RTL8201(L)
2002-01-18 Rev.1.04
18
7.2 Auto-negotiation and Parallel Detection
The RTL8201(L) supports IEEE 802.3u clause 28 Auto-negotiation operation which can cooperate with other transceivers
supporting auto-negotiation. By this mechanism, the RTL8201(L) can auto detect the link partner’s ability and determine the
highest speed/duplex configuration and transmit/receive in this configuration. If the link partner does not support
Auto-negotiation, then the RTL8201(L) will enable half duplex mode and enter parallel detection. The RTL8201(L) will
default to transmit FLP and wait for the link partner to respond. If the RTL8201(L) receives FPL, then the auto-negotiation
process will go on. If it receives NLP, then the RTL8201(L) will change to 10Mbps and half duplex mode. If it receives a
100Mbps IDLE pattern, it will change to 100Mbps and half duplex mode.
To enable the auto-negotiation mode operation on the RTL8201, pull the ANE pin high and the SPEED pin and DUX pin will
enable the mode. The auto-negotiation mode can be externally disabled by pulling the ANE pin low. In this case, the SPEED
pin and DUX pin will change the media configuration of the RTL8201.
Below is a list for all configurations of the ANE/SPEED/DUX pins and their operation mode.
ANE SPEED DUX Operation
H L L Auto-negotiation enabled: the ability field does not support 100Mbps or full duplex mode
operation
H L H Auto-negotiation enabled: the ability field does not support 100Mbps operation
H H L Auto-negotiation enabled: the ability field does not support full duplex mode operation
H H H Default setup, auto-negotiation enabled: the RTL8201(L) will support 10BaseT/100BaseTX,
half/full duplex mode operation
L L L Auto-negotiation disabled: forces the RTL8201(L) into 10BaseT and half duplex mode
L L H Auto-negotiation disabled: forces the RTL8201(L) into 10BaseT and full duplex mode
L H L Auto-negotiation disabled: forces the RTL8201(L) into 100BaseTX and half duplex mode
L H H Auto-negotiation disabled: forces the RTL8201(L) into 100BaseTX and full duplex mode
7.3 Flow control support
The RTL8201(L) supports flow control indications. The MAC can program the MII register to indicate to the PHY that flow
control is supported. When MAC supports the Flow Control mechanism, setting bit 10 of the ANAR register by MDC/MDIO
interface, then the RTL8201(L) will add the ability to its N-Way ability. If the Link partner also supports Flow Control, then
the RTL8201(L) can recognize the Link partner’s N-Way ability by examining bit 10 of ANLPAR (register 5).
Tel: +49(0)234-9351135 · Fax: +49(0)234-9351137 E-MAIL:info@cornelius-consult.de http://www.cornelius-consult.de
To Next Page
Loading...