16-bit High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX
Datasheet
Table 4.2 CRS Behavior
CRS BEHAVIOR
MODE
SPEED
DUPLEX
ACTIVITY
(Note 4.1)
Manual
Manual
10 Mbps
10 Mbps
10 Mbps
10 Mbps
100 Mbps
100 Mbps
100 Mbps
100 Mbps
10 Mbps
10 Mbps
10 Mbps
10 Mbps
100 Mbps
100 Mbps
100 Mbps
100 Mbps
Half-Duplex
Half-Duplex
Full-Duplex
Full-Duplex
Half-Duplex
Half-Duplex
Full-Duplex
Full-Duplex
Half-Duplex
Half-Duplex
Full-Duplex
Full-Duplex
Half-Duplex
Half-Duplex
Full-Duplex
Full-Duplex
Transmitting
Receiving
Active
Active
Low
Manual
Transmitting
Receiving
Manual
Active
Active
Active
Low
Manual
Transmitting
Receiving
Manual
Manual
Transmitting
Receiving
Manual
Active
Active
Active
Low
Auto-Negotiation
Auto-Negotiation
Auto-Negotiation
Auto-Negotiation
Auto-Negotiation
Auto-Negotiation
Auto-Negotiation
Auto-Negotiation
Transmitting
Receiving
Transmitting
Receiving
Active
Active
Active
Low
Transmitting
Receiving
Transmitting
Receiving
Active
Note 4.1 The LAN9217 10/100 PHY internal CRS signal operates in two modes: Active and Low.
When in Active mode, the internal CRS will transition high and low upon line activity, where
a high value indicates a carrier has been detected. In Low mode, the internal CRS stays
low and does not indicate carrier detection. The internal CRS signal and No Carrier (bit 10
of the TX Status word) cannot be used as a verification method of transmitted packets
when transmitting in 10/100 Mbps full-duplex mode.
4.8
HP Auto-MDIX
HP Auto-MDIX facilitates the use of CAT-3 (10 Base-T) or CAT-5 (100 Base-T) media UTP interconnect
cable without consideration of interface wiring scheme. If a user plugs in either a direct connect LAN
cable, or a cross-over patch cable, as shown in Figure 4.3, the SMSC LAN9217 Auto-MDIX PHY is
capable of configuring the TPO and TPI twisted pair pins for correct transceiver operation.
The internal logic of the device detects the TX and RX pins of the connecting device. Since the RX
and TX line pairs are interchangeable, special PCB design considerations are needed to accommodate
the symmetrical magnetics and termination of an Auto-MDIX design.
The Auto-MDIX function can be disabled through an internal register 27.15, or the external control pins
AMDIX_EN. When disabled the TX and RX pins can be configured with the Channel Select
(CH_SELECT) pin as desired.
Revision 1.8 (06-06-07)
68
SMSC LAN9217
DATASHEET
SMSC [ SMSC CORPORATION ]
