The PES24N3 supports static lane reversal. For example, lane reversal
for upstream port A may be configured by asserting the PCI Express
Port A Lane Reverse (PEALREV) input signal or through serial
EEPROM or SMBus initialization. Lane reversal for ports B and C may
be enabled via a configuration space register, serial EEPROM, or the
SMBus.
Processor
North
Bridge
Memory
Memory
Memory
Memory
PES24N3
PES24N3
PES24N3
PCI Express
Slots
I/O
10GbE
I/O
10GbE
I/O
SATA
I/O
SATA
Figure 2 I/O Expansion Application
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IDT 89HPES24N3 Data Sheet
Pin Description
The following tables list the functions of the pins provided on the PES24N3. Some of the functions listed may be multiplexed onto the same pin.
The active polarity of a signal is defined using a suffix. Signals ending with an “N” are defined as being active, or asserted, when at a logic zero (low)
level. All other signals (including clocks, buses, and select lines) will be interpreted as being active, or asserted, when at a logic one (high) level.
Signal
PEALREV
Type
I
Name/Description
PCI Express Port A Lane Reverse.
When this bit is asserted, the lanes of
PCI Express Port A are reversed. This value may be overridden by modify-
ing the value of the PALREV bit in the PA_SWCTL register.
PCI Express Port A Serial Data Receive.
Differential PCI Express receive
pairs for port A.
PCI Express Port A Serial Data Transmit.
Differential PCI Express trans-
mit pairs for port A
PCI Express Port B Lane Reverse.
When this bit is asserted, the lanes of
PCI Express Port B are reversed. This value may be overridden by modify-
ing the value of the PBLREV bit in the PA_SWCTL register.
PCI Express Port B Serial Data Receive.
Differential PCI Express receive
pairs for port B.
PCI Express Port B Serial Data Transmit.
Differential PCI Express trans-
mit pairs for port B
PCI Express Port C Lane Reverse.
When this bit is asserted, the lanes of
PCI Express Port C are reversed. This value may be overridden by modify-
ing the value of the PCLREV bit in the PA_SWCTL register.
PCI Express Port C Serial Data Receive.
Differential PCI Express receive
pairs for port C.
PCI Express Port C Serial Data Transmit.
Differential PCI Express trans-
mit pairs for port C
PCI Express Reference Clock.
Differential reference clock pair input. This
clock is used as the reference clock by on-chip PLLs to generate the clocks
required for the system logic and on-chip SerDes. The frequency of the dif-
ferential reference clock is determined by the REFCLKM signal.
PCI Express Reference Clock Mode Select.
These signals select the fre-
quency of the reference clock input.
0x0 - 100 MHz
0x1 - 125 MHz
Table 1 PCI Express Interface Pins
PEARP[7:0]
PEARN[7:0]
PEATP[7:0]
PEATN[7:0
PEBLREV
I
O
I
PEBRP[7:0]
PEBRN[7:0]
PEBTP[7:0]
PEBTN[7:0]
PECLREV
I
O
I
PECRP[7:0]
PECRN[7:0]
PECTP[7:0]
PECTN[7:0]
PEREFCLKP[1:0]
PEREFCLKN[1:0]
I
O
I
REFCLKM
I
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IDT 89HPES24N3 Data Sheet
Signal
MSMBADDR[4:1]
MSMBCLK
MSMBDAT
SSMBADDR[5,3:1]
SSMBCLK
SSMBDAT
Type
I
I/O
I/O
I
I/O
I/O
Name/Description
Master SMBus Address.
These pins determine the SMBus address of the
serial EEPROM from which configuration information is loaded.
Master SMBus Clock.
This bidirectional signal is used to synchronize
transfers on the master SMBus.
Master SMBus Data.
This bidirectional signal is used for data on the mas-
ter SMBus.
Slave SMBus Address.
These pins determine the SMBus address to
which the slave SMBus interface responds.
Slave SMBus Clock.
This bidirectional signal is used to synchronize trans-
fers on the slave SMBus.
Slave SMBus Data.
This bidirectional signal is used for data on the slave
SMBus.
Table 2 SMBus Interface Pins
Signal
GPIO[0]
GPIO[1]
GPIO[2]
Type
I/O
I/O
I/O
Name/Description
General Purpose I/O.
This pin can be configured as a general purpose I/O pin.
General Purpose I/O.
This pin can be configured as a general purpose I/O pin.
General Purpose I/O.
This pin can be configured as a general purpose I/O pin.