MII/RMII 10/100 Ethernet
Transceiver with HP Auto-MDIX
and flexPWR
®
Technology in a
Small Footprint
PRODUCT FEATURES
Highlights
Sin gle-Chip Ethernet Physical Layer Transceiver
(PHY)
Co mprehensive flexPWR
— Flexible Power Management Architecture
— Power savings of up to 40% compared to competition
— LVCMOS Variable I/O voltage range: +1.6V to +3.6V
— Integrated 1.2V regulator with disable feature
HP Au to-MDIX support
Small footprint 32 pin QFN le ad-free RoHS compliant
package (5 x 5 x 0.9mm height)
Target Applications
Set-Top Boxes
Ne tworked Printers and Servers
Test Instrumentation
L AN on Motherboard
Embed ded Telecom Applications
Video Record/Playback Systems
Ca ble Modems/Routers
DSL Modems/Routers
Di gital Video Recorders
IP and Video Phones
W ireless Access Points
Di gital Televisions
Di gital Media Adaptors/Servers
Gaming Consoles
POE Appli cations
®
Technology
Datasheet
Key Benefits
H igh-Performance 10/100 Ethernet Transceiver
— Compliant with IEEE802.3/802.3u (Fast Ethernet)
— Compliant with ISO 802-3/IEEE 802.3 (10BASE-T)
— Loop-back modes
— Auto-negotiation
— Automatic polarity detection and correction
— Link status change wake-up detection
— Vendor specific register functions
— Supports both MII and the reduced pin count RMII
interfaces
Po wer and I/Os
— Various low power modes
— Integrated power-on reset circuit
— Two status LED outputs
— Latch-Up Performance Exceeds 150mA per EIA/JESD
78, Class II
— May be used with a single 3.3V supply
Packaging
— 32-pin QFN (5x5 mm) Lead-Free RoHS Compliant
package with MII and RMII
Environmental
— Extended Commercial Temperature Range (0°C to
+85°C)
— Industrial Temperature Range (-40°C to +85°C) version
available (LAN8710i)
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ORDER NUMBER(S):
LAN8710A-EZK FOR 32-PIN, QFN LEAD-FREE ROHS COMPLIANT PACKAGE (0 TO +85°C TEMP)
LAN8710Ai-EZK FOR 32-PIN, QFN LEAD-FREE ROHS COMPLIANT PACKAGE (-40 TO +85°C TEMP)
LAN8710A-EZK-TR FOR 32-PIN, QFN LEAD-FREE ROHS COMPLIANT PACKAGE (0 TO +85°C TEMP)
LAN8710Ai-EZK-TR FOR 32-PIN, QFN LEAD-FREE ROHS COMPLIANT PACKAGE (-40 TO +85°C TEMP)
construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate, no responsibility is assumed for inaccuracies. SMSC
reserves the right to make changes to specifications and product descriptions at any time without notice. Contact your local SMSC sales office to obtain the latest specifications
before placing your product order. The provision of this information does not convey to the purchaser of the described semiconductor devices any licenses under any patent
rights or other intellectual property rights of SMSC or others. All sales are expressly conditional on your agreement to the terms and conditions of the most recently da ted
version of SMSC's standard Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design defects or errors
known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon request. SMSC products are not
designed, intended, authorized or warranted for use in any life support or other application where product failure could cause or contribute to personal injury or severe property
damage. Any and all such uses without prior written approval of an Officer of SMSC and further testing and/or modification will be fully at the risk of the customer. Copies of
this document or other SMSC literature, as well as the Terms of Sale Agreement, may be obtained by visiting SMSC’s website at http://www.smsc.com. SMSC is a registered
trademark of Standard Microsystems Corporation (“SMSC”). Product names and company names are the trademarks of their respective holders.
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FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND AGAINST INFRINGEMENT AND THE LIKE, AND ANY AND ALL WARRANTIES ARISING FROM ANY COURSE
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TO HAVE FAILED OF ITS ESSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
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Datasheet
Chapter 1 Introduction
1.1 General Terms and Conventions
The following is list of the general terms used in this docu ment:
BYTE8-bits
FIFOFirst In First Out buffer; often used for elasticity buffer
MACMedia Access Controller
MIIMedia Independent Interface
RMIITM Reduced Media Independent InterfaceTM
N/ANot Applicable
XIndicates that a logic state is “don’t care” or undefined.
RESERVEDRefers to a reserved bit field or address. Unless otherwise noted, reserved
SMISerial Management Interface
bits must always be zero for write operations. Unless otherwise noted, values
are not guaranteed when reading reserved bits. Unless otherwise noted, do
not read or write to reserved addresses.
1.2General Description
The LAN8710/LAN8710i is a low-power 10BASE-T/100BASE-TX physical layer (PHY) transceiver that
transmits and receives on unshielded twisted-pair cable. A typical system application is shown in
Figure 1.2. It is available in both extended commercial and industrial temperature operating versions.
The LAN8710/LAN8710i interfaces to the MAC layer using a variable voltage digital interface via the
standard MII (IEEE 802.3u). Support for RMII makes a reduced pin-count interface available. The
digital interface pins are tolerant to 3.6V.
The LAN8710/LAN8710i implements Auto-Negotiation to automatically determine the best possible
speed and duplex mode of operation. HP Auto-MDIX su pport allows using a direct conne ct LAN cable,
or a cross-over path cable.
The LAN8710 referenced throughout this document applies to both the extended commercial
temperature and industrial temperature components. The LAN8710i refers to only the industrial
temperature component.
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10/100
Ethernet
MAC
MII o r
RMII
MODE
Figure 1.1 LAN8710/LAN8710i System Block D iagram
LAN8710
Ethernet
Transceiver
1.3 Architectural Overview
The LAN8710/LAN8710i is compliant with IEEE 802.3-2 005 standards (MII Pins tolerant to 3.6V) and
supports both IEEE 802.3-2005 compliant and vendor-specific register functions. It contains a fullduplex 10-BASE-T/100BASE-TX transceiver and supports 10-Mbps (10BASE-T) operation, and 100Mbps (100BASE-TX) operation. The LAN8710/LAN8710i can be configured to operate on a single 3.3V
supply utilizing an integrated 3.3V to 1.2V linear regulator. An option is available to disable the linear
regulator to optimize system designs that have a 1.2V power supply available. This allows for the use
of a high efficiency external regulator for lower system power dissipation.
Crystal or
Clock Osc
MDI
LED Status
TransformerRJ45
1.3.1Configuration
The LAN8710 will begin normal operation following reset, an d no regi ster access is required . The initial
configuration may be selected with configuration pins as described in Section 5.3.9. In addition,
register-selectable configuration options may be used to further define the functionality of the
transceiver. For example, the device can be set to 10BASE-T only. The LAN8710 supports both IEEE
802.3-2005 compliant and vendor-specific register functions.
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Chapter 3 Pin Description
This chapter describes the signals on each pin. When a lower case “n” is used at the beginning of the
signal name, it indicates that the signal is active low. For example, nRST indicates that the reset signal
is active low. The buffer type for each signal is indicated in the TYPE column, and a description of the
buffer types is provided in Table 3.1.
Table 3.1 Buffer Types
BUFFER TYPEDESCRIPTION
I8Input.
O8Output with 8mA sink and 8mA source.
IOD8Input/Open-drain output with 8mA sink.
Datasheet
IPU
Note 3.1
IPD
Note 3.1
IOPU
Note 3.1
IOPD
Note 3.1
AIAnalog input
AIOAnalog bi-directional
ICLKCrystal oscillator input pin
OCLKCrystal oscillator output pin
PPower pin
Note 3.1Unless otherwise noted in the pin description, internal pull-u p and pull-down resistors are
Note: The dig ital signals are not 5V tolerant.They are variable vol tage from +1.6V to +3.6V, as shown
Input with 67k (typical) internal pull-up.
Input with 67k (typical) internal pull-down.
Input/Output with 67k (typical) internal pull-up. Output has 8 mA sink and 8mA source.
Input/Output with 67k (typical) internal pull-down. Output has 8mA sink and 8 mA source.
always enabled. The internal pull-up and pull -down resistors prevent unconnected inputs
from floating, and must not be relied upon to drive signals external to
When connected to a load that must be pulled hi gh or low, an external resistor must be
added.
in Table 7.1.
LAN8710/LAN8710i.
3.1 MAC Interface Signals
T ab le 3.2 MII/RMII Signals 32-QFN
SIGNAL
NAME
TXD022I8Tr a ns m it D a ta 0: The MAC transmits data to the transceiver using this
TXD123I8Tr a ns m it D a ta 1: The MAC transmits data to the transceiver using this
Revision 1.0 (04-15-09)14SMSC LAN8710/LAN8710i
32-QFN
PIN #TYPEDESCRIPTION
signal in all modes.
signal in all modes
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TXD224I8Tr a ns m it D a ta 2: The MAC transmits data to the transceiver using this
signal in MII Mode.
This signal should be g rounded in RMII Mode.
TXD325I8Tr a ns m it D a ta 3: The MAC transmits data to the transceiver using thi s
signal in MII Mode.
This signal should be g rounded in RMII Mode.
nINT/
TXER/
TXD4
18IOPUnINT – Active low interrupt output. Place an external resistor pull-up to
VDDIO.
See Section 4.10 for information on how nINTSEL is used to determine
the function for this pin.
TXER – MII Transmit Error: When driven high, the 4B/5B encode process
substitutes the Transmit Error code-group (/H/) for the encoded data word.
This input is ignored in 10Base-T operation.
TXD4 – MII Transmit Data 4: In Symbol Interface (5B Decoding) mode, this
signal becomes the MII Transmit Data 4 line, the MSB of the 5-bit symbol
code-group.
TXD4 is not used i n RMII Mode.
This signal is mu x’d with nINT
TXEN21IPDTransmit Enable: Indicates that valid data is presented on the TXD[3:0]
signals, for transmission. In RMII Mode, only TXD[1:0] have vali d data.
TXCLK20O8Tr a ns m it C l oc k : Used to latch data from the MAC into the transceiver.
MII (100BT): 25MHz
MII (10BT): 2.5MHz
This signal is not used in R MII Mode.
RXD0/
MODE0
RXD1/
MODE1
RXD2/
RMIISEL
RXD3/
PHYAD2
11IOPURXD0 – Rece ive Data 0: Bit 0 of the 4 data bits that are sent by the
transceiver in the receive path.
MODE0 – PHY Operating Mode Bit 0: set the default MODE of the PHY.
See Section 5.3.9.2 for information on the MODE options.
10IOPURXD1 – Receive Data 1: Bit 1 of the 4 data bits that are sent by the PHY
in the receive path.
MODE1 – PHY Operating Mode Bit 1: set the default MODE of the PHY.
See Section 5.3.9.2 for information on the MODE options.
9IOPDRXD2 – Receive Data 2: Bit 2 of the 4 data bits that are sent by the
transceiver in the receive path.
The RXD2 signa l is not used in RMII Mode.
RMIISEL –MII/RMII Mode Selection: Latched on the rising edge of the
internal reset (nRESET) based on the following strapping:
By default, MII mode is selected.
Pull this pin high to VDDIO with an external resistor to select RMII mo de,
8IOPDRXD3 – Receive Data 3: Bit 3 of the 4 data bits that are sent by the
transceiver in the receive path.
This signal is not used in R MII Mode.
This signal is mu x’d with PHYAD2
PHYAD2 – PHY Address Bit 2: set the SMI address of the transceiver.
See Section 5.3.9.1 for information on the ADDRESS options.
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13IOPDRXER – Receive Error: Asserted to indicate that an error was detected
somewhere in the frame presently being transferred from the transceiver.
The RXER signal is optional in RMII Mode.
RXD4 – MII Receive Data 4: In Symbol Interface (5B Decoding) mode, this
signal is the MII Receive Data 4 signal, the MSB of the received 5-bit
symbol code-group. Unless configured in this mode, the pin functions as
RXER.
This signal is mu x’d with PHYAD0
PHYAD0 – PHY Address Bit 0: set the SMI address of the PHY.
See Section 5.3.9.1 for information on the ADDRESS options.
RXCLK/
PHYAD1
7IOPDRXCLK – Receive Clock: In MII mode, this pin is the receive clock output.
25MHz in 100Base-TX mode. 2.5MHz in 10Base-T mode.
This signal is mu x’d with PHYAD1
PHYAD1 – PHY Address Bit 1: set the SMI address of the transceiver.
See Section 5.3.9.1 for information on the ADDRESS options.
RXDV26O8Receive Data Valid: Indicates that recovered and decoded data is being
presented on RXD pins.
COL/
CRS_DV/
MODE2
15IOPUCOL – MII Mode Collision Detect: Asserted to indicate detection of
Asserted to indicate when the receive medium is non-idle. When a 10BT
packet is received, CRS_DV is asserted, but RXD[1:0] is held low until the
SFD byte (10101011) is received. In 10BT, half-duplex mode, transmitted
data is not looped back onto the receive data pins, per the RMII standard.
MODE2 – PHY Operating Mode Bit 2: set the default MODE of the PHY.
See Section 5.3.9.2 for information on the MODE options.
CRS14IOPDCarrier Sense: Indicates detection of carrier.
3.2 LED Signals
Table 3.3 LED Signals 32-QFN
SIGNAL
NAME
LED1/
REGOFF
32-QFN
PIN #TYPEDESCRIPTION
3IOPDLED1 – Link activity LED Indication.
See Section 5.3.7 for a description of LED modes.
REGOFF – Regulator Off: This pin may be used to configure the internal
1.2V regulator off. As described in Section 4.9, this pin is sampled during th e
power-on sequence to determine if the internal regul ator should turn on.
When the regulator is disabled, external 1.2V must be supplied to VDDCR.
When LED1/REGOFF is pulled high to VDD2A with an external resistor, the
internal regulator is disabled.
When LED1/REGOFF is floating or p ulled low, the internal regulator is
enabled (default).
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Table 3.3 LED Signals 32-QFN (continued)
SIGNAL
NAME
LED2/
nINTSEL
32-QFN
PIN #TYPEDESCRIPTION
2IOPULED2 – Link Speed LED Indication.
See Section 5.3.7 for a description of LED modes.
nINTSEL: On power-up or external reset, the mode of the nINT/TXER/TXD4
pin is selected.
When LED2/nINTSEL i s floated or pulled to VDDIO, nINT is selected for
operation on pin nINT/TXER/TXD4 (default).
When LED2/nINTSEL is pulled low to VSS through a resistor, TXER/TXD4
is selected for operation on pin nINT/TXER/TXD4.
See Section 4.10 for additional information.
3.3 Management Signals
Table 3.4 Management Signals 32-QFN
SIGNAL
NAME
MDIO16IOD8Management Data Input/OUTPUT: Serial management data input/output.
MDC17I8Management Clock: Serial management cl ock.
32-QFN
PIN #TYPEDESCRIPTION
3.4 General Signals
T ab le 3.5 General Signals 32-QFN
SIGNAL
NAME
XTAL1/
CLKIN
XTAL24OCLKClock Output: Crystal connection.
nRST19IOPUExternal Reset: Input of the system reset. This signal is active LOW.
32-QFN
PIN #TYPEDESCRIPTION
5ICLKClock Input: Crystal connection or external clock input.
Float this pin when an external clock is driven to XTAL1/CLKIN.
3.5 10/100 Line Interface Signals
Table 3.6 10/100 Line Interface Signals 32-QFN
SIGNAL
NAME
TXP29AIOTransmit/Receive Positive Channel 1.
32-QFN
PIN #TYPEDESCRIPTION
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Table 3.6 10/100 Line Interface Signals (continued) 32-QFN (continued)
RBIAS32AIExternal 1% Bias Resistor. Requires a 12.1k ohm (1%) resistor to ground
32-QFN
PIN #TYPEDESCRIPTION
connected as described in the Analog Layout Guidelines. The nomin al
voltage is 1.2V and the resistor will dissipate approximately 1mW of power.
3.7 Power Signals
Table 3.8 Power Signals 32-QFN
SIGNAL
NAME
VDDIO
VDDCR6P+1.2V (Core voltage) - 1.2V for digital circuitry on chip. Supplied by the on-
VDD1A27P+3.3V Analog Port Power to Channel 1.
VDD2A1P+3.3V Analog Port Power to Channel 2 and to internal regulator.
VSSFLAGGNDThe flag must be connected to the ground plane with a via array under the
32-QFN
PIN #TYPEDESCRIPTION
12P+1.6V to +3.6V Variable I/O Pad Power
chip regulator unless configured for regulator off mode us ing the
LED1/REGOFF pin. A 1uF decoupling capacitor to ground should be used on
this pin when using the internal 1.2V regulator.
exposed flag. This is the ground connection for the IC.
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Chapter 4 Architecture Details
4.1 Top Level Functional Architecture
Functionally, the transceiver can be divided into the following sections:
100Base-TX transmit and rece ive
10Base-T transmit and receive
MII or RMII interface to the controller
Auto-negotiation to automatically determi ne the best speed and duplex possible
Management Control to read status registers and write control reg isters
TX_CLK
(for MII only)
PLL
MAC
125 Mbps Serial
Ex t Re f_ CL K (fo r RMII on ly )
MII 25 Mhz by 4 bits
or
RMII 50Mhz by 2 bits
NRZI
Converter
M II/R MII
NRZI
Magnetics
25MHz
by 4 bits
MLT-3
Converter
MLT-3
4B/5B
Encoder
MLT-3
Figure 4.1 100Base-TX Data Path
4.2 100Base-TX Transmit
The data path of the 100Base-TX is shown in Figure 4.1. Each majo r block is explained below.
4.2.1100M Transmit Data Across the MII/RMII Interface
25MHz by
5 bits
Tx
Driver
MLT-3MLT-3
Scrambler
and PISO
CAT-5RJ45
For MII, the MAC controller drives the transmit data onto the TXD bus and asserts TXEN to indicate
valid data. The data is latched by the transceiver ’s MII block on the rising edge of TXCLK. The data
is in the form of 4-bit wide 25MHz data.
For RMII, the MAC controller drives the transmit data onto the TXD bus and asserts TXEN to indicate
valid data. The data is latched by the transceiver’s RMII block on the rising edge of REF _CLK. The
data is in the form of 2-bit wide 50MHz data.
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4.2.24B/5B Encoding
The transmit data passes from the MII block to the 4B/5B encoder. This block encodes the data from
4-bit nibbles to 5-bit symbols (known as “code-groups”) according to Table 4.1. Each 4-bit data-nibble
is mapped to 16 of the 32 possible code-groups. The remaining 16 code-groups are either used for
control information or are not valid.
The first 16 code-groups are referred to by the hexadecimal values of their corre sponding data nibbles,
0 through F. The remaining code-groups are given letter designations with slashes on either side. For
example, an IDLE code-group is /I/, a transmit error code-group is /H/, etc.
MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX and flexPWR® Technology in a Small Footprint
Datasheet
The encoding process may be bypassed by clearing bit 6 of register 31. When the encoding is
bypassed the 5
th
transmit data bit is equivalent to TXER.
Note that encoding can be bypassed only when the MAC interface is configured to operate in MII
mode.
Table 4.1 4B/5B Code Table
CODE
GROUPSYM
RECEIVER
INTERPRETATION
TRANSMITTER
INTERPRETATION
11110000000 DATA00000 DATA
0100111000110001
1010022001020010
1010133001130011
0101044010040100
0101155010150101
01110 66 011060110
0111177 011170111
1001088 100081000
10011 99 100191001
10110 AA 1010A1010
10111 BB 1011B1011
11010 CC 1100C1100
11011DD 1101D1101
11100EE 1110E1110
11101FF 1111F1111
11111IIDLESent after /T/R until TXEN
11000JFirst nibble of SSD, translated to “0101”
Sent for rising TXEN
following IDLE, else RXER
10001KSecond n ibble of SSD, translated to
Sent for rising TXEN
“0101” following J, else RXER
01101TFirst nibble of ESD, causes de-assertion
Sent for falling TXEN
of CRS if followed by /R/, else assertion
of RXER
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Table 4.1 4B/5B Code Table (continued)
CODE
GROUPSYM
00111RSecond nibble of ESD, causes
deassertion of CRS if following /T/, else
assertion of RXER
00100HTransmit Error SymbolSent for rising TXER
00110VINVALID, RXER if during RXDVINVALID
11001VINVALID, RXER if during RXDVINVALID
00000VINVALID, RXER if during RXDVINVALID
00001VINVALID, RXER if during RXDVINVALID
00010VINVALID, RXER if during RXDVINVALID
00011VINVALID, RXER if during RXDVINVALID
00101VINVALID, RXER if during RXDVINVALID
01000VINVALID, RXER if during RXDVINVALID
01100VINVALID, RXER if during RXDVINVALID
10000VINVALID, RXER if during RXDVINVALID
RECEIVER
INTERPRETATION
TRANSMITTER
INTERPRETATION
Sent for falling TXEN
4.2.3Scrambling
Repeated data patterns (especially the IDLE code-group) can have power spectral densities with large
narrow-band peaks. Scrambling the data helps eliminate these peaks and spread the signal power
more uniformly over the entire channel bandwidth. This uniform spectral density is required by FCC
regulations to prevent excessive EMI fr om being radiated by the physical wiring.
The seed for the scrambler is generated from the transceiver addre ss, PHYAD[4:0], ensuring that in
multiple-transceiver applications, such as repeaters or switches, each transceiver will have its own
scrambler sequence.
The scrambler also performs the Parallel In Serial Out conversion (PISO) of the data.
4.2.4NRZI and MLT3 Encoding
The scrambler block passes the 5-bit wide parallel data to the NRZI converter where it becomes a
serial 125MHz NRZI data stream. The NRZI is encoded to MLT-3. MLT3 is a tri-level code where a
change in the logic level represents a code bit “1” an d the logic output remaining at the same level
represents a code bit “0”.
4.2.5100M Transmit Driver
The MLT3 data is then passed to the analog transmitter, which drives the differential MLT-3 signal, on
outputs TXP and TXN, to the twisted pair media across a 1:1 ratio isolation transformer. The 10BaseT and 100Base-TX signals pass through the same transformer so that common “magnetics” can be
used for both. The transmitter drives into the 100Ω impedance of the CAT-5 cable. Cable termination
and impedance matching require external components.
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4.2.6100M Phase Lock Loop (PLL)
The 100M PLL locks onto reference clo ck and generates the 125MHz clock used to drive the 125
MHz logic and the 100Base-Tx Transmitter.
TX_CLK
(for MII only)
Datasheet
PLL
MAC
125 Mbps Serial
Ex t Re f_ CL K (fo r RMII on ly )
MII 25 Mhz by 4 bits
or
RMII 50Mhz by 2 bits
NRZI
Converter
M II/R MII
Magnetics
Figure 4.2 Receive Data Path
4.3 100Base-TX Receive
The receive data path is shown in Figure 4.2. Detailed descriptions are given below.
4.3.1100M Receive Input
NRZI
25MHz
by 4 bits
MLT-3
Converter
MLT-3
4B/5B
Encoder
MLT-3
25MHz by
5 bits
Tx
Driver
MLT-3MLT-3
Scrambler
and PISO
CAT-5RJ45
The MLT-3 from the cable is fed into the transceiver (on inputs RXP and RXN) via a 1:1 ratio
transformer. The ADC samples the incoming differential signal at a rate of 125M samples per second.
Using a 64-level quanitizer it generates 6 digital bits to represent each sample. The DSP adjusts the
gain of the ADC according to the observed signal levels such that the full dynamic range of the ADC
can be used.
4.3.2Equalizer, Baseline Wander Correction and Clock and Data Recovery
The 6 bits from the ADC are fed into the DSP block. The equalizer in the DSP section compensates
for phase and amplitude distortion caused by the physical channel consisting of magnetics, connectors,
and CAT- 5 cable. The equalizer can restore the signal for any good-quality CAT-5 cable between 1m
and 150m.
If the DC content of the signal is such that the low-frequency components fall below the low frequency
pole of the isolation transformer, then the droop characteristics of the transformer will become
significant and Baseline Wander (BLW) on the received signal will result. To prevent corruption of the
received data, the transceiver corrects for BLW and can receive the ANSI X3.263-1995 FDDI TP-PMD
defined “killer packet” with no bit errors.
The 100M PLL generates multiple phases of the 125MHz clock. A multiplexer, controlled by the timing
unit of the DSP, selects the optimum phase for sampling the data. This is used as the received
recovered clock. This clock is used to extract the serial data from the received signal.
Revision 1.0 (04-15-09)22SMSC LAN8710/LAN8710i
DATASHEET
MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX and flexPWR® Technology in a Small Footprint
Datasheet
4.3.3NRZI and MLT-3 Decoding
The DSP generates the MLT-3 recovered levels that are fed to the MLT-3 converter. The MLT-3 is then
converted to an NRZI data stream.
4.3.4Descrambling
The descrambler performs an inverse function to the scramb ler in the transmitter and also performs
the Serial In Parallel Out (SIPO) conversion of the data.
During reception of IDLE (/I/) symbols. the descrambler synchronizes its descrambler key to the
incoming stream. Once synchronization is achieved, the descrambler locks on this key and is able to
descramble incoming data.
Special logic in the descrambler ensures synchronization with the remote transceiver by searching for
IDLE symbols within a window of 4000 bytes (40us). This window ensures tha t a maximum packet size
of 1514 bytes, allowed by the IEEE 802.3 standard, can be received with no interference. If no IDLEsymbols are detected within this time-period, receive operation is aborted and the descra m bler re-starts
the synchronization process.
The descrambler can be bypassed by setting bit 0 of register 31.
4.3.5Alignment
The de-scrambled signal is then aligned into 5-bit cod e-groups by recognizing the /J/K/ Start-of-Stream
Delimiter (SSD) pair at the start of a packet. Once the code-word alignment is determined, it is stored
and utilized until the next start of frame.
4.3.65B/4B Decoding
The 5-bit code-groups are translated into 4-bit data nibbles according to the 4B/5B table. The
translated data is presented on the RXD[3:0] signal lines. The SSD, /J/K/, is translated to “0101 0101”
as the first 2 nibbles of the MAC preamble. Recepti on of the SSD causes the transceiver to assert the
RXDV signal, indicating that valid data is available on the RXD bus. Successive valid code-groups are
translated to data nibbles. Reception of either the End of Stream Delimiter (ESD) consisting of the /T/R/
symbols, or at least two /I/ symbols causes the transceiver to de-assert carrier sense and RXDV.
These symbols are not translated into data.
The decoding process may be bypassed by clearing bit 6 of register 31. When the decoding is
bypassed the 5
only when the MAC interface is in MII mode.
th
receive data bit is driven out on RXER/RXD4/PHYAD0. Decoding may be bypassed
4.3.7Receive Data Valid Signal
The Receive Data Valid signal (RXDV) indicates that recovered and decoded nibbles are being
presented on the RXD[3:0] outputs synchronous to RXCLK. RXDV becomes active after the /J/K/
delimiter has been recognized and RXD is aligned to nibble boundaries. It remains active until either
the /T/R/ delimiter is recognized or link test indicates failure or SIGDET becomes false.
RXDV is asserted when the first nibble of translated /J/K/ is ready for transfer over the Media
Independent Interface (MII mode).
SMSC LAN8710/LAN8710i23Revision 1.0 (04-15-09)
DATASHEET
MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX and flexPWR® Technology in a Small Footprint
5D5
CLEAR-TEXT
5JK
data data data data
RX_CLK
RX_DV
5D5data data data data
RXD
555
Figure 4.3 Relationship Betwee n Received Data and Specific MII Signals
4.3.8Receiver Errors
During a frame, unexpected code-groups are considered receive errors. Expected code groups are the
DATA set (0 through F), and the /T/R/ (ESD) symbol pair. When a receive error occurs, the RXER
signal is asserted and arbitrary data is driven onto the RXD[3:0] lines. Should an error be detected
during the time that the /J/K/ delimiter is being decoded (bad SSD error), RXER is asserted true and
the value ‘1110’ is driven onto the RXD[3:0] lines. Note that the Valid Data signal is not yet asserted
when the bad SSD error occurs.
4.3.9100M Receive Data Across the MII/RMII Interface
TR
Datasheet
Idle
In MII mode, the 4-bit data nibbles are sent to the MII block. These data nibbles are clocked to the
controller at a rate of 25MHz. The controller samples the data on the rising edge of RXCLK. To ensure
that the setup and hold requirements are met, the nibbles are clocked out of the transceiver on the
falling edge of RXCLK. RXCLK is the 25MHz output clock for the MII bus. It is recovered from the
received data to clock the RXD bus. If there is no received signal, it is derived from the system
reference clock (XTAL1/CLKIN).
When tracking the received data, RXCLK has a maximum jitter of 0.8ns (provided that the jitter of the
input clock, XTAL1/CLKIN, is below 100ps).
In RMII mode, the 2-bit data nibbles are sent to the RMII block. These data nibbles are clocked to the
controller at a rate of 50MHz. The controller samples the data on the rising edge of XTAL1/CLKIN
(REF_CLK). To ensure that the setup and hold requirements are met, the nibbles are clocked out of
the transceiver on the falling edge of XTAL1/CLKIN (REF_CLK).
4.4 10Base-T Transmit
Data to be transmitted comes from the MAC layer controller. The 10Base-T transmitter receives 4-bit
nibbles from the MII at a rate of 2.5MHz and converts them to a 10Mbps serial data stream. The data
stream is then Manchester-encoded and sent to the analog transmitter, which drives a signal onto the
twisted pair via the external magnetics.
4.4.110M Transmit Data Across the MII/RMII Interface
The MAC controller drives the transmit data onto the TXD BUS. For MII, when the controller has driven
TXEN high to indicate valid data, the data is latched by the MII block o n the rising edge of TXCLK.
The data is in the form of 4-bit wide 2.5MHz data.
Revision 1.0 (04-15-09)24SMSC LAN8710/LAN8710i
DATASHEET
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