Browse Prior Art Database

Continuous Scrolling of Displays

IP.com Disclosure Number: IPCOM000089636D
Original Publication Date: 1977-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Daniels, WE: AUTHOR

Abstract

Currently when information on a TV-type display terminal is scrolled (moved up or down), it is done in discrete steps of at least a line of characters or a half or full page at a time, thus making the whole screen appear to blink. If the scrolling is done one scan line at a time, the information will appear to move continuously and be readable continuously. The user should be given control of the rate of scrolling via a potentiometer which controls the speed and direction of scrolling. A switch which temporarily freezes the current display is also needed. The changes to conventional circuits to do this should be easy.

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Continuous Scrolling of Displays

Currently when information on a TV-type display terminal is scrolled (moved up or down), it is done in discrete steps of at least a line of characters or a half or full page at a time, thus making the whole screen appear to blink. If the scrolling is done one scan line at a time, the information will appear to move continuously and be readable continuously. The user should be given control of the rate of scrolling via a potentiometer which controls the speed and direction of scrolling. A switch which temporarily freezes the current display is also needed. The changes to conventional circuits to do this should be easy.

One possible way is to provide at least one line of characters more than necessary to fill the screen, if refresh began at the top of a character line. The scrolling is then provided by ignoring the first N scan lines of the first character line and using the first N scan lines of the last character line. Use a circular buffer with a register pointing to the current first character line. With a circular buffer new information can be put in the buffer at either the top or bottom of the screen when the character scan line counter N is O. The rate control is provided by a timer which controls the rate at which the starting scan line counter is incremented, and the freeze is provided by inhibiting the change of the scan line counter.

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