Page 11
4 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 denes a serial point-to-point connection, the so-called Link:
Selectable Width
D
ev
ic
e
A
D
ev
ic
e
B
Ref. Clock
Ref. Clock
The data transfer within a Link is done via Lanes, representing one wire pair for sending and one wire pair for
receiving data:
TX
Logic
D+
Component A
Component B
D+
V
BIAS
V
BIAS
D-
D-
RX
Logic
RX
Logic
TX
Logic
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 Meinberg GPS receivers for example) can always be used in slots
with a higher lane width (x4, x8, x16):
Interoperability
Slot
x1
x4
x8
x16
Card
x1
Yes Yes Yes Yes
x4
No
Yes Yes Yes
x8 No No Yes Yes
X16 No
No No Yes
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.
PTP270PEX
Date: 22nd November 2012
11
Summary of Contents for PTP270PEX
Page 1: ...MANUAL PTP270PEX IEEE 1588 Computer Clock 22nd November 2012 Meinberg Radio Clocks GmbH Co KG...
Page 2: ......
Page 18: ...7 3 IRIG Standard Format Page 15 7 3 IRIG Standard Format PTP270PEX Date 22nd November 2012 15...
Page 19: ...Page 16 7 Time codes 7 4 AFNOR Standard Format 16 Date 22nd November 2012 PTP270PEX...
