Smbus registers – AMD SB600 User Manual

Page 123

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©2008 Advanced Micro Devices, Inc.

SMBus Module and ACPI Block (Device 20, Function 0)

AMD SB600 Register Reference Manual

Proprietary

Page 123

2.3.2 SMBus

Registers

Register Name

Offset Address

SMBusStatus 00h

SMBusSlaveStatus 01h

SMBusControl 02h

SMBusHostCmd 03h

SMBusAddress 04h

SMBusData0 05h
SMBusData1 06h

SMBusBlockData 07h

SMBusSlaveControl 08h
SMBusShadowCmd 09h

SMBusSlaveEvent 0A-0Bh

SlaveData 0C-0Dh

SMBusTiming 0Eh

Note: The SMBus registers are located at the IO memory space base address defined by PCI configuration
register 90-93h

SMBusStatus - RW - 8 bits - [SMBUS:00h]

Field Name

Bits

Default

Description

HostBusy

0

0b

This bit indicates the SMBus controller is in the process of
completing a command. When this bit is set, software should
not access any other SMBus registers [Read-only]

SMBusInterrupt

1

0b

This bit is set by hardware to indicate the completion of the last
host command. This bit can be cleared by writing an 1 to it.

DeviceErr

2

0b

This bit is set by hardware to indicate an error of one of the
following: 1) illegal command field, 2) unclaimed cycle, 3) host
device time-out. This bit can be cleared by writing an 1 to it.

BusCollision

3

0b

This bit is set by hardware to indicate SMBus transaction
collision; this bit can be cleared by writing an 1 to it.

Failed

4

0b

This bit is set by hardware to indicate a failed bus transaction,
set when SMBusControl.Kill bit is set. This bit is cleared by
writing an 1 to it

Reserved 7:5

000b

SMBusSlaveStatus - RW - 8 bits - [SMBUS:01h]

Field Name

Bits

Default

Description

SlaveBusy

0

0b

This bit indicates the SMBus controller slave interface is in the
process of receiving data. Software should not try to access
any other SMBus register when this bit is set. [Read-only]

SlaveInit

1

0b

Writing a 1 to this bit will initialize the slave. It is unnecessary to
write it back to 0. A read from it will always return a 0.

SlaveStatus

2

0b

This bit is set by hardware to indicate a slave cycle event match
of the SMBus slave command and SMBus Slave Event match.
This bit can be cleared by writing an 1 to it.

Shadow1Status

3

0b

This bit is set by hardware to indicate a slave cycle address
match of the SMB_Shadow1 port. This bit can be cleared by
writing a 1 to it.

Shadow2Status

4

0b

This bit is set by hardware to indicate a slave cycle address
match of the SMB_Shadow2 port. This bit can be cleared by
writing a 1 to it.

AlertStatus

5

0b

This bit is set by hardware to indicate SMBALERT_ signal. This
function is not supported. [Read-only]

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