ADLINK PMC-8246 - Manual (Page 13)

Introduction 1
PMC-8246
1 Introduction
PMC-8246 is a high performance 2-port Gigabit Ethernet (GbE)
PCI-X PMC module providing bypass capability, which can con-
nect GbE signals on the two GbE connectors while the system is
powered down or under software halt.
1.1 Block Diagram
The PMC-8246 is based on the Intel 82546GB dual port Gigabit
Ethernet controller. The Intel 82546GB is a highly integrated chip,
includes Ethernet MAC, PHY, and provides PCI-X 133MHz capa-
bility. Please refer to the Intel 82546GB datasheet for more infor-
mation on the GbE ports.
The PMC-8246’s bypass capability uses a mechanical relay array
to control the physical routing of the GbE signals. There are two
communications states for the GbE signal routing: 1) Normal
State, 2) Bypass State. Please refer to section 1.4 for block dia-
grams of the two states.
Trans-
former
Trans-
former
PCI-X
Bus
Relay Array
RJ-45
RJ-45
Relay
Drivers
WDT & Bypass
Control Logic
Circuit
GbE #1
GbE #2
Status
Feedback
1
2
3
4 ON
82546GB
Dual GbE
SDP (GPIO)
Control Switch