Register Description

4.8.12CAPID – Capabilities Identification Register (Device #0)

Address Offset:

40-44h

Default Value:

chipset independent

Access:

Read Only

Size:

40 bits

The Capability Identification Register uniquely identifies chipset capabilities as defined in the table below. The bits in this register are intended to define a capability ceiling for each feature, not a capability select. The capability selection for each feature is implemented elsewhere. The mechanism to select the capability for each feature must comprehend these Capability registers and not allow a selected setting above the ceiling specified in these registers. The BIOS must read this register to identify the part and comprehend the capabilities specified within when configuring the effected portions of the GMCH.

The default setting, in most cases, allows the maximum capability. Exceptions are noted in the individual bits. This register is Read Only. Writes to this register have no effect.

Bit

Descriptions

 

 

39:37

Capability ID [2:0]:

 

000: Intel® 82854 GMCH

 

001-111: Reserved

 

 

36:28

Reserved

 

 

27:24

CAPREG Version: This field has the value 0001b to identify the first revision of the CAPREG

 

definition.

 

 

23:16

Cap_length: This field has the value 05h indicating the structure length.

 

 

15:0

Reserved

 

 

D15343-003

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Intel D15343-003 manual Capid Capabilities Identification Register Device #0, Capability ID