Host Controller Data Manual

4–10

4.10 GUID High Register

The GUID high register represents the upper quadlet in a 64-bit global unique ID (GUID) which maps to the third

quadlet in the Bus_Info_Block. This register contains node_vendor_ID and chip_ID_hi fields. This register initializes

to 0s on a hardware reset, which is an illegal GUID value. If a serial ROM is detected, then the contents of this register

are loaded through the serial ROM interface after a PCI reset. At that point, the contents of this register cannot be

changed. If no serial ROM is detected, then the contents of this register are loaded by the BIOS after a PCI reset.

At that point, the contents of this register cannot be changed.

Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16

Name GUID high

Type R R R R R R R R R R R R R R R R

Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Name GUID high

Type R R R R R R R R R R R R R R R R

Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Type: Read-only

Offset: 24h

Default: 0000 0000h

4.11 GUID Low Register

The GUID low register represents the lower quadlet in a 64-bit global unique ID (GUID) which maps to chip_ID_lo

in the Bus_Info_Block. This register initializes to 0s on a hardware reset and behaves identically to the GUID high

Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16

Name GUID low

Type R R R R R R R R R R R R R R R R

Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Name GUID low

Type R R R R R R R R R R R R R R R R

Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Type: Read-only

Offset: 28h

Default: 0000 0000h