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Universal Serial Bus (USB) Configuration
13-2 Intel® 460GX Chipset Software Developer’s Manual
13.2 USB Host Controller Register Descriptions (PCI
Function 2)
This section describes in detail the registers associated with the IFB USB Host Controller
Functions. This includes UHCI compatible registers and Legacy Keyboard registers.
13.2.1 VID–Vendor Identification Register (Function 2)
Address Offset: 00–01h
Default Value: 8086h
Attribute: Read only
The VID Register contains the vendor identification number. This register, along with the Device
Identification Register, uniquely identifies any PCI device. Writes to this register have no effect.
13.2.2 DID–Device Identification Register (Function 2)
Address Offset: 02-03h
Default Value: 7602h
Attribute: Read only
The DID Register contains the device identification number. This register, along with the VID
Register, defines the IFB USB Host Controller. Writes to this register have no effect.
13.2.3 PCICMD–PCI Command Register (Function 2)
Address Offset: 04-05h
Default Value: 00h
Attribute: Read/Write
This register controls access to the I/O space registers.
Bit Description
15:0 Vendor Identification Number. This is a 16-bit value assigned to Intel.
Bit Description
15:0 Device Identification Number. This is a 16-bit value assigned to the IFB USB Host Controller.
Bit Description
15:10 Reserved. Read 0.
9 Fast Back to Back Enable (Not Implemented). This bit is hardwired to 0.
8:5 Reserved. Read as 0.
4 Memory Write and Invalidate Enable (Not Implemented). This bit is hardwired to 0.
3 Special Cycle Enable (Not Implemented). This bit is hardwired to 0.
2 Bus Master Enable (BME). This bit controls the IFB’s ability to act as a master on the PCI bus for
the host controller transfers. A value of 0 disables the device from generating PCI accesses. A
value of 1 allows the device to behave as a USB host controller bus master. This bit must be set to
1 before USB transactions can start.