts or default fonts loaded from a controller BIOS. The video controller detects attempts by a host CPU to write data into plane two of display memory (where character font bit maps reside). The address generated by the host CPU is scrambled to produce a video font cache address. The character font bit maps are stored in a video font cache at the scrambled address. The font select bits of the CPU generated address are used as a byte select to store a particular font at a byte location at a selected video font cache address. In the preferred embodiment, eight fonts may be stored in the video font cache, one scan line each font of each character as a different byte at each address of the video font cache in a 64 bit wide DRAM.