Hub Datasheet

Intel
®
E7505 Chipset MCH Datasheet 159
Functional Description
5.4.3 AGP 3.0 and AGP 2.0 Signaling Mode Differences
Table 5-1. Key Differences Between AGP 3.0 and AGP 2.0 Signaling Modes
Parameter
AGP 3.0 Signaling
Mode
AGP 2.0 Signaling
Mode
Comments
Data Rate 8x or 4x 4x, 2x, or 1x
Electricals
0.8 V swing, parallel
termination
1.5 V swing serial
termination
Signal Polarity
Most controls signals
active high
Most control signals
active low
This change was necessary to
eliminate current flow in the idle
stare. Parallel termination has a
large current flow for a high level.
Hi/ Low priority
commands
Only low priority
(renamed Async)
High and low priority
commands supported
Strobe Protocol
Strobe First-Strobe
Second Protocol
Strobe-Strobe# protocol
Long
Transactions
Removed Supported
PIPE# Support No Yes SBA required for AGP 3.0.
Calibration Cycle Required No New to AGP 3.0.
Dynamic Bus
Inversion
8x Yes
4x receive only
No New to AGP 3.0.
Coherency
Required for AGP
accesses outside of the
aperture, and for
FRAME-based accesses
Required only for FRAME
based accesses