Design Guide
117
Intel
®
82870P2 (P64H2)
M66EN Diode Solution
Another possible solution is to use diodes to isolate the individual slots from one another while still
allowing the P64H2 to drive the M66EN signals to ground. The P64H2 PCI interface PxM66EN
signal should be pulled to 3.3 V through a 100
k
Ω
± 5% resistor. This signal would then be
connected to the individual slots through a reverse biased diode (one diode per slot). The PCI slots
should also be pulled up individually to 3.3 V through a resistor of value such that the equivalent of
all the resistances on the M66EN bus is approximately 5
k
Ω
(the PCI recommended value). This
circuit will allow the P64H2 to pull the slots’ M66EN to ground during initial power-up. During
normal operation, each of the slots’ M66EN signals will be isolated from one another allowing for
polling of the Hot Plug HxM66EN input for slot capability.
shows the diode solution
implemented in Serial Mode, where “Slot x M66EN” is a serialized input to the Hot Plug
Controller.
.
NOTE:
All PCI signals, muxed or not, must follow PCI Specification 2.2 pull-up requirements.
Figure 8-18. M66EN Diode Solution
Slot
4
Slot
3
Slot
2
Slot
1
20 k
Ω
3.3V
20 k
Ω
3.3V
20 k
Ω
3.3V
20 k
Ω
3.3V
100 k
Ω
3.3V
M66EN
M66EN
M66EN
M66EN
Slot 3 M66EN
Slot 4 M66EN
Slot 2 M66EN
Slot 1 M66EN
PxM66EN
P64H2 PCI
Interface
P64H2 Hot
Plug Interface
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 ...