±15kV ESD Protected MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX Support and flexPWR® Technology in a Small Footprint
Datasheet
The RX10M block also detects valid 10Base-T IDLE signals - Normal Link Pulses (NLPs) - to maintain
the link.
4.5.3
4.5.4
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 RX_CLK.
For RMII, the 2bit 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, that results in holding the TX_EN input for
a long period. Special logic is used to detect the jabber state and abort the transmission to the line,
within 45ms. Once TX_EN is deasserted, the logic resets the jabber condition.
As shown in Table 5.31, bit 1.1 indicates that a jabber condition was detected.
4.6
MAC Interface
The MII/RMII block is responsible for the communication with the controller. Special sets of hand-shake
signals are used to indicate that valid received/transmitted data is present on the 4 bit receive/transmit
bus.
The device must be configured in MII or RMII mode. See Section 4.6.3, "MII vs. RMII Configuration,"
on page 28.
4.6.1
MII
The MII includes 16 interface signals:
transmit data - TXD[3:0]
transmit strobe - TX_EN
transmit clock - TX_CLK
transmit error - TX_ER/TXD4
receive data - RXD[3:0]
receive strobe - RX_DV
receive clock - RX_CLK
receive error - RX_ER/RXD4
collision indication - COL
carrier sense - CRS
In MII mode, on the transmit path, the PHY drives the transmit clock, TX_CLK, to the controller. The
controller synchronizes the transmit data to the rising edge of TX_CLK. The controller drives TX_EN
high to indicate valid transmit data. The controller drives TX_ER high when a transmit error is detected.
On the receive path, the PHY drives both the receive data, RXD[3:0], and the RX_CLK signal. The
controller clocks in the receive data on the rising edge of RX_CLK when the PHY drives RX_DV high.
The PHY drives RX_ER high when a receive error is detected.
Revision 2.3 (04-12-11)
SMSC LAN8700/LAN8700i
DATA2S6HEET
SMSC [ SMSC CORPORATION ]
