CompactPCI Serial is an industrial standard for modular computer systems. It is based on the established PICMG 2.0 CompactPCI standard, [1] which uses the parallel PCI bus for communication among a system's card components. In contrast to this, CompactPCI Serial uses only serial point-to-point connections. CompactPCI Serial was officially adopted by the PCI Industrial Computer Manufacturers Group PICMG as PICMG CPCI-S.0 CompactPCI Serial in March 2011. Its mechanical concept is based on the proven standards of IEEE 1101-1-1998 [2] and IEEE 1101-10-1996 [3] (19" technology). CompactPCI Serial includes different connectors that permit very high data rates. The new technology standard succeeding parallel CompactPCI comprises another specification called PICMG 2.30 CompactPCI PlusIO. This is why CompactPCI Serial and CompactPCI PlusIO as a whole were also called CompactPCI Plus. PICMG's first working title of CompactPCI Serial was CPLUS.0. (See also #Compatibility and Migration.) CompactPCI Serial backplanes and chassis are developed by Schroff, Elmа, and Pixus Technologies companies, as for the CompactPCI Serial board level electronics – they are developed by MEN Mikro Elektronik, Fastwel, EKF, Emerson Embedded Computing, ADLINK, and Kontron.
Fast serial point-to-point connections have become the state-of-the-art technology and are gradually replacing the classic bus architecture in computers. The CompactPCI standard as it is now does not offer a standardized solution for the kind of modular, serial connectivity requested for the future. This is why CompactPCI Serial was defined as the new future standard. It introduces a serial topology while keeping the proven basic concepts of CompactPCI. [4]
Thanks to modern chipset architecture, the structure of computers is slowly changing from bus-based interconnections between interface controllers to a star topology built up of serial point-to-point connections. CompactPCI Serial incorporates this star architecture: one system slot can control up to eight peripheral slots. Two of these connections can be PCI Express x8 fat pipes. At the same time, CompactPCI Serial does not need bridges, switched fabrics, or special backplanes. The star connection by standard includes PCI Express, SATA/SAS, and USB.
CompactPCI Serial can connect a total of nine cards in a system (one system slot, eight peripheral) through a full Ethernet mesh that supports the IEEE 802.3 Ethernet standard. In this way the new specification is optimized for symmetrical multiprocessing and redundant system topologies.
The PICMG CPCI-S.0 system slot supports the following interfaces at the backplane connectors:
The PICMG CPCI-S.0 peripheral slot supports the following interfaces at the backplane connectors:
PICMG CPCI-S.0 defines a single 12-V power supply both for system slots and peripheral slots.
The PICMG subcommittee drafting the standard has proposed a new, denser backplane connector type with a 2 mm x 1.4 mm pitch that supports higher transfer rates of up to 12 Gbit/s without a need for bridges or switches. It offers up to 184 pin pairs on a 3U board. A major difference compared to CompactPCI is that with CompactPCI Serial the plug connector is on the board, while the receptacle is on the backplane. This approach is intended to make the standard more robust by avoiding twisted pins on the backplane: If a pin fails, only the plug-in board must be exchanged. The system slot of CompactPCI Serial has six connectors: P1 to P6. On peripheral boards only P1 is mandatory, while P2 to P6 are optional.
A peripheral CompactPCI Serial slot only has a small connector with 6 rows of contacts for power and signals. The remainder of a 3U single Eurocard is free for user-defined I/O and offers a total of 128 differential contact pairs or 384 contacts. This is significantly more than in 32-bit CompactPCI. 6U double Eurocards provide the entire upper section of the board for user-defined I/O, as do PICMG 2.0 CompactPCI boards of this size. An advantage of the new architecture is that front and rear I/O boards are inserted directly into one another. By contrast to CompactPCI, no midplane or transfer connector is needed here, which reduces costs and increases system flexibility.
The mechanical specification of PICMG CPCI-S.0 CompactPCI Serial is 100% compliant with PICMG 2.0 CompactPCI except for its new backplane connectors. Since the two standards have a different topology, there is no direct "bus compatibility". For this reason, PICMG has also created an extension to CompactPCI: PICMG 2.30 CompactPCI PlusIO. This standard is intended as a migration path from CompactPCI to CompactPCI Serial. It is 100% compatible with CompactPCI but includes a fixed definition of fast serial I/O interfaces at its backplane J2 connector. Also, it has a new J2 connector that is compatible but supports higher data rates compared to CompactPCI. Hybrid backplanes support several cards of the three different standards PICMG 2.0, 2.30, and CPCI-S.0. [5] [6]
In August 2017, PICMG ratified the CompactPCI Serial Space specification CPCI-S.1 R1.0, which provides a highly ruggedized implementation of CompactPCI Serial. It is used in satellites as the payload controller as well as ground-based control systems.
A backplane or backplane system is a group of electrical connectors 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 to connect several printed circuit boards together to make up a complete computer system. Backplanes commonly use a printed circuit board, but wire-wrapped backplanes have also been used in minicomputers and high-reliability applications.
In computer architecture, a bus is a communication system that transfers data between components inside a computer, or between computers. This expression covers all related hardware components and software, including communication protocols.
Eurocard is an IEEE standard format for printed circuit board (PCB) cards that can be plugged together into a standard chassis which, in turn, can be mounted in a 19-inch rack. The chassis consists of a series of slotted card guides on the top and bottom, into which the cards are slid so they stand on end, like books on a shelf. At the spine of each card is one or more connectors which plug into mating connectors on a backplane that closes the rear of the chassis.
A motherboard is the main printed circuit board (PCB) in general-purpose computers and other expandable systems. It holds and allows communication between many of the crucial electronic components of a system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals. Unlike a backplane, a motherboard usually contains significant sub-systems, such as the central processor, the chipset's input/output and memory controllers, interface connectors, and other components integrated for general use.
Universal Serial Bus (USB) is an industry standard that allows data exchange and delivery of power between many types of electronics. It specifies its architecture, in particular its physical interface, and communication protocols for data transfer and power delivery to and from hosts, such as personal computers, to and from peripheral devices, e.g. displays, keyboards, and mass storage devices, and to and from intermediate hubs, which multiply the number of a host's ports.
In computing, an expansion card is a printed circuit board that can be inserted into an electrical connector, or expansion slot on a computer's motherboard to add functionality to a computer system. Sometimes the design of the computer's case and motherboard involves placing most of these slots onto a separate, removable card. Typically such cards are referred to as a riser card in part because they project upward from the board and allow expansion cards to be placed above and parallel to the motherboard.
PCI Express, officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. It is the common motherboard interface for personal computers' graphics cards, capture cards, sound cards, hard disk drive host adapters, SSDs, Wi-Fi, and Ethernet hardware connections. PCIe has numerous improvements over the older standards, including higher maximum system bus throughput, lower I/O pin count and smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism, and native hot-swap functionality. More recent revisions of the PCIe standard provide hardware support for I/O virtualization.
SATA is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier Parallel ATA (PATA) standard to become the predominant interface for storage devices.
A single-board computer (SBC) is a complete computer built on a single circuit board, with microprocessor(s), memory, input/output (I/O) and other features required of a functional computer. Single-board computers are commonly made as demonstration or development systems, for educational systems, or for use as embedded computer controllers. Many types of home computers or portable computers integrate all their functions onto a single printed circuit board.
CompactPCI is a computer bus interconnect for industrial computers, combining a Eurocard-type connector and PCI signaling and protocols. Boards are standardized to 3U or 6U sizes, and are typically interconnected via a passive backplane. The connector pin assignments are standardized by the PICMG US and PICMG Europe organizations. The connectors and the electrical rules allow for eight boards in a PCI segment. Multiple bus segments are allowed with bridges.
PC/104 is a family of embedded computer standards which define both form factors and computer buses by the PC/104 Consortium. Its name derives from the 104 pins on the interboard connector (ISA) in the original PC/104 specification and has been retained in subsequent revisions, despite changes to connectors. PC/104 is intended for specialized environments where a small, rugged computer system is required. The standard is modular, and allows consumers to stack together boards from a variety of COTS manufacturers to produce a customized embedded system.
PICMG, or PCI Industrial Computer Manufacturers Group, is a consortium of over 140 companies in the fields of computer science and engineering. Founded in 1994, the group was originally formed to adapt PCI technology for use in high-performance telecommunications, military, and industrial computing applications, but its work has grown to include newer technologies. PICMG currently focuses on developing and implementing specifications and guidelines for open standards–based computer architectures from a wide variety of interconnects.
Advanced Telecommunications Computing Architecture is the largest specification effort in the history of the PCI Industrial Computer Manufacturers Group (PICMG), with more than 100 companies participating. Known as AdvancedTCA, the official specification designation PICMG 3.x was ratified by the PICMG organization in December 2002. AdvancedTCA is targeted primarily to requirements for "carrier grade" communications equipment, but has recently expanded its reach into more ruggedized applications geared toward the military/aerospace industries as well. This series of specifications incorporates the latest trends in high speed interconnect technologies, next-generation processors, and improved Reliability, Availability and Serviceability (RAS).
Advanced Mezzanine Cards are printed circuit boards (PCBs) that follow a specification of the PCI Industrial Computers Manufacturers Group (PICMG). Known as AdvancedMC or AMC, the official specification designation is AMC.x. Originally AMC was targeted to requirements for carrier grade communications equipment, but later used in other markets.
ETX, standing for Embedded Technology eXtended, is an integrated and compact 95 × 125 mm (3.7 × 4.9 in) computer-on-module (COM) form factor, which can be used in a design application much like an integrated circuit component. Each ETX COM integrates core CPU and memory functionality, the common I/O of a PC/AT, USB, audio, graphics, and Ethernet. All I/O signals as well as a full implementation of ISA and PCI buses are mapped to four high-density, low-profile connectors on the bottom side of the module.
CompactPCI PlusIO is an extension to the PICMG 2.0 CompactPCI industrial standard for modular computer systems. CompactPCI PlusIO was officially adopted by the PCI Industrial Computer Manufacturers Group PICMG 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.
PICMG 1.3 is a PICMG specification which is commonly referred to as SHB Express. SHB Express is a modernization of PICMG 1.0 single-board computer specification. SHB Express, or System Host Board – Express, uses the same physical form factor as PICMG 1.0 boards. The board-to-backplane interfaces are PCI Express instead of PCI and ISA, although the use of PCI remains as an option.
M.2, pronounced m dot two and formerly known as the Next Generation Form Factor (NGFF), is a specification for internally mounted computer expansion cards and associated connectors. M.2 replaces the Mini SATA (mSATA) standard and the Mini PCIe (mPCIe) standard. Employing a more flexible physical specification, M.2 allows different module widths and lengths, which, paired with the availability of more advanced interfacing features, makes M.2 more suitable than mSATA in general for solid-state storage applications, particularly in smaller devices such as ultrabooks and tablets.
SATA Express is a computer bus interface that supports both Serial ATA (SATA) and PCI Express (PCIe) storage devices, initially standardized in the SATA 3.2 specification. The SATA Express connector used on the host side is backward compatible with the standard SATA data connector, while it also provides two PCI Express lanes as a pure PCI Express connection to the storage device.
MicroTCA is a modular, open standard, created and maintained by the PCI Industrial Computer Manufacturers Group (PICMG). It provides the electrical, mechanical, thermal and management specifications to create a switched fabric computer system, using Advanced Mezzanine Cards (AMC), connected directly to a backplane. MicroTCA is a descendant of the AdvancedTCA standard.