Agp Checklist - Intel Pentium 4 Design Manual

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15.5

AGP Checklist

Checklist Items
G_FRAME#
G_IRDY#
G_TRDY#
G_DEVSEL#
G_STOP#
G_SERR#
G_PERR#
G_RBF#
G_PIPE#
G_REQ#
G_GNT#
G_PAR
AD_STB[0:1]
SB_STB
WBF#
AD_STB#[0:1]
SB_STB#
INTA#
INTB#
VREFCG[B66]
VREFGC[A66]
G_REF[1:0]
TYPEDET# [A2]
PME#
3.3Vaux
(B24)
® ®
Intel Pentium 4 Processor / Intel
Recommendations
• These signals require pull-up resistors
to V .
DDQ
• Acceptable values are between 4 k
Ω
and 16 k . The recommended value
Ω
is 8.2 k .
• These signals require pull-down
resistors.
• Acceptable values are between 4 k
Ω
and 16 k . The recommended value
Ω
is 8.2 k .
Ω
• 8.2 k pull-up resistors to 3.3 V
Ω Ω
• Range is 4 k – 16 k
• VREFCG should be tied to a resistor
divider near the AGP device.
• VREFGC should be a no connect.
Ω Ω
• A 220
– 330 series resistor
should be connected from the voltage
divider network to the G_REF[1:0]
pins on the MCH.
• Intel 850 chipset only supports 1.5 V
add-in card. Therefore, TYPEDET#
detection on the motherboard is not
required.
• Connect to PCI PME#
• Connect to 3.3V
SB
®
850 Chipset Family Platform Design Guide
Schematic Review Checklist
Reason/Impact
• V = 1.5 V for 1X, 2X and 4X
DDQ
mode
Ω • Pull up to V ensures that stable
DDQ
values are maintained when agents
are not actively driving the bus.
• Refer to Section 7.1.9.
• Pull down to GND ensures that
stable values are maintained when
agents are not actively driving the
Ω
bus.
• Refer to Section 7.1.9.
• These signals should be pulled up
only once (for both PCI and AGP).
They should be pulled to 3.3 V and
MUST NOT be pulled to 5 V.
• INTB# is for a two function device
and may not be seen with AGP
down
• Refer to Section 7.1.9 this
document.
• The V
divider network should be
REF
placed near the AGP interface to
achieve the common mode power
supply effect. A 0.1 µF decoupling
capacitor should be placed near the
G_REF[1:0
• Refer to Section 7.1.7.
• Refer to Section 7.1.6.
• This is an open drain signal from
the AGP connector and does not
require pull-up resistor to VCC3_3 if
connected to ICH2.
• May not be seen with AGP down
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