Browse Prior Art Database

Use of Random Access Memory as Refresh Buffer for Display

IP.com Disclosure Number: IPCOM000076630D
Original Publication Date: 1972-Mar-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 20K

Publishing Venue

IBM

Related People

Lindsey, RD: AUTHOR

Abstract

In a system having a large character capacity dynamic shift register (DSR) and a display device, which displays relatively small portions of the data in the DSR, a random-access memory is utilized as a refresh buffer for the display device.

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Use of Random Access Memory as Refresh Buffer for Display

In a system having a large character capacity dynamic shift register (DSR) and a display device, which displays relatively small portions of the data in the DSR, a random-access memory is utilized as a refresh buffer for the display device.

In order to avoid synchronization problems between the main DSR and the display device and also be able to trap the desired data to be displayed, an intermediate DSR (IDSR), having limited character capacity, is incorporated into the system to accept part of the data from the main DSR for later loading into the random-access memory. The random-access memory cycle time is one-half the cycle time of the intermediate DSR and one-half the cycle time required to maintain display synchronization. The display device is continuously refreshed from the random-access memory, using every other random-access memory cycle, and the random-access memory is loaded from the IDSR on alternate memory cycles, as required. The display sweep operation and the DSR shifting may operate synchronously.

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