Product specifications

VT8235 V-Link South Bridge
Revision 1.22 October 24, 2002 -79- Device 17 Function 0 Power Management Registers
System Management Bus-Specific Configuration Registers
Offset D1-D0 – SMBus I/O Base ......................................RW
15-4 I/O Base (16-byte I/O space) ............... default = 00h
3-0 Fixed ................................ always reads 0001b
Offset D2 – SMBus Host Configuration..........................RW
7-4 Reserved ........................................ always reads 0
3 SMBus Interrupt Type
0 SMI .................................................... default
1 SCI
2 Reserved ........................................ always reads 0
1 SMBus Interrupt Enable
0 Disable SCI / SMI ................................. default
1 Enable SCI / SMI
0 SMBus Host Controller Enable
0 Disable SMB controller functions......... default
1 Enable SMB controller functions
Offset D3 – SMBus Host Slave Command ......................RW
7-0 SMBus Host Slave Command Code ......... default=0
Offset D4 – SMBus Slave Address for Port 1..................RW
7-1 SMBus Slave Address for Port 1............... default=0
0 Read / Write for Shadow Port 1
Offset D5 – SMBus Slave Address for Port 2..................RW
7-1 SMBus Slave Address for Port 2............... default=0
0 Read / Write for Shadow Port 2
Offset D6 – SMBus Revision ID ....................................... RO
7-0 SMBus Revision Code
SMB GPIO Slave Command Codes
SMBus Command Code 0 – GPIO Slave Input Port......RO
7-0 Input Data ...................................... default per pins
Reflects the incoming logic levels of the pins,
regardless of whether the pin is defined as an input or
an output. Writes to this register have no effect.
SMBus Command Code 1 – GPIO Slave Output Port.. RW
7-0 Output Data ..............................................default = 0
Controls the levels of the GPIO output pins defined
as outputs. Bit values in this register have no effect
on pins defined as inputs. Reads from this register
reflect the saved value last written, not the actual pin
value.
SMBus Cmd Code 2 – GPIO Slave Polarity Inversion.. RW
7-0 Polarity Inversion.................................default = 0Fh
This register enables polarity inversion of pins
defined as inputs by Command Code 3.
0 Corresponding pin’s polarity unchanged
1 Corresponding pin’s polarity inverted
SMBus Cmd Code 3 – GPIO Slave I/O Configuration.. RW
7-0 Input / Output Configuration........... default = 0FFh
This register configures the directions of the I/O pins.
0 Corresponding pin is an output
1 Corresponding pin is an input...............default