Browse Prior Art Database

Video Preprocessing Diagnostic for an Optical Scanner

IP.com Disclosure Number: IPCOM000079196D
Original Publication Date: 1973-May-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Valesano, PP: AUTHOR

Abstract

This diagnostic technique completely diagnoses the thresholding, video control, and data transfer hardware without the use of an oscilloscope. Any failures to a FRU (Field Replaceable Unit) are indicated to the technician, assuring prompt repair. Diagnosis is under control of a microprogramming unit (MPU), which communicates with the hardware via external registers that can be set by either the MPU or hardware. The drawing shows a block diagram of the video preprocessing (VPP) hardware functions which includes: 1) thresholding, 2) video control and 3) data transfer.

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Video Preprocessing Diagnostic for an Optical Scanner

This diagnostic technique completely diagnoses the thresholding, video control, and data transfer hardware without the use of an oscilloscope. Any failures to a FRU (Field Replaceable Unit) are indicated to the technician, assuring prompt repair. Diagnosis is under control of a microprogramming unit (MPU), which communicates with the hardware via external registers that can be set by either the MPU or hardware. The drawing shows a block diagram of the video preprocessing (VPP) hardware functions which includes: 1) thresholding,
2) video control and 3) data transfer.

The hardware is diagnosed by using in-line error checking and off-line diagnostics. External register 2 is a dual-purpose register which is used both during in-line checking and off-line diagnostics. When a particular error is detected, the hardware sets an associated bit in register 2. At the end of a line on each document, the control program interrogates this register and stores its contents if an error occurred. After it is established that an error condition exists, the diagnostic program is run off-line.

The VPP logic diagnostic consists of the following steps:

1. Pulse the Recognition and Control Processor (RCP) control lines to the VPP, and verify that the VPP video control logic generates the correct signals.

2. Test VPP to Video Storage Module (VSM) data transfer by sending 00, FF, 00, AA, 00, 55, 00, FF through the VPP output register to...