ETC HT7520

Version 1.3 2002
PowerDrive HT7520
16-bit HyperTransport interface (Side A)
offers a maximum bandwidth of 6.4GB/s
8-bit HyperTransport interface (Side B)
offers a maximum bandwidth of 3.2GB/s
Connects to the host and a downstream
HyperTransport technology-compliant
Supports double hosted chains (CPU on
each port)
Each Side supports HyperTransport
technology-defined reduced bit widths—
8-bit, 4-bit, and 2-bit
Each side supports transfer rates of 1600,
1200, 800, and 400 mega-transfers per
Offers independent transfer rate and bit
width selection
Link disconnect protocol supported
Two PCI-X bridges (Bridge A and Bridge
B) each support the following:
o A 64-bit data bus
o PCI-X modes and legacy PCI
revision 2.2 modes
o 133-, 100- and 66MHz transfer rates
in PCI-X mode
o 66- and 33-MHz PCI 2.2 modes
o Independent transfer rates and
operational modes
o Up to five PCI masters
o An I/O Advance Programmable
Interrupt Controller (IOAPIC) with
four redirection registers – legacy
interrupt controller and IOAPIC
modes supported
o Hot Plug controller and support
829-ball OBGA package
HyperTransport Tunnel-to-Dual PCI-X Bridge
The Most Scalable, Highest Performance HyperTransport
Interconnect Bridge
Ever increasing CPU bus clock
speeds, coupled with faster peripheral
devices, have engendered I/O
bottlenecks in high-speed, networked
applications such as switches, routers
and storage servers. The
HyperTransport technology is a fast,
non-proprietary, point-to-point link
that offers the speed necessary for
these advanced systems.
PLX Technology has developed the PowerDrive™ HT7520, a HyperTransport
Tunnel-to-Dual PCI-X bridge that interfaces HyperTransport-based devices to
PCI-based peripherals. The HT7520 offers flexible connectivity and high
performance, enabling today’s high-speed embedded systems.
PowerDrive devices provide maximum scalability through an onboard bidirectional HyperTransport tunnel interface. The tunnel enables daisy chaining of
up to 31 other HyperTransport devices on a single bus. The PowerDrive device
couples a HyperTransport tunnel with two PCI-X bridges. The PCI-X bridge
provides a connection between HyperTransport based processors and PCI based
peripherals. Together, the two PCI-X bridges enable support for connectivity of up
to 10 PCI masters. As a result, PowerDrive enables higher capacity systems via
connections to multiple PCI-X devices and HyperTransport peripherals.
High Performance
PowerDrive devices significantly increase performance over PCI-only based
systems. The HyperTransport Tunnel has a 16-bit interface (Side A) and an 8-bit
interface (Side B). PowerDrive also offers a full, 800MHz DDR clock rate. As a
result, Side A of the tunnel provides a maximum bandwidth of 6.4 GB/s, a 48X
speed up over standard PCI. Side B provides a maximum of 3.2 GB/s, giving a
24X speed up. These high-speed interfaces provide fast peripheral accesses
to/from memory.
Performance is also maximized through the PCI-X bridges. Each 64-bit wide
bridge is capable of a maximum speed of 133 MHz. In PCI-X mode, 133-, 100and 66MHz transfer rates are supported. In PCI mode, each bridge supports 66and 33MHz transfer rates. For optimum performance networks, PowerDrive does
not require the highest speed device to be slowed down to the
performance of the slowest peripheral. Instead, the
PowerDrive device allows high-speed loads to
operate on a separate bridge, enabling high-speed
traffic to run full tilt. A high bandwidth tunnel and
multiple high-speed bridges are the enablers
for high-performance embedded applications.
The PowerDrive HT7520 is a highspeed device that provides two
independent, high-performance
PCI-X bridges, integrated with a
high-speed HyperTransport
technology tunnel. The tunnel
function provides connection
capability to other downstream
HyperTransport technology
devices, allowing greater system
connectivity. As shown in Figure 1,
the front-end HyperTransport
interface (Side A) provides a
configurable 16-bit wide
communication path to the host,
offering up to 6.4GB/s of
bandwidth. Similarly, the back-end
HyperTransport interface (Side B)
provides a configurable 8-bit wide
communication path to a
downstream device, offering up to
3.2GB/s of bandwidth.
o HyperTransport Tunnel is
compliant to the HyperTransport
I/O Link Specification, version
o Side A of the HyperTransport
Tunnel is a 16-bit interface; Side
B is 8-bit
o Either side of the tunnel can be
connected to a host or another
downstream HT device
o Supports double hosted chains
(CPU on each port)
o Each side of the tunnel has
independently programmable
8-bit, 4-bit and 2-bit widths
o Each side supports
independently programmable
transfer rates of 800, 600, 400
and 200 MHz
o Each HyperTransport link
implements TX and RX
unidirectional, 1.2V LVDS
o Link disconnect protocol
Dual PCI-X
o PCI-X version 1.0a compliant
o 64-bit wide data bus
o Operational modes of PCI-X and legacy
PCI Local Bus Specification, Revision 2.2
o Support for 133-, 100- and 66MHz
transfer rates in PCI-X mode
o Support for 66- and 33MHz transfer rates
in PCI mode
o Independent transfer rates and operational
modes for each bridge
o Support for up to 5 PCI Masters, per
bridge, with clock, request, and grant
o IOAPIC with up to 12 programmable
interrupts; Legacy Interrupt Controller
and IOAPIC modes supported
o SHPC-compliant, version 1.1, Hot Plug
controller and support
Electrical/Mechanical Features
o 829-pin Organic BGA (OBGA)
o 37.5 x 37.5 mm
o Low power 1.8V core
o 3.3V PCI-X signaling; 1.2V link
o Commercial temperature range
PLX HT7520 HyperTransport
PCI-X Tunnel
Side A
Side B
8-bit upstream link
8-bit downstream link
16-bit upstream link
16-bit downstream link
Bridge A
Bridge B
PCI Peripheral
PCI Peripheral
PCI-X Peripheral
Figure 1. PLX HT7520 HyperTransport™ PCI-X Tunnel
Switches & Routers
Today’s routers and switches
process high-speed traffic that are
bottlenecked across the I/O bus.
Switch and router manufacturers
are seeking out new I/O
interconnect solutions that address
their ever-increasing need for
speed, robustness and scalability.
HT Interface
The dual PCI-X bridge provides maximum
scalability while maintaining interoperability
with legacy PCI components. The PowerDrive
HT7520 is a high-performance solution
enabling faster, simpler and scalable features
for next-generation switches and routers.
Figure 2 shows the PowerDrive
HT7520 implemented in a LAN-toWAN bridge/router. A point-to-point,
high-speed interconnect simplifies
the system architecture and
dramatically increases the overall
Dual GE
Dual GE
PCI Device 0
PCI Device 1
PCI Device 2
Figure 2. Block Diagram of a LAN-to-WAN Bridge/Router
HT Interface
PCI Device 0
PCI Device 1
Figure 3. Block Diagram of VPN Gateway
VPN Gateways
Some of the biggest challenges
facing hardware designers of VPN
equipment include designing
efficient encryption/decryption
technologies. These technologies
must provide increased security and
privacy, as well as sender/target
authentication, identification and
tracking. Current solutions increase
security and privacy, but require
the trade
PLX Technology, Inc.
870 Maude Ave.
Sunnyvale, CA 94085 USA
Tel: 1-800-759-3735
Tel: 1-408-774-9060
Fax: 1-408-774-2169
Email: [email protected]
Web Site:
off of large amounts of data
overhead. At low bandwidth speeds,
transmitting the payload plus
authentication additions slows down
data transmission times to a snail's
pace. As shown in Figure 3, the
PowerDrive HT7520 connects the
CPU to a security processor over a
6.4MB/s point-to-point interconnect
bus. VPN applications benefit
immediately through decreased
transmission times of secure,
encrypted data.
By adding the PowerDrive device, there is a
48X bandwidth increase over a standard 33
MHz PCI connection. High-speed network
connectivity is also enhanced via the
availability of two 133 MHz PCI-X bridges.
The PowerDrive HT7520 is a high-speed,
scalable HyperTransport solution that
alleviates VPN interconnect bottlenecks and
provides expandability for tomorrow's
Product Ordering Information
Part Number
PLX PowerDrive HT7520 HyperTransport
Tunnel-to-Dual PCI-X Bridge
Please visit the PLX Web site at or contact PLX sales at 408-774-9060 for sampling.
© 2002 PLX Technology, Inc. All rights reserved. PLX and the PLX logo are registered trademarks of PLX Technology, Inc. PowerDrive and the PowerDrive logo are
trademarks of PLX Technology, Inc., which may be registered in some jurisdiction. All other product names that appear in this material are for identification purposes only
and are acknowledged to be trademarks or registered trademarks of their respective companies. Information supplied by PLX is believed to be accurate and reliable, but
PLX Technology, Inc. assumes no responsibility for any errors that may appear in this material. PLX Technology, Inc. reserves the right, without notice, to make changes in
product design or specification.
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