Hub Datasheet

Intel

E7505 Chipset MCH Datasheet 71

Greater Than Four Gigabyte Support (GT4GIG). Hardwired to 0. The MCH does not

support addresses greater than 4 GB.

Fast Write Support (FW). Hardwired to a 1. The MCH supports Fast Writes from the

processor to the AGP master. It is

AGP 3.0 Signaling Mode. This bit is set by the hardware on reset based on the AGP

8x detection via the VREF Comparator.

0 = AGP 2.0 signaling mode (1.5 V).

1 = Graphics card is AGP 8x mode.

2:0

111b or

01xb

Data Rate Support (RATE). The value of this field is determined by the AGP 3.0

signaling mode bit above.

In AGP 3. 0 signaling mode (AGP 3.0 signaling mode bit = 1), these bits are 01X,

indicating that 8x mode is supported. A 1 indicates that the 4x data rate is supported in

8x mode.

In AGP 2.0 signaling mode, these bits are 111 indicating that 1x, 2x, and 4x modes are

all supported.

Signaling mode is determined by bit 3 (AGP 3.0 signaling mode bit) above.

Bits

Default,

Access

Description

2.0 Signaling (1.5 V) Bit 2 Bit 1 BIt 0

Data Rate 4x 2x 1x

MCH Value 1 (supported) 1 (supported) 1 (supported)

3.0 Signaling (0.8 V) Bit 2 Bit 1 BIt 0

Data Rate reserved 8x 4x

MCH value 0 1 (supported) Programmable by

BIOS