Browse Prior Art Database

Screen Digitizer

IP.com Disclosure Number: IPCOM000060992D
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 3 page(s) / 55K

Publishing Venue

IBM

Related People

Shipley, ML: AUTHOR

Abstract

This article describes a software-driven hardware device capable of reading a computer screen (monochrome or color) and converting this information into hexadecimal values which can then be checked for accuracy against known values contained in the software. This device will plug into an IBM Personal Computer (PC) I/O slot and have the capabilities of testing up to seven display drivers at once. Presently a method of "burning in" a PC system board using a burn- in chamber has shown that the burn-in process greatly reduces any defects which would otherwise show up in the field. This burn-in process requires a method of testing the display cards inside the chamber. The display cards are tested dynamically in a sealed environment in which the temperature is ramped up and down.

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Screen Digitizer

This article describes a software-driven hardware device capable of reading a computer screen (monochrome or color) and converting this information into hexadecimal values which can then be checked for accuracy against known values contained in the software. This device will plug into an IBM Personal Computer (PC) I/O slot and have the capabilities of testing up to seven display drivers at once. Presently a method of "burning in" a PC system board using a burn- in chamber has shown that the burn-in process greatly reduces any defects which would otherwise show up in the field. This burn-in process requires a method of testing the display cards inside the chamber. The display cards are tested dynamically in a sealed environment in which the temperature is ramped up and down. Due to the number of cards being tested and not being able to connect monitors, visual inspection of a screen is not feasible. The means of testing disclosed herein determines if the display drivers are operating properly In addition, the display drivers to be tested have different character sizes, different horizontal and vertical frequencies and clock rates. The software programmable device of this disclosure, known as the screen digitizer, is capable of reading the video information of a PC screen and turning this information into a series of numbers. Inserted in a PC and under software control, the device controlling the screen can be tested quicker and without visual inspection to a greater degree of accuracy. The computer screen, however, need not be connected to perform this test. The display cards operate at different frequencies, and generate characters of different sizes. Therefore, the screen digitizer is programmable to character width, horizontal and vertical frequencies, intensity, and video dot rates. The screen digitizer can also be programmed to test the red, green, and blue guns in the color cards. Up to seven display drivers can be connected to each screen digitizer. The block diagram of Fig. 1 shows the scheme designed to capture the video patterns as they leave the display card. Two programmable peripheral interface devices (8255s) are used to create six 8- bit programmable ports. The starting location of the column of interest is sent to port 1. A column counter keeps trac...