The PCI Express bus is becoming increasingly common. It has significant advantages over other buses such as its transfer speed and low signal-count. Until now it was necessary to use Intel processors to operate it, but PowerPC and ARM architectures which possess PCIe are increasingly common, as are FPGA’s with integrated PCIe transceivers. Therefore, the PCIe has become an excellent bus to use on industrial platforms, for both the expansion of peripherals and backplane communication.
In this example 8 independent Ethernets are provided to a Com Express over a 4 lanes PCIe. To achieve it a PLX PCIe switch is used and controlled impedance must be granted in all the PCIe connections.