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Method for an auto-detect mechanism to enumerate an LPC bus

IP.com Disclosure Number: IPCOM000010974D
Publication Date: 2003-Feb-05
Document File: 3 page(s) / 74K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for an auto-detect mechanism to enumerate a low pin count (LPC) bus. Benefits include improved functionality.

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Method for an auto-detect mechanism to enumerate an LPC bus

 

Disclosed is a method for an auto-detect mechanism to enumerate a low pin count (LPC) bus.  Benefits include improved functionality.

Background

                            Infiniband is a trademarked name owned by Infiniband Trade Assn. Specification 1.0 has a release date of October 24, 2000.          

              An Infiniband hybrid channel allocation (HCA) design can have several attached firmware hubs (FWHs) that store program or software information. Up to 16 FWHs can be attached in parallel on an LPC bus. To direct the FWHs’ control signals, an Infiniband HCA controller device must know the number and size of the FWHs attached to the bus.

              A conventional method of performing this function is to hard-code this information in advance. Another method is to store the FWH information in some form of read-only memory that the controller device reads before interfacing with the firmware hubs.

General description

              The disclosed method is the auto-detection of FWHs each time the controller recovers from a reset condition. The controller is not dependant on possibly outdated stored information.

              After reset, the controller sends a Read Size Register command to each of the 16 available device addresses on the LPC bus. If a response is received, it contains the value stored in the device’s size register. As a result, the controller is informed of the presence or absence of a device and the size of the detected device. The device location is stored in a 16-bit register (see Figure 1). Size information is stored in a 1 or 2 bit register, assuming the size is uniform for all attac...