10/100 ethernet mac (emac), 1 description, 2 block diagram – Rainbow Electronics AT91CAP9S250A User Manual

Page 791

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6264A–CAP–21-May-07

AT91CAP9S500A/AT91CAP9S250A

42. 10/100 Ethernet MAC (EMAC)

42.1

Description

The EMAC module implements a 10/100 Ethernet MAC compatible with the IEEE 802.3 stan-
dard using an address checker, statistics and control registers, receive and transmit blocks, and
a DMA interface.

The address checker recognizes four specific 48-bit addresses and contains a 64-bit hash regis-
ter for matching multicast and unicast addresses. It can recognize the broadcast address of all
ones, copy all frames, and act on an external address match signal.

The statistics register block contains registers for counting various types of event associated
with transmit and receive operations. These registers, along with the status words stored in the
receive buffer list, enable software to generate network management statistics compatible with
IEEE 802.3.

42.2

Block Diagram

Figure 42-1. EMAC Block Diagram

APB

Slave

Register Interface

DMA Interface

Address Checker

Statistics Registers

Control Registers

Ethernet Receive

Ethernet Transmit

MDIO

MII/RMII

RX FIFO

TX FIFO

AHB

Master

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