Browse Prior Art Database

Method of Card Protection From Misplugging Errors

IP.com Disclosure Number: IPCOM000037180D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Dotson, MW: AUTHOR [+2]

Abstract

Due to a printed circuit card's unique connector assignments on a printed circuit mother board connector, a method is desirable to be able to verify that all unique cards are plugged into their assigned board positions. If a card is misplugged, it is desirable to be able to easily detect the misplug and prevent power on, thus preventing damage to the misplugged card or the mother board to which it is plugged.

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Method of Card Protection From Misplugging Errors

Due to a printed circuit card's unique connector assignments on a printed circuit mother board connector, a method is desirable to be able to verify that all unique cards are plugged into their assigned board positions. If a card is misplugged, it is desirable to be able to easily detect the misplug and prevent power on, thus preventing damage to the misplugged card or the mother board to which it is plugged.

In order to save connector pins or define more card "IDs" with the same number of pins, one uses pattern matching on the card and board. In addition, by using a common ground between the detector circuit and the board ID pins, one is able to monitor for the misplug with only one wire.

Using the same shorting pattern on a card and its assigned board connector pins provides a way to verify that it is safe to power on the system and at the same time use fewer connector pins to do the job for a given number of IDs.

There is created two circuit nodes with the shorting pattern, on the card as well as the board, and a monitoring circuit is used to detect a short between the two nodes on the board when a card is misplugged. The monitor circuit can prevent power up, which protects the hardware, and provide an error indication on the maintenance panel. If one of the nodes is tied to a common ground with the monitor circuit, then the short between the nodes can be detected with one wire on the board.

The figure shows a...