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January 5, 2009
IDT 89HPES24NT3 Data Sheet
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Highly Integrated Solution
– Requires no external components
– Incorporates on-chip internal memory for packet buffering and
queueing
– Integrates twenty-four 2.5 Gbps embedded full duplex
SerDes, 8B/10B encoder/decoder (no separate transceivers
needed)
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Reliability, Availability, and Serviceability (RAS) Features
– Upstream port can be dynamically swapped with non-trans-
parent downstream port to support failover applications
– Internal end-to-end parity protection on all TLPs ensures data
integrity even in systems that do not implement end-to-end
CRC (ECRC)
– Supports ECRC pass-through in transparent and non-trans-
parent ports
– Supports Hot-Swap
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Power Management
– Supports PCI Power Management Interface specification,
Revision 1.1 (PCI-PM)
– Unused SerDes are disabled
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Testability and Debug Features
– Built in SerDes Pseudo-Random Bit Stream (PRBS) generator
– Ability to read and write any internal register via the SMBus
– Ability to bypass link training and force any link into any mode
– Provides statistics and performance counters
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Two SMBus Interfaces
– Slave interface provides full access to all software-visible
registers by an external SMBus master
– Master interface provides connection for an optional serial
EEPROM used for initialization
– Master and slave interfaces may be tied together so the switch
can act as both master and slave
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Eight General Purpose Input/Output pins
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Packaged in 27x27mm 420-ball BGA with 1mm ball spacing
Product Description
Utilizing standard PCI Express interconnect, the PES24NT3 provides
the most efficient high-performance I/O connectivity solution for applica-
tions requiring high throughput, low latency, and simple board layout
with a minimum number of board layers. With support for non-trans-
parent bridging, the PES24NT3, as a standalone switch or as a chipset
with IDT PCIe System Interconnect Switches, enables multi-host and
intelligent I/O applications requiring inter-domain communication. The
PES24NT3 provides 96 Gbps (12 GBps) of aggregated, full-duplex
switching capacity through 24 integrated serial lanes, using proven and
robust IDT technology. Each lane provides 2.5 Gbps of bandwidth in
both directions and is fully compliant with PCI Express Base specifica-
tion 1.0a.
The PES24NT3 is based on a flexible and efficient layered architec-
ture. The PCI Express layer consists of SerDes, Physical, Data Link and
Transaction layers in compliance with PCI Express Base specification
Revision 1.0a. The PES24NT3 can operate either as a store and
forward or cut-through switch depending on the packet size 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. This includes round robin port arbitration, guaranteeing
bandwidth allocation and/or latency for critical traffic classes in applica-
tions such as high throughput 10 GbE I/Os, SATA controllers, and Fibre
Channel HBAs.
Switch Configuration
The PES24NT3 is a three port switch that contains 24 PCI Express
lanes. Each of the three ports is statically allocated 8 lanes with ports
labeled as A, B and C. Port A is the upstream port, port B is the trans-
parent downstream port, and port C is the non-transparent downstream
port.
During link training, link width is automatically negotiated. Each
PES24NT3 port is capable of independently negotiating to a x8, x4, x2
or x1 width. Thus, the PES24NT3 may be used in virtually any three port
switch configuration (e.g., {x8, x8, x8}, {x4, x4, x4}, {x4, x2, x1}, etc.).
The PES24NT3 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.