no t re co m m e n d e d fo r n ew d e s i g n s ? p l e a s e u s e p e x 8 5 1 8 fo r n ew d e s i g n s pex 8516 version 1.4 2006
flexible & versatile pci express switch features ? pex 8516 general features o 16-lane pci express switch - integrated serdes o up to four configurable ports o 27mmx27mm, 312 pin pbga package o maximum power: 4.36 watts ? pex 8516 key features o standards compliant - pci express base specification, r1.0a - pci shpc specification, r1.0 o high performance - non-blocking switch fabric - full line rate on all ports o non-transparent bridging - configurable non- transparent port for multi-host or intelligent i/o support o flexible configuration - four highly flexible & configurable ports (x1, x2, x4, or x8) - configurable with strapping pins, eeprom, or host software - lane and polarity reversal o pci express power management - link power management states: l0, l0s, l1, l2/l3 ready, and l3 - device states: d0 and d3hot o quality of service (qos) - two virtual channels per port - eight traffic classes per port - fixed and round-robin virtual channel port arbitration o reliability, availability, serviceability - 4 standard hot-plug controllers - upstream port as hot-plug client - transaction layer end-to-end crc - poison bit - advanced error reporting in addition to pcie baseline error reporting - lane status bits and gpo available - per port performance monitoring ? average packet size ? number of packets ? crc errors and more - jtag boundary scan multi-purpose, feature rich expresslane? pci express switch the expresslane pex 8516 device offers pci express switching capability enabling users to add scalable high bandwidth, non-blocking interconnection to a wide variety of applications including servers, storage systems, communications platforms, blade servers, and embedded-control products. the pex 8516 is well suited for fan-out, aggregation, peer-to-peer, and in telligent i/o module applications. highly flexible port configurations the expresslane pex 8516 offers highly configurable ports. there are a maximum of 4 ports that can be configured to any legal width from x1 to x8, in any combination to support your specific bandwidth needs. the ports can be symmetric (each port having the same lane width) or asymmetric (ports having different lane widths). any of the ports can be designat ed as the upstream port, which can be changed dynamically. end-to-end packet integrity the expresslane pex 8516 provides end-to-end crc protection (ecrc) and poison bit support to enable designs that require guaranteed error-free packets . these features are optional in the pci express specificati on, but plx provides them across its entire expresslane switch product line. non-transparent ?bridging? in a pci express switch the expresslane pex 8516 product supports full non-transparent bridging (ntb) functionality to allow implementation of multi-host systems and intelligent i/o modules in applications such as communications , storage , and blade servers . to ensure quick product migration, the non-transparency features are implemented in the same fashion as in st andard pci applications. non-transparent bridges allow systems to isolate memory domains by presenting the processor subsystem as an endpoint, rath er than another me mory system. base address registers are used to translate addr esses; doorbell registers are used to send interrupts between the address domains; a nd scratchpad registers are accessible from both address domains to allow inter-processor communication. two virtual channels the expresslane pex 8516 switch supports 2 full-featured virtual channels (vcs) and a full 8 traffic classes (tcs). the mappi ng of traffic classes to port-specific virtual channels allows for different mappings for different ports. in addition, the devices offer user-selectable virtual channe l arbitration algorithms to enable users to fine tune the quality of service (qos) required for a specific application. low power with granular serdes control the expresslane pex 8516 provides low power capability that is fully compliant with the pci express power management specification. in addition, the serdes physical links can be turned off wh en unused for even lower power. pex 8516 version 1.4 2006
flexible port width configuration the lane width for each port can be individually configured through auto-negotiation, hardware strapping, upstream software configuration, or through an optional eeprom. the pex 8516 supports a large number of port configurations. for example, if you are using the pex 8516 in a fan-out application, you may configure the upstream port as x8 and the downstream ports as three x2 ports; two x2 & one x4 ports; three x1 ports; or other combinations, as long as you don?t run out of lanes (16) or ports (4). in a port aggregation application you can configure three x2 or x1 ports for aggregation into one x8 or x4 port. figure 1 shows the most common port configurations. figure 1. common port configurations hot plug for high availability hot plug capability allows users to replace hardware modules and perform maintenance without powering down the system. the pex 8516 hot plug capability and advanced error reporting features makes it suitable for high availability (ha) applications . each downstream port includes a standard hot plug controller. if the pex 8516 is used in an application where one or more of its downstream ports connect to pci express slots, each port?s hot pl ug controller can be used to manage the hot-plug event of its associated slot. furthermore, its upstream port is a hot-plug client , allowing it to be used on hot-pluggable adapter cards, backplanes, and fabric modules . fully compliant power management for applications that requir e power management, the pex 8516 device supports both link (l0, l0s, l1, l2/l3 ready, and l3) and device (d0 and d3hot) power management states, in compliance with the pci express power management specification. serdes power and signal management the expresslane pex 8516 supports software contr ol of the serdes outputs to allow optimization of power and signal strength in a system. the plx serdes implementation supports four levels of power ? off, low, typical, and high. the serdes block also supports loop-back modes and advanced reporting of error conditions , which enables efficient debug and management of the entire system. flexible virtual channel arbitration the expresslane pex 8516 switches support hardware fixed and round robin arbitration schemes for two virtual channels on each port. this allows for the fine tuning of quality of service for efficient use of packet buffers and system bandwidth. applications suitable for host-centric as well as intelligent i/o applications expresslane pex 8516 can be configured for a wide variety of form factors and applications. host-centric fan-out the expresslane pex 8516 switch, with its symmetric or asymmetric lane configuration capability, allows user specific tuning to a variety of host-centric as well as peer-to-peer applications . figure 2. fan-in/out usage figure 2 shows a typical server-based design, where the root complex provides a pci express link that needs to be fanned into a larger number of smaller ports for a variety of i/o functions, each with differen t bandwidth requirements. in this example, the pex 8516 would typically have an 8-lane upstream port, and as many as 3 downstream ports. the downstream ports can be of differing widths if required. the figure also shows how some of the ports can be bridged to provide pci or pci-x slots through the use of the expresslane pex 8114 and pex 8111 pcie bridging devices. adapter card aggregation the number and variety of pci express native-mode devices is growing quickly. as these devices become mainstream, it will be necessary to create multifunction and multi-port adapter cards with pci express capability.
the pex 8516 can be used to create an adapter or mezzanine card that aggregates the pci expr ess devices into a single port that can be plugged into a backplane or motherboard. figure 3 shows the pex 8516 in this application. figure 3. aggregation adapter card the adapter card in figure 3 can be transparent , in which case the pci express i/o devices are just standard i/o endpoints such as ethernet or fibre channel. or the pex 8516 can provide a non-transparent port to the system (via the card?s edge connector). in this case, one of the pci express devices can be a cpu or other ?intelligent? device with on- chip processing capability ? thus needing address domain isolation from the rest of the system. this approach is commonly used in raid controllers . intelligent adapter card the pex 8516 supports the non-transparency feature. figure 4 illustrates a host system using an intelligent adapter card. figure 4. intelligent adapter usage in this figure, the cpu on the adapter card is isolated from the host cpu. the pex 8516 non-transparent port allows the two cpus to be isolated but communicate with each other through various registers that are designed in the pex 8516 for that purpose. the host cpu can dynamically re- assign both the upstream port and the non-transparent port of pex 8516 allowing the system to be reconfigured. dual host/fabric model the expresslane pex 8516 supports applications requiring dual host , host failover , and load-sharing applications through the non-transparency feature. figure 5 illustrates a dual host system with dual switch fabric in dual-star configuration. the redundancy of the host and the fabric can be achieved through many possible configurations using ntb function of pex 8516. in the configuration shown below the host 1 controls the switch 1 and associated i/os and the host 2 controls the switch 2 and associated i/os. the hosts and switches are isolated using ntb functionality of pex 8516 on the host boards. if one of the hosts fails the surviving host can remove the failing host from the configuration while controlling both the switches and all i/os. similarly, if one of the switches fails the host associated with that switch can send control messages to its i/os through the surviving switch using ntb function. figure 5. dual host/fabric mode embedded systems the pex 8516 can also be utilized in embedded applications. figure 6 shows several independent modules connecting through the pex 8516. the port widths for each module can be configured as required. the peer-to-peer communication feature of the pex 8516 allows these modules to communicate with each other without any centralized control. figure 6. embedded systems
software usage model from a system model viewpoint, each pci express port is a virtual pci to pci bridge device and has its own set of pci express configuration registers. it is through the upstream port that the bios or host can configure the other ports using standard pci enumeration. the virtual pci to pci bridges within the pex 8516 are compliant to the pci and pci express system models. the configuration space registers (csrs) in a virtual primary/secondary pci to pci bridge are accessible by type 0 configurati on cycles through the virtual primary bus interface (matching bus number, device number, and function number). interrupt sources/events the pex 8516 supports the intx interrupt message type (compatible with pci 2.3 interrupt signals) or message signaled interrupts (msi) when enabled. interrupts/messages are generated by pex 8516 for hot plug events, doorbell interrupts, baseline error reporting, and advanced error reporting. development tools plx offers hardware and software tools to enable rapid customer design activity. these tools consist of a hardware module (pex 8516rdk), hardware documentation, and a software development kit (sdk). expresslane tm pex 8516rdk the rdk hardware module includes the pex 8516 with one x4 (card-edge slot) port and three additional x4 ports (see figure 7). the rdk is available with x4 card edge connector and adapters for x1 edge connectors are available to plug the rdk into smaller slots. the pex 8516rdk hardware module can be installed in a motherboar d, used as a riser card, or configured as a bench-top board. the pex 8516rdk can be used to test and validate customer software. additionally, it can be used as an evaluation vehicle for pex 8516 features and benefits. sdk the sdk tool set includes: - linux & windows drivers - c/c++ source code, objects, libraries - user?s guides & application examples 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: info@plxtech.com web site: www.plxtech.com product ordering information part number description pex8516-bb25bi 16 lane, 4 port pcie switch, 312-ball pbga 27x27mm pkg pex8516-bb25bi g 16 lane, 4 port pcie switch, 312-ball pbga 27x27mm pkg, pb-free pex 8516rdk-4 pex 8516 rapid development kit with x4 connector pex 8516rdk-1 pex 8516 rapid development kit with x4 connector and x1 adapter please visit the plx web site at http://www.plxtech.com or contact plx sales at 408-774-9060 for sampling. ? 2006 plx technology, inc. all rights reserved. plx and the plx l ogo are registered trademarks of plx technology, inc. express lane is a trademark of plx technology, inc., which may be registered in some juri sdiction. all other product names that appear in this material are for identification purposes only and are acknowledged to be trademarks or registered trademarks of th eir respective companies. information supplied by plx is believed to be accurate and r eliable, but plx technology, inc. assumes no responsibility for any errors that may appear in this material. plx technology, in c. reserves the right, without notice, to mak e changes in product design or specification. pex8516-sil-pb-p1-1.4 08/06 figure 7. pex 8516rdk
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