EP80579 Datasheet, PDF (1559/1916 Pages) Intel Corporation – Intel® EP80579 Integrated Processor Product Line

Intel^® EP80579 Integrated Processor
38.0 Global Configuration Unit
38.1
38.2
38.3
38.3.1
Overview
The Global Configuration Unit (GCU) implements the configuration space registers for
system-level, EP80579 features. This unit also implements an MDIO interface to
support the Ethernet interfaces.
Feature List
The following is a list of features/register sets implemented in the Global Configuration
Unit:
• MDIO interface
— Command and Status registers
— MDIO Drive Strength register
— MDC Drive Strength register
• RCOMP registers
— Local Expansion bus (LEB)
— GbE (one set for all three interfaces)
• Drive Strength registers
— SSP Signal Group Drive Strength register
— TDM outputs
— CAN (one for both)
Usage Model
All configuration writes and reads are word accesses. Addresses to configuration reads
and writes are word aligned.
RCOMP
The RCOMP circuitry dynamically compensates the IO output drivers for variations in
operating conditions due to process, temperature, voltage and PCB layout. These
variations are measured through a resistive mechanism in two special IO pads. The
resistive mechanism on those IO pads reference external resistors the user provides to
match output driver strength to. Thus the output driver impedance can be tuned
specifically to the application PCB characteristics for nominal signal transfer into the
transmission lines formed by the PCB traces. The RCOMP design is nominally set to
operate at 50ohms, but the user is free to set the impedance in the range 45ohms to
55ohms.
August 2009
Order Number: 320066-003US
Intel^® EP80579 Integrated Processor Product Line Datasheet
1559