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# 1.2.5.5 Ethernet GMAC Driver Library

The Ethernet Media Access Controller (GMAC) module implements a 10/100 Mbps Ethernet MAC, compatible with the IEEE 802.3 standard. The GMAC can operate in either half or full duplex mode at all supported speeds.

Embedded Characteristics

- Compatible with IEEE Standard 802.3

- 10, 100 Mbps operation

- Full and half duplex operation at all supported speeds of operation

- Statistics Counter Registers for RMON/MIB

- MII interface to the physical layer

- Integrated physical coding

- Direct memory access (DMA) interface to external memory

- Support for 6 priority queues in DMA

- 8 KB transmit RAM and 4 KB receive RAM

- Programmable burst length and endianism for DMA

- Interrupt generation to signal receive and transmit completion, errors or other events

- Automatic pad and cyclic redundancy check (CRC) generation on transmitted frames

- Automatic discard of frames received with errors

- Receive and transmit IP, TCP and UDP checksum offload. Both IPv4 and IPv6 packet types supported

- Address checking logic for four specific 48-bit addresses, four type IDs, promiscuous mode, hash matching of unicast and multicast destination addresses and Wake-on-LAN

- Management Data Input/Output (MDIO) interface for physical layer management

- Support for jumbo frames up to 10240 Bytes

- Full duplex flow control with recognition of incoming pause frames and hardware generation of transmitted pause frames

- Half duplex flow control by forcing collisions on incoming frames

- Support for 802.1Q VLAN tagging with recognition of incoming VLAN and priority tagged frames

- Support for 802.1Qbb priority-based flow control

- Programmable Inter Packet Gap (IPG) Stretch

- Recognition of IEEE 1588 PTP frames

- IEEE 1588 time stamp unit (TSU)

- Support for 802.1AS timing and synchronization

- Supports 802.1Qav traffic shaping on two highest priority queues