RTL8201CL
Datasheet
7.2. Auto-Negotiation and Parallel Detection
The RTL8201CL supports IEEE 802.3u clause 28 Auto-negotiation for operation with other transceivers
supporting auto-negotiation. The RTL8201CL can auto detect the link partner’s abilities and determine
the highest speed/duplex configuration possible between the two devices. If the link partner does not
support auto-negotiation, then the RTL8201CL will enable half duplex mode and enter parallel detection
mode. The RTL8201CL will default to transmit FLP (Fast Link Pulse) and wait for the link partner to
respond. If the RTL8201CL receives FLP, then the auto-negotiation process will go on. If it receives NLP
(Normal Link Pulse), then the RTL8201CL 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 auto-negotiation mode operation on the RTL8201CL, pull the ANE (Auto-Negotiation Enable)
pin high. The SPEED and DUPLEX pins will set the ability content of the auto-negotiation register.
Auto-negotiation mode can be externally disabled by pulling the ANE pin low. In this case, the SPEED
pin and DUPLEX pin will change the media configuration of the RTL8201CL.
Below is a list of all configurations of the ANE/SPEED/DUPLEX pins and their operation in Fiber or
UTP mode.
7.2.1. Setting the Medium Type and Interface Mode to MAC
Table 22. Setting the Medium Type and Interface Mode to MAC
FX (Pin 24)
MII/SNIB (Pin 44)
Operation Mode
L
L
H
H
L
X
UTP mode and MII interface.
UTP mode and SNI interface.
Fiber mode and MII interface.
7.2.2. UTP Mode and MII Interface
Table 23. UTP Mode and MII Interface
ANE
(Pin 37)
SPEED
(Pin 39)
DUPLEX
(Pin 38)
Operation
Auto-negotiation enabled. The ability field does not support 100Mbps or
full duplex mode operation.
Auto-negotiation enabled. The ability field does not support 100Mbps
operation.
Auto-negotiation enabled. The ability field does not support full duplex
mode operation.
Default setup, auto-negotiation enabled. The RTL8201CL supports 10Base-
T /100Base-TX, half/full duplex mode operation.
Auto-negotiation disabled. Forces the RTL8201CL into 10Base-T and half
duplex mode.
Auto-negotiation disabled. Forces the RTL8201CL into 10Base-T and full
duplex mode.
Auto-negotiation disabled. Forces the RTL8201CL into 100Base-TX and half
duplex mode.
Auto-negotiation disabled. Forces the RTL8201CL into 100Base-TX and full
duplex mode.
H
H
H
H
L
L
L
L
L
L
L
H
L
H
H
L
H
L
L
H
L
H
H
H
Single-Chip/Port 10/100 Fast Ethernet PHYceiver
16
Track ID: JATR-1076-21 Rev. 1.24
REALTEK [ Realtek Semiconductor Corp. ]
