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Variable-Format CRT Data Display

IP.com Disclosure Number: IPCOM000063543D
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18

Publishing Venue

IBM

Related People

Authors:
Gundrum, R Rockrohr, J [+details]

Abstract

A variable-format CRT display can be constructed that can handle a wide range of differing display formats, using a programmable cathode ray tube controller (CRTC), and digital-to-analog converters interposed between the CRTC and the usual raster-generating beam deflection circuits of the CRT. In the figure, the CRT analog system is enclosed in dashed lines. It consists of a CRT 1, with associated horizontal deflection circuits 2, vertical deflection circuits 3 and video drive circuits 4. The application processor 5 may be a host or local processor. The CRTC 6 is programmed, i.e., its control registers are loaded, by processor 5 with the necessary data to construct the desired format, and it generates the horizontal sync 7 and vertical sync 8 signals to drive the analog circuits 2, 3.