EtherMAC is a part of Ethernet interface. It is not easy to introduce full function of Ethernet because the interface has very complicated structure. This is just a brief explanation regarding Ethernet.
Ethernet can be mainly divided into four hierarchical layers which are physical layer, data link layer, network layer and the upper layers. EtherMAC handles the lowest two layers, physical and data link ones.
An Ethernet cable consists of four signal wires. Two twisted wires are used for output data and another two twisted wires, for input data. This cable has good noise immunity even without electric shield. There are no clock lines so Ethernet is an asynchronous interface. In order to comprehend the concept of Ethernet, 10Base-T is introduced here even though 100Base-TX is the most popular version today because 10Base-T is fundamental and much simpler than 100Base-TX.
10Base-T is an interface which has 10Mbps transfer rate and Base band format with using a twist pair cable. Manchester Code format is applied to the signal transfer. In Manchester Code data “1” and “0” are defined with rise transition and fall one, respectively.