LAN9221_12 Datasheet, PDF (75/151 Pages) SMSC Corporation – High-Performance 16-bit Non-PCI 10/100 Ethernet Controller with Variable Voltage I/O

High-Performance 16-bit Non-PCI 10/100 Ethernet Controller with Variable Voltage I/O
Datasheet
full-duplex transmission. Therefore, these signals cannot be used as a verification method of
transmitted packets when transmitting in 10/100 Mbps full-duplex modes.
MODE
Manual
Manual
Manual
Manual
Manual
Manual
Manual
Manual
Auto-Negotiation
Auto-Negotiation
Auto-Negotiation
Auto-Negotiation
Auto-Negotiation
Auto-Negotiation
Auto-Negotiation
Auto-Negotiation
Table 4.2 CRS Behavior
SPEED
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
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
Half-Duplex
Half-Duplex
Full-Duplex
Full-Duplex
ACTIVITY
Transmitting
Receiving
Transmitting
Receiving
Transmitting
Receiving
Transmitting
Receiving
Transmitting
Receiving
Transmitting
Receiving
Transmitting
Receiving
Transmitting
Receiving
CRS BEHAVIOR
(Note 4.1)
Active
Active
Low
Active
Active
Active
Low
Active
Active
Active
Low
Active
Active
Active
Low
Active
4.8
Note 4.1
The LAN9221/LAN9221i 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.
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 LAN9221/LAN9221i 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.
SMSC LAN9221/LAN9221i
75
DATASHEET
Revision 2.9 (03-01-12)