Specifications

PCIe/104 and PCI/104-Express Specification Revision 3.0 February 17, 2015 Page 10
Glossary of Terms
Terms Definitions
ATX Advanced Technology Extended
A specification for PC motherboards, power supplies, and system chassis. One of its most
notable features is support for “Standby” and “Soft-Off” power savings modes.
Device A logical device attached to a PCI Express Link. Generally an add-in card.
DMA Direct Memory Access
A method for peripherals to efficiently access system memory without CPU intervention.
EBX Form factor for SBC’s
Host The central connection of a PCI Express system, typically a CPU module. This is called the
“Root Complex” by the PCI Express specification.
ISA Bus Industry Standard Architecture
A legacy bus used on earlier PCs. It has been phased out of desktop PCs, but is still common in
embedded systems.
Lane Fundamental unit of a PCI Express connection. A set of differential signal pairs, one pair for
transmission, and one pair for reception. Multiple lanes may be combined to increase
bandwidth (up to x16). A “by-N Link” is comprised of N Lanes.
Link The collection of one or more PCI Express Lanes, plus an additional differential pair for a
clock, which make up a standard PCI Express interconnect. According to PCI Express
Specification 1.1 a Link can be comprised of 1, 4, 8, or 16 Lanes.
Packet Switch A device used to attach multiple PCI Express devices to a single link on the HOST. The PCI
Express Specification refers to this simply as a “Switch.” In this document, the term “Packet
Switch” is used to differentiate from a “Signal Switch.”
PCIe PCI Express
PEG PCI Express Graphics
SBC Single Board Computer
SDVO Serial Digital Video Output used from Intel 915/945/965 chipsets
Signal Switch An analog switch used to select between multiple PCI Express devices to attach to a single PCI
Express link, or multiple links to attach to a single device. Also called a “Channel Switch.”
SMBus System Management Bus
USB Universal Serial Bus
LPC Low pin count bus, a bus specification for legacy devices
SATA Serial ATA Bus