Datasheet

Register Description
R
Datasheet 131
3.9.8 HDR – Header Type Register (Device #0)
Address Offset: 0Eh
Default Value: 80h
Access: Read Only
Size: 8 bits
This register identifies the header layout of the configuration space. No physical register exists at
this location.
Bit Description
7:0 PCI Header (HDR): This field always returns 80 to indicate that Device #0 is a
multifunction device. If Functions other than #0 are disabled this field returns a 00 to
indicate that the GMCH/MCH is a single function device with standard header layout.
The default is 80 Reads and Writes to this location have no effect.
3.9.9 SVID – Subsystem Vendor Identification Register (Device
#0)
Address Offset: 2C-2Dh
Default Value: 0000h
Access: Read/Write Once
Size: 16 bits
This value is used to identify the vendor of the subsystem.
Bit Description
15:0 Subsystem Vendor ID (SUBVID): This field should be programmed during boot-up to
indicate the vendor of the system board. After it has been Written once, it becomes
Read Only.
3.9.10 ID – Subsystem Identification Register (Device #0)
Address Offset: 2E-2Fh
Default Value: 0000h
Access: Read/Write Once
Size: 16 bits
This value is used to identify a particular subsystem.
Bit Description
15:0 Subsystem ID (SUBID): This field should be programmed during BIOS initialization.
After it has been Written once, it becomes Read Only.