Intel 440GX, Design Manual

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Intel
®
440GX AGPset Design Guide 2-1
Motherboard Layout and Routing Guidelines
Motherboard Layout and Routing
Guidelines
2
This chapter describes layout and routing recommendations to insure a robust design. Follow these
guidelines as closely as possible. Any deviations from the guidelines listed here should be
simulated to insure adequate margin is still maintained in the design
2.1 BGA Quadrant Assignment
Intel assigned pins on the 82443GX to simplify routing and keep board fabrication costs down, by
permitting a motherboard to be routed in 4-layers.
Figure 2-1 shows the 4 signal quadrants of the
82443GX. The component placement on the motherboard should be done with this general flow in
mind. This simplifies routing and minimizes the number of signals which must cross. The
individual signals within the respective groups have also been optimized to be routed using only 2
PCB layers.
Note: The Intel
®
82443GX AGPset Datasheet contains a complete list of signals and Ball assignments.
Figure 2-1. Major Signal Sections (82443GX Top View)
Pin #1 Corner
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
24 25 26
A
B
C
D
E
F
G
H
J
K
L
M
N
P
R
T
U
V
W
Y
AA
A B
A C
A D
A E
AF
A G P
Quadrant
P C I
Quadrant
G T L +
Quadrant
S D R A M
Quadrant
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