Intel Pentium 4 User Manual

AGP Interface Routing
R
Intel
®
Pentium
®
4 Processor / Intel
®
850 Chipset Family Platform Design Guide 119
Figure 77. AGP 2.0 V
REF
Generation and Distribution for 1.5 V Cards
82 Ω 1%
GREF[1:0]
VDDQ
AGP
Add-in
Card
MCH
1 kΩ 1%
1 kΩ 1%
500 pF
500 pF
82 Ω 1%
AGP_2V_VREF_Gen
Vrefgc
Pin A66
Vrefcg
Pin B66
220–330 Ω
0.1 uF
7.1.8 Intel
®
MCH AGP Interface Buffer Compensation
The MCH AGP interface supports resistive buffer compensation (GRCOMP[1:0]). The
GRCOMP[1:0] signals must be tied to a 40 Ω ± 2% or 39 Ω ± 1% pull-down resistor to ground.
This trace should be kept to 10 mils wide and less than 0.5 inches long.
7.1.9 AGP Pull-ups/Pull-down on AGP Signals
Some of the AGP signals may require either a pull-up resistor to VDDQ (not VCC3.3) or pull-
down resistor to GND. This is to ensure stable values are maintained when agents are not actively
driving the bus. The recommended AGP pull-up/pull-down resistor value is 8.2 Ω at 10%
tolerance (4 kΩ <
R
value
< 16 kΩ). The AGP interface does not require external termination.
The trace stub length to the pull-up/pull-down resistor should be kept to a minimum to avoid
signal reflection. This trace length is different for 1x and 2x/4x modes. Below are the
recommended stub lengths for 1x and 2x/4x modes.
• 1x mode, trace stub to pull-up resistor should be kept to less than 0.5 inches
• 2x/4x mode, trace stub to pull-up resistor should be kept to less than 0.1 inches
Short stub lengths help minimize signal reflections from the stub. The strobe signals require pull-
up/pull-down on the motherboard to ensure stable values when there are no agents driving the bus.
Note: The G_GNT# and G_PAR signals require pull-ups to VDDQ.
The MCH G_GNT# output signal will be tri-stated during RSTIN# assertion. This signal must
have an external pull-up resistor to keep it from floating during the RSTIN# assertion. The
recommended value is the same as the other AGP common clock signals.

Intel Pentium 4 Specifications

General

Architecture	x86
Core Count	1
Microarchitecture	NetBurst
Manufacturer	Intel
Core Names	Willamette, Northwood, Prescott, Cedar Mill
Virtualization Technology	No
Release Date	November 20, 2000
Clock Speed	1.3 GHz to 3.8 GHz
FSB Speed	400 MHz to 1066 MHz
Socket	Socket 423, Socket 478, LGA 775
Introduced	2000
Product Line	Pentium
Front Side Bus	400 MHz to 1066 MHz
Hyper-Threading	Yes (Prescott and later)
64-bit Support	Yes (Prescott and later)
Instruction Set	MMX, SSE, SSE2, SSE3
Discontinued	2008
Process Technology	180 nm, 130 nm, 90 nm, 65 nm
L2 Cache	256 KB, 512 KB, 1 MB, 2 MB
Lithography	180 nm, 130 nm, 90 nm, 65 nm
L1 Cache	8 KB