Universal Serial Bus (USB) Configuration

13.2USB 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.

13.2.1VID–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.

Bit

Description

15:0 Vendor Identification Number. This is a 16-bit value assigned to Intel.

13.2.2DID–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.

Bit

Description

15:0 Device Identification Number. This is a 16-bit value assigned to the IFB USB Host Controller.

13.2.3PCICMD–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

15:10 Reserved. Read 0.

9Fast Back to Back Enable (Not Implemented). This bit is hardwired to 0.

8:5 Reserved. Read as 0.

4Memory Write and Invalidate Enable (Not Implemented). This bit is hardwired to 0.

3Special Cycle Enable (Not Implemented). This bit is hardwired to 0.

2Bus 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.

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Intel® 460GX Chipset Software Developer’s Manual