*Notice: The information in this document is subject to change without notice
September 7, 2007
Advance Information
IDT 89HPES8T5A Data Sheet
◆
◆
11 General Purpose Input/Output Pins
– Each pin may be individually configured as an input or output
– Each pin may be individually configured as an interrupt input
– Some pins have selectable alternate functions
Packaged in a 15mm x 15mm 196-ball BGA with 1mm ball spacing
Product Description
Utilizing standard PCI Express interconnect, the PES8T5A provides the most efficient I/O connectivity solution for applications requiring high
throughput, low latency, and simple board layout with a minimum number of board layers. It provides 3 GBps (24 Gbps) of aggregated, full-duplex
switching capacity through 6 integrated serial lanes, using proven and robust IDT technology. Each lane provides 2.5 Gbps of bandwidth in both direc-
tions and is fully compliant with PCI Express Base specification revision 1.1.
The PES8T5A is based on a flexible and efficient layered architecture. The PCI Express layer consists of SerDes, Physical, Data Link and Trans-
action layers in compliance with PCI Express Base specification Revision 1.1. The PES8T5A can operate either as a store and forward or cut-through
switch and is designed to switch memory and I/O transactions. It supports eight Traffic Classes (TCs) and one Virtual Channel (VC) with sophisticated
resource management to allow efficient switching for applications requiring additional narrow port connectivity.
North
Bridge
Memory
Memory
Memory
Memory
South
Bridge
x4
PES8T5A
x1
GE
LOM
x1
GE
LOM
x1
GE
x1
1394
Figure 2 I/O Expansion Application
SMBus Interface
The PES8T5A contains two SMBus interfaces. The slave interface provides full access to the configuration registers in the PES8T5A, allowing
every configuration register in the device to be read or written by an external agent. The master interface allows the default configuration register
values of the PES8T5A to be overridden following a reset with values programmed in an external serial EEPROM. The master interface is also used
by an external Hot-Plug I/O expander.
Six pins make up each of the two SMBus interfaces. These pins consist of an SMBus clock pin, an SMBus data pin, and 4 SMBus address pins. In
the slave interface, these address pins allow the SMBus address to which the device responds to be configured. In the master interface, these
address pins allow the SMBus address of the serial configuration EEPROM from which data is loaded to be configured. The SMBus address is set up
on negation of PERSTN by sampling the corresponding address pins. When the pins are sampled, the resulting address is assigned as shown in
Table 1.
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Advance Information
Processor
Processor
IDT 89HPES8T5A Data Sheet
Bit
1
2
3
4
5
6
7
Slave
SMBus
Address
SSMBADDR[1]
SSMBADDR[2]
SSMBADDR[3]
0
SSMBADDR[5]
1
1
Master
SMBus
Address
MSMBADDR[1]
MSMBADDR[2]
MSMBADDR[3]
MSMBADDR[4]
1
0
1
Table 1 Master and Slave SMBus Address Assignment
In the split configuration, the master and slave SMBuses operate as two independent buses and thus multi-master arbitration is never required.
The PES8T5A supports reading and writing of the serial EEPROM on the master SMBus via the slave SMBus, allowing in system programming of the
serial EEPROM.
PES8T5A
Processor
SMBus
Master
Serial
EEPROM
...
Other
SMBus
Devices
PES8T5A
Processor
SMBus
Master
...
Other
SMBus
Devices
SSMBCLK
SSMBDAT
MSMBCLK
MSMBDAT
SSMBCLK
SSMBDAT
MSMBCLK
MSMBDAT
Serial
EEPROM
(a) Unified Configuration and Management Bus
(b) Split Configuration and Management Buses
Figure 3 SMBus Interface Configuration Examples
Hot-Plug Interface
The PES8T5A supports PCI Express Hot-Plug on each downstream port. To reduce the number of pins required on the device, the PES8T5A
utilizes an external I/O expander, such as that used on PC motherboards, connected to the SMBus master interface. Following reset and configura-
tion, whenever the state of a Hot-Plug output needs to be modified, the PES8T5A generates an SMBus transaction to the I/O expander with the new
value of all of the outputs. Whenever a Hot-Plug input changes, the I/O expander generates an interrupt which is received on the IOEXPINTN input pin
(alternate function of GPIO) of the PES8T5A. In response to an I/O expander interrupt, the PES8T5A generates an SMBus transaction to read the
state of all of the Hot-Plug inputs from the I/O expander.
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Advance Information
As shown in Figure 3, the master and slave SMBuses may be used in a unified or split configuration. In the unified configuration, shown in Figure
3(a), the master and slave SMBuses are tied together and the PES8T5A acts both as a SMBus master as well as a SMBus slave on this bus. This
requires that the SMBus master or processor that has access to PES8T5A registers supports SMBus arbitration. In some systems, this SMBus master
interface may be implemented using general purpose I/O pins on a processor or micro controller, and may not support SMBus arbitration. To support
these systems, the PES8T5A may be configured to operate in a split configuration as shown in Figure 3(b).
IDT 89HPES8T5A Data Sheet
General Purpose Input/Output
The PES8T5A provides 11 General Purpose Input/Output (GPIO) pins that may be used by the system designer as bit I/O ports. Each GPIO pin
may be configured independently as an input or output through software control. Some GPIO pins are shared with other on-chip functions. These
alternate functions may be enabled via software, SMBus slave interface, or serial configuration EEPROM.
Pin Description
The following tables lists the functions of the pins provided on the PES8T5A. 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
PE0RP[3:0]
PE0RN[3:0]
PE0TP[3:0]
PE0TN[3:0]
PE2RP[0]
PE2RN[0]
PE2TP[0]
PE2TN[0]
PE3RP[0]
PE3RN[0]
PE3TP[0]
PE3TN[0]
PE4RP[0]
PE4RN[0]
PE4TP[0]
PE4TN[0]
PE5RP[0]
PE5RN[0]
PE5TP[0]
PE5TN[0]
PEREFCLKP
PEREFCLKN
Type
I
O
I
O
I
O
I
O
I
O
I
Name/Description
PCI Express Port 0 Serial Data Receive.
Differential PCI Express receive
pairs for port 0.
PCI Express Port 0 Serial Data Transmit.
Differential PCI Express trans-
mit pairs for port 0.
PCI Express Port 2 Serial Data Receive.
Differential PCI Express receive
pair for port 2.
PCI Express Port 2 Serial Data Transmit.
Differential PCI Express trans-
mit pair for port 2.
PCI Express Port 3 Serial Data Receive.
Differential PCI Express receive
pair for port 3.
PCI Express Port 3 Serial Data Transmit.
Differential PCI Express trans-
mit pair for port 3.
PCI Express Port 4 Serial Data Receive.
Differential PCI Express receive
pair for port 4.
PCI Express Port 4 Serial Data Transmit.
Differential PCI Express trans-
mit pair for port 4.
PCI Express Port 5 Serial Data Receive.
Differential PCI Express receive
pair for port 5.
PCI Express Port 5 Serial Data Transmit.
Differential PCI Express trans-
mit pair for port 5.
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.
This signal selects the fre-
quency of the reference clock input.
0x0 - 100 MHz
0x1 - 125 MHz
Table 2 PCI Express Interface Pins
REFCLKM
I
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September 7, 2007
Advance Information
IDT 89HPES8T5A 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 3 SMBus Interface Pins
Signal
GPIO[0]
Type
I/O
Name/Description
General Purpose I/O.
This pin can be configured as a general purpose I/O pin.
Alternate function pin name: P2RSTN
Alternate function pin type: Output
Alternate function: Reset output for downstream port 2
General Purpose I/O.
This pin can be configured as a general purpose I/O pin.
Alternate function pin name: P4RSTN
Alternate function pin type: Output
Alternate function: Reset output for downstream port 4
General Purpose I/O.
This pin can be configured as a general purpose I/O pin.
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