CompactPCI® Serial PCI Express® External Cabling Target Side Adapter • Enables PCIe Based Peripheral Cards in a CompactPCI® Serial Target System

Most computer systems are based on the PCI Express® standard as a high speed backbone for interconnection of peripheral components with a host CPU. Typically all PCI Express® based devices are located closely in a common enclosure.
The PCI-SIG PCI Express® External Cabling Specification for Gen1 and Gen2 data transfer rates addresses extended applications, such as split-systems or I/O expansion by means of a suitable copper cable, available e.g. for a x8 PCI Express® link, up to 7m length. When used with an AOC (Active Optical Cable), distances of up to 300m can be bridged between host and target systems. Beyond the PCI-SIG cabling specification, the Samtec PCIEO series of AOC addresses also Gen3 speed up to 100m.
The SXC-LOOP is a target system adapter card for PCIe x8 external cabling. The SXC-LOOP fits into the system slot of a CompactPCI® Serial target system backplane. The on-board packet switch is used to replicate two PCI Express® Gen3 x8 links across a 3-slot CompactPCI® Serial backplane. Thus, two CompactPCI® Serial ‘fat pipe’ slot cards in a target system can be controlled by the remote host system CPU, with a transfer rate of up to 64Gbps, suitable e.g. for NVMe based SSD mass storage boards or GPU cards.
The advantages of PCI Express® compared e.g. to 10Gbps Ethernet are higher data transfer speed at lower latency, and primarily merging distributed subsystems virtually into a single PCI Express® based computer assembly. The SXC-LOOP allows to control a CompactPCI® Serial target (downstream) system by a remote host CPU via PCI Express® external cabling. The host (upstream) system may be any computer with a PCI Express® external cabling adapter, not necessarily a CompactPCI® Serial system.
Being mainly a powerful PCI Express® packet switch, the SXC-LOOP is organized similar to a CompactPCI® Serial system slot controller card, however restricted to the PCI Express® resources of the CompactPCI® Serial backplane.
The SXC-LOOP is linked to the host system by a PCI Express® x8 front panel cabling connector (upstream), and delivers two PCI Express® links to its backplane connectors (downstream), for two CompactPCI® Serial ‘fat pipe’ peripheral cards in a target system. Both links/slots on the CompactPCI® Serial backplane are organized as Gen3 x8, for demanding boards such as SSD mass storage, GPU or FPGA cards, or high resolution camera I/O. With the SXC-LOOP, PCI Express® based devices in the target system can be controlled by the remote host system CPU in an identical manner as its local resources.

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Application Notes

General Information


  • PCI Express® external cabling target side adapter
  • PICMG® CompactPCI® Serial (CPCI-S.0) system slot controller (PCIe resources only)
  • Single Size Eurocard 3U 100x160mm2, front panel width 4HP
  • cPCI-S Backplane connectors P1, P2, P5 for 2 PCI Express® Gen3 links
  • Peripheral slots organized x8/x8
  • Clamshell available for extremely rugged applications e.g. ATR & conductive cooled assembly (CCA)

Simplified Block Diagram

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