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Buffered Convergence Data in a Bus Oriented Color CRT Display

IP.com Disclosure Number: IPCOM000048382D
Original Publication Date: 1982-Jan-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Rockrohr, JD: AUTHOR [+2]

Abstract

U.S. Patents 4,203,051 and 4,203,054 describe systems wherein data are provided for use in synchronism with the operation of a cathode ray tube (CRT) display whereby convergence signals are made available in timed relation to the operation of the display throughout the display screen.

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Buffered Convergence Data in a Bus Oriented Color CRT Display

U.S. Patents 4,203,051 and 4,203,054 describe systems wherein data are provided for use in synchronism with the operation of a cathode ray tube (CRT) display whereby convergence signals are made available in timed relation to the operation of the display throughout the display screen.

This article describes the management of such signals in a variable format bus-oriented display. By "bus-oriented" is meant a system having a processor, an I/O bus for the same, and memory, display control module (DCM) and other modules interconnected via the bus. In such a display, the convergence tables or on the fly convergence calculations may be present in portions of the system other than the CRT display module and available to the latter only via the I/O bus. Thus if tables are calculated for the given display format, they may be resident in the main storage of the system, or if dynamic calculations are needed, the processor of the system will be involved. In either case, it is necessary that the data be available at the display module on a reel time basis, and this may present traffic problems on the I/O bus of the system.

To overcome this, a pair of alternately employed "ping-pong" buffers can be provided in tbe DCM which are loaded at the convenience of the processor with data for a number of display screen areas in sequence for real time availability to the display module. Alternatively, the display logic can h...