LAN8710A-EZK-TR SMSC, LAN8710A-EZK-TR Datasheet - Page 30

• Manufacturer Part Number: LAN8710A-EZK-TR
• Description: Ethernet ICs 10/100 Ethernet XCVR w/HPAutoMDIX FlexPwr
• Manufacturer: SMSC
• Type: Single Chipr

Specifications of LAN8710A-EZK-TR

• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Product: Ethernet Transceivers
• Number Of Transceivers: 1
• Standard Supported: IEEE 802.3 or IEEE 802.3u
• Data Rate: 125 Mbps
• Supply Voltage (max): 3.6 V
• Supply Voltage (min): 1.6 V or 3 V
• Maximum Operating Temperature: + 85 C
• Package / Case: QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Revision 1.2 (11-10-10)
3.4.2.1
3.4.2.2
3.4.3
CRS_DV - Carrier Sense/Receive Data Valid
The CRS_DV is asserted by the device when the receive medium is non-idle. CRS_DV is asserted
asynchronously on detection of carrier due to the criteria relevant to the operating mode. In 10BASE-
T mode when squelch is passed, or in 100BASE-X mode when 2 non-contiguous zeroes in 10 bits are
detected, the carrier is said to be detected.
Loss of carrier shall result in the deassertion of CRS_DV synchronous to the cycle of REF_CLK which
presents the first di-bit of a nibble onto RXD[1:0] (i.e. CRS_DV is deasserted only on nibble
boundaries). If the device has additional bits to be presented on RXD[1:0] following the initial
deassertion of CRS_DV, then the device shall assert CRS_DV on cycles of REF_CLK which present
the second di-bit of each nibble and de-assert CRS_DV on cycles of REF_CLK which present the first
di-bit of a nibble. The result is, starting on nibble boundaries, CRS_DV toggles at 25 MHz in 100Mbps
mode and 2.5 MHz in 10Mbps mode when CRS ends before RXDV (i.e. the FIFO still has bits to
transfer when the carrier event ends). Therefore, the MAC can accurately recover RXDV and CRS.
During a false carrier event, CRS_DV shall remain asserted for the duration of carrier activity. The data
on RXD[1:0] is considered valid once CRS_DV is asserted. However, since the assertion of CRS_DV
is asynchronous relative to REF_CLK, the data on RXD[1:0] shall be “00” until proper receive signal
decoding takes place.
Reference Clock (REF_CLK)
The RMII REF_CLK is a continuous clock that provides the timing reference for CRS_DV, RXD[1:0],
TXEN, TXD[1:0] and RXER. The device uses REF_CLK as the network clock such that no buffering
is required on the transmit data path. However, on the receive data path, the receiver recovers the
clock from the incoming data stream, and the device uses elasticity buffering to accommodate for
differences between the recovered clock and the local REF_CLK.
MII vs. RMII Configuration
The device must be configured to support the MII or RMII bus for connectivity to the MAC. This
configuration is done via the RMIISEL configuration strap. MII or RMII mode selection is configured
based on the strapping of the RMIISEL configuration strap as described in
MII/RMII Mode Configuration," on page
Most of the MII and RMII pins are multiplexed.
relationship of the related device pins to the MII and RMII mode signal names.
carrier sense - CRS_DV
Reference Clock - (RMII references usually define this signal as REF_CLK)
DATASHEET
Small Footprint MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX and flexPWR
36.
30
Table 3.2, "MII/RMII Signal Mapping"
SMSC LAN8710A/LAN8710Ai
Section 3.7.3, "RMIISEL:
describes the
Datasheet
®
Technology