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Method for an external SMC to put an I/O controller hub in a sleep mode and wake it up later using an enhanced SMBUS implementation

IP.com Disclosure Number: IPCOM000010052D
Publication Date: 2002-Oct-16
Document File: 3 page(s) / 72K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for an external system management controller (SMC) to put an I/O controller hub (ICH) in a sleep mode and wake it up later using an enhanced system management bus (SMBus) implementation. Benefits include improved functionality.

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Method for an external SMC to put an I/O controller hub in a sleep mode and wake it up later using an enhanced SMBUS implementation

Disclosed is a method for an external system management controller (SMC) to put an I/O controller hub (ICH) in a sleep mode and wake it up later using an enhanced system management bus (SMBus) implementation. Benefits include improved functionality.

Background

              Conventional implementations of ICH devices do not provide a mechanism to put the ICH in a sleep state through the SMBus by an external system management controller.

              The conventional format of the SMBus write command is 20 bits long (see Figure 1).

Description

              The disclosed method enables an external system management controller (SMC) to put an I/O controller hub (ICH) in a sleep mode and wake it up later using an enhanced system management bus (SMBus) implementation (see Figure 2). The method adds a write command type, 21h, and changes the use of type 20h for toggling the pwrbtnB signal (see Figure 3).

              When the external SMC issues command type 20h, the SMBus Logic drives the pwrbtnB bit active. When the 20h command is followed by a type 21h command, the SMC drives the pwrbtnB bit to inactive. The sending module ID (SMI#) or serial communications interface (SCI) sends a system request to transition to a sleep state. If the system is already in a sleep state, issuing command type 20 followed by command type 21 causes a wake event. In conventional impl...