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:
Mar. 01, 1983
Filed:
Jun. 16, 1980
David B O'Keefe, Westford, MA (US);
Robert C Miller, Braintree, MA (US);
Honeywell Information Systems Inc., Waltham, MA (US);
Abstract
A refresh memory address generation apparatus for a video display controller is disclosed wherein rows of character information stored in a display refresh memory may be relocated without requiring the reconstruction of the display information as stored in the display refresh memory. A roll register and PROMs precoded to perform modular addition and multiplication are used to generate an address used to access the display controller refresh memory such that all but one stationary row of information on the display screen may be scrolled (rolled) up. The scrolling of the information on the display screen is accomplished without requiring movement of the display information in the refresh memory, and the only rewrite of information in the refresh memory is done to blank the one row of information which is vacated.