Cortina Systems®LXT972M Single-Port
10/100 Mbps PHY Transceiver
Datasheet
The Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver (LXT972M PHY) directly
supports both 100BASE-TX and 10BASE-T applications. The LXT972M PHY is IEEE compliant and
provides a Media Independent Interface (MII) for easy attachment to 10/100 Media Access Controllers
(MACs). The LXT972M PHY supports full-duplex operation at 10 Mbps and 100 Mbps. Operating
conditions for the LXT972M PHY can be set using auto-negotiation, parallel detection, or manual control.
The LXT972M PHY is fabricated with an advanced CMOS process and requires only a single 2.5/3.3 V
power supply.
Applications
Product Features
Combination 10BASE-T/100BASE-TX Network
Interface Cards (NICs)
Wireless access points
Network printers
10/100 Mbps PCMCIA cards
Cable Modems and Set-Top Boxes
3.3 V Operation
Low power consumption (300 mW typical)
10BASE-T and 100BASE-TX using a single RJ-
45 connection
IEEE 802.3-compliant 10BASE-T or 100BASE-
TX ports with integrated filters
Auto-negotiation and parallel detection
MII interface with extended register capability
Robust baseline wander correction
Carrier Sense Multiple Access / Collision
Detection (CSMA/CD) or full-duplex operation
JTAG boundary scan
MDIO serial port or hardware pin configurable
Integrated, programmable LED drivers
48-pin Low-profile Quad Flat Package
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
Legal Disclaimers
INFORMATION IN THIS DOCUMENT IS PROV ID ED IN CONNECTION WITH CORTINA SYSTEMS®PRODUCTS.
NO LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS
GRANTED BY THIS DOCUMENT.
EXCEPT AS PROVIDED IN CORTINA’S TERMS AND CONDITIONS OF SALE OF SUCH PRODUCTS, CORTINA ASSUMES
NO LIABILITY WHATSOEVER, AND CORTINA DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE
SALE AND/OR USE OF CORTINA PRODUCTS, INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A
PARTICULAR PURPOSE, MERCHANTABILITY OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER
INTELLECTUAL PROPERTY RIGHT.
Cortina products are not intended for use in medical, life saving, life sustaining, critical control or safety systems, or in nuclear
facility applications.
Cortina Systems® and the Cortina Systems logo are the trademarks or registered trademarks of Cortina Systems, Inc. and its
subsidiaries in the U.S. and other countries. Other names and brands may be claimed as the property of others.
Copyright © 2001−2007 Cortina Systems, Inc. All rights reserved.
Page 2Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
Page 3Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
Contents
Contents
1.0 Introduction to This Document ..................................................................................................10
1.1 Document Overview ...........................................................................................................10
1.2 Related Documents ............................................................................................................10
2.0 Block Diagram .............................................................................................................................11
3.0 Ball and Pin Assignments ..........................................................................................................12
4.0 Signal Descriptions.....................................................................................................................16
5.0 Functional Description................................................................................................................21
5.1 Device Overview .................................................................................................................21
5.1.1 Comprehensive Functionality ................................................................................21
5.1.2 Optimal Signal Processing Architecture................................................................. 21
5.2 Network Media / Protocol Support ......................................................................................22
5.2.1 10/100 Network Interface.......................................................................................22
5.2.2 MII Data Interface ..................................................................................................23
5.2.3 Configuration Management Interface ....................................................................23
5.3 Operating Requirements.....................................................................................................25
5.3.1 Power Requirements .............................................................................................25
5.3.2 Clock Requirements .............................................................................................. 25
5.4 Initialization .........................................................................................................................25
5.4.1 MDIO Control Mode and Hardware Control Mode.................................................27
5.4.2 Reduced-Power Modes .........................................................................................27
5.4.3 Reset .....................................................................................................................27
5.4.4 Hardware Configuration Settings ...........................................................................28
5.5 Establishing Link .................................................................................................................28
5.5.1 Auto-Negotiation ....................................................................................................29
5.5.2 Parallel Detection...................................................................................................30
5.6 MII Operation ......................................................................................................................30
5.6.1 MII Clocks ..............................................................................................................31
5.6.2 Transmit Enable.....................................................................................................32
5.6.3 Receive Data Valid ................................................................................................32
5.6.4 Carrier Sense.........................................................................................................33
5.6.5 Error Signals ..........................................................................................................33
5.6.6 Collision .................................................................................................................33
5.6.7 Loopback ............................................................................................................... 33
5.7 100 Mbps Operation ........................................................................................................... 35
5.7.1 100BASE-X Network Operations ...........................................................................35
5.7.2 Collision Indication ................................................................................................. 37
5.7.3 100BASE-X Protocol Sublayer Operations............................................................38
5.8 10 Mbps Operation .............................................................................................................42
5.8.1 10BASE-T Preamble Handling ..............................................................................42
5.8.2 10BASE-T Carrier Sense.......................................................................................42
5.8.3 10BASE-T Dribble Bits ..........................................................................................42
5.8.4 10BASE-T Link Integrity Test ................................................................................42
5.8.5 Link Failure ............................................................................................................43
5.8.6 10BASE-T SQE (Heartbeat) ..................................................................................43
5.8.7 10BASE-T Jabber ..................................................................................................43
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Contents
5.8.8 10BASE-T Polarity Correction ............................................................................... 43
5.9 Monitoring Operations ........................................................................................................43
5.9.1 Monitoring Auto-Negotiation ..................................................................................43
5.9.2 Monitoring Next Page Exchange ...........................................................................44
5.9.3 LED Functions .......................................................................................................44
5.9.4 LED Pulse Stretching.............................................................................................44
5.10 Boundary Scan (JTAG 1149.1) Functions ..........................................................................45
5.10.1 Boundary Scan Interface .......................................................................................45
5.10.2 State Machine........................................................................................................ 45
5.10.3 Instruction Register................................................................................................45
5.10.4 Boundary Scan Register ........................................................................................ 46
5.10.5 Device ID Register .................................................................................................46
6.0 Application Information ..............................................................................................................47
6.1 Magnetics Information ........................................................................................................47
6.2 Typical Twisted-Pair Interface ............................................................................................47
7.0 Electrical Specifications .............................................................................................................51
7.1 DC Electrical Parameters ...................................................................................................51
7.2 AC Timing Diagrams and Parameters ................................................................................54
8.0 Register Definitions - IEEE Base Registers ..............................................................................64
9.0 Register Definitions - Product-Specific Registers ...................................................................72
10.0 Package Specifications...............................................................................................................80
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Figures
Figures
1 Block Diagram ...............................................................................................................................11
2 48-Pin LQFP Package: Pin Assignments ......................................................................................13
3 Management Interface Read Frame Structure ............................................................................. 24
4 Management Interface Write Frame Structure .............................................................................24
5 Initialization Sequence...................................................................................................................26
6 Link Establishment Overview .......................................................................................................29
7 Clocking for 10BASE-T .................................................................................................................31
8 Clocking for 100BASE-X ..............................................................................................................32
9 Clocking for Link Down Clock Transition ...................................................................................... 32
10 Loopback Paths.............................................................................................................................34
11 100BASE-X Frame Format ...........................................................................................................35
12 100BASE-TX Data Path ...............................................................................................................36
13 100BASE-TX Reception with No Errors .......................................................................................36
14 100BASE-TX Reception with Invalid Symbol ...............................................................................37
15 100BASE-TX Transmission with No Errors ..................................................................................37
16 100BASE-TX Transmission with Collision ....................................................................................37
17 Protocol Sublayers .......................................................................................................................38
18 LED Pulse Stretching ...................................................................................................................45
19 Typical Twisted-Pair Interface - Switch .........................................................................................48
20 Typical Twisted-Pair Interface - NIC ..............................................................................................49
21 Typical Media Independent Interface ............................................................................................50
22 100BASE-TX Receive Timing .......................................................................................................55
23 100BASE-TX Transmit Timing ......................................................................................................56
24 10BASE-T Receive Timing............................................................................................................57
25 10BASE-T Transmit Timing ..........................................................................................................58
26 10BASE-T Jabber and Unjabber Timing ......................................................................................59
27 10BASE-T SQE (Heartbeat) Timing .............................................................................................59
28 Auto-Negotiation and Fast Link Pulse Timing ............................................................................... 60
29 Fast Link Pulse Timing .................................................................................................................. 60
30 MDIO Input Timing ........................................................................................................................ 61
31 MDIO Output Timing...................................................................................................................... 61
32 Power-Up Timing........................................................................................................................... 62
33 RESET_L Pulse Width and Recovery Timing ...............................................................................62
34 PHY Identifier Bit Mapping ...........................................................................................................67
35 LQFP Package Specifications .......................................................................................................80
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Ta b l e s
Tables
1 Related Documents .......................................................................................................................10
2 PHY Signal Types .........................................................................................................................12
3 LQFP Numeric Pin List ..................................................................................................................13
4 PHY Signal Types .........................................................................................................................16
5 LXT972M: MII Data Interface Signal Descriptions.........................................................................17
6 LXT972M: MII Controller Interface Signal Descriptions.................................................................18
7 LXT972M: Network Interface Signal Descriptions .........................................................................18
8 LXT972M: Standard Bus and Interface Signal Descriptions .........................................................18
9 LXT972M: Configuration and LED Driver Signal Descriptions ......................................................18
10 LXT972M: Power, Ground, No-Connect Signal Descriptions ........................................................19
11 LXT972M: JTAG Test Signal Descriptions .................................................................................... 19
12 LXT972M:Pin Types and Modes ...................................................................................................20
13 PHY Device Address Selections ...................................................................................................24
14 Hardware Configuration Settings...................................................................................................28
15 Carrier Sense, Loopback, and Collision Conditions ......................................................................33
16 4B/5B Coding ................................................................................................................................ 39
17 BSR Mode of Operation ................................................................................................................46
18 Device ID Register.........................................................................................................................46
19 Magnetics Requirements............................................................................................................... 47
20 I/O Pin Comparison of NIC and Switch RJ-45 Setups...................................................................47
21 Absolute Maximum Ratings ...........................................................................................................51
22 Recommended Operating Conditions ...........................................................................................51
23 Digital I/O Characteristics (Except for MII, XI/XO, and LED/CFG Pins) ........................................52
24 Digital I/O Characteristics1 - MII Pins ............................................................................................52
25 I/O Characteristics - REFCLK/XI and XO Pins ..............................................................................53
26 I/O Characteristics - LED/CFG Pins ..............................................................................................53
27 100BASE-TX PHY Characteristics ................................................................................................53
28 10BASE-T PHY Characteristics ....................................................................................................54
29 10BASE-T Link Integrity Timing Characteristics............................................................................54
30 Thermal Characteristics.................................................................................................................54
31 100BASE-TX Receive Timing Parameters - 4B Mode ..................................................................56
32 10BASE-T Receive Timing Parameters ........................................................................................57
33 10BASE-T Jabber and Unjabber Timing .......................................................................................59
34 PHY 10BASE-T SQE (Heartbeat) Timing......................................................................................59
35 Auto-Negotiation and Fast Link Pulse Timing Parameters ............................................................60
36 MDIO Timing .................................................................................................................................61
37 Power-Up Timing........................................................................................................................... 62
38 RESET_L Pulse Width and Recovery Timing ...............................................................................63
39 Register Set for IEEE Base Registers ...........................................................................................64
40 Control Register - Address 0, Hex 0 ..............................................................................................65
41 MII Status Register #1 - Address 1, Hex 1 ....................................................................................66
42 PHY Identification Register 1 - Address 2, Hex 2 ..........................................................................67
43 PHY Identification Register 2 - Address 3, Hex 3 ..........................................................................67
44 Auto-Negotiation Advertisement Register - Address 4, Hex 4.......................................................68
45 Auto-Negotiation Link Partner Base Page Ability Register - Address 5, Hex 5 .............................69
46 Auto-Negotiation Expansion - Address 6, Hex 6 ...........................................................................70
47 Auto-Negotiation Next Page Transmit Register - Address 7, Hex 7 .............................................. 70
48 Auto-Negotiation Link Partner Next Page Receive Register - Address 8, Hex 8 ..........................71
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Ta b l e s
49 Register Set for Product-Specific Registers ..................................................................................72
50 Configuration Register - Address 16, Hex 10 ................................................................................72
51 Status Register #2 - Address 17, Hex 11 ......................................................................................73
52 Interrupt Enable Register - Address 18, Hex 12 ............................................................................75
53 Status Change Register - Address 19, Hex 13.............................................................................. 75
54 LED Configuration Register - Address 20, Hex 14 ........................................................................77
55 Digital Configuration Register - Address 26, Hex 1A.....................................................................78
56 Transmit Control Register - Address 30, Hex 1E ..........................................................................79
Page 8Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
Revision History
Revision History
Revision 5.2
Revision Date: 13 September 2007
• Removed outdated Figure 3: 64-Pin Pb-Free LQFP Pack age: Pins Assignments
• Removed the ordering information. This information is now available from www.cortina-systems.com.
Revision 5.1
Revision Date: 23 July 2007
Added Section 10.0, Package Specifications back into Datasheet.
Revision 5.0
Revision Date: 2 July 2007
First release of this document from Cortina Systems, Inc.
Revision 004
Revision Date: 01 January 2007
Internal release. No changes.
Revision 003
Revision Date: 14 July 2004
Figure 3, LXT972M Transceiver Block Diagram - Deleted ECL Driver from figure.
Section 5.1, Device Overview - Text changed.
Section 5.2.1.1, Twisted-Pair Interface - Added text on MDI crossover.
Section 5.2.1.5, Remote Fault Detection and Reporting - Text changed.
Section 5.3.2.1, External Crystal/Oscillator - Text changed.
Table 37, Hardware Configuration Settings for Cortina Systems® LXT977 Transceiver - Bit value for 0.8 changed.
Section 5.5.2, Parallel Detection - Text changed.
Section 5.6.2, Transmit Enable - Text changed.
Section 5.6.4, Carrier Sens e - Text changed.
Section 5.7.3.1.1, Preamble Handling - Text changed.
Section 5.7.3.2.1, Link - Added text.
Section 5.7.3.2.2, Link Failure Override - Added text.
Section 5.7.3.2.4, Receive Data Valid - Text changed.
Section 5.7.3.3.2, Polarity Correction - Text changed.
Section 5.9.4, LED Pulse Stretching - Text changed.
Table 123, Auto-Negotiation Next Page Transmit Register - Address 7, Hex 7 - Bits 7.10:0 and 7.13 changed.
Table 124, Auto-Negotiation Link Partner Next Page Receive Register - Address 8, Hex 8 - Bits 8.18 and 8.10:0 changed.
Table 131, LED Configuration Register - Address 20, Hex 14 - Bit 20.0 changed.
Revision 002
Revision Date: 14 July 2004
Text changed.
Figure 3, LXT972M Transceiver Block Diagram - Deleted ECL Driver from figure.
Section 5.1, Device Overvie w - Text changed.
Page 9Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
Revision History
Section 5.2.1.1, Twisted-Pair Interface - Added text on MDI crossover.
Section 5.2.1.5, Comment: for LXT972A/972M/977-->Remote Fault Detection and Reporting - Text changed.
Section 5.3.2.1, External Crystal/Oscillator - Text changed.
Table 37, Hardware Configuration Settings for Cortina System s® LXT977 Transceiver - Bit value for 0.8 changed.
Section 5.5.2, Parallel Detection - Text changed.
Section 5.6.2, Transmit Enable - Text changed.
Section 5.6.4, Carrier Sense - Text changed.
Section 5.7.3.1.1, Preamble Handling - Text changed.
Section 5.7.3.2.1, Link - Added text.
Section 5.7.3.2.2, Link Failure Override - Added text.
Section 5.7.3.2.4, Receive Data Valid - Text changed.
Section 5.7.3.3.2, Polarity Correction - Text changed.
Section 5.9.4, LED Pulse Stret ching - Text changed.
Table 123, Auto-Negotiation Next Page Transmit Register - Address 7, Hex 7 - Bits 7.10:0 and 7.13 changed.
Table 124, Auto-Negotiation Link Partner Next Page Receive Register - Address 8, Hex 8 - Bits 8.18 and 8.10:0 changed.
Table 131, LED Configuration Register - Address 20, Hex 14 - Bit 20.0 changed.
Revision 001
Revision Date: 02 July 2004
Initial release of this document.
Revision 002
Revision Date: 14 July 2004
Page 10Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
1.0 Introduction to This
Document
1.0 Introduction to This Document
This document includes information on the Cortina Systems®LXT972M Single-Port 10/
100 Mbps PHY Transceiver (LXT972M PHY).
1.1 Document Overview
This document includes the following subjects:
2.0, Block Diagram, on page 11
3.0, Ball and Pin Assignments, on page 12
4.0, Signal Descriptions, on page 16
5.0, Fun ct ion al Descr ipti on, on page 21
6.0, Application Information, on page 47
7.0, Electrical Specifications, on page 51
8.0, Register Definitions - IEEE Base Registers, on page 64
9.0, Register Definitions - Product-Specific Registers, on page 72
1.2 Related Documents
Table 1 Related Documents
Document Title Document
Number
Cortina Systems® LXT971A, LXT972A, LXT972M Single-Port 10/
100 Mbps PHY Specification Update 249354
Cortina Systems® LXT971A, LXT972A, and LXT972M 3.3 V PHY
Design and Layout Guide - Application Note 249016
Magnetic Manufacturers for Networking Product Applications -
Application Note 248991
Page 11Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
2.0 Block Diagram
2.0 Block Diagram
Figure 1 Block Diagram
TX_EN
RX_ER
CRS
Power Supply
Management /
Mode Select
Logic
ADDR[1:0]
MDIO
MDC
RX_DV
TPON
TPOP
TPIN
TPIP
REFCLK/XI
VCC
GND
COL
RX_CLK
TX_CLK
TXD[3:0]
Decoder &
Descrambler
+
-
Serial-to-
Parallel
Converter
Scrambler
& Encoder
Parallel/Serial
Converter
Carrier Sense
Data Valid
Error Detect
Auto
Negotiation
Manchester
Decoder
Manchester
Encoder 10
100
10
100
Media
Select
TP
Driver TP Out
Register
Set
Register Set Clock
Generator
+
-
10BT
Collision
Detect Clock
Generator
OSP
Adaptive EQ with
Baseline Wander
Cancellation
OSP
Slicer
OSP
Pulse
Shaper
RXD[3:0]
+
-
100TX
TP In
RX PCS
JTAG 5TDO
TMS
TCK
TRST_L
RESET_L
B3387-13
LED/CFG[3:1]
TDI
TX PCS
XO
Page 12Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
3.0 Ball and Pin Assignments
3.0 Ball and Pin Assignments
See the following diagrams for signal placement:
•Figure 2, 48-Pin LQFP Package: Pin Assignments, on page 13
See the following tables for signal lists:
•Table 3, LQFP Numeric Pin List, on page 13
Note:
Table 2 list the signal type abbreviations used in the signal tables.
Table 2 PHY Signal Types
Abbreviation Definition
AI Analog Input
AO Analog Output
I Input
I/O Input/Output
O Output
OD Open Drain
Page 13Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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302875, Revision 5.3
31 October 2007
3.0 Ball and Pin Assignments
Figure 2 48-Pin LQFP Package: Pin Assignments
Table 3 LQFP Numeric Pin List (Sheet 1 of 2)
Pin Symbol Type
1CRS O
2 REFCLK/XI AI
3XO AO
4 RESET_L I
5GND –
6 VCCIO –
7NC –
8NC –
9GND –
10 ADDR0 I
B3814-03
1
2
3
4
5
6
7
8
9
10
11
12
CRS
REFCLK/ X1
X0
RESET_ L
GND
VCCIO
NC
NC
GND
ADDR0
ADDR1
RBI A S
GNDA
TPOP
TPON
VCCA
TPIP
TPIN
TDI
TDO
TMS
TCK
TRST_L
GND
COL
TXD3
TXD2
TXD1
TXD0
TX_EN
TX_CLK
RX_ER
RX_CLK
VCCD
GND
RX_DV
36
35
34
33
32
31
30
29
28
27
26
25
13
14
15
16
17
18
19
20
21
22
23
24
37
38
39
40
41
42
43
44
45
46
47
48
RXD0
RXD1
RXD 2
RXD 3
MDC
MDIO
GND
VCCIO
LED/ CFG1
LED/ CFG2
LED/ CFG3
GND
DJ972M A4
XXXXXXXX
'Y Y
Year
Pi n 1
FPO
Number
C
M
Par t
Number
Re v i si o n
Number
Page 14Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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31 October 2007
3.0 Ball and Pin Assignments
11 ADDR1 I
12 RBIAS AI
13 GNDA –
14 TPOP AO
15 TPON AO
16 VCCA –
17 TPIP AI
18 TPIN AI
19 TDI I
20 TDO O
21 TMS I
22 TCK I
23 TRST_L I
24 GND –
25 GND –
26 LED/CFG3 I/O
27 LED/CFG2 I/O
28 LED/CFG1 I/O
29 VCCIO –
30 GND –
31 MDIO I/O
32 MDC I
33 RXD3 O
34 RXD2 O
35 RXD1 O
36 RXD0 O
37 RX_DV O
38 GND –
39 VCCD –
40 RX_CLK O
41 RX_ER O
42 TX_CLK O
43 TX_EN I
44 TXD0 I
45 TXD1 I
46 TXD2 I
47 TXD3 I
48 COL O
Table 3 LQFP Numeric Pin List (Sheet 2 of 2)
Pin Symbol Type
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3.0 Ball and Pin Assignments
Page 16Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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31 October 2007
4.0 Signal Descriptions
4.0 Signal Descriptions
Cortina recommends the following configurations for unused pins:
•Unused inputs. Configure all unused inputs and unused multi-function pins for
inactive states.
•Unused outputs. Leave all unused outputs floating.
•No connects. Do not use pins designated as NC (no connect), and do not terminate
them.
Note:
Table 4 list the signal type abbreviations used in the signal tables.
Tables in this section include the following:
•Table 5, LXT972M: MII Data Interface Signal Descriptions, on page 17
•Table 6, LXT972M: MII Controller Interface Signal Descriptions, on page 18
•Table 7, LXT972M: Network Interface Signal Descriptions, on page 18
•Table 8, LXT972M: Standard Bus and Interface Signal Descriptions, on page 18
•Table 9, LXT972M: Configuration and LED Driver Signal Descriptions, on page 18
•Table 10, LXT972M: Power, Ground, No-Connect Signal Descriptions, on page 19
•Table 11, LXT972M: JTAG Test Signal Descriptions, on page 19
•Table 12, LXT972M:Pin Types and Modes, on page 20
Table 4 PHY Signal Types
Abbreviation Definition
AI Analog Input
AO Analog Output
I Input
I/O Input/Output
O Output
OD Open Drain
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31 October 2007
4.0 Signal Descriptions
Table 5 LXT972M: MII Data Interface Signal Descriptions
LQFP
Pin# Symbol Type Signal Description
47
46
45
44
TXD3
TXD2
TXD1
TXD0
I
Transmit Data.
TXD is a group of parallel data signals that are driven by the MAC.
TXD[3:0] transition synchronously with respect to TX_CLK.
TXD[0] is the least-significant bit.
43 TX_EN I
Transmi t Enab le.
The MAC asserts this signal when it drives valid data on TXD.
This signal must be synchronized to TX_CLK.
42 TX_CLK O
Transmit Clock.
TX_CLK is sourced by the PHY in both 10 and 100 Mbps operations.
2.5 MHz for 10 Mbps operation
25 MHz for 100 Mbps operation.
33
34
35
36
RXD3
RXD2
RXD1
RXD0
O
Receive Data.
RXD is a group of parallel signals that transition synchronously with
respect to RX_CLK.
RXD[0] is the least-significant bit.
37 RX_DV O
Receive Data Valid.
The LXT972M PHY asserts this signal when it drives valid data on RXD.
This output is synchronous to RX_CLK.
41 RX_ER O
Receive Error.
Signals a receive error condition has occurred.
This output is synchronous to RX_CLK.
40 RX_CLK O
Receive Clock.
25 MHz for 100 Mbps operation.
2.5 MHz for 10 Mbps operation.
For details, see Section 5.3.2, Clock Requirements, on page 25 in the
Functional Description section.
48 COL O
Collision Detected.
The LXT972M PHY asserts this output when a collision is detected.
This output remains High for the duration of the collision.
This signal is asynchronous and is inactive during full- duplex operation.
1 CRS O
Carrier Sense.
During half-duplex operation (register bit 0.8 = 0), the LXT972M PHY
asserts this output when either transmitting or receiving data packets.
During full-duplex operation (register bit 0.8 = 1), CRS is asserted only
during receive.
CRS assertion is asynchronous with respect to RX_CLK. CRS is de-
asserted on loss of carrier, synchronous to RX_CLK.
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31 October 2007
4.0 Signal Descriptions
Table 6 LXT972M: MII Controller Interface Signal Descriptions
LQFP
Pin# Symbol Type Signal Description
32 MDC I
Management Data Clock.
Clock for the MDIO serial data channel.
Maximum frequency is 8 MHz.
31 MDIO I/O Manag e men t Data Input/Out put.
Bidirectional serial data channel for PHY/STA communication.
Table 7 LXT972M: Network Interface Signal Descriptions
LQFP
Pin# Symbol Type Signal Description
14
15
TPOP
TPON AO
Twisted-Pair Outputs, Positive and Negative.
During 100BASE-TX or 10BASE-T operation, TPOP/N pins drive IEEE
802.3 compliant pulses onto the line.
17
18
TPIP
TPIN AI
Twisted-Pair Inputs, Positive and Negative.
During 100BASE-TX or 10BASE-T operation, TPIP/N pins receive
differential 100BASE-TX or 10BASE-T signals from the line.
Table 8 LXT972M: Standard Bus and Interface Signal Descriptions
LQFP
Pin# Symbol Type Signal Description
10
11
ADDR0
ADDR1 IAddress.
Set device address.
Table 9 LXT972M: Configuration and LED Driver Signal Descriptions (Sheet 1 of 2)
LQFP
Pin# Symbol Type Signal Description
Note: Implement 10 kΩ pull-up/pull-down resistors if LEDs are not used in the design.
4 RESET_L I
Reset.
This active Low input is Read with the control register Reset bit (register
bit 0.15). The LXT972M PHY reset cycle is extended to 258 μs (nominal)
after reset is de-asserted.
Page 19Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
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31 October 2007
4.0 Signal Descriptions
12 RBIAS AI
Reference Current Bias.
This pin provides bias current for the internal circuitry. Must be tied to
ground through a 22.1 kΩ, 1% resistor.
2
3
REFCLK/XI
XO
AI and
AO
Reference Clo c k Input / Cryst a l Input and Crys tal Output.
A 25 MHz crystal oscillator circuit can be connected across XI and XO. A
clock can also be used at XI. Refer to Section 5.3.2, Clock
Requirements, on page 25 in the Functional Description section.
26
27
28
LED/CFG3
LED/CFG2
LEDCFG1
I/O
LED Drivers 1-3.
These pins drive LED indicators. Each LED can display one of several
available status conditions as selected by the LED Configuration
Register. (For details, see Table 54, LED Configuration Register -
Address 20, Hex 14, on page 77.)
Configuration Inputs 1-3.
These pins also provide initial configuration settings. (For details, see
Table 14, Hardware Configuration Settings, on page 28.)
Table 10 LXT972M: Power, Ground, No-Connect Signal Descriptions
LQFP
Pin# Symbol Type Signal Description
13 GNDA – Analog Ground.
5, 9, 24,
25, 30, 38 GND – Ground Input/Output .
Ground return for digital I/O circuits (VCCIO).
6, 29 VCCIO –
MII Power.
Requires either a 3.3 V or a 2.5 V supply. Must be supplied from the
same source used to power the MAC on the other side of the MII.
VCCIO is 3.3 V.
16 VCCA – Analog Power.
Requires a 3.3 V power supply.
39 VCCD – Digital Power.
Requires a 3.3 V power supply.
7, 8 NC – No Connection.
These pins are not used and must not be terminated.
Table 11 LXT972M: JTAG Test Signal Descriptions (Sheet 1 of 2)
LQFP
Pin# Symbol Type Signal Description
Note: These pins do not need to be terminated If a JTAG port is not used.
19 TDI I Test Data Input.
Test data sampled with respect to the rising edge of TCK.
20 TDO O Test Data Output.
Test data driven with respect to the falling edge of TCK.
Table 9 LXT972M: Configuration and LED Driver Signal Descriptions (Sheet 2 of 2)
LQFP
Pin# Symbol Type Signal Description
Page 20Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
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31 October 2007
4.0 Signal Descriptions
21 TMS I Test Mode Select.
22 TCK I Test Cl ock .
Clock input for boundary scan.
23 TRST_L I Test Reset.
This active-low test reset input is sourced by ATE.
Table 12 LXT972M:Pin Types and Modes
Modes RXD3:0 RX_DV
Tx/Rx
CLKS
Output
RX_ER
Output
COL
Output
CRS
Output
TXD3:0
Input
TX_EN
Input
HWReset DLDLDHDLDLDL ID ID
SFTPWRDN DL DL Active DL DL DL ID ID
ISOLATE HZ with
ID
HZ with
ID
HZ with
ID
HZ with
ID
HZ with
ID
HZ with
ID ID ID
• DH = Driven High (Logic 1)
• DL = Driven Low (Logic 0)
• HZ = High Impedance
• ID = Internal Pull-Down (Weak)
Table 11 LXT972M: JTAG Test Signal Descriptions (Sheet 2 of 2)
LQFP
Pin# Symbol Type Signal Description
Page 21Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.0 Functional Description
5.0 Functional Description
This chapter has the following sections:
•Section 5.1, Device Overview, on page 21
•Section 5.2, Network Media / Protocol Support, on page 22
•Section 5.3, Operating Requirements, on page 25
•Section 5.4, Initialization, on page 25
•Section 5.5, Establishing Link, on page 28
•Section 5.6, MII Operation, on page 30
•Section 5.7, 100 Mbps Operation, on page 35
•Section 5.8, 10 Mbps Operation, on page 42
•Section 5.9, Monitoring Operations, on page 43
•Section 5.10, Boundary Scan (JTAG 1149.1) Functions, on page 45
5.1 Device Overview
The LXT972M PHY is a single-port Fast Ethernet 10/100 PHY that supports 10 Mbps and
100 Mbps networks. It complies with applicable requirements of IEEE 802.3. It directly
drives either a 100BASE-TX line or a 10BASE-T line.
5.1.1 Comprehensive Functionality
The LXT972M PHY provides a standard Media Independent Interface (MII) for 10/100
MACs. The LXT972M PHY performs all functions of the Physical Coding Sublayer (PCS)
and Physical Media Attachment (PMA) sublayer as defined in the IEEE 802.3 100BASE-X
standard. It also performs all functions of the Physical Media Dependent (PMD) sublayer
for 100BASE-TX connections.
If the LXT972M PHY is not set for forced operation, it uses auto-negotiation/parallel
detection to automatically determine line operating conditions. If the PHY device on the
other side of the link supports auto-negotiation, the LXT972M PHY auto-negotiates with it
using Fast Link Pulse (FLP) Bursts. If the PHY partner does not support auto-negotiation,
the LXT972M PHY automatically detects the presence of either link pulses (10 Mbps
PHY) or Idle symbols (100 Mbps PHY) and sets its operating conditions accordingly.
The LXT972M PHY provides half-duplex and full-duplex operation at 100 Mbps and
10 Mbps.
5.1.2 Optimal Signal Processing Architecture
The LXT972M PHY incorporates high-efficiency Optimal Signal Processing (OSP) design
techniques, which combine optimal properties of digital and analog signal processing.
The receiver utilizes decision feedback equalization to increase noise and cross-talk
immunity by as much as 3 dB over an ideal all-analog equalizer. Using OSP mixed-signal
processing techniques in the receive equalizer avoids the quantization noise and
calculation truncation errors found in traditional DSP-based receivers (typically complex
DSP engines with A/D converters). This results in improved receiver noise and cross-talk
performance.
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LXT972M PHY
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31 October 2007
5.2 Network Media / Protocol
Support
The OSP signal processing scheme also requires substantially less computational logic
than traditional DSP-based designs. This lowers power consumption and also reduces the
logic switching noise generated by DSP engines. This logic switching noise can be a
considerable source of EMI generated on the device’s power supplies.
The OSP-based LXT972M PHY provides improved data recovery, EMI performance, and
low power consumption.
5.2 Network Media / Protocol Support
This section includes the following:
•Section 5.2.1, 10/100 Network Interface
•Section 5.2.2, MII Data Interface
•Section 5.2.3, Configuration Management Interface
The LXT972M PHY supports both 10BASE-T and 100BASE-TX Ethernet over twisted-
pair
5.2.1 10/100 Network Interface
The network interface port consists of two differential signal pairs. For specific pin
assignments, see Section 4.0, Signal Descriptions, on page 16.
The LXT972M PHY output drivers can generate one of the following outputs:
• 100BASE-TX
• 10BASE-T
When not transmitting data, the LXT972M PHY generates IEEE 802.3-compliant link
pulses or idle code. Depending on the mode selected, input signals are decoded as one of
the following:
• 100BASE-TX
• 10BASE-T
Auto-negotiation/parallel detection or manual control is used to determine the speed of
this interface.
5.2.1.1 Twisted-Pair Interface
The LXT972M PHY supports either 100BASE-TX or 10BASE-T connections over 100 Ω,
Category 5, Unshielded Twisted Pair (UTP) cable. When operating at 100 Mbps, the
LXT972M PHY continuously transmits and receives MLT3 symbols. When not transmitting
data, the LXT972M PHY generates “IDLE” symbols.
During 10 Mbps operation, Xilink* Manchester-encoded data is exchanged. When no data
is being exchanged, the line is left in an idle state. Link pulses are transmitted periodically
to keep the link up.
Only a transformer, RJ-45 connector, load resistor and bypass capacitors are required to
complete this interface. On the transmit side, the LXT972M PHY has an active internal
termination and does not require external termination resistors. Cortina’s waveshaping
technology shapes the outgoing signal to help reduce the need for external EMI filters.
Four slew rate settings allow the designer to match the output waveform to the magnetic
Page 23Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
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31 October 2007
5.2 Network Media / Protocol
Support
characteristics. On the receive side, the internal impedance is high enough that it has no
practical effect on the external termination circuit. (For the slew rate settings, see
Table 56, Transmit Control Register - Address 30, Hex 1E, on page 79.)
Note:
The MDIX crossover (MDIX) is supported by board design.
5.2.1.2 Remote Fault Detection and Reporting
The LXT972M PHY supports the remote fault detection and reporting mechanisms.
“Remote Fault” refers to a MAC-to-MAC communication function that is transparent to
PHY layer devices. It is used only during auto-negotiation, and is applicable only to
twisted-pair links.
Remote Fault Detection. register bit 4.13 in the Auto-Negotiation Advertisement Register
is reserved for Remote Fault indications. It is typically used when re-starting the auto-
negotiation sequence to indicate to the link partner that the link is down because the
advertising device detected a local fault.
When the LXT972M PHY receives a Remote Fault indication from its partner during auto-
negotiation, the following occurs:
• register bit 5.13 in the Link Partner Base Page Ability Register is set.
• Remote Fault register bit 1.4 in the MII Status Register is set to pass this information
to the local controller.
5.2.2 MII Data Interface
The LXT972M PHY supports a standard Media Independent Interface (MII). The MII
consists of a data interface and a management interface. The MII Data Interface passes
data between the LXT972M PHY and a Media Access Controller (MAC). Separate parallel
buses are provided for transmit and receive. This interface operates at either 10 Mbps or
100 Mbps. The speed is set automatically, once the operating conditions of the network
link have been determined. For details, see Section 5.6, MII Operati on, on page 30.
Increased MII Drive S trength. A higher Media Independent Interface (MII) drive strength
may be desired in some designs to drive signals over longer PCB trace lengths, or over
high-capacitive loads, through multiple vias, or through a connector. The MII drive
strength in the LXT972M PHY can be increased by setting register bit 26.11 through
software control. Setting register bit 26.11 = 1 through the MDC/MDIO interface sets the
MII pins (RXD[3:0], RX_DV, RX_CLK, RX_ER, COL, CRS, and TX_CLK) to a higher drive
strength.
5.2.3 Configuration Management Interface
The LXT972M PHY provides both an MDIO interface and a reduced hardware control
interface for device configuration and management.
5.2.3.1 MDIO Management Interface
MDIO management interface topics include the following:
•Section 5.2.3.1.1, MDIO Addressing
•Section 5.2.3.1.2, MDIO Frame Structure
Page 24Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
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31 October 2007
5.2 Network Media / Protocol
Support
The LXT972M PHY supports the IEEE 802.3 MII Management Interface also known as
the Management Data Input/Output (MDIO) Interface. This interface allows upper-layer
devices to monitor and control the state of the LXT972M PHY. The MDIO interface
consists of a physical connection, a specific protocol that runs across the connection, and
an internal set of addressable registers.
Some registers are required and their functions are defined by the IEEE 802.3 standard.
The LXT972M PHY also supports additional registers for expanded functionality. The
LXT972M PHY supports multiple internal registers, each of which is 16 bits wide. Specific
register bits are referenced using an “X.Y” notation, where X is the register number (0-31)
and Y is the bit number (0-15).
5.2.3.1.1 MDIO Addressing
The MDIO addressing protocol allows a controller to communicate with multiple PHYs.
Pins ADDR[1:0] determine the PHY device address that is selected (see Tab le 13).
5.2.3.1.2 MDIO Frame Structure
The physical interface consists of a data line (MDIO) and clock line (MDC). The frame
structure is shown in Figure 3 and Figure 4 (Read and Write).
MDIO Interface timing is given in Section 7.0, Electrical Specifications.
Table 13 PHY Device Address Selections
ADDR1
(Pin 11)
ADDR0
(Pin 10)
PHY Device
Address
Selected
00 0
01 1
10 28
11 29
Figure 3 Management Interface Read Frame Structure
Figure 4 Management Interface Write Frame Structure
MDC
MDIO
(Read) 32 "1"s 0110
Preamble ST Op Code PHY Address Turn
Around
Z0
A4 A3 A0 R4 R3 R0
Register Address
D15 D14 D1
Data
Write Read
D15 D14 D1 D0
Idle
High Z
B3489-01
MDC
MDIO
(Write) 32 "1"s 0101
Preamble ST Op Code PHY Address Turn
Around
10
A4 A3 A0 R4 R3 R0
Register Address
D15 D14 D1 D0
Data Idle
Idle
Write
B3490-01
Page 25Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
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31 October 2007
5.3 Operating Requirements
5.2.3.2 Hardware Control Interface
The LXT972M PHY provides a Hardware Control Interface for applications where the
MDIO is not desired. The Hardware Control Interface uses the hardware configuration
pins to set device configuration. For details, see Section 5.4.4, Hardware Configuration
Settings, on page 28.
5.3 Operating Requirements
5.3.1 Power Requirements
The LXT972M PHY requires three power supply inputs:
• VCCA
• VCCD
• VCCIO
The digital and analog circuits require 3.3 V supplies (VCCA and VCCD). These inputs
may be supplied from a single source. Each supply input must be de-coupled to ground.
An additional supply may be used for the MII (VCCIO). The supply may be either 2.5 V or
3.3 V. Also, the inputs on the MII interface are tolerant to 5 V signals from the controller on
the other side of the MII interface. For MII I/O characteristics, see Table 24, Digital I/O
Characteristics1 - MII Pins, on page 52.
Notes:
1. Bring up power supplies as close to the same time as possible.
2. As a matter of good practice, keep power supplies as clean as possible.
5.3.2 Clock Requirements
5.3.2.1 External Crystal/Oscillator
The LXT972M PHY requires a reference clock input that is used to generate transmit
signals and recover receive signals. It may be provided by either of two methods: by
connecting a crystal across the oscillator pins (XI and XO) with load capacitors, or by
connecting an external clock source to pin XI.
The connection of a clock source to the XI pin requires the XO pin to be left open. To
minimize transmit jitter, Cortina recommends a crystal-based clock instead of a derived
clock (that is, a PLL-based clock).
A crystal is typically used in NIC applications. An external 25 MHz clock source, rather
than a crystal, is frequently used in switch applications. For clock timing requirements, see
Table 25, I/O Characteristics - REFCLK/XI and XO Pins, on page 53.
5.3.2.2 MDIO Clock
The MII management channel (MDIO) also requires an external clock. The managed data
clock (MDC) speed is a maximum of 8 MHz.
5.4 Initialization
This section includes the following topics:
•Section 5.4.1, MDIO Control Mode and Hardware Control Mode
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31 October 2007
5.4 Initialization
•Section 5.4.2, Reduced-Power Modes
•Section 5.4.3, Reset
•Section 5.4.4, Hardware Configuration Settings
When the LXT972M PHY is first powered on, reset, or encounters a link failure state, it
checks the MDIO register configuration bits to determine the line speed and operating
conditions to use for the network link.
Figure 5 shows the LXT972M PHY initialization sequence. The configuration bits may be
set by the Hardware Control or MDIO interface.
Figure 5 Initialization Sequence
Reset MDIO Registers to
values read at H/W
Control Interface at last
Hardware Reset or
Power-Up Reset
Pass Control to MDIO
Interface
Power-up or Reset
Initialize MDIO Registers
Read H/W Control
Interface
Software
Reset?
Yes
B3502-02
Page 27Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.4 Initialization
5.4.1 MDIO Control Mode and Hardware Control Mode
In the MDIO Control mode, the LXT972M PHY reads the Hardware Control Interface pins
to set the initial (default) values of the MDIO registers. Once the initial values are set, bit
control reverts to the MDIO interface.
The following modes are available using either Hardware Control or MDIO control:
• Force network link operation to:
— 100BASE-TX, Full-Duplex
— 100BASE-TX, Half-Duplex
— 10BASE-T, Full-Duplex
— 10BASE-T, Half-Duplex
• Allow auto-negotiation/parallel-detection
On power-up or hardware reset, the LXT972M PHY reads the Hardware Control Interface
pins and sets the MDIO registers accordingly.
The following modes are available using the Hardware Control:
• Auto-negotiation-enabled advertising, either:
— 10/100 BASE-T Full/Half Duplex
— 10/100 BASE-T Half Duplex
• Device ID enable
• Link Hold-off
When the network link is forced to a specific configuration, the LXT972M PHY
immediately begins operating the network interface as commanded. When auto-
negotiation is enabled, the LXT972M PHY begins the auto-negotiation/parallel-detection
operation.
5.4.2 Reduced-Power Modes
This section discusses the LXT972M PHY reduced-power modes.
5.4.2.1 Software Power Down
Software power-down control is provided by register bit 0.11 in the Control Register.
During soft power-down, the following conditions are true:
• The network port is shut down.
• The MDIO registers remain accessible.
5.4.3 Reset
The LXT972M PHY provides both hardware and software resets, each of which manage
differently the configuration control of auto-negotiation, speed, and duplex-mode
selection.
For a software reset, register bit 0.15 = 1. For register bit definitions used for software
reset, see Table 40, Control Register - Address 0, Hex 0, on page 65.
• During a software reset, bit settings in Table 44, Auto-Negotiation Advertisement
Register - Address 4, Hex 4, on page 68 are not re-read from the LXT972M PHY
configuration pins. Instead, the bit settings revert to the values that were read in
Page 28Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
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31 October 2007
5.5 Establishing Link
during the last hardware reset. Therefore, any changes to pin values made since the
last hardware reset are not detected during a software reset.
• During a software reset, registers are available for reading. To see when the
LXT972M PHY has completed reset, the reset bit can be polled (that is, register bit
0.15 = 0).
For pin settings used during a hardware reset, see Section 5.4.4, Hardware Configuration
Settings. During a hardware reset, configuration settings for auto-negotiation and speed
are read in from pins, and register information is unavailable for 1 ms after de-assertion of
the reset.
5.4.4 Hardware Configuration Settings
The LXT972M PHY provides a hardware option to set the initial device configuration. As
listed in Table 14, the hardware option uses the hardware configuration pins, the settings
for which provide control bits.
5.5 Establishing Link
Figure 6 shows an overview of link establishment for the LXT972M PHY.
Note:
When a link is established by using parallel detection, the LXT972M PHY sets the duplex
mode to half-duplex, as defined by the IEEE 802.3 standard.
Table 14 Hardware Configuration Settings
Desired Mode
LED/CFG
Pin
Settings1
Resulting register bit Values
Control Register Auto-Negotiation Advertisement
Register
Auto-Neg. Speed
(Mbps) Duplex 123
Auto-
Neg.
0.12
Speed
0.13
Full-
Duplex
0.8
100
BASE-TX
Full-
Duplex
4.8
100
BASE-
TX
4.7
10
BASE-T
Full-
Duplex
4.6
10
BASE-T
4.5
Disabled
10
Half LLL
0
00
N/A
Auto-Negotiation
Advertisement
Full L L H 0 1
100
Half L H L 1 0
Full L H H 1 1
Enabled
100
Only
Half H L L
1
10 0 1 0 0
Full/Half H L H 1 1 1 1 0 0
10/100
Half Only H H L 1 0 0 1 0 1
Full or Half H H H 1 1 1 1 1 1
1. L = Low, and H = High. For LED/CFG pin assignments, see Section 3.0, Ball and Pin Assignments
Page 29Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
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31 October 2007
5.5 Establishing Link
5.5.1 Auto-Negotiation
If not configured for forced operation, the LXT972M PHY attempts to auto-negotiate with
its link partner by sending Fast Link Pulse (FLP) bursts. Each burst consists of up to 33
link pulses spaced 62.5 μs apart. Odd link pulses (clock pulses) are always present. Even
link pulses (data pulses) may be absent or present to indicate a ‘0’ or a ‘1’. Each FLP burst
exchanges 16 bits of data, which are referred to as a “link code word”. All devices that
support auto-negotiation must implement the “Base Page” defined by the IEEE 802.3
standard (Registers 4 and 5).
The LXT972M PHY also supports the optional “Next Page” function as listed in Table 47,
Auto-Negotiation Next Page Transmit Register - Address 7, Hex 7, on page 70 and
Table 48, Auto-Negotiation Link Partner Next Page Receive Register - Address 8, Hex 8,
on page 71.
5.5.1.1 Base Page Exchange
By exchanging Base Pages, the LXT972M PHY and its link partner communicate their
capabilities to each other. Both sides must receive at least three consecutive identical
base pages for negotiation to continue. Each side identifies the highest common
capabilities that both sides support, and each side configures itself accordingly.
5.5.1.2 Manual Next Page Exchange
“Next Page Exchange” information is additional information that exceeds the information
required by Base Page exchange and that is sent by “Next Pages”. The LXT972M PHY
fully supports the IEEE 802.3 standard method of negotiation through the Next Page
exchange.
The Next Page exchange uses Register 7 to send information and Register 8 to receive it.
Next Page exchange occurs only if both ends of the link partners advertise their ability to
exchange Next Pages. register bit 6.1 is used to make manual next page exchange easier
Figure 6 Link Establishment Overview
Check Value
0.12
Start
Done
Enable
Auto-Neg/Parallel Detection
Go To Forced
Settings
Attempt Auto-
Negotiation
Listen for 10T
Link Pulses
Listen for 100TX
Idle Symbols
Link Up? NOYES
Power-Up, Reset,
or Link Failure
Disable
Auto-Negotiation 0.12 = 0 0.12 = 1
B3496-01
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31 October 2007
5.6 MII Operation
for software. This register bit is cleared when a new negotiation occurs, preventing the
user from reading an old value in Register 6 and assuming there is valid information in
Registers 5 and 8.
5.5.1.3 Controlling Auto-Negotiation
When auto-negotiation is controlled by software, Cortina recommends the following steps:
1. After power-up, power-down, or reset, the power-down recovery time (specified in
Table 38, RESET_L Pulse Width and Recovery Timing, on page 63) must be
exhausted before proceeding.
2. Set the Auto-Negotiation Advertisement register bits.
3. Enable auto-negotiation. (Set MDIO register bit 0.12 = 1.)
4. To ensure proper operation, enable or restart auto-negotiation as soon as possible
after writing to Register 4.
5.5.2 Parallel Detection
In parallel with auto-negotiation, the LXT972M PHY also monitors for 10 Mbps Normal
Link Pulses (NLP) or 100 Mbps Idle symbols. If either symbol is detected, the device
automatically reverts to the corresponding speed in half-duplex mode. Parallel detection
allows the LXT972M PHY to communicate with devices that do not support auto-
negotiation.
When parallel detection resolves a link, the link must be established in half-duplex mode.
According to IEEE standards, the forced link partner cannot be configured to full-duplex. If
the auto-negotiation link partner does not advertise half-duplex capability at the speed of
the forced link partner, link is not established. The IEEE Standard prevents full-duplex-to-
half-duplex link connections.
5.6 MII Operation
This section includes the following topics:
•Section 5.6.1, MII Clocks
•Section 5.6.2, Transmit Enable
•Section 5.6.3, Receive Data Val id
•Section 5.6.4, Carrier Sense
•Section 5.6.5, Error Signal s
•Section 5.6.6, Collision
•Section 5.6.7, Loopback
The LXT972M PHY implements the Media Independent Interface (MII) as defined by the
IEEE 802.3 standard. Separate channels are provided for transmitting data from the MAC
to the LXT972M PHY (TXD), and for passing data received from the line (RXD) to the
MAC. Each channel has its own clock, data bus, and control signals.
The following signals are used to pass received data to the MAC:
•COL
• CRS
•RX_CLK
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31 October 2007
5.6 MII Operation
•RX_DV
• RX_ER
•RXD[3:0]
The following signals are used to transmit data from the MAC:
•TX_CLK
•TX_EN
• TXD[3:0]
The LXT972M PHY supplies both clock signals as well as separate outputs for carrier
sense and collision. Data transmission across the MII is normally implemented in 4-bit-
wide nibbles.
5.6.1 MII Clocks
The LXT972M PHY is the master clock source for data transmission, and it supplies both
MII clocks (RX_CLK and TX_CLK). It automatically sets the clock speeds to match link
conditions.
• When the link is operating at 100 Mbps, the clocks are set to 25 MHz.
• When the link is operating at 10 Mbps, the clocks are set to 2.5 MHz.
Figure 7 through Figure 9 show the clock cycles for each mode.
Note:
The transmit data and control signals must always be synchronized to TX_CLK by the
MAC. The LXT972M PHY samples these signals on the rising edge of TX_CLK.
Figure 7 Clocking for 10BASE-T
RX_CLK
2.5 MHz during auto-negotiation and 10BASE-T Data & Idle
TX_CLK
2.5 MHz during auto-negotiation and 10BASE-T Data & Idle
Constant 25 MHz
XI
B3390-01
Page 32Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.6 MII Operation
5.6.2 Transmit Enable
The MAC must assert TX_EN the same time as the first nibble of preamble and de-assert
TX_EN after the last nibble of the packet.
5.6.3 Receive Data Valid
The LXT972M PHY asserts RX_DV when it receives a valid packet. Timing changes
depend on line operating speed:
• For 100BASE-TX links, RX_DV is asserted from the first nibble of preamble to the last
nibble of the data packet.
• For 10BASE-T links, the entire preamble is truncated. RX_DV is asserted with the first
nibble of the Start of Frame Delimiter (SFD) “5D” and remains asserted until the end
of the packet.
Figure 8 Clocking for 100BASE-X
Figure 9 Clocking for Link Down Clock Transition
Any
Clock
2.5 MHz
Clock
Clock transition time does not exceed
2X the nominal clock period:
10 Mbps = 2.5 MHz
100 Mbps = 25 MHz
Link-Down Condition/Auto-Negotiate Enabled
RX_CLK
TX_CLK
B3503-01
Page 33Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.6 MII Operation
5.6.4 Carrier Sense
Carrier Sense (CRS) is an asynchronous output.
• CRS is always generated when the LXT972M PHY receives a packet from the line.
• CRS is also generated when the LXT972M PHY is in half-duplex mode when a packet
is transmitted.
Table 15 summarizes the conditions for assertion of carrier sense, data loopback, and
collision signals. Carrier sense is not generated when a packet is transmitted and in full-
duplex mode.
.
5.6.5 Error Signals
When the LXT972M PHY is in 100 Mbps mode and receives an invalid symbol from the
network, it asserts RX_ER and drives “0101” on the RXD pins.
The TX_ER function that forces ‘H’ symbols out on the TPOP/TPON twisted pair is not
implemented in the LXT972M PHY.
5.6.6 Collision
The LXT972M PHY asserts its collision signal asynchronously to any clock whenever the
line state is half-duplex and the transmitter and receiver are active at the same time.
Table 15 summarizes the conditions for assertion of carrier sense, data loopback, and
collision signals.
5.6.7 Loopback
The LXT972M PHY provides the following loopback functions:
•Section 5.6.7.1, Operational Loopback
•Section 5.6.7.2, Internal Digital Loopback (Test Loopback)
Figure 10 shows LXT972M PHY operational and test loopback paths. For more
information on loopback functions, see Table 15, Carrier Sense, Loopback, and Collision
Conditions, on page 33.)
Table 15 Carrier Sense, Loopback, and Collision Conditions
Speed Duplex Condition Carrier Sense
Test
Loop-
back1, 2
Operational
Loop-
back1, 2 Collision
100 Mbps
Full-Duplex Receive Only Yes No None
Half-Duplex Transmit or Receive No No Transmit and Receive
10 Mbps
Full-Duplex Receive Only Yes No None
Half-Duplex,
register bit 16.8 = 0 Transmit or Receive Yes Yes Transmit and Receive
Half-Duplex,
register bit 16.8 = 1 Transmit or Receive No No Transmit and Receive
1. Test Loopback is enabled when register bit 0.14 = 1.
2. For descriptions of Test Loopback and Operational Loopback, see Section 5.6.7, Loopback, on page 33.
Page 34Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.6 MII Operation
5.6.7.1 Operational Loopback
• Operational loopback is provided for 10 Mbps half-duplex links when register bit 16.8
= 0. Data that the MAC (TXData) transmits loops back on the receive side of the MII
(RXData).
• Operational loopback is not provided for 100 Mbps links, full-duplex links, or when
Register 16.8 = 1.
5.6.7.2 Internal Digital Loopback (Test Loopback)
A test loopback function is provided for diagnostic testing of the LXT972M PHY. During
test loopback, twisted-pair and fiber interfaces are disabled. Data transmitted by the MAC
is internally looped back by the LXT972M PHY and returned to the MAC.
Test loopback is available for both 100BASE-TX and 10BASE-T operation, and is enabled
by setting the following register bits:
• register bit 0.14 = 1 (Setting to enable loopback mode)
• register bit 0.8 = 1 (Setting for full-duplex mode)
• register bit 0.12 = 0 (Disable auto-negotiation)
Note:
Parallel detection can resolve the PHY configuration.
Figure 10 Loopback Paths
B3485-02
10T
Loopback Digital
Block
MII
100X
Loopback Analog
Block
LXT97x PHY
Operational
Loopback Test Loopback
TX
Driver
Page 35Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.7 100 Mbps Operation
5.7 100 Mbps Operation
5.7.1 100BASE-X Network Operations
During 100BASE-X operation, the LXT972M PHY transmits and receives 5-bit symbols
across the network link.
Figure 11 shows the structure of a standard frame packet in 100BASE-X mode. When the
MAC is not actively transmitting data, the LXT972M PHY sends out Idle symbols on the
line.
As Figure 11 shows, the MAC starts each transmission with a preamble pattern. As soon
as the LXT972M PHY detects the start of preamble, it transmits a Start-of-Stream
Delimiter (SSD, symbols J and K) to the network. It then encodes and transmits the rest of
the packet, including the balance of the preamble, the SFD, packet data, and CRC.
Once the packet ends, the LXT972M PHY transmits the End-of-Stream Delimiter (ESD,
symbols T and R) and then returns to transmitting Idle symbols.
For details on the symbols used, see 4B/5B coding listed in Table 16, 4B/5B Coding, on
page 39.
As shown in Figure 12, in 100BASE-TX mode, the LXT972M PHY scrambles and
transmits the data to the network using MLT-3 line code. MLT-3 signals received from the
network are de-scrambled, decoded, and sent across the MII to the MAC.
Figure 11 100BASE-X Frame Format
P0 P1 P6 SFD
64-Bit Preamble
(8 Octets)
Start-of-Frame
Delimiter (SFD)
DA DA SA SA
Destination and Source
Address (6 Octets each)
L1 L2
Packet Length
(2 Octets)
D0 D1 Dn
Data Field
(Pad to minimum packet size)
Frame Check Field
(4 Octets)
CRC I0
InterFrame Gap / Idle Code
(> 12 Octets)
Replaced by
/T/R/ code-groups
End-of-Stream Delimiter (ESD)
IFG
Replaced by
/J/K/ code-groups
Start-of-Stream
Delimiter (SSD)
B3466-01
Page 36Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.7 100 Mbps Operation
Figure 13 shows normal reception with no errors.
As shown in Figure 14, when the LXT972M PHY receives invalid symbols from the line, it
asserts RX_ER.
Figure 12 100BASE-TX Data Path
S0
S1
S2
S3
S4
Parallel
to
Serial
Serial
to
Parallel
MLT3
0
+1
-1
00
Transition = 1.
No Transition = 0.
All transitions must follow
pattern: 0, +1, 0, -1, 0, +1...
Scrambler Bypass Dat a Flow
S0 S1 S2 S3 S4
Standard Data Flow
D0
D1
D2
D3
Parallel
to
Serial
Serial
to
Parallel
D0 D1 D2 D3 4B/5B S0 S1 S2 S3 S4 MLT3
0
+1
-1
00
Transition = 1.
No Transition = 0.
All transitions must follow
pattern: 0, +1, 0, -1, 0, +1...
Scramble
De-
Scramble
B3467-01
Figure 13 100BASE-TX Reception with No Errors
RX_CLK
RX_DV
RXD<3:0>
RX_ER
preamble SFD SFD DA DA DA DA CRC CRC CRC CRC
B3468-01
Page 37Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.7 100 Mbps Operation
5.7.2 Collision Indication
Figure 15 shows normal transmission.
Upon detection of a collision, the COL output is asserted and remains asserted for the
duration of the collision as shown in Figure 16.
Figure 14 100BASE-TX Reception with Invalid Symbol
RX_CLK
RX_DV
RXD<3:0>
RX_ER
preamble SFD SFD DA DA XX XX XX XX XX XX XX XX XX XX
B3469-01
Figure 15 100BASE-TX Transmission with No Errors
DA DA DA DA DA DADA DA DA
TX_CLK
TX_EN
TXD<3:0>
CRS
COL
PR EA MB LE
B3470-01
Figure 16 100BASE-TX Transmission with Collision
JAM
TX_CLK
TX_EN
TXD<3:0>
CRS
COL
PR EA MB LE JAM JAM JAM
B3471-01
Page 38Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.7 100 Mbps Operation
5.7.3 100BASE-X Protocol Sublayer Operations
With respect to the 7-layer communications model, the LXT972M PHY is a Physical Layer
1 (PHY) device.
The LXT972M PHY implements the following sublayers of the reference model defined by
the IEEE 802.3 standard, and discussed from the reference model point of view:
•Section 5.7.3.1, Physical Coding Sublayer
•Section 5.7.3.2, Physical Medium Attachment Sublayer
•Section 5.7.3.3, Twisted-Pair Physical Medium Dependent Sublayer
Figure 17 shows the LXT972M PHY protocol sublayers.
5.7.3.1 Physical Coding Sublayer
The Physical Coding Sublayer (PCS) provides the MII interface, as well as the 4B/5B
encoding/decoding function.
For 100BASE-TX operation, the PCS layer provides IDLE symbols to the PMD-layer line
driver as long as TX_EN is de-asserted.
5.7.3.1.1 Preamble Handling
When the MAC asserts TX_EN, the PCS substitutes a /J/K symbol pair, also known as the
Start-of-Stream Delimiter (SSD), for the first two nibbles received across the MII. The PCS
layer continues to encode the remaining MII data, following the 4B/5B coding in Ta b le 16,
until TX_EN is de-asserted. It then returns to supplying IDLE symbols to the line driver.
In the receive direction, the PCS layer performs the opposite function, substituting two
preamble nibbles for the SSD. In 100 Mbps operation, preamble is always passed through
the PCS layer to the MII interface.
Figure 17 Protocol Sublayers
Encoder /Decoder
Serializer /De-serializer
Link/Carrier Detect
PCS
Sublayer
PMA
Sublayer
MII Interface
LXT 9 7x PHY
100BASE-TX
Scrambler/
De-scrambler
PMD
Sublayer
B3514 -02
Page 39Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.7 100 Mbps Operation
Table 16 4B/5B Coding (Sheet 1 of 2)
Code Type 4B Code
3 2 1 0 Name 5B Code
4 3 2 1 0 Interpretation
DATA
0 0 0 0 0 1 1 1 1 0 Data 0
0 0 0 1 1 0 1 0 0 1 Data 1
0 0 1 0 2 1 0 1 0 0 Data 2
0 0 1 1 3 1 0 1 0 1 Data 3
0 1 0 0 4 0 1 0 1 0 Data 4
0 1 0 1 5 0 1 0 1 1 Data 5
0 1 1 0 6 0 1 1 1 0 Data 6
0 1 1 1 7 0 1 1 1 1 Data 7
1 0 0 0 8 1 0 0 1 0 Data 8
1 0 0 1 9 1 0 0 1 1 Data 9
1 0 1 0 A 1 0 1 1 0 Data A
1 0 1 1 B 1 0 1 1 1 Data B
1 1 0 0 C 1 1 0 1 0 Data C
1 1 0 1 D 1 1 0 1 1 Data D
1 1 1 0 E 1 1 1 0 0 Data E
1 1 1 1 F 1 1 1 0 1 Data F
IDLE undefined I 1 1 1 1 11 Used as inter-stream fill code
CONTROL
0 1 0 1 J 2 1 1 0 0 0 Start-of-Stream Delimiter (SSD),
part 1 of 2
0 1 0 1 K 2 1 0 0 0 1 Start-of-Stream Delimiter (SSD),
part 2 of 2
Undefined T 3 0 1 1 0 1 End-of-Stream Delimiter (ESD),
part 1 of 2
Undefined R 3 0 0 1 1 1 End-of-Stream Delimiter (ESD),
part 2 of 2
1. The /I/ (Idle) code group is sent continuously between frames.
2. The /J/ and /K/ (SSD) code groups are always sent in pairs, and /K/ follows /J/.
3. The /T/ and /R/ (ESD) code groups are always sent in pairs, and /R/ follows /T/.
4. An /H/ (Error) code group is used to signal an error condition.
Page 40Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.7 100 Mbps Operation
5.7.3.2 Physical Medium Attachment Sublayer
5.7.3.2.1 Link
In 100 Mbps mode, link is established when the descrambler becomes locked and
remains locked for approximately 50 ms. Link remains up unless the descrambler
receives less than 16 consecutive idle symbols in any 2 ms period. This operation filters
out small noise hits that may disrupt the link.
For short periods, MLT-3 idle waveforms meet all criteria for 10BASE-T start delimiters. A
working 10BASE-T receive may temporarily indicate link to 100BASE-TX waveforms.
However, the PHY does not bring up a permanent 10 Mbps link.
The LXT972M PHY reports link failure through the MII status bits (register bits 1.2 and
17.10). Link failure causes the LXT972M PHY to re-negotiate if auto-negotiation is
enabled.
5.7.3.2.2 Link Failure Override
The LXT972M PHY normally transmits data packets only if it detects the link is up. Setting
register bit 16.14 = 1 overrides this function, allowing the LXT972M PHY to transmit data
packets even when the link is down. This feature is provided as a transmit diagnostic tool.
Note:
Auto-negotiation must be disabled to transmit data packets in the absence of link. If auto-
negotiation is enabled, the LXT972M PHY automatically transmits FLP bursts if the link is
down.
Caution:
During normal operation, Cortina does not recommend setting register bit 16.14 for
100 Mbps receive functions because receive errors may be generated.
INVALID
Undefined H 4 0 0 1 0 0 Transmit Error. Used to force signaling
errors
Undefined Invalid 0 0 0 0 0 Invalid
Undefined Invalid 0 0 0 0 1 Invalid
Undefined Invalid 0 0 0 1 0 Invalid
Undefined Invalid 0 0 0 1 1 Invalid
Undefined Invalid 0 0 1 0 1 Invalid
Undefined Invalid 0 0 1 1 0 Invalid
Undefined Invalid 0 1 0 0 0 Invalid
Undefined Invalid 0 1 1 0 0 Invalid
Undefined Invalid 1 0 0 0 0 Invalid
Undefined Invalid 1 1 0 0 1 Invalid
Table 16 4B/5B Coding (Sheet 2 of 2)
Code Type 4B Code
3 2 1 0 Name 5B Code
4 3 2 1 0 Interpretation
1. The /I/ (Idle) code group is sent continuously between frames.
2. The /J/ and /K/ (SSD) code groups are always sent in pairs, and /K/ follows /J/.
3. The /T/ and /R/ (ESD) code groups are always sent in pairs, and /R/ follows /T/.
4. An /H/ (Error) code group is used to signal an error condition.
Page 41Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.7 100 Mbps Operation
5.7.3.2.3 Carrier Sense
For 100BASE-TX links, a start-of-stream delimiter (SSD) or /J/K symbol pair causes
assertion of carrier sense (CRS). An end-of-stream delimiter (ESD) or /T/R symbol pair
causes de-assertion of CRS. The PMA layer also de-asserts CRS if IDLE symbols are
received without /T/R. However, in this case RX_ER is asserted for one clock cycle when
CRS is de-asserted.
Cortina does not recommend using CRS for Interframe Gap (IFG) timing for the following
reasons:
• CRS de-assertion time is slightly longer than CRS assertion time. As a result, an IFG
interval appears somewhat shorter to the MAC than it actually is on the wire.
• CRS de-assertion is not aligned with TX_EN de-assertion on transmit loopbacks in
half-duplex mode.
5.7.3.2.4 Receive Data Valid
The LXT972M PHY asserts RX_DV to indicate that the received data maps to valid
symbols. In 100 Mbps operation, RX_DV is active with the first nibble of preamble.
5.7.3.3 Twisted-Pair Physical Medium Dependent Sublayer
The twisted-pair Physical Medium Dependent (PMD) layer provides signal scrambling and
de-scrambling functions, line coding and decoding functions (MLT-3 for 100BASE-TX,
Manchester for 10BASE-T), as well as receiving, polarity correction, and baseline wander
correction functions.
5.7.3.3.1 Scrambler/Descrambler
The purpose of the scrambler/descrambler is to spread the signal power spectrum and
further reduce EMI using an 11-bit, data-independent polynomial. The receiver
automatically decodes the polynomial whenever IDLE symbols are received.
Scrambler Seeding. Once the transmit data (or Idle symbols) are properly encoded, they
are scrambled to further reduce EMI and to spread the power spectrum using an 11-bit
scrambler seed. Five seed bits are determined by the PHY address, and the remaining
bits are hard coded in the design.
Scrambler Bypass. The scrambler/de-scrambler can be bypassed by setting register bit
16.12 = 1. Scrambler bypass is provided for diagnostic and test support.
5.7.3.3.2 Polarity Correction
The 100 Mbps twisted pair signaling is not polarity sensitive. As a result, the polarity
status is not a valid status indicator.
5.7.3.3.3 Baseline Wander Correction
The LXT972M PHY provides a baseline wander correction function for when the
LXT972M PHY is under network operating conditions. The MLT3 coding scheme used in
100BASE-TX is by definition “unbalanced”. As a result, the average value of the signal
voltage can “wander” significantly over short time intervals (tenths of seconds). This
wander can cause receiver errors at long-line lengths (100 meters) in less robust designs.
Exact characteristics of the wander are completely data dependent.
The LXT972M PHY baseline wander correction characteristics allow the device to recover
error-free data while receiving worst-case packets over all cable lengths.
Page 42Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.8 10 Mbps Operation
5.7.3.3.4 Programmable Slew Rate Control
The LXT972M PHY device supports a programmable slew-rate mechanism whereby one
of four pre-selected slew rates can be used. (For details, see Table 56, Transmit Control
Register - Address 30, Hex 1E, on page 79.) The slew-rate mechanism allows the
designer to optimize the output waveform to match the characteristics of the magnetics.
5.8 10 Mbps Operation
The LXT972M PHY operates as a standard 10BASE-T PHY and LXT972M PHY supports
standard 10 Mbps functions. During 10BASE-T operation, the LXT972M PHY transmits
and receives Xilinks* Manchester-encoded data across the network link. When the MAC
is not actively transmitting data, the LXT972M PHY drives link pulses onto the line.
In 10BASE-T mode, the polynomial scrambler/de-scrambler is inactive. Manchester-
encoded signals received from the network are decoded by the LXT972M PHY and sent
across the MII to the MAC.
5.8.1 10BASE-T Preamble Handling
The LXT972M PHY offers two options for preamble handling, selected by register bit 16.5.
• In 10BASE-T mode when register bit 16.5 = 0, the LXT972M PHY strips the entire
preamble off of received packets. CRS is asserted coincident with the start of the
preamble. RX_DV is held Low for the duration of the preamble. When RX_DV is
asserted, the very first two nibbles driven by the LXT972M PHY are the SFD “5D” hex
followed by the body of the packet.
• In 10BASE-T mode when register bit 16.5 = 1, the LXT972M PHY passes the
preamble through the MII and asserts RX_DV and CRS simultaneously. (In
10BASE-T loopback, the LXT972M PHY loops back whatever the MAC transmits to it,
including the preamble.)
5.8.2 10BASE-T Carrier Sense
For 10BASE-T links, CRS assertion is based on reception of valid preamble, and CRS de-
assertion is based on reception of an end-of-frame (EOF) marker. register bit 16.7 allows
CRS de-assertion to be synchronized with RX_DV de-assertion. For details, see Table 50,
Configuration Register - Address 16, Hex 10, on page 72.
5.8.3 10BASE-T Dribble Bits
The LXT972M PHY handles dribble bits in all modes. If one to four dribble bits are
received, the nibble is passed across the MII, padded with ones if necessary. If five to
seven dribble bits are received, the second nibble is not sent to the MII bus.
5.8.4 10BASE-T Link Integrity Test
In 10BASE-T mode, the LXT972M PHY always transmits link pulses.
• If the Link Integrity Test function is enabled (the normal configuration), the LXT972M
PHY monitors the connection for link pulses. Once link pulses are detected, data
transmission is enabled and remains enabled as long as either the link pulses or data
transmission continue. If the link pulses stop, the data transmission is disabled.
Page 43Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.9 Monitoring Operations
• If the Link Integrity Test function is disabled (which can be done by setting
Configuration register bit 16.14 to ‘1’), the LXT972M PHY transmits to the connection
regardless of detected link pulses.
5.8.5 Link Failure
Link failure occurs if the Link Integrity Test is enabled and link pulses or packets stop
being received. If this condition occurs, the LXT972M PHY returns to the auto-negotiation
phase if auto-negotiation is enabled. If the Link Integrity Test function is disabled by
setting Configuration register bit 16.14 to ‘1’, the LXT972M PHY transmits packets,
regardless of link status.
5.8.6 10BASE-T SQE (Heartbeat)
By default, the Signal Quality Error (SQE) or heartbeat function is disabled on the
LXT972M PHY. To enable this function, set register bit 16.9 = 1. When this function is
enabled, the LXT972M PHY asserts its COL output for 5 to 15 bit times (BT) after each
packet. For SQE timing parameters, see Figure 27, 10BASE-T SQE (Heartbeat) Timing,
on page 59.
5.8.7 10BASE-T Jabber
If a transmission exceeds the jabber timer, the LXT972M PHY disables the transmit and
loopback functions. For jabber timing parameters, see Figure 26, 10BASE-T Jabber and
Unjabber Timing, on page 59.
The LXT972M PHY automatically exits jabber mode after the unjabber time has expired.
This function can be disabled by setting register bit 16.10 = 1.
5.8.8 10BASE-T Polarity Correction
The LXT972M PHY automatically detects and corrects for the condition in which the
receive signal (TPIP/N) is inverted. Reversed polarity is detected if eight inverted link
pulses, or four inverted end-of-frame (EOF) markers, are received consecutively. If link
pulses or data are not received by the maximum receive time-out period (96 to 128 ms),
the polarity state is reset to a non-inverted state.
When polarity reversal is detected in 10BASE-T operation, register 17.5 is set to 1. (For
details, see bit 17.5 in Ta bl e 5 1, Status Register #2 - Address 17, Hex 11, on page 73.)
5.9 Monitoring Operations
5.9.1 Monitoring Auto-Negotiation
Auto-negotiation can be monitored as follows:
• register bit 17.7 is set to ‘1’ once the auto-negotiation process is completed.
• register bits 1.2 and 17.10 are set to ‘1’ once the link is established.
• register bits 17.14 and 17.9 can be used to determine the link operating conditions
(speed and duplex).
Note:
When the LXT972M PHY detects incorrect polarity for a 10BASE-T operation, register bit
17.5 is set to ‘1’.
Page 44Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.9 Monitoring Operations
5.9.2 Monitoring Next Page Exchange
The LXT972M PHY offers an Alternate Next Page mode to simplify the next page
exchange process. Normally, register bit 6.1 (Page Received) remains set until read.
When Alternate Next Page mode is enabled, register bit 6.1 is automatically cleared
whenever a new negotiation process takes place. This action prevents the user from
reading an old value in bit 6.1 and assuming that Registers 5 and 8 (Partner Ability)
contain valid information. Additionally, the LXT972M PHY uses register bit 6.5 to indicate
when the current received page is the base page. This information is useful for
recognizing when next pages must be resent due to a new negotiation process starting.
register bits 6.1 and 6.5 are cleared when read.
5.9.3 LED Functions
The LXT972M PHY has these direct LED driver pins: LED1/CFG1, LED2/CFG2, and
LED3/CFG3.
On power-up, all the drivers are asserted for approximately 1 second after reset de-
asserts. Each LED driver can be programmed using the LED Configuration Register
(Table 54, LED Configuration Register - Address 20, Hex 14, on page 77) to indicate one
of the following conditions:
• Collision Condition
• Duplex Mode
• Link Status
• Operating Speed
• Receive Activity
• Transmit Activity
The LED drivers can also be programmed to display various combined status conditions.
For example, setting register bits 20.15:12 to ‘1101’ produces the following combination of
Link and Activity indications:
• If Link is down, LED is off. If activity is detected from the MAC, the LED still blinks
even if the link is down.
• If Link is up, LED is on.
• If Link is up and activity is detected, the LED blinks at the stretch interval selected by
register bits 20.3:2 and continues to blink as long as activity is present.
The LXT972M PHY LED driver pins also provide initial configuration settings. The LED
pins are sensitive to polarity and automatically pull up or pull down to configure for either
open drain or open collector circuits (10 mA Max current rating) as required by the
hardware configuration. For details, see the discussion of Section 5.4.4, Hardware
Configur ation Settin gs, on page 28.
5.9.4 LED Pulse Stretching
The LED Configuration Register also provides optional LED pulse stretching to 30, 60, or
100 ms. The pulse stretch time is extended further if the event occurs again during this
pulse stretch period.
Page 45Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.10 Boundary Scan (JTAG
1149.1) Functions
When an event such as receiving a packet occurs, the event is edge detected and it starts
the stretch timer. The LED driver remains asserted until the stretch timer expires. If
another event occurs before the stretch timer expires, then the stretch timer is reset and
the stretch time is extended.
When a long event (such as duplex status) occurs, the event is edge detected and it starts
the stretch timer. When the stretch timer expires, the edge detector is reset so that a long
event causes another pulse to be generated from the edge detector, which resets the
stretch timer and causes the LED driver to remain asserted.
Figure 18 shows how the stretch operation functions.
5.10 Boundary Scan (JTAG 1149.1) Functions
The LXT972M PHY includes a IEEE 1149.1 boundary scan test port for board level
testing. All digital input, output, and input/output pins are accessible.
Note:
For the related BSDL file, contact your local sales office or access the Cortina website
(www.cortina-systems.com).
5.10.1 Boundary Scan Interface
The boundary scan interface consists of five pins (TMS, TDI, TDO, TRST_L, and TCK). It
includes a state machine, data register array, and instruction register. The TMS and TDI
pins are pulled up internally. TCK is pulled down internally. TDO does not have an internal
pull-up or pull-down.
5.10.2 State Machine
The TAP controller is a state machine, with 16 states driven by the TCK and TMS pins.
Upon reset, the TEST_LOGIC_RESET state is entered. The state machine is also reset
when TMS and TDI are high for five TCK periods.
5.10.3 Instruction Register
After the state machine resets, the IDCODE instruction is always invoked. The decode
logic ensures the correct data flow to the Data registers according to the current
instruction.
Table 17 lists valid LXT972M PHY JTAG instructions.
Figure 18 LED Pulse Stretching
Event
LED
Note: The direct drive LED outputs in this diagra m ar e shown a s a ctive Low.
stretch stretch stretch
B3475-01
Page 46Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
5.10 Boundary Scan (JTAG
1149.1) Functions
5.10.4 Boundary Scan Register
Each Boundary Scan Register (BSR) cell has two stages. A flip-flop and a latch are used
for the serial shift stage and the parallel output stage. Table 17 lists the four BSR modes of
operation.
5.10.5 Device ID Register
Table 18 lists the bits for the Device ID register. For the current version of the JEDEC
continuation characters, see the specification update for the LXT972M PHY.
Table 17 BSR Mode of Operation
Mode Description
1 Capture
2Shift
3 Update
4 System Function
Table 18 Device ID Register
Bits 31:28 Bits 27:12 Bits 11:8 Bits 7:1 Bit 0
Version Part ID (Hex) JEDEC Continuation Characters JEDEC ID1Reserved
XXXX 03CB 0000 111 1110 1
1. The JEDEC ID is an 8-bit identifier. The MSB is for parity and is ignored. The JEDEC ID is FE
(1111 1110), which becomes 111 1110.
Page 47Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
6.0 Application Information
6.0 Application Information
6.1 Magnetics Information
The LXT972M PHY requires a 1:1 ratio for both the receive and transmit transformers.
The transformer isolation voltage should be rated at 2 kV to protect the circuitry from static
voltages across the connectors and cables. For transformer/magnetics requirements, see
Table 19.
Note:
Before committing to a specific component, contact the manufacturer for current product
specifications and validate the magnetics for the specific application.
6.2 Typical Twisted-Pair Interface
Table 20 provides a comparison of the RJ-45 connections for NIC and Switch applications
in a typical twisted-pair interface setting.
Figure 19 shows the LXT972M PHY in a typical twisted-pair interface, with the RJ-45
connections crossed over for a Switch configuration.
Table 19 Magnetics Requirements
Parameter Min Nom Max Units Test Condition
Rx turns ratio – 1 : 1 – – –
Tx turns ratio – 1 : 1 – – –
Insertion loss 0.0 0.6 1.1 dB –
Primary inductance 350 – – μH–
Transformer isolation – 1.5 – kV –
Differential to common mode rejection
40 – – dB 0.1 to 60 MHz
35 – – dB 60 to 100 MHz
Return Loss
-16 – – dB 30 MHz
-10 – – dB 80 MHz
Table 20 I/O Pin Comparison of NIC and Switch RJ-45 Setups
Symbol
RJ-45
Switch NIC
TPIP 1 3
TPIN 2 6
TPOP 3 1
TPON 6 2
Page 48Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
6.2 Typical Twisted-Pair
Interface
Figure 20 shows the LXT972M PHY in a typical twisted-pair interface, with the RJ-45
connections configured for a NIC application.
Figure 19 Typical Twisted-Pair Interface - Switch
TPIP
TPIN
RJ-45
* = 0.001 μF / 2.0 kV
To T wisted-Pair N etwork
3
6
1
2
1:1
LXT97x PHY
50 Ω
50 Ω50 Ω
50 Ω
50 Ω
50 Ω
4
5
8
7
1:1
1
TPOP
TPON
VCCA
GND
0.1μF.01μF
2
270 pF 5%
270 pF 5%
0.01 μF
50Ω 1%
50Ω 1%
**
3
4
0.1μF
1. Center tap current may be supplied from 3.3 V VCCA as shown. Additional power savings may be
realized by supplying the center tap from a 2.5 V current source. A separate ferrite bead (rated at 50 mA)
should be used to supply center tap current.
2. The 100 Ω transmit load termination resistor typically required is integrated in the PHY.
3. Magnetics without a receive pair center-tap do not require a 2 kV termination.
4. RJ-45 connections shown are for a standard switch application.
Page 49Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
6.2 Typical Twisted-Pair
Interface
Figure 20 Typical Twisted-Pair Interface - NIC
TPIP
TPIN
* = 0.001 μF / 2.0 kV
To Twisted-Pair Network
1:1
LXT97x PHY
1:1
1
TPOP
TPON
VCCA
GND
0.1μF.01μF
2
270 pF 5%
270 pF 5%
0.01 μF
50Ω 1%
50Ω 1%
**
3
SD/TP_L
6
3
8
7
5
4
1
2
50 Ω
50 Ω50 Ω
RJ-45
50 Ω
50 Ω
50 Ω
4
0.1μF
B3399-03
1. Center tap current may be supplied from 3.3 V VCCA as shown. Additional power savings may be
realized by supplying the center tap from a 2.5 V current source. A separate ferrite bead (rated at 50 mA)
should be used to supply center-tap current.
2. The 100 Ω transmit load termination resistor typically required is integrated in the PHY.
3. Magnetics without a receive pair center tap do not require a 2 kV termination.
4. RJ-45 connections shown for standard NIC. TX/RX crossover may be required for repeater and switch
applications.
Page 50Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
6.2 Typical Twisted-Pair
Interface
Figure 21 show a typical media independent interface (MII) for the LXT972M PHY.
Figure 21 Typical Media Independent Interface
MAC
TX_EN
TX_ER
TXD[3:0]
TX_CLK
RX_DV
RX_ER
RXD[3:0]
CRS
COL
RX_CLK
LXT97x
PHY Trans-
former RJ-45
B3400-03
Page 51Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
7.0 Electrical Specifications
7.0 Electrical Specifications
This chapter includes test specifications for the LXT972M PHY. These specifications are
guaranteed by test except where noted “by design”.
7.1 DC Electrical Parameters
See the following DC specifications:
• Table 21, Absolute Maximum Ratings, on page 51
• Table 22, Recommended Operating Conditions, on page 51
• Table 23, Digital I/O Characteristics (Except for MII, XI/XO, and LED/CFG Pins), on
page 52
• Table 24, Digital I/O Characteristics1 - MII Pins, on page 52
• Table 25, I/O Characteristics - REFCLK/XI and XO Pins, on page 53
• Table 26, I/O Characteristics - LED/CFG Pins, on page 53
• Table 27, 100BASE-TX PHY Characteristics, on page 53
• Table 28, 10BASE-T PHY Characteristics, on page 54
• Table 29, 10BASE-T Link Integrity Timing Characteristics, on page 54
• Table 30, Thermal Characteristics, on page 54
Caution:
Exceeding the absolute maximum rating values may cause permanent damage.
Functional operation under these conditions is not implied.
Exposure to maximum rating conditions for extended periods may affect device reliability.
Table 21 Absolute Maximum Ratings
Parameter Sym Min Max Units
Supply Voltage VCC -0.3 4.0 V
Storage Temperature TST -65 +150 ºC
Table 22 Recommended Operating Conditions (Sheet 1 of 2)
Parameter Sym Min Typ1Max Units
Recommended operating temperature TOPA0–70ºC
Recommended supply voltage2 - Analog and digital Vcca, Vccd 3.14 3.3 3.45 V
Recommended supply voltage2- I/O Vccio 2.35 – 3.45 V
VCC current - 100 BASE-TX ICC –92110mA
VCC current - 10 BASE-T ICC –6682mA
1. Typical values are at 25 °C and are for design aid only, not guaranteed, and not subject to production
testing.
2. Voltages are with respect to ground unless otherwise specified.
Page 52Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
7.1 DC Electrical Parameters
Hard Power Down ICC –– 1mA
Soft Power Down Icc – 51 – mA
Auto-Negotiation ICC –90110mA
Table 23 Digital I/O Characteristics (Except for MII, XI/XO, and LED/CFG Pins)
Parameter Sym Min Typ1Max Units Test Conditions
Input Low voltage VIL ––0.8V–
Input High voltage VIH 2.0 – – V –
Input current II-10 – 10 μA0.0 < VI < VCC
Output Low voltage VOL ––0.4VIOL = 4 mA
Output High voltage VOH 2.4 – – V IOH = -4 mA
1. Typical values are at 25 °C and are for design aid only, not guaranteed, and not subject to production
testing.
Table 24 Digital I/O Characteristics1 - MII Pins
Parameter Sym Min Typ2Max Units Test Conditions
Input Low voltage VIL ––0.8V–
Input High voltage VIH 2.0 – – V –
Input current II-10 – 10 μA0.0 < VI < VCCIO
Output Low voltage VOL ––0.4VIOL = 4 mA
Output High voltage
VOH 2.2 – – V IOH = -4 mA, VCCIO = 3.3 V
VOH 2.0 – – V IOH = -4 mA, VCCIO = 2.5 V
Driver output resistance
(Line driver output
enabled)
RO3– 100 – ΩVCCIO = 2.5 V
RO3– 100 – ΩVCCIO = 3.3 V
1. MII digital I/O pins are tolerant to 5 V inputs.
2. Typical values are at 25 °C and are for design aid only, not guaranteed, and not subject to production
testing.
3. Parameter is guaranteed by design and not subject to production testing.
Table 22 Recommended Operating Conditions (Sheet 2 of 2)
Parameter Sym Min Typ1Max Units
1. Typical values are at 25 °C and are for design aid only, not guaranteed, and not subject to production
testing.
2. Voltages are with respect to ground unless otherwise specified.
Page 53Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
7.1 DC Electrical Parameters
Table 25 I/O Characteristics - REFCLK/XI and XO Pins
Parameter Symbol Min Typ1Max Units Test Conditions
Input Low Voltage VIL ––0.8V –
Input High Voltage VIH 2.0 – – V –
Input Clock Frequency Tolerance2Δf––±100 ppm –
Input Clock Duty Cycle2Tdc 35 – 65 % –
Input Capacitance CIN –3.0–pF –
1. Typical values are at 25 °C and are for design aid only, not guaranteed, and not subject to production
testing.
2. Parameter is guaranteed by design and not subject to production testing.
Table 26 I/O Characteristics - LED/CFG Pins
Parameter Symbol Min Typ Max Units Test Conditions
Input Low Voltage VIL ––0.8 V –
Input High Voltage VIH 2.0 – – V –
Input Current II-10 – 10 μA0 < VI < VCCIO
Output Low Voltage VOL ––0.4 VIOL = 10 mA
Output High Voltage VOH 2.0 – – V IOH = -10 mA
Table 27 100BASE-TX PHY Characteristics
Parameter Symbol Min Typ1Max Units Test Conditions
Peak differential output voltage VP0.95 – 1.05 V Note 2
Signal amplitude symmetry Vss 98 – 102 % Note 2
Signal rise/fall time TRF 3.0 – 5.0 ns Note 2
Rise/fall time symmetry TRFS – – 0.5 ns Note 2
Duty cycle distortion DCD 35 50 65 %
Offset from 16 ns pulse
width at 50% of pulse
peak
Overshoot/Undershoot VOS –– 5 % –
Jitter (measured differentially) – – – 1.4 ns –
1. Typical values are at 25 °C and are for design aid only, not guaranteed, and not subject to production
testing.
2. Measured at the line side of the transformer, line replaced by 100 Ω(+/-1%) resistor.
Page 54Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
7.2 AC Timing Diagrams and
Parameters
7.2 AC Timing Diagrams and Parameters
See the following timing diagrams and AC parameters:
• Figure 22, 100BASE-T X Receive Timing, on page 55
• Figure 23, 100BASE-TX Transmit Timing, on page 56
• Figure 25, 10BASE-T Tran smit Timing, on page 58
Table 28 10BASE-T PHY Characteristics
Parameter Symbol Min Typ Max Units Test Conditions
Transmitter
Peak differential output
voltage VOP 2.2 2.5 2.8 V
With transformer, line
replaced by 100 Ω
resistor
Transition timing jitter added
by the MAU and PLS
sections
–0211ns
After line model
specified by IEEE
802.3 for 10BASE-T
MAU
Receiver
Receive Input Impedance ZIN ––22kΩ–
Differential Squelch
Threshold VDS 300 420 585 mV –
Table 29 10BASE-T Link Integrity Timing Characteristics
Parameter Symbol Min Typ Max Units Test Conditions
Time Link Loss Receive TLL 50 – 150 ms –
Link Pulse TLP 2 – 7 Link Pulses –
Link Min Receive Timer TLR MIN 2–7 ms –
Link Max Receive Timer TLR MAX 50 – 150 ms –
Link Transmit Period Tlt 8 – 24 ms –
Link Pulse Width Tlpw 60 – 150 ns –
1. Typical values are at 25 °C and are for design aid only, not guaranteed, and not subject to production
testing.
Table 30 Thermal Characteristics
Parameter Value
Package 1 0x 10 x1.4 64 LD LQFP
Theta-JA 58 C/W
Theta-JC 27 C/W
Psi - JT 3.4 C/W
Page 55Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
7.2 AC Timing Diagrams and
Parameters
• Figure 26, 10BASE-T Jabber and Unjabber Timing, on page 59
• Figure 27, 10BASE-T SQE (Heartbeat) Timing, on page 59
• Figure 28, Auto-Negotiation and Fast Link Pulse Timing, on page 60
• Figure 29, Fast Link Pulse Timing, on page 60
• Figure 30, MDIO Input Timing, on page 61
• Figure 31, MDIO Output Timing, on page 61
• Figure 32, Power-Up Timing, on page 62
• Figure 33, RESET_L Pulse Width and Recovery Timing, on page 62
Figure 22 100BASE-TX Receive Timing
t4 t5
t3
t6 t7
0 ns 250 ns
CRS
RX_DV
RXD[3:0]
RX_CLK
COL
t1
t2
TPI
B3492-03
Note: Timing diagram depicts 4B mode.
Page 56Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
7.2 AC Timing Diagrams and
Parameters
Table 31 100BASE-TX Receive Timing Parameters - 4B Mode
Parameter Sym Min Typ1Max Units2Test Conditions
RXD[3:0], RX_DV, RX_ER3 setup to
RX_CLK High t1 10 – – ns –
RXD[3:0], RX_DV, RX_ER hold
from RX_CLK High t2 10 – – ns –
CRS asserted to RXD[3:0], RX_DV t3 3 – 5 BT –
Receive start of “J” to CRS asserted t4 12 – 16 BT –
Receive start of “T” to CRS de-asserted t5 10 – 17 BT –
Receive start of “J” to COL asserted t6 16 – 22 BT –
Receive start of “T” to COL de-asserted t7 17 – 20 BT –
1. Typical values are at 25 °C and are for design aid only, not guaranteed, and not subject to production
testing.
2. BT (Bit Time) is the duration of one bit as transferred to and from the Mac and is the reciprocal of the bit
rate. 100BASE-T bit time = 10-8 s or 10 ns.
3. RX_ER is not shown in the figure.
Figure 23 100BASE-TX Transmit Timing
t1
t2
t5
t3 t4
0ns 250ns
TXCLK
TX_EN
TXD[3:0]
TPO
CRS
B3454-03
Note: Timing diagram depicts 4B mode.
Page 57Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
7.2 AC Timing Diagrams and
Parameters
Figure 24 10BASE-T Receive Timing
Table 32 10BASE-T Receive Timing Parameters
Parameter Sym Min Typ1Max Units2Test Conditions
RXD, RX_DV, RX_ER Setup to
RX_CLK High t1 10 – – ns –
RXD, RX_DV, RX_ER Hold from
RX_CLK High t2 10 – – ns –
TPIP/N in to RXD out (Rx latency) t3 4.2 – 6.6 BT –
CRS asserted to RXD, RX_DV,
RX_ER asserted t4 5 – 32 BT –
RXD, RX_DV, RX_ER de-asserted to
CRS de-asserted t5 0.3 – 0.5 BT –
TPI in to CRS asserted t6 2 – 28 BT –
TPI quiet to CRS de-asserted t7 6 – 10 BT –
TPI in to COL asserted t8 1 – 31 BT –
TPI quiet to COL de-asserted t9 5 – 10 BT –
1. Typical values are at 25 °C and are for design aid only, not guaranteed, and not subject to production
testing.
2. BT (Bit Time) is the duration of one bit as transferred to and from the MAC and is the reciprocal of the bit
rate. 10BASE-T bit time = 10-7 s or 100 ns.
RX_CLK
RXD,
RX_DV,
RX_ER
CRS
TPI
t3
t4
t2
t6
t1
t7
t5
COL t8
t9
B3457-01
Page 58Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
7.2 AC Timing Diagrams and
Parameters
Figure 25 10BASE-T Transmit Timing
TX_CLK
TXD,
TX_EN,
TX_ER
CRS
TPO
t1
t3t4
t5
t2
B3460-01
Page 59Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
7.2 AC Timing Diagrams and
Parameters
Figure 26 10BASE-T Jabber and Unjabber Timing
Table 33 10BASE-T Jabber and Unjabber Timing
Parameter Symbol Min Typ1Max Units Test Conditions
Maximum transmit time t1 20 – 150 ms –
Unjabber time t2 250 – 750 ms –
1. Typical values are at 25 °C and are for design aid only, not guaranteed, and not subject to production
testing.
Figure 27 10BASE-T SQE (Heartbeat) Timing
Table 34 PHY 10BASE-T SQE (Heartbeat) Timing
Parameter Symbol Min Typ1Max Units Test Conditions
COL (SQE) Delay after TX_EN off t1 0.65 – 1.6 us –
COL (SQE) Pulse duration t2 0.5 – 1.5 us –
1. Typical values are at 25 °C and are for design aid only, not guaranteed, and not subject to production
testing.
TXD
COL
t1
t2
TX_EN
B3455-01
TX_CLK
TX_EN
t1
t2
COL
B3458-01
Page 60Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
7.2 AC Timing Diagrams and
Parameters
Figure 28 Auto-Negotiation and Fast Link Pulse Timing
Figure 29 Fast Link Pulse Timing
Table 35 Auto-Negotiation and Fast Link Pulse Timing Parameters
Parameter Symbol Min Typ1Max Units Test
Conditions
Clock/Data pulse width t1 – 100 – ns –
Clock pulse to Data pulse t2 55.5 – 63.8 μs–
Clock pulse to Clock pulse t3 123 – 127 μs–
FLP burst width t4 – 2 – ms –
FLP burst to FLP burst t5 8 12 24 ms –
Clock/Data pulses per burst – 17 – 33
Each clock
pulse or data
pulse
–
1. Typical values are at 25 °C and are for design aid only, not guaranteed, and not subject to production
testing.
TPOP
t1 t1
t2
t3
Clock Pulse Data Pulse Clock Pulse
B3464-01
t4
t5
FLP Burst FLP Burst
TPOP
B3465-01
Page 61Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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Datasheet
302875, Revision 5.3
31 October 2007
7.2 AC Timing Diagrams and
Parameters
Figure 30 MDIO Input Timing
Figure 31 MDIO Output Timing
Table 36 MDIO Timing
Parameter Symbol Min Typ1Max Units Test Conditions
MDIO setup before MDC, sourced
by STA t1 10––ns –
MDIO hold after MDC, sourced by
STA t2 5 ––ns –
MDC to MDIO output delay,
sourced by PHY t3 – – 150 ns –
MDC period t4 125 – – ns MDC = 8 MHz
1. Typical values are at 25° C and are for design aid only, not guaranteed, and not subject to production
testing.
t1
MDC
MDIO
t2
t3
MDC
MDIO
t4
Page 62Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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Datasheet
302875, Revision 5.3
31 October 2007
7.2 AC Timing Diagrams and
Parameters
Figure 32 Power-Up Timing
Table 37 Power-Up Timing
Parameter Symbol Min Typ1Max Units Test Conditions
Voltage threshold v1 – 2.9 – V –
Power Up delay2t1 – – 300 μs–
1. Typical values are at 25° C and are for design aid only, not guaranteed, and not subject to production
testing.
2. Power-up delay is specified as a maximum value because it refers to the PHY guaranteed performance.
The PHY comes out of reset after a delay of no more than 300 μs. System designers should consider this
value as a minimum value. After threshold v1 is reached, the MAC should delay no less than 300 μs before
accessing the MDIO port.
Figure 33 RESET_L Pulse Width and Recovery Timing
t1
VCC
MDIO, and
so on
v1
B3494-01
t2
RESET_L
MDIO, and
so on
t1
B3495-01
Page 63Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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Datasheet
302875, Revision 5.3
31 October 2007
7.2 AC Timing Diagrams and
Parameters
Table 38 RESET_L Pulse Width and Recovery Timing
Parameter Symbol Min Typ1Max Units Test Conditions
RESET_L pulse width t1 10 – – ns –
RESET_L recovery delay2t2 – 300 μs–
1. Typical values are at 25° C and are for design aid only, not guaranteed, and not subject to production
testing.
2. Reset Recovery Delay is specified as a maximum value because it refers to the PHY guaranteed
performance. The PHY comes out of reset after a delay of no more than 300 μs. System designers should
consider this value as a minimum value. After de-asserting RESET_L, the MAC should delay no less than
300 μs before accessing the MDIO port.
Page 64Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
8.0 Register Definitions - IEEE
Base Registers
8.0 Register Definitions - IEEE Base Registers
This chapter includes definitions for the IEEE base registers used by the LXT972M PHY.
Section 9.0, Register Definitions - Product-Specific Registers includes definitions of
additional product-specific LXT972M PHY registers, which are defined in accordance with
the IEEE 802.3 standard for adding unique device functions.
The LXT972M PHY register set has multiple 16-bit registers.
•Table 39 is a register set listing of the IEEE base registers.
•Table 40 through Ta b l e 4 8 provide bit descriptions of the base registers (address 0
through 8), which are defined in accordance with the “Reconciliation Sublayer and
Media Independent Interface” and “Physical Layer Link Signaling for 10/100 Mbps
Auto-Negotiation” sections of the IEEE 802.3 standard.
Table 39 Register Set for IEEE Base Registers
Address Register Name Bit Assignments
0 Control Register See Table 40 on page 65
1 Status Register #1 See Table 41 on page 66
2 PHY Identification Register 1 See Table 42 on page 67
3 PHY Identification Register 2 See Table 43 on page 67
4 Auto-Negotiation Advertisement Register See Table 44 on page 68
5 Auto-Negotiation Link Partner Base Page Ability Register See Table 45 on page 69
6 Auto-Negotiation Expansion Register See Table 46 on page 70
7 Auto-Negotiation Next Page Transmit Register See Table 47 on page 70
8 Auto-Negotiation Link Partner Next Page Receive Register See Table 48 on page 71
9 1000BASE-T/100BASE-T2 Control Register Not Implemented
10 1000BASE-T/100BASE-T2 Status Register Not Implemented
11 to 14 Reserved Not Implemented
15 Extended Status Register Not Implemented
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302875, Revision 5.3
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8.0 Register Definitions - IEEE
Base Registers
Table 40 Control Register - Address 0, Hex 0
Bit Name Description Type 1Default
0.15 Reset 0 = Normal operation
1 = PHY reset
R/W
SC 0
0.14 Loopback 0 = Disable loopback mode
1 = Enable loopback mode R/W 0
0.13 Speed Selection
0.6 0.13 Speed Selected
R/W Note 2
0
0
1
1
0
1
0
1
10 Mbps
100 Mbps
1000 Mbps (not supported)
Reserved
0.12 Auto-Negotiation
Enable
0 = Disable auto-negotiation process
1 = Enable auto-negotiation process R/W Note 2
0.11 Power-Down 0 = Normal operation
1 = Power-down R/W 0
0.10 Isolate 0 = Normal operation
1 = Electrically isolate PHY from MII R/W 0
0.9 Restart Auto-
Negotiation
0 = Normal operation
1 = Restart auto-negotiation process
R/W
SC 0
0.8 Duplex Mode 0 = Half-duplex
1 = Full-duplex R/W Note 2
0.7 Collision Test 0 = Disable COL signal test
1 = Enable COL signal test R/W 0
0.6 Speed Selection
0.6 0.13 Speed Selected
R/W 0
0
0
1
1
0
1
0
1
10 Mbps
100 Mbps
1000 Mbps (not supported)
Reserved
0.5:0 Reserved Write as ‘0’. Ignore on Read. R/W 00000
1. R/W = Read/Write
SC = Self Clearing
2. Some bits have their default values determined at reset by hardware configuration pins. For default details
for these bits, see Section 5.4.4, Hardware Configuration Settings.
Page 66Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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8.0 Register Definitions - IEEE
Base Registers
Table 41 MII Status Register #1 - Address 1, Hex 1
Bit Name Description Type 1Default
1.15 100BASE-T4
Not Supported
0 = PHY not able to perform 100BASE-T4
1 = PHY able to perform 100BASE-T4 RO 0
1.14 100BASE-X Full-
Duplex
0 = PHY not able to perform full-duplex 100BASE-
X
1 = PHY able to perform full-duplex 100BASE-X
RO 1
1.13 100BASE-X Half-
Duplex
0 = PHY not able to perform half-duplex
100BASE-X
1 = PHY able to perform half-duplex 100BASE-X
RO 1
1.12 10 Mbps Full-Duplex
0 = PHY not able to operate at 10 Mbps full-duplex
mode
1 = PHY able to operate at 10 Mbps in full-duplex
mode
RO 1
1.11 10 Mbps Half-Duplex
0 = PHY not able to operate at 10 Mbps in half-
duplex
1 = PHY able to operate at 10 Mbps in half-duplex
mode
RO 1
1.10
100BASE-T2 Full-
Duplex
Not Supported
0 = PHY not able to perform full-duplex
100BASE-T2
1 = PHY able to perform full-duplex 100BASE-T2
RO 0
1.9
100BASE-T2 Half-
Duplex
Not Supported
0 = PHY not able to perform half-duplex
100BASE-T2
1 = PHY able to perform half-duplex 100BASE-T2
RO 0
1.8 Extended Status 0 = No extended status information in register 15
1 = Extended status information in register 15 RO 0
1.7 Reserved Ignore when read. RO 0
1.6 MF Preamble
Suppression
0 = PHY cannot accept management frames with
preamble suppressed
1 = PHY accepts management frames with
preamble suppressed
RO 0
1.5 Auto-Negotiation
complete
0 = Auto-negotiation not complete
1 = Auto-negotiation complete RO 0
1.4 Remote Fault 0 = No remote fault condition detected
1 = Remote fault condition detected RO/LH 0
1.3 Auto-Negotiation
Ability
0 = PHY is not able to perform auto-negotiation
1 = PHY is able to perform auto-negotiation RO 1
1.2 Link Status 0 = Link is down
1 = Link is up RO/LL 0
1.1 Jabber Detect 0 = Jabber condition not detected
1 = Jabber condition detected RO/LH 0
1.0 Extended Capability 0 = Basic register capabilities
1 = Extended register capabilities RO 1
1. RO = Read Only
LL = Latching Low
LH = Latching High
Page 67Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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31 October 2007
8.0 Register Definitions - IEEE
Base Registers
Table 42 PHY Identification Register 1 - Address 2, Hex 2
Bit Name Description Type 1Default
Note: See Figure 34 for identifier bit mapping.
2.15:0 PHY ID Number The PHY identifier is composed of bits 3 through 18
of the Organizationally Unique Identifier (OUI). RO 0013 hex
1. RO = Read Only
Table 43 PHY Identification Register 2 - Address 3, Hex 3
Bit Name Description Type 1Default
Note: See Figure 34 for identifier bit mapping.
3.15:1
0PHY ID number The PHY identifier is composed of bits 19 through
24 of the OUI. RO 011110
3.9:4 Manufacturer’s
model number 6 bits containing manufacturer’s part number. RO 001110
3.3:0 Manufacturer’s
revision number 4 bits containing manufacturer’s revision number. RO
For current
revision ID
information,
see the
Specificatio
n Update.
1. RO = Read Only
Figure 34 PHY Identifier Bit Mapping
B3504-01
Note: The Intel OUI is 00207B hex
7B
PHY ID Register #1 (Address 2) = 0013
Organizationally Unique Identifier (QUI)
PHY ID Register #2 (Address 3)
Manufacturer's
Model Number
Revision
Number
50
9101515 43 00
11011110000111 000001000000000000
a b c r s x
00
03
2000
Note: The Cortina OUI is 00207B hex
Page 68Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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31 October 2007
8.0 Register Definitions - IEEE
Base Registers
Table 44 Auto-Negotiation Advertisement Register - Address 4, Hex 4
Bit Name Description Type 1Default
4.15 Next Page 0 = Port has no ability to send multiple pages.
1 = Port has ability to send multiple pages. R/W 0
4.14 Reserved Ignore when read. RO 0
4.13 Remote Fault 0 = No remote fault.
1 = Remote fault. R/W 0
4.12 Reserved Write as ‘0’. Ignore on Read. R/W 0
4.11 Asymmetric Pause Pause operation defined in IEEE 802.3 Standard,
Clause 40 and 27 R/W 0
4.10 Pause 0 = Pause operation disabled.
1 = Pause operation enabled for full-duplex link. R/W 0
4.9 100BASE-T4
0 = 100BASE-T4 capability is not available.
1 = 100BASE-T4 capability is available.
Note: The LXT972M PHY does not support
100BASE-T4 but allows this bit to be set
to advertise in the auto-negotiation
sequence for 100BASE-T4 operation. An
external 100BASE-T4 PHY can be
switched in if this capability is desired.
R/W 0
4.8
100BASE-TX
full-duplex
(For LXT972M PHY)
0 = Port is not 100BASE-TX full-duplex capable.
1 = Port is 100BASE-TX full-duplex capable. R/W Note 3
4.7 100BASE-TX
(For LXT972M PHY)
0 = Port is not 100BASE-TX capable.
1 = Port is 100BASE-TX capable. R/W Note 3
4.6
10BASE-T
full-duplex
(ForLXT972M PHY)
0 = Port is not 10BASE-T full-duplex capable.
1 = Port is 10BASE-T full-duplex capable. R/W Note 3
4.5 10BASE-T 0 = Port is not 10BASE-T capable.
1 = Port is 10BASE-T capable. R/W Note 3
4.4:0 Selector Field,
S<4:0>
00001 =IEEE 802.3.
00010 =IEEE 802.9 ISLAN-16T.
00000 =Reserved for future auto-negotiation
development.
11111 = Reserved for future auto-negotiation
development.
Note: Unspecified or reserved combinations
must not be transmitted.
R/W 00001
1. R/W = Read/Write
RO = Read Only
2. Some bits have their default values determined at reset by hardware configuration pins. For default details
for these bits, see Section 5.4.4, Hardware Configuration Settings.
Page 69Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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302875, Revision 5.3
31 October 2007
8.0 Register Definitions - IEEE
Base Registers
Table 45 Auto-Negotiation Link Partner Base Page Ability Register - Address 5, Hex 5
Bit Name Description Type 1 Default
5.15 Next Page
0 = Link Partner has no ability to send multiple
pages.
1 = Link Partner has ability to send multiple pages.
RO 0
5.14 Acknowledge
0 = Link Partner has not received Link Code Word
from the LXT972M PHY.
1 = Link Partner has received Link Code Word
from the LXT972M PHY.
RO 0
5.13 Remote Fault 0 = No remote fault.
1 = Remote fault. RO 0
5.12 Reserved Ignore when read. RO 0
5.11 Asymmetric Pause
Pause operation defined in IEEE 802.3 Standard,
Clause 40 and 27.
0 = Link Partner is not Pause capable.
1 = Link Partner is Pause capable.
RO 0
5.10 Pause 0 = Link Partner is not Pause capable.
1 = Link Partner is Pause capable. RO 0
5.9 100BASE-T4 0 = Link Partner is not 100BASE-T4 capable.
1 = Link Partner is 100BASE-T4 capable. RO 0
5.8 100BASE-TX
Full-Duplex
0 = Link Partner is not 100BASE-TX full-duplex
capable.
1 = Link Partner is 100BASE-TX full-duplex
capable.
RO 0
5.7 100BASE-TX 0 = Link Partner is not 100BASE-TX capable.
1 = Link Partner is 100BASE-TX capable. RO 0
5.6 10BASE-T
Full-Duplex
0 = Link Partner is not 10BASE-T full-duplex
capable.
1 = Link Partner is 10BASE-T full-duplex capable.
RO 0
5.5 10BASE-T 0 = Link Partner is not 10BASE-T capable.
1 = Link Partner is 10BASE-T capable. RO 0
5.4:0 Selector Field
S<4:0>
<00001> = IEEE 802.3.
<00010> = IEEE 802.9 ISLAN-16T.
<00000> = Reserved for future auto-negotiation
development.
<11111> = Reserved for future auto-negotiation
development.
Unspecified or reserved combinations must not be
transmitted.
RO 0
1. RO = Read Only
Page 70Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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31 October 2007
8.0 Register Definitions - IEEE
Base Registers
Table 46 Auto-Negotiation Expansion - Address 6, Hex 6
Bit Name Description Type 1Default
6.15:6 Reserved Ignore when read. RO 0
6.5 Base Page
This bit indicates the status of the auto-negotiation
variable base page. It flags synchronization with
the auto-negotiation state diagram, allowing
detection of interrupted links. This bit is used only
if register bit 16.1 (that is, Alternate NP feature) is
set.
0 = Base page = False (base page not received)
1 = Base page = True (base page received)
RO/LH 0
6.4 Parallel
Detection Fault
0 = Parallel detection fault has not occurred.
1 = Parallel detection fault has occurred. RO/LH 0
6.3 Link Partner Next
Page Able
0 = Link partner is not next page able.
1 = Link partner is next page able. RO 0
6.2 Next Page Able 0 = Local device is not next page able.
1 = Local device is next page able. RO 1
6.1 Page Received
This bit is cleared on Read. If register bit 16.1 is
set, the Page Received bit is also cleared when
either mr_page_rx = false or transmit_disable =
true.
1 = Indicates a new page is received and the
received code word is loaded into Register 5
(Base Pages) or Register 8 (Next Pages) as
specified in Clause 28 of IEEE 802.3.
RO/LH 0
6.0 Link Partner A/N Able 0 = Link partner is not auto-negotiation able.
1 = Link partner is auto-negotiation able. RO 0
1. RO = Read Only LH = Latching High
Table 47 Auto-Negotiation Next Page Transmit Register - Address 7, Hex 7
Bit Name Description Type 1Default
7.15 Next Page (NP) 0 = Last page
1 = Additional next pages follow R/W 0
7.14 Reserved Ignore when read. RO 0
7.13 Message Page (MP)
0 = register bits 7.10:0 are user defined.
1 = register bits 7.10.0 follow IEEE message page
format.
R/W 1
7.12 Acknowledge 2
(ACK2)
0 = Cannot comply with message
1 = Complies with message R/W 0
7.11 Toggle (T)
0 = Previous value of the transmitted Link Code
Word equalled logic one
1 = Previous value of the transmitted Link Code
Word equalled logic zero
R/W 0
7.10:0
Message/
Unformatted Code
Field
If register bits 7.13 = 0, register bits 7.10:0 are
user-defined.
If register bits 7.13 = 1, register bits 7.10:0 follow
IEEE message page format.
R/W
0000
0000
001
1. RO = Read Only. R/W = Read/Write
Page 71Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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31 October 2007
8.0 Register Definitions - IEEE
Base Registers
Table 48 Auto-Negotiation Link Partner Next Page Receive Register - Address 8, Hex 8
Bit Name Description Type 1Default
8.15 Next Page (NP)
0 = Link Partner has no additional next pages to
send
1 = Link Partner has additional next pages to send
RO 0
8.14 Acknowledge (ACK)
0 = Link Partner has not received Link Code Word
from LXT972M PHY.
1 = Link Partner has received Link Code Word
from LXT972M PHY.
RO 0
8.13 Message Page (MP)
0 = register bits 8.10:0 are user defined.
1 = register bits 8.10:0 follow IEEE message page
format.
RO 0
8.12 Acknowledge 2
(ACK2)
0 = Link Partner cannot comply with the message
1 = Link Partner complies with the message RO 0
8.11 Toggle (T)
0 = Previous value of transmitted Link Code Word
equal to logic one
1 = Previous value of transmitted Link Code Word
equal to logic zero
RO 0
8.10:0
Message/
Unformatted Code
Field
If register bit 8.13 = 0, register bits 18.10:0 are
user defined.
If register bit 8.13 = 1, register bits 18.10:0 follow
IEEE message page format.
RO
0000
0000
00
1. RO = Read Only.
Page 72Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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302875, Revision 5.3
31 October 2007
9.0 Register Definitions -
Product-Specific Registers
9.0 Register Definitions - Product-Specific Registers
This chapter includes definitions of product-specific LXT972M PHY registers that are
defined in accordance with the IEEE 802.3 standard for adding unique device functions.
(For definitions of the IEEE base registers used by the LXT972M PHY, see Section 8.0,
Register Definitions - IEEE Base Registers.)
•Table 49 lists the register set of the product-specific registers.
•Table 50 through Ta b l e 5 6 provide bit descriptions of the product-specific registers
(address 17 through 30).
Table 49 Register Set for Product-Specific Registers
Address Register Name Bit Assignments
16 Port Configuration Register See Table 50
17 Status Register #2 See Table 51
18 Interrupt Enable Register See Table 52
19 Status Change Register See Table 53
20 LED Configuration Register See Table 54
21 Reserved —
22-25 Reserved —
26 Digital Configuration Register See Table 55
27 Reserved —
28 Reserved —
29 Reserved —
30 Transmit Control Register See Table 56
31 Reserved —
Table 50 Configuration Register - Address 16, Hex 10 (Sheet 1 of 2)
Bit Name Description Type 1Default
16.15 Reserved Write as ‘0’. Ignore on Read. R/W 0
16.14 Force Link Pass 0 = Normal operation
1 = Force Link pass R/W 0
16.13 Transmit Disable 0 = Normal operation
1 = Disable Twisted Pair transmitter R/W 0
16.12 Bypass Scrambler
(100BASE-TX)
0 = Normal operation
1 = Bypass Scrambler and Descrambler R/W 0
16.11 Reserved Write as ‘0’. Ignore on Read. R/W 0
16.10 Jabber
(10BASE-T)
0 = Normal operation
1 = Disable Jabber Correction R/W 0
16.9 SQE
(10BASE-T)
0 = Disable Heart Beat
1 = Enable Heart Beat R/W 0
1. R/W = Read /Write
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302875, Revision 5.3
31 October 2007
9.0 Register Definitions -
Product-Specific Registers
16.8 TP Loopback
(10BASE-T)
0 = Normal operation
1 = Disable TP loopback during half-duplex
operation
R/W 0
16.7 CRS Select
(10BASE-T)
0 = Normal Operation
1 = CRS deassert extends to RX_DV deassert R/W 1
16.6 Reserved Write as ‘0’. Ignore on Read. R/W 0
16.5 PRE_EN
Preamble Enable.
0 = Set RX_DV high coincident with SFD.
1 = Set RX_DV high and RXD = preamble when
CRS is asserted.
Note: Preamble is always enabled in 100 Mbps
operation.
R/W 0
16.4:3 Reserved Write as ‘0’. Ignore on Read. R/W 00
16.2 Reserved Write as ‘0’. Ignore on Read. R/W 0
16.1 Alternate NP feature
0 = Disable alternate auto negotiate next page
feature.
1 = Enable alternate auto negotiate next page
feature.
Note: This bit enables or disables the register
bit 6.5 capability.
R/W 0
16.0 Reserved Write as ‘0’. Ignore on Read. R/W 0
Table 51 Status Register #2 - Address 17, Hex 11 (Sheet 1 of 2)
Bit Name Description Type 1Default
17.15 Reserved Always 0. RO 0
17.14 10/100 Mode
0 = LXT972M PHY is not operating 100BASE-TX
mode.
1 = LXT972M PHY is operating in 100BASE-TX
mode.
RO 0
17.13 Transmit Status 0 = LXT972M PHY is not transmitting a packet.
1 = LXT972M PHY is transmitting a packet. RO 0
17.12 Receive Status 0 = LXT972M PHY is not receiving a packet.
1 = LXT972M PHY is receiving a packet. RO 0
17.11 Collision Status 0 = No collision.
1 = Collision is occurring. RO 0
17.10 Link 0 = Link is down.
1 = Link is up. RO 0
17.9 Duplex Mode 0 = Half-duplex.
1 = Full-duplex. RO 0
17.8 Auto-Negotiation 0 = LXT972M PHY is in manual mode.
1 = LXT972M PHY is in auto-negotiation mode. RO 0
1. RO = Read Only. R/W = Read/Write
Table 50 Configuration Register - Address 16, Hex 10 (Sheet 2 of 2)
Bit Name Description Type 1Default
1. R/W = Read /Write
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302875, Revision 5.3
31 October 2007
9.0 Register Definitions -
Product-Specific Registers
17.7 Auto-Negotiation
Complete
0 = Auto-negotiation process not completed.
1 = Auto-negotiation process completed.
This bit is valid only when auto negotiate is
enabled. The value is equivalent to the value of
register bit 1.5.
RO 0
17.6 Reserved Always 0. RO 0
17.5 Polarity
0 = Polarity is not reversed.
1 = Polarity is reversed.
Note: Polarity is not a valid status in 100 Mbps
mode.
RO 0
17.4 Pause 0 = The LXT972M PHY is not Pause capable.
1 = The LXT972M PHY is Pause capable. R0
17:3 Error
0 = No error occurred
1 = Error occurred (Remote Fault, jabber, parallel
detect fault)
Note: The register bit is cleared when the
registers that generate the error condition
are read.
RO 0
17:2 Reserved Always 0. RO 0
17:1 Reserved Always 0. RO 0
17.0 Reserved Always 0. RO 0
Table 51 Status Register #2 - Address 17, Hex 11 (Sheet 2 of 2)
Bit Name Description Type 1Default
1. RO = Read Only. R/W = Read/Write
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Datasheet
302875, Revision 5.3
31 October 2007
9.0 Register Definitions -
Product-Specific Registers
Table 52 Interrupt Enable Register - Address 18, Hex 12
Bit Name Description Type 1 Default
18.
15:9 Reserved Write as ‘0’. Ignore on Read. R/W N/A
18.8 Reserved Write as ‘0’. Ignore on Read. R/W 0
18.7 ANMSK
Mask for Auto Negotiate Complete
0 = Do not allow event to cause interrupt.
1 = Enable event to cause interrupt.
R/W 0
18.6 SPEEDMSK
Mask for Speed Interrupt
0 = Do not allow event to cause interrupt.
1 = Enable event to cause interrupt.
R/W 0
18.5 DUPLEXMSK
Mask for Duplex Interrupt
0 = Do not allow event to cause interrupt.
1 = Enable event to cause interrupt.
R/W 0
18.4 LINKMSK
Mask for Link Status Interrupt
0 = Do not allow event to cause interrupt.
1 = Enable event to cause interrupt.
R/W 0
18.3 Reserved Write as ‘0’. Ignore on Read. R/W 0
18.2 Reserved Write as ‘0’. Ignore on Read. R/W 0
18.1 Reserved
Write as ‘0’. Ignore on Read.
Question 1
R/W 0
18.0 Reserved Write as ‘0’. Ignore on Read. R/W 0
1. R/W = Read /Write
Table 53 Status Change Register - Address 19, Hex 13 (Sheet 1 of 2)
Bit Name Description Type 1 Default
19.15:9 Reserved Ignore on Read. RO N/A
19.8 Reserved Ignore on Read. RO 0
19.7 ANDONE
Auto-negotiation Status
0 = Auto-negotiation has not completed.
1 = Auto-negotiation has completed.
RO/
SC N/A
19.6 SPEEDCHG
Speed Change Status
0 = A Speed Change has not occurred since last
reading this register.
1 = A Speed Change has occurred since last reading
this register.
RO/
SC 0
19.5 DUPLEXCHG
Duplex Change Status
0 = A Duplex Change has not occurred since last
reading this register.
1 = A Duplex Change has occurred since last
reading this register.
RO/
SC 0
1. R/W = Read/Write, RO = Read Only, SC = Self Clearing.
Page 76Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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Datasheet
302875, Revision 5.3
31 October 2007
9.0 Register Definitions -
Product-Specific Registers
19.4 LINKCHG
Link Status Change Status
0 = A Link Change has not occurred since last
reading this register.
1 = A Link Change has occurred since last reading
this register.
RO/
SC 0
19.3 Reserved Ignore on Read. RO 0
19.2 Reserved Ignore on Read. RO 0
19.1 Reserved Ignore on Read. RO 0
19.0 Reserved Ignore on Read. RO 0
Table 53 Status Change Register - Address 19, Hex 13 (Sheet 2 of 2)
Bit Name Description Type 1 Default
1. R/W = Read/Write, RO = Read Only, SC = Self Clearing.
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31 October 2007
9.0 Register Definitions -
Product-Specific Registers
Table 54 LED Configuration Register - Address 20, Hex 14 (Sheet 1 of 2)
Bit Name Description Type 1Default
20.15:12
LED1
Programming
bits
0000 =Display Speed Status (Continuous, Default)
0001 =Display Transmit Status (Stretched)
0010 =Display Receive Status (Stretched)
0011 =Display Collision Status (Stretched)
0100 =Display Link Status (Continuous)
0101 =Display Duplex Status (Continuous)
0110 =Unused
0111 = Display Receive or Transmit Activity (Stretched)
1000 =Test mode - turn LED on (Continuous)
1001 =Test mode - turn LED off (Continuous)
1010 =1010 = Test mode - blink LED fast (Continuous)
1011 =Test mode - blink LED slow (Continuous)
1100 =Display Link and Receive Status combined 2
(Stretched)3
1101 =Display Link and Activity Status combined 2
(Stretched)3
1110 = Display Duplex and Collision Status combined 4
(Stretched)3
1111 = Unused
R/W 0000
20.11:8
LED2
Programming
bits
0000 =0000 = Display Speed Status
0001 =Display Transmit Status
0010 =Display Receive Status
0011 =Display Collision Status
0100 =Display Link Status (Default)
0101 =Display Duplex Status
0110 =Unused
0111 = Display Receive or Transmit Activity
1000 =Test mode - turn LED on
1001 =Test mode - turn LED off
1010 =Test mode - blink LED fast
1011 =Test mode - blink LED slow
1100 =Display Link and Receive Status combined 2
(Stretched)3
1101 =Display Link and Activity Status combined 2
(Stretched)3
1110 = Display Duplex and Collision Status combined 4
(Stretched)3
1111 = Unused
R/W 0100
1. R/W = Read /Write. RO = Read Only. LH = Latching High
2. Link status is the primary LED driver. The LED is asserted (solid ON) when the link is up.
The secondary LED driver (Receive or Activity) causes the LED to change state (blink).
Activity causes the LED to blink, regardless of the link status.
3. Combined event LED settings are not affected by Pulse Stretch register bit 20.1. These display settings
are stretched regardless of the value of 20.1.
4. Duplex status is the primary LED driver. The LED is asserted (solid ON) when the link is full-duplex.
Collision status is the secondary LED driver. The LED changes state (blinks) when a collision occurs.
5. Values are approximations. Not guaranteed or production tested.
Page 78Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
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302875, Revision 5.3
31 October 2007
9.0 Register Definitions -
Product-Specific Registers
20.7:4
LED3
Programming
bits
0000 =Display Speed Status
0001 =Display Transmit Status
0010 =Display Receive Status (Default)
0011 =Display Collision Status
0100 =Display Link Status
0101 =Display Duplex Status
0110 =Unused
0111 = Display Receive or Transmit Activity
1000 =Test mode- turn LED on
1001 =Test mode- turn LED off
1010 =Test mode- blink LED fast
1011 =Test mode- blink LED slow
1100 =Display Link and Receive Status combined 2
(Stretched)3
1101 =Display Link and Activity Status combined 2
(Stretched)3
1110 = Display Duplex and Collision Status combined 4
(Stretched)3
1111 = Unused
R/W 0010
20.3:2 LEDFREQ5
00 = Stretch LED events to 30 ms.
01 = Stretch LED events to 60 ms.
10 = Stretch LED events to 100 ms.
11 = Reserved.
R/W 00
20.1 PULSE-
STRETCH
0 = Disable pulse stretching of all LEDs.
1 = Enable pulse stretching of all LEDs. R/W 1
20.0 Reserved Write as ‘0’. Ignore on Read. R/W 0
Table 55 Digital Configuration Register - Address 26, Hex 1A (Sheet 1 of 2)
Bit Name Description Type 1Default
26.15:12 Reserved Write as ‘0’. Ignore on Read. R/W 0000
26.11 MII Drive Strength
MII Drive Strength
0 = Normal MII drive strength
1 = Increase MII drive strength
R/W 0
26.10 Reserved Write as ‘0’. Ignore on Read. R/W 0
26.9 Show Symbol Error
Show Symbol Error
0 = Normal MII_RXER
1 = 100BASE-X Error Signal to MII_RxER
R/W 0
26.8:6 Reserved Write as ‘0’. Ignore on Read. RO 0
1. R/W = Read /Write, RO = Read Only
Table 54 LED Configuration Register - Address 20, Hex 14 (Sheet 2 of 2)
Bit Name Description Type 1Default
1. R/W = Read /Write. RO = Read Only. LH = Latching High
2. Link status is the primary LED driver. The LED is asserted (solid ON) when the link is up.
The secondary LED driver (Receive or Activity) causes the LED to change state (blink).
Activity causes the LED to blink, regardless of the link status.
3. Combined event LED settings are not affected by Pulse Stretch register bit 20.1. These display settings
are stretched regardless of the value of 20.1.
4. Duplex status is the primary LED driver. The LED is asserted (solid ON) when the link is full-duplex.
Collision status is the secondary LED driver. The LED changes state (blinks) when a collision occurs.
5. Values are approximations. Not guaranteed or production tested.
Page 79Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
9.0 Register Definitions -
Product-Specific Registers
26.5:4 Reserved Write as ‘0’. Ignore on Read. R/W 00
26.3 Reserved Write as ‘0’. Ignore on Read. RO 0
26.2:0 Reserved Write as ‘0’. Ignore on Read. R/W 0
Table 56 Transmit Control Register - Address 30, Hex 1E
Bit Name Description Type2Default
30.15:13 Reserved Write as ‘0’. Ignore on Read. R/W 000
30.12 Transmit Low Power
Transmit Low Power
0 = Normal transmission.
1 = Forces the transmitter into low power mode.
Also forces a zero-differential transmission.
R/W 0
30.11:10 Port Rise Time Control1
Port Rise Time Control
00 = 3.0 ns (Default = Setting on TXSLEW[1:0]
pins)
01 = 3.4 ns
10 = 3.9 ns
11 = 4.4 ns
R/W Note 3
30.4:0 Reserved Ignore on Read. R/W 0
1. Values are approximations and may vary outside indicated values based upon implementation loading
conditions.
2. R/W = Read/Write
3. Latch State during Reset is based on the state of hardware configuration pins at RESET_L.
Table 55 Digital Configuration Register - Address 26, Hex 1A (Sheet 2 of 2)
Bit Name Description Type 1Default
1. R/W = Read /Write, RO = Read Only
Page 80Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
10.0 Package Specifications
10.0 Package Specifications
Figure 35 LQFP Package Specifications
D
D
1
A
1
A
2
L
A
B
L
1
θ
3
θ
3
θ
E
E
1
e
/
2
e
48-Pin Low-Profile Quad Flat Pack
Note: The package figure is generic and used only to demonstrate package dimensions.
Dim
Millimeters
Min Max
A – 1.60
A10.05 0.15
A21.35 1.45
B0.170.27
D8.809.20
D16.90 7.10
E8.809.20
E16.90 7.10
e 0.50 BSC1
L0.450.75
L11.00 REF
θ311
o13o
q0
o7o
1. Basic Spacing between Centers
Page 81
~ End of Document ~
Cortina Systems®LXT972M Single-Port 10/100 Mbps PHY Transceiver
LXT972M PHY
Datasheet
302875, Revision 5.3
31 October 2007
Contact Information
Contact Information
Cortina Systems, Inc.
840 W. California Ave
Sunnyvale, CA 94086
408-481-2300
sales@cortina-systems.com
apps@cortina-systems.com
www.cortina-systems.com
For additional product and ordering information:
www.cortina-systems.com
To provide comments on this document:
documentation@cortina-systems.com