BCM1250/BCM1125/BCM1125H
User Manual
10/21/02
B r o a d c o m C o r p o r a t i o n
Page
264
Section 9: Ethernet MACs
Document
1250_1125-UM100CB-R
I
NTERFACE
O
VERVIEW
shows the block diagram of a single Ethernet interface. The interface to the system bus is provided
through I/O Bridge 1. This allows the CPU to access the interface control registers, the RMON statistical
counters and the DMA control interface. It also provides the connection from the DMA engines into the part.
Figure 51: Ethernet Interface Block Diagram
I/O Bridge 1
Receive
DMA
Transmit
DMA
Receive
Transmit
FIFO
FIFO
Packet FIFO
Ethernet or Packet FIFO Select
GMII Interface
Interface
Control
Data
Data
Packer
Unpacker
Ethernet or Packet FIFO Select and Synchronizer
Control
Registers
RMON
Counters
Address
Filter
Receive
DMA Channel
Engine
To ZBbus
MAC
RX
Flow
RX
TX
Flow
TX
Selector
or
Packet Interface