CompactPCI PlusIO
Encyclopedia
Introduction
CompactPCI PlusIO is an extension to the PICMG 2.0 CompactPCICompactPCI
A CompactPCI system is a 3U or 6U Eurocard-based industrial computer, where all boards are connected via a passive PCI backplane. The connector pin assignments are standardized by the PICMG US and PICMG Europe organizations. PICMG stands for PCI Industrial Computers Manufacturers Group...
industrial standard for modular computer systems.
CompactPCI PlusIO was officially adopted by the PCI Industrial Computer Manufacturers Group PICMG
PICMG
The PCI Industrial Computer Manufacturers Group is a consortium of over 227 companies. The group, founded in 1994, was originally formed to adapt PCI technology for use in high-performance telecommunications, military and industrial computing applications but its work has now grown to include...
as PICMG 2.30 CompactPCI PlusIO in November 2009. Being 100% compatible with CompactPCI, PICMG 2.30 defines a migration path to the future CompactPCI Serial standard. It defines a fixed rear I/O pin assignment that focuses on modern, fast serial point-to-point connections.
The new technology succeeding parallel CompactPCI comprises both CompactPCI Serial and CompactPCI PlusIO.
History
The CompactPCI standard uses one main bus connector, J1, and defines user I/O pins and a 64-bit extension for the legacy PCI bus on connector J2. J1 and J2 are the only connectors on 3URack unit
A rack unit or U is a unit of measure used to describe the height of equipment intended for mounting in a 19-inch rack or a 23-inch rack...
single Eurocards. The CompactPCI definition for 6U double Eurocards includes additional connectors (J3, J4, J5) for rear I/O. A true rear I/O standard, however, exists only for J3 – through the PICMG 2.16 CompactPCI Packet Switching Backplane specification that defines Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
interfaces at the backplane
Backplane
A backplane is a group of connectors connected in parallel with each other, so that each pin of each connector is linked to the same relative pin of all the other connectors forming a computer bus. It is used as a backbone to connect several printed circuit boards together to make up a complete...
of 6U cards.
In recent years, fast serial point-to-point connections have become the state-of-the-art technology and are gradually replacing the classic bus architecture in computers. Also, 3U-based systems are very popular because of their small footprint. This is especially true for modular embedded applications, for example in the field of communications. As a result, several manufacturers tried to implement their own rear I/O concepts using the J2 connector, but had no standard to make their J2 pin assignments compatible with other cards. Another approach to realize serial high-speed interfaces were so-called switched fabric
Switched fabric
Switched fabric, switching fabric, or just fabric, is a network topology where network nodes connect with each other via one or more network switches . The term is popular in telecommunication, Fibre Channel storage area networks and other high-speed networks, including InfiniBand...
s, which used additional switches and bridges to connect to each other. This involved higher costs and still provided solutions that were too specialized to be compatible with each other.
The CompactPCI standard as it is does not offer a standardized solution for the kind of modular connectivity requested for the future. The additional PICMG 2.30 CompactPCI PlusIO specification provides this connectivity on the well-known platform of CompactPCI. It stays compatible with but extends the existing standard by a new definition of the rear J2 connector, adding a number of serial interfaces to provide fast and standardized rear I/O also on 3U format. Through these serial point-to-point connections, CompactPCI PlusIO also bridges the gap between parallel CompactPCI and the serial CompactPCI Serial standard.
Interfaces
PICMG 2.30 CompactPCI PlusIO standardizes the following interfaces at the rear J2 connector:- 4 x PCI ExpressPCI ExpressPCI Express , officially abbreviated as PCIe, is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP bus standards...
(one lane each) - 2 x EthernetEthernetEthernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
1000BASE-TGigabit EthernetGigabit Ethernet is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second , as defined by the IEEE 802.3-2008 standard. It came into use beginning in 1999, gradually supplanting Fast Ethernet in wired local networks where it performed... - 4 x USBUniversal Serial BusUSB is an industry standard developed in the mid-1990s that defines the cables, connectors and protocols used in a bus for connection, communication and power supply between computers and electronic devices....
2.0 - 4 x SATASataSata is a traditional dish from the Malaysian state of Terengganu, consisting of spiced fish meat wrapped in banana leaves and cooked on a grill.It is a type of Malaysian fish cake, or otak-otak...
/SASSerial Attached SCSISerial Attached SCSI is a computer bus used to move data to and from computer storage devices such as hard drives and tape drives. SAS depends on a point-to-point serial protocol that replaces the parallel SCSI bus technology that first appeared in the mid 1980s in data centers and workstations,...
Backplane Connectors
The PICMG 2.30 extension introduces a new J2 connector type on the plug-in board, an Ultra Hard Metric (UHM) connector with virtual coaxial box shielding technology, which reduces crosstalk at high speeds. This connector supports high frequencies of 5 Gb/s, even when mated with the CompactPCI-standard unshielded 2-mm hard-metric headers.The matching P2 backplane connector remains the same as for CompactPCI, as do the J1/P1 connectors.
Compatibility with Legacy CompactPCI and CompactPCI Serial
PICMG 2.30 gives the J2 pins a fixed interface functionality. This makes 64-bit bus communication impossible.The new J2 connector type itself is 100% compatible with the legacy one. The J1 bus connector conforms with the CompactPCI definition.
In all, CompactPCI PlusIO is 100% compatible with legacy 32-bit CompactPCI in 3U and 6U format (single and double Eurocards). At the same time, its serial rear I/O connectivity and higher-speed connector form a bridge towards future CompactPCI Serial system architecture. Hybrid backplanes support several cards of the three different standards PICMG 2.0, 2.30, and CPCI-S.0.