This section describes the functional overview of a typical Ethernet solution.

A typical Ethernet system is shown in Figures 1 and 2. The Ethernet controller may be a separate, standalone device, or it may be integrated with the host microcontroller (MCU). The Ethernet controller transmits and receives data from the Ethernet cable and manages Ethernet protocol. Ethernet controllers are often separated into two pieces, the Media Access Control (MAC) and the Physical Layer (PHY).

Figure 1: Overall Ethernet System Diagram – standalone Ethernet controller

Figure 2: Overall Ethernet System Diagram – Integrated Ethernet

Media Access Control (MAC)

The MAC provides addressing and channel access control mechanisms for several terminals or network nodes to communicate within a multi-point network, typical a local area network (LAN). As part of the channel access control, it provides multiple access protocol that allows for an automatic retransmission when a collision occurs. It also emulates a full-duplex logical communication channel in a multi-point network. This channel may provide unicast, multicast or broadcast communication service.

Physical Layer (PHY)

The PHY provides the means of transmitting raw bits over a physical data link (i.e. twisted pair cable). The PHY module interfaces to a signal transformer, which in turn connects to the RJ-45 Ethernet socket. The host controller receives data from the Ethernet controller and applies the necessary protocol rules. The host controller also formats outgoing data and places it into the Ethernet controller transmit buffer.

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