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Video Pattern Diagnostic Asynchronous Sequential Circuit Checkout

IP.com Disclosure Number: IPCOM000077740D
Original Publication Date: 1972-Sep-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Casler, D: AUTHOR [+2]

Abstract

This diagnostic circuit checkout method allows the user to design specific tests for functions of hardware and, in this instance, the segmentation circuitry of a character recognition machine connected on-line to a computer system and controlled by a Micro Area Controller (MAC). The testing is done by loading specially selected video patterns into video memory of the character recognition machine via the computer system and MAC controller. and stopping segmentation at predefined stop points to check the condition of the hardware. Stop points can be defined that would yield information as to minor or major errors. Thus, an exhaustive circuit checkout need not be done if all functions of the circuit are checked. Timing tests are also accomplished, since the circuits run at normal speed with actual video patterns.

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Video Pattern Diagnostic Asynchronous Sequential Circuit Checkout

This diagnostic circuit checkout method allows the user to design specific tests for functions of hardware and, in this instance, the segmentation circuitry of a character recognition machine connected on-line to a computer system and controlled by a Micro Area Controller (MAC). The testing is done by loading specially selected video patterns into video memory of the character recognition machine via the computer system and MAC controller. and stopping segmentation at predefined stop points to check the condition of the hardware. Stop points can be defined that would yield information as to minor or major errors. Thus, an exhaustive circuit checkout need not be done if all functions of the circuit are checked. Timing tests are also accomplished, since the circuits run at normal speed with actual video patterns.

The operation of the diagnostic program in the computer system is such that after it starts, it first loads the Micro Area Controller (MAC) with a diagnostic control program. Then video data from the computer system is loaded into MAC memory and the MAC program is told to put the data into VIDEO MEMORY (VM) of the character recognition machine.

After VM is loaded with 120 scans of 64 bits each, the diagnostic program starts both the MAC and Segmentation hardware. The hardware asks for permission to cycle steal with a Left of Block (LOB), which the MAC acknowledges with the address of the vid...