Draft 6/5/00
A-22
Application Information
Copyright 2000 by LSI Logic Corporation. All rights reserved.
A.14 Repeater Applications
This section describes how to set up the L80223 to act as a repeater.
A.14.1 MII-Based Repeaters
Using the standard MII as the interface to the repeater core, the L80223
can be used as the physical interface for MII-based repeaters. For most
repeaters, it is necessary to disable the internal CRS loopback. To do
this, set the TXEB_CRS bit in the MI serial port Configuration 1 register.
For some particular types of repeaters, it may be desirable to either
enable or disable AutoNegotiation, force Half-Duplex operation, and
enable either 100 Mbits/s or 10 Mbits/s operation. To configure any of
these modes, set the appropriate bits in the MI serial port Control
register or appropriately assert or deassert the SPEED, DUPLX, and
ANEG pins on the device.
The L80223 has a RPTR pin that, when asserted, automatically
configures the device for one common type of repeater application. When
the RPTR pin is asserted:
TX_EN to CRS loopback is disabled
AutoNegotiation is disabled
Half-Duplex operation is selected
100 Mbits/s operation is selected
The MII requires 16 signals between the L80223 and a repeater core.
The MII signal count to a repeater core is 16 multiplied by the number of
ports, which can be quite large. The signal count between the L80223
and the repeater core can be reduced by 8 per device if the receive
output pins are shared and the RX_EN pin is used to enable only that
port where CRS is asserted. Refer to
Section A.9, “MII Controller
Interface,” page A-15
for more details about using the RX_EN pin.
A.14.2 Non-MII Based Repeaters
The FBI interface available on the L80223 can be used to connect to
non-MII based repeaters that employ the industry popular five bit wide
interface.