L80227 LSI, L80227 Datasheet - Page 52

• Manufacturer Part Number: L80227
• Manufacturer: LSI

Specifications of L80227

• Lead Free Status / RoHS Status: Not Compliant

2.6.1 Forcing Full-/Half-Duplex Operation
2.6.2 Full/Half Duplex Indication
2.6.3 Loopback
2.6.3.1 Internal CRS Loopback
2-34
To independently force a channel into either the Full- or Half-Duplex
mode, set the Duplex Mode Select (DPLX) bit in the MI serial port
Control register, assuming that AutoNegotiation is not enabled with the
ANEG_EN bit in the MI serial port Control register.
The device automatically configures itself for Full- or Half-Duplex mode.
To do this, the device uses the AutoNegotiation algorithm to advertise
and detect Full- and Half-Duplex capabilities to and from a remote
device. To enable AutoNegotiation, set the AutoNegotiation Enable
(ANEG_EN) bit in the MI serial port Control register.
To select the advertised Full/-Half-Duplex capability, appropriately set the
bits in the MI serial port AutoNegotiation Advertisement register.
AutoNegotiation functionality is described in more detail in
2.3.10, “Link Integrity and
Full-Duplex detection can be monitored through the DPLX_DET bit in the
MI serial port Status Output register, or it can also be programmed to
appear on the PLED1n pin.
In the MI serial port Configuration register, set the LED function select
bits (LED_DEF[1:0]) so that the Full-Duplex condition activity is indicated
at the PLED1n output. Set the PLED2_[1:0] bits in the same register to
0b11 (normal). When the PLED1n pin is programmed to be a Full-Duplex
detect output, it is asserted LOW when the device is configured for
Full-Duplex operation. The PLED1n output has both pullup and pulldown
driver transistors and a weak pullup resistor, so it can drive an LED from
either V
See
program the LED output pins to indicate various conditions.
TX_EN is internally looped back onto CRS during every transmit packet.
This internal CRS loopback is disabled during collision, in Full-Duplex
Functional Description
Section 2.3.13, “LED Drivers,” page 2-28
DD
or GND and can also drive a digital input.
Copyright © 2000, 2001, 2002 by LSI Logic Corporation. All rights reserved.
AutoNegotiation”.
for more details on how to
Section