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Enhanced Presence Detection Scheme

IP.com Disclosure Number: IPCOM000013548D
Original Publication Date: 2000-Jan-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Abstract

2 Disclosed is a system that uses a serial IC bus connection to detect the number and type of functions installed in a server. Use of 2 the serial IC bus eliminates the need for separate "Presence Detection" signals to be separately wired from each function to a central point. This serial bus connection and associated circuitry also ensures that the logic can detect that a function is present and not working versus a function that is not present.

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Enhanced Presence Detection Scheme

2Disclosed is a system that uses a serial IC bus connection to detect the number and type of functions installed in a server. Use of 2the serial IC bus eliminates the need for separate "Presence Detection" signals to be separately wired from each function to a central point. This serial bus connection and associated circuitry also ensures that the logic can detect that a function is present and not working versus a function that is not present.

The next generation of servers will have the capability of logically being different from each other even though the base planar wiring is the same. A method must be devised to allow the Basic Input/Output System (BIOS) to determine which functions are currently installed in a server. This can be done by a serial link routed to all possible logical elements or by separate presence detection signals to each logical element. When using a serial link, the BIOS can address each logical element in the system and determine the type of element and if it is present. However, if this serial link fails on a logical element, BIOS has no way of determining if the logical element is present and not working, or the logical element is not present. Separate presence detection signals overcome this problem, but must be routed from different parts of the system (sometimes in a physically different place) to a central site and detected by BIOS. Whereas separate presence detection signals are more reliable, they are difficult to manage because they consume a large number of General Purpose Input/Output (GPIO) ports in any logical detection element. A combination of both methods implemented on the base pl...