Datasheet

Datasheet 97

3.7.28 AGPSTAT – AGP Status Register (Device #0)

Address Offset: A4–A7h

Default Value: 1F000217h

Access: Read Only

Size: 32 bits

This register reports AGP device capability/status.

Bit Description

31:24 Request (RQ). Indicates a maximum of 32 outstanding AGP command requests can be

handled by the GMCH/MCH.

Default =1Fh to allow a maximum of 32 outstanding AGP command requests.

23:10 Reserved

9 Side Band Addressing (SBA). Indicates that the GMCH/MCH supports side band addressing.

8:6 Reserved

5 Address Support Above 4 GB (4 GB). Indicates that the GMCH/MCH does not support

addresses greater than 4 gigabytes.

4 Fast Writes.

1 = The GMCH/MCH supports Fast Writes from the CPU to the AGP master. (Default)

3 Reserved

2:0 RATE. After reset the GMCH/MCH reports its data transfer rate capability. Bit 0 identifies if AGP

device supports 1X data transfer mode, bit 1 identifies if AGP device supports 2X data transfer

mode, bit 2 identifies if AGP device supports 4X data transfer mode. 1X , 2X , and 4X data

transfer modes are supported by the GMCH/MCH and therefore this bit field has a Default Value

= 111.

NOTE: The selected data transfer mode applies to both AD bus and SBA bus.