Pci express (pcie) – Meinberg TCR170PEX User Manual
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PCI Express (PCIe)
The main technical inovation of PCI Express is a serial data transmission compared
to the parallel interfaces of other computer bus systems like ISA, PCI and PCI-X.
PCI Express defines a serial point-to-point connection, the so-called Link:
The data transfer within a Link is done via Lanes, representing one wire pair for
sending and one wire pair for receiving data:
This design leads to a full duplex connection clocked with 2.5 GHz capable of
transfering a data volume of 250 MB/s per lane in each direction. Higher bandwith is
implemented by using multiple lanes silmutaneously. A PCI Express x16 slot for
example uses sixteen lanes providing a data volume of 4 GB/s. For comparison: when
using conventional PCI the maximum data transfer rate is 133 MB/s, PCI-X allows 1
GB/s but only in one direction respectively. A PCIe expansion board (x1 like
TCR170PEX for example) can always be used in slots with a higher lane width
(x4, x8, x16):
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One of the strong points of PCI Express is the 100% software compatibility to the
well known PCI bus, leading to a fast spreading. The computer and the operating
system are „seeing“ the more powerfull PCIe bus just as the convetional PCI bus
without any software update.