LAN9215-MT SMSC, LAN9215-MT Datasheet - Page 68

• Manufacturer Part Number: LAN9215-MT
• Description: CONTROLLER, ENET, NON-PCI, 100TQFP
• Manufacturer: SMSC

Specifications of LAN9215-MT

• Data Rate: 100Mbps
• No. Of Ports: 2
• Ethernet Type: IEEE 802.3 / 802.3u
• Supply Current: 40mA
• Supply Voltage Range: 2.97V To 3.63V
• Operating Temperature Range: 0°C To +70°C
• Digital Ic Case Style: TQFP
• Interface Type: HBI
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Revision 1.2 (03-29-06)
4.7
4.7.1
4.7.2
4.7.3
4.8
abilities will be advertised. Auto-negotiation can also be disabled via software by clearing register 0,
bit 12.
The LAN9215does not support “Next Page" capability.
If the LAN9215 is connected to a device lacking the ability to auto-negotiate (i.e. no FLPs are
detected), it is able to determine the speed of the link based on either 100M MLT-3 symbols or 10M
Normal Link Pulses. In this case the link is presumed to be half-duplex per the IEEE standard. This
ability is known as “Parallel Detection. This feature ensures inter operability with legacy link partners.
If a link is formed via parallel detection, then bit 0 in register 6 is cleared to indicate that the Link
Partner is not capable of auto-negotiation. The Ethernet MAC has access to this information via the
management interface. If a fault occurs during parallel detection, bit 4 of register 6 is set.
Register 5 is used to store the Link Partner Ability information, which is coded in the received FLPs.
If the Link Partner is not auto-negotiation capable, then register 5 is updated after completion of parallel
detection to reflect the speed capability of the Link Partner.
Re-starting Auto-negotiation
Auto-negotiation can be re-started at any time by setting register 0, bit 9. Auto-negotiation will also re-
start if the link is broken at any time. A broken link is caused by signal loss. This may occur because
of a cable break, or because of an interruption in the signal transmitted by the Link Partner. Auto-
negotiation resumes in an attempt to determine the new link configuration.
If the management entity re-starts Auto-negotiation by writing to bit 9 of the control register, the
LAN9215will respond by stopping all transmission/receiving operations. Once the break_link_timer is
done, in the Auto-negotiation state-machine (approximately 1200ms) the auto-negotiation will re-start.
The Link Partner will have also dropped the link due to lack of a received signal, so it too will resume
auto-negotiation.
Disabling Auto-negotiation
Auto-negotiation can be disabled by setting register 0, bit 12 to zero. The device will then force its
speed of operation to reflect the information in register 0, bit 13 (speed) and register 0, bit 8 (duplex).
The speed and duplex bits in register 0 should be ignored when auto-negotiation is enabled.
Half vs. Full-Duplex
half-duplex operation relies on the CSMA/CD (Carrier Sense Multiple Access / Collision Detect)
protocol to handle network traffic and collisions. In this mode, the carrier sense signal, CRS, responds
to both transmit and receive activity.
a collision results.
In full-duplex mode, the PHY is able to transmit and receive data simultaneously. In this mode, CRS
responds only to receive activity. The CSMA/CD protocol does not apply and collision detection is
disabled.
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
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.
Parallel Detection
HP Auto-MDIX
DATASHEET
In this mode, If data is received while the PHY is transmitting,
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Highly Efficient 10/100 Ethernet Controller with HP Auto-MDIX
Figure
4.3, the SMSC LAN9215 Auto-MDIX PHY is
SMSC LAN9215
Datasheet