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.
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...