LAN8710A Datasheet, PDF (26/82 Pages) SMSC Corporation – Small Footprint MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX and flexPWR Technology

Small Footprint MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX and flexPWR^® Technology
Datasheet
3.1.4.3
3.1.4.4
10M Receive Data Across the MII/RMII Interface
For MII, the 4-bit data nibbles are sent to the MII block. In MII mode, these data nibbles are valid on
the rising edge of the 2.5 MHz RXCLK.
For RMII, the 2-bit data nibbles are sent to the RMII block. In RMII mode, these data nibbles are valid
on the rising edge of the RMII REF_CLK.
Jabber Detection
Jabber is a condition in which a station transmits for a period of time longer than the maximum
permissible packet length, usually due to a fault condition, which results in holding the TXEN input for
a long period. Special logic is used to detect the jabber state and abort the transmission to the line
within 45ms. Once TXEN is deasserted, the logic resets the jabber condition.
As shown in Section 4.2.2, "Basic Status Register," on page 53, the Jabber Detect bit indicates that a
jabber condition was detected.
3.2
Auto-negotiation
The purpose of the auto-negotiation function is to automatically configure the transceiver to the
optimum link parameters based on the capabilities of its link partner. Auto-negotiation is a mechanism
for exchanging configuration information between two link-partners and automatically selecting the
highest performance mode of operation supported by both sides. Auto-negotiation is fully defined in
clause 28 of the IEEE 802.3 specification.
Once auto-negotiation has completed, information about the resolved link can be passed back to the
controller via the Serial Management Interface (SMI). The results of the negotiation process are
reflected in the Speed Indication bits of the PHY Special Control/Status Register, as well as in the Auto
Negotiation Link Partner Ability Register. The auto-negotiation protocol is a purely physical layer
activity and proceeds independently of the MAC controller.
The advertised capabilities of the transceiver are stored in the Auto Negotiation Advertisement
Register. The default advertised by the transceiver is determined by user-defined on-chip signal
options.
The following blocks are activated during an Auto-negotiation session:
„ Auto-negotiation (digital)
„ 100M ADC (analog)
„ 100M PLL (analog)
„ 100M equalizer/BLW/clock recovery (DSP)
„ 10M SQUELCH (analog)
„ 10M PLL (analog)
„ 10M Transmitter (analog)
When enabled, auto-negotiation is started by the occurrence of one of the following events:
„ Hardware reset
„ Software reset
„ Power-down reset
„ Link status down
„ Setting the Restart Auto-Negotiate bit of the Basic Control Register
On detection of one of these events, the transceiver begins auto-negotiation by transmitting bursts of
Fast Link Pulses (FLP), which are bursts of link pulses from the 10M transmitter. They are shaped as
Normal Link Pulses and can pass uncorrupted down CAT-3 or CAT-5 cable. A Fast Link Pulse Burst
Revision 1.4 (08-23-12)
26
DATASHEET
SMSC LAN8710A/LAN8710Ai