Design Guide
97
Intel
®
82870P2 (P64H2)
8.1.4
Loop Clock Configuration
You must tie PxPCLKO[6] to PxPCLKI because this clock always runs and is needed by the
internal PCI PLLs to properly align output signals with the external clocks by removing clock
insertion delay. The PxPCLKO[6] signal does not have to be routed through a bus switch before
returning to PxPCLKI.
NOTES:
1. The clock signal and feedback loops are closely related. Refer to
for L2 and
for L
fbi
.
Figure 8-5. Loop Clock Configuration
Table 8-6. Loop Clock Configuration Routing Length Parameters
Clock Speed / Config
L
fbo
(inches)
L
fbi
(inches)
33 MHz / No HP
3.5 – 5.5
2.9 – 7.9
66 MHz / No HP
4.5 – 5.5
3.9 – 4.9
66 MHz / With HP
0.25 – 1.0
7.0 – 12.0
100 MHz / No HP
≤
1.0
L2 + 2.5
1
100 MHz / With HP
4.5 – 5.5
3.9 – 4.9
133 MHz / No HP
0.25 – 1.0
L2 + 2.5
1
133 MHz / With HP
3.5 – 4.0
5.5 – 5.7
Intel
®
P64H2
33
Ω
PxPCLKO[6]
PxPCLKI
L
fbi
L
fbo
Summary of Contents for Xeon
Page 24: ...Introduction 24 Design Guide This page is intentionally left blank ...
Page 30: ...Component Quadrant Layout 30 Design Guide This page is intentionally left blank ...
Page 52: ...Platform Clock Routing Guidelines 52 Design Guide This page is intentionally left blank ...
Page 66: ...System Bus Routing Guidelines 66 Design Guide This page is intentionally left blank ...
Page 118: ...Intel 82870P2 P64H2 118 Design Guide This page is intentionally left blank ...
Page 146: ...I O Controller Hub 146 Design Guide This page is intentionally left blank ...
Page 148: ...Debug Port 148 Design Guide This page is intentionally left blank ...
Page 210: ...Schematic Checklist 210 Design Guide This page is intentionally left blank ...
Page 220: ...Layout Checklist 220 Design Guide This page is intentionally left blank ...
Page 222: ...Schematics 222 Design Guide This page is intentionally left blank ...