82801FB Datasheet, PDF (223/786 Pages) Intel Corporation – Intel I/O Controller Hub 6 (ICH6) Family

Functional Description
Table 5-52. Command Types (Sheet 2 of 2)
Command
Type
Description
SMLINK_SLV_SMI. When ICH6 detects this command type while in the S0 state, it sets the
SMLINK_SLV_SMI_STS bit (see Section 10.9.5). This command should only be used if the
system is in an S0 state. If the message is received during S1–S5 states, the ICH6
acknowledges it, but the SMLINK_SLV_SMI_STS bit does not get set.
8
NOTE: It is possible that the system transitions out of the S0 state at the same time that the
SMLINK_SLV_SMI command is received. In this case, the SMLINK_SLV_SMI_STS bit
may get set but not serviced before the system goes to sleep. Once the system returns
to S0, the SMI associated with this bit would then be generated. Software must be able
to handle this scenario.
9–FFh Reserved
5.21.7.2 Format of Read Command
The external master performs Byte Read commands to the ICH6 SMBus Slave I/F. The
“Command” field (bits 18:11) indicate which register is being accessed. The Data field (bits 30:37)
contain the value that should be read from that register. Table 5-53 shows the Read Cycle Format.
Table 5-54 shows the register mapping for the data byte.
Table 5-53. Read Cycle Format
Bit
Description
1
Start
Driven by
External Microcontroller
8:2 Slave Address - 7 bits External Microcontroller
9
Write
10 ACK
External Microcontroller
Intel^® ICH6
18:11 Command code - 8 bits External Microcontroller
19 ACK
20 Repeated Start
ICH6
External Microcontroller
27:21 Slave Address - 7 bits External Microcontroller
28 Read
29 ACK
External Microcontroller
ICH6
37:30 Datay Byte
ICH6
38 NOT ACK
39 Stop
External Microcontroller
External Microcontroller
Comment
Must match value in Receive Slave
Address register
Always 0
Indicates which register is being
accessed See Table 5-54
Must match value in Receive Slave
Address register
Always 1
Value depends on register being
accessed. See Table 5-54
Intel^® I/O Controller Hub 6 (ICH6) Family Datasheet
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