Tri-Speed Ethernet MAC

Overview

The Tri-Speed Ethernet Media Access Controller (TSMAC) core can be configured to operate in either the Gigabit mode (1000Mbits/sec data rate) or the Fast Ethernet mode (10/100 Mbits/sec data rate). Operation in either Gigabit mode or Fast Ethernet mode is selected by setting an internal register bit.

The Tri-Speed Ethernet MAC transmits and receives data between a host processor and an Ethernet network. The main function of the Ethernet MAC is to ensure that the Media Access rules specified in the 802.3 IEEE standard are met while transmitting a frame of data over Ethernet. On the receiving side, the Ethernet MAC extracts the different components of a frame and transfers them to higher applications through the FIFO interface.

The data received from the G/MII interface is first buffered until sufficient data is available to be processed by the Receive MAC (Rx MAC). The Preamble and the Start of Frame Delimiter (SFD) information are then extracted from the incoming frame to determine the start of a valid frame. The Receive MAC checks the address of the received packet and validates whether the frame can be received before transferring it into the FIFO. Only valid frames are transferred into the FIFO. This feature has the following two benefits: the systems need not re-calculate the Frame Check Sequence (FCS) again when the frame is being transmitted, and it also keeps the receive MAC relatively simple. The Tri-Speed MAC, however, always calculates CRC to check whether the frame was received error-free.

Features

• Compliant to IEEE 802.3z standard
• Generic 8-bit host interface
• 8-bit wide internal data path
• Generic transmit and receive FIFO interface
• Full-duplex operation in 1G mode
• Full- and half-duplex operation in 10/100 mode
• Transmit and receive statistics vector
• Programmable Inter-Packet Gap (IPG)
• Multicast address filtering
• Selectable MAC operating options
  • Classic Tri-Speed MAC with G/MII
  • Gigabit MAC with GMII
  • SGMII Easy Connect MAC with GMII, configurable option available on LatticeECP3™, LatticeECP2/M, and LatticeSC/M devices
• Supports
  • Full-duplex control using PAUSE frames
  • VLAN tagged frames
  • Automatic re-transmission on collision
  • Automatic padding of short frames
  • Multicast and Broadcast frames
  • Optional FCS transmission and reception
  • Optional MII management interface module
  • Jumbo frames up to 9600 bytes

Performance and Resource Utilization

Demo

A demo is available for the LatticeXP family and highlights the capability of the Tri-Speed Ethernet MAC IP core to function in a real network environment.   For more information about this demo, please click here.

Ordering Information