NSC DP83848M

®
DP83848M PHYTER Mini - Commercial Temperature
Single 10/100 Ethernet Transceiver
Features
General Description
The DP83848M PHYTER Mini addresses the quality, reli- • Low-power 3.3V, 0.18µm CMOS technology
ability and small form factor required for space sensitive • Auto-MDIX for 10/100 Mb/s
applications in embedded systems.
• Energy Detection Mode
The device offers performance far exceeding the IEEE • 3.3V MAC Interface
specifications, with superior interoperability and industry
leading performance beyond 137m of Cat-V cable. The • RMII Rev. 1.2 Interface (configurable)
DP83848M also offers Auto-MDIX to remove cabling com- • MII Interface
plications. DP83848M has superior ESD protection, • MII serial management interface (MDC and MDIO)
greater than 4KV Human Body Model, providing extremely
high reliability and robust operation, ensuring a high level • IEEE 802.3u Auto-Negotiation and Parallel Detection
• IEEE 802.3u ENDEC, 10BASE-T transceivers and filters
performance in all applications.
National’s DP83848M incorporates a number of system • IEEE 802.3u PCS, 100BASE-TX transceivers and filters
cost-reducing features not found on other supplier’s Physi- • Integrated ANSI X3.263 compliant TP-PMD physical subcal layer products. For example, the DP83848M incorpolayer with adaptive equalization and Baseline Wander
rates a 25MHz clock out that eliminates the need and
compensation
hence the space and cost, of an additional Media Access
Control (MAC) clock source component. In addition, both • Error-free Operation up to 137 meters
MII and RMII are supported ensuring ease and flexibility of • ESD protection - 4KV Human body model
design.
• Configurable LED for link and activity
The DP83848M is offered in a tiny 6mm x 6mm LLP 40-pin • Supports system clock from oscillator
package and is ideal for industrial controls, building/factory
• Single register access for complete PHY status
automation, transportation, test equipment and wireless
• 10/100 Mb/s packet BIST (Built in Self Test)
base stations.
• 40 pin LLP package (6mm) x (6mm) x (0.8mm)
Applications
•
•
•
•
Peripheral devices
Mobile devices
Factory and building automation
Base stations
MII/RMII
10/100 Ethernet
Transceiver
Clock
Source
RJ-45
DP83848M
Magnetics
MPU/CPU
Media Access Controller
System Diagram
10BASE-T
or
100BASE-TX
Status
LED
Typical Ethernet Application
PHYTER® is a registered trademark of National Semiconductor Corporation.
© 2008 National Semiconductor Corporation
www.national.com
DP83848M PHYTER® Mini - Commercial Temperature Single 10/100 Ethernet Transceiver
May 2008
DP83848M
RX_CLK
RXD[3:0]
RX_DV
RX_ER
COL
MDC
MDIO
TX_EN
TX_CLK
TXD[3:0]
SERIAL
MANAGEMENT
CRS/CRS_DV
MII/RMII
MII/RMII INTERFACE
TX_DATA
RX_CLK
TX_CLK
RX_DATA
MII
Registers
10BASE-T &
100BASE-TX
10BASE-T &
100BASE-TX
Auto-Negotiation
State Machine
Transmit Block
Receive Block
Clock
Generation
ADC
DAC
LED
Driver
Auto-MDIX
TD±
RD±
REFERENCE CLOCK
Figure 1. DP83848M Functional Block Diagram
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2
LED
1.0 Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.1 Serial Management Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
1.2 MAC Data Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
1.3 Clock Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
1.4 LED Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
1.5 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
1.6 Strap Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
1.7 10 Mb/s and 100 Mb/s PMD Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
1.8 Special Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
1.9 Power Supply Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
1.10 Package Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
2.0 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1 Auto-Negotiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
2.1.1
2.1.2
2.1.3
2.1.4
2.1.5
2.1.6
Auto-Negotiation Pin Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auto-Negotiation Register Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auto-Negotiation Parallel Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auto-Negotiation Restart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Enabling Auto-Negotiation via Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auto-Negotiation Complete Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
15
16
16
16
16
2.2 Auto-MDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
2.3 PHY Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
2.3.1 MII Isolate Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.4 LED Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
2.4.1 LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.4.2 LED Direct Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.5 Half Duplex vs. Full Duplex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
2.6 Internal Loopback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
2.7 BIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
3.0 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.1 MII Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
3.1.1 Nibble-wide MII Data Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.1.2 Collision Detect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.1.3 Carrier Sense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.2 Reduced MII Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
3.3 802.3u MII Serial Management Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
3.3.1 Serial Management Register Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.3.2 Serial Management Access Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.3.3 Serial Management Preamble Suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.0 Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1 100BASE-TX TRANSMITTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
4.1.1
4.1.2
4.1.3
4.1.4
Code-group Encoding and Injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scrambler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
NRZ to NRZI Encoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Binary to MLT-3 Convertor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25
25
25
25
4.2 100BASE-TX RECEIVER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
4.2.1 Analog Front End . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.2 Digital Signal Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.2.1 Digital Adaptive Equalization and Gain Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.2.2 Base Line Wander Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.3 Signal Detect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.4 MLT-3 to NRZI Decoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.5 NRZI to NRZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.6 Serial to Parallel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.7 Descrambler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.8 Code-group Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
25
25
27
28
28
28
28
28
29
29
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DP83848M
Table of Contents
DP83848M
4.2.9 4B/5B Decoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.2.10 100BASE-TX Link Integrity Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.2.11 Bad SSD Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.3 10BASE-T TRANSCEIVER MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
4.3.1 Operational Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.2 Smart Squelch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.3 Collision Detection and SQE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.4 Carrier Sense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.5 Normal Link Pulse Detection/Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.6 Jabber Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.7 Automatic Link Polarity Detection and Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.8 Transmit and Receive Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.9 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.10 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
29
30
30
30
30
31
31
31
31
31
5.0 Design Guidelines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.1
5.2
5.3
5.4
5.5
5.6
TPI Network Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
ESD Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Clock In (X1) Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Power Feedback Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Power Down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Energy Detect Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
6.0 Reset Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
6.1 Hardware Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
6.2 Software Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
7.0 Register Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
7.1 Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
7.1.1
7.1.2
7.1.3
7.1.4
7.1.5
7.1.6
7.1.7
7.1.8
7.1.9
Basic Mode Control Register (BMCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Basic Mode Status Register (BMSR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PHY Identifier Register #1 (PHYIDR1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PHY Identifier Register #2 (PHYIDR2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auto-Negotiation Advertisement Register (ANAR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auto-Negotiation Link Partner Ability Register (ANLPAR) (BASE Page) . . . . . . . . . . . . . . . .
Auto-Negotiation Link Partner Ability Register (ANLPAR) (Next Page) . . . . . . . . . . . . . . . . .
Auto-Negotiate Expansion Register (ANER) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auto-Negotiation Next Page Transmit Register (ANNPTR) . . . . . . . . . . . . . . . . . . . . . . . . . .
40
42
43
43
43
45
46
46
47
7.2 Extended Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
7.2.1 PHY Status Register (PHYSTS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.2 False Carrier Sense Counter Register (FCSCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.3 Receiver Error Counter Register (RECR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.4 100 Mb/s PCS Configuration and Status Register (PCSR) . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.5 RMII and Bypass Register (RBR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.6 LED Direct Control Register (LEDCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.7 PHY Control Register (PHYCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.8 10Base-T Status/Control Register (10BTSCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.9 CD Test and BIST Extensions Register (CDCTRL1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.10 Energy Detect Control (EDCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
48
50
50
51
52
53
54
56
57
58
8.0 Electrical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
8.1 DC Specs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
8.2 AC Specs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
8.2.1 Power Up Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.2 Reset Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.3 MII Serial Management Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.4 100 Mb/s MII Transmit Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.5 100 Mb/s MII Receive Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.6 100BASE-TX Transmit Packet Latency Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.7 100BASE-TX Transmit Packet Deassertion Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.8 100BASE-TX Transmit Timing (tR/F & Jitter) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.9 100BASE-TX Receive Packet Latency Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.10 100BASE-TX Receive Packet Deassertion Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2.11 10 Mb/s MII Transmit Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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61
62
63
63
64
64
65
66
67
67
68
10 Mb/s MII Receive Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10BASE-T Transmit Timing (Start of Packet) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10BASE-T Transmit Timing (End of Packet) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10BASE-T Receive Timing (Start of Packet) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10BASE-T Receive Timing (End of Packet) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 Mb/s Heartbeat Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 Mb/s Jabber Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10BASE-T Normal Link Pulse Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auto-Negotiation Fast Link Pulse (FLP) Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
100BASE-TX Signal Detect Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
100 Mb/s Internal Loopback Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 Mb/s Internal Loopback Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RMII Transmit Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RMII Receive Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Isolation Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25 MHz_OUT Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
100 Mb/s X1 to TX_CLK Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
68
69
69
70
70
71
71
72
72
73
73
74
75
76
77
77
78
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DP83848M
8.2.12
8.2.13
8.2.14
8.2.15
8.2.16
8.2.17
8.2.18
8.2.19
8.2.20
8.2.21
8.2.22
8.2.23
8.2.24
8.2.25
8.2.26
8.2.27
8.2.28
Figure 1. DP83848M Functional Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Figure 2. PHYAD Strapping Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 3. AN0 Strapping and LED Loading Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 4. Typical MDC/MDIO Read Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 5. Typical MDC/MDIO Write Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 6. 100BASE-TX Transmit Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 7. 100BASE-TX Receive Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 8. EIA/TIA Attenuation vs. Frequency for 0, 50, 100, 130 & 150 meters of CAT 5 cable . . . . . 27
Figure 9. 100BASE-TX BLW Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 10. 10BASE-T Twisted Pair Smart Squelch Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Figure 11. 10/100 Mb/s Twisted Pair Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Figure 12. Crystal Oscillator Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 13. Power Feeback Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
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DP83848M
List of Figures
Table 1. Auto-Negotiation Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 2. PHY Address Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table 3. LED Mode Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Table 4. Supported packet sizes at +/-50ppm +/-100ppm for each clock . . . . . . . . . . . . . . . . . . . . . . 21
Table 5. Typical MDIO Frame Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Table 6. 4B5B Code-Group Encoding/Decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 7. 25 MHz Oscillator Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 8. 50 MHz Oscillator Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 9. 25 MHz Crystal Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 10. Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Table 11. Register Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Table 12. Basic Mode Control Register (BMCR), address 0x00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Table 13. Basic Mode Status Register (BMSR), address 0x01 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Table 14. PHY Identifier Register #1 (PHYIDR1), address 0x02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 15. PHY Identifier Register #2 (PHYIDR2), address 0x03 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 16. Negotiation Advertisement Register (ANAR), address 0x04 . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 17. Auto-Negotiation Link Partner Ability Register (ANLPAR) (BASE Page), address 0x05 . . . 45
Table 18. Auto-Negotiation Link Partner Ability Register (ANLPAR) (Next Page), address 0x05 . . . . 46
Table 19. Auto-Negotiate Expansion Register (ANER), address 0x06 . . . . . . . . . . . . . . . . . . . . . . . . 46
Table 20. Auto-Negotiation Next Page Transmit Register (ANNPTR), address 0x07 . . . . . . . . . . . . . 47
Table 21. PHY Status Register (PHYSTS), address 0x10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Table 22. False Carrier Sense Counter Register (FCSCR), address 0x14 . . . . . . . . . . . . . . . . . . . . . 50
Table 23. Receiver Error Counter Register (RECR), address 0x15 . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Table 24. 100 Mb/s PCS Configuration and Status Register (PCSR), address 0x16 . . . . . . . . . . . . . 51
Table 25. RMII and Bypass Register (RBR), addresses 0x17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Table 26. LED Direct Control Register (LEDCR), address 0x18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Table 27. PHY Control Register (PHYCR), address 0x19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Table 28. 10Base-T Status/Control Register (10BTSCR), address 0x1A . . . . . . . . . . . . . . . . . . . . . . 56
Table 29. CD Test and BIST Extensions Register (CDCTRL1), address 0x1B . . . . . . . . . . . . . . . . . . 57
Table 30. Energy Detect Control (EDCR), address 0x1D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
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DP83848M
List of Tables
DP83848M
Pin Layout
RX_CLK 31
RX_DV/MII_MODE 32
CRS/CRS_DV/LED_CFG 33
RX_ER/MDIX_EN 34
COL/PHYAD0 35
RXD_0/PHYAD1 36
RXD_1/PHYAD2 37
RXD_2/PHYAD3 38
RXD_3/PHYAD4 39
IOGND 40
IOVDD33
1
30 PFBIN2
TX_CLK
2
29 DGND
TX_EN
3
28 X1
TXD_0
4
27 X2
TXD_1
5
TXD_2
6
TXD_3
7
24 MDIO
RESERVED
8
23 RESET_N
RESERVED
9
RESERVED
10
26 IOVDD33
DP83848M
25 MDC
22 LED_LINK/AN0
DAP
21 25MHz_OUT
20 RBIAS
19 PFBOUT
18 AVDD33
17 AGND
16 PFBIN1
15 TD +
14 TD -
13 AGND
12 RD +
11 RD -
Note: Die Attached Pad (DAP) provides thermal dissipation, connection to GND plane optional.
Top View
Order Number DP83848M
NS Package Number NSQAU040
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8
The DP83848M pins are classified into the following interface categories (each interface is described in the sections that follow):
Note: Strapping pin option. Please see Section 1.61.6 for
strap definitions.
—
—
—
—
—
—
—
—
—
Type: I
Type: O
Type: I/O
Type: PD,PU
Type: S
All DP83848M signal pins are I/O cells regardless of the
particular use. The definitions below define the functionality of the I/O cells for each pin.
Serial Management Interface
MAC Data Interface
Clock Interface
LED Interface
Reset
Strap Options
10/100 Mb/s PMD Interface
Special Connect Pins
Power and Ground pins
Input
Output
Input/Output
Internal Pulldown/Pullup
Strapping Pin (All strap pins have weak internal pull-ups or pull-downs. If the default
strap value is needed to be changed then an
external 2.2 kΩ resistor should be used.
Please see Section 1.6 1.6 for details.)
1.1 Serial Management Interface
Signal Name
Type
Pin #
Description
MDC
I
25
MANAGEMENT DATA CLOCK: Synchronous clock to the MDIO
management data input/output serial interface which may be
asynchronous to transmit and receive clocks. The maximum clock
rate is 25 MHz with no minimum clock rate.
MDIO
I/O
24
MANAGEMENT DATA I/O: Bi-directional management instruction/data signal that may be sourced by the station management
entity or the PHY. This pin requires a 1.5 kΩ pullup resistor.
Type
Pin #
Description
O
2
MII TRANSMIT CLOCK: 25 MHz Transmit clock output in 100
Mb/s mode or 2.5 MHz in 10 Mb/s mode derived from the 25 MHz
reference clock.
1.2 MAC Data Interface
Signal Name
TX_CLK
Unused in RMII mode. The device uses the X1 reference clock input as the 50 MHz reference for both transmit and receive.
TX_EN
I, PD
3
MII TRANSMIT ENABLE: Active high input indicates the presence of valid data inputs on TXD[3:0].
RMII TRANSMIT ENABLE: Active high input indicates the presence of valid data on TXD[1:0].
TXD_0
I
4
TXD_1
5
TXD_2
6
TXD_3
RX_CLK
I, PD
7
O
31
MII TRANSMIT DATA: Transmit data MII input pins, TXD[3:0],
that accept data synchronous to the TX_CLK (2.5 MHz in 10 Mb/s
mode or 25 MHz in 100 Mb/s mode).
RMII TRANSMIT DATA: Transmit data RMII input pins, TXD[1:0],
that accept data synchronous to the 50 MHz reference clock.
MII RECEIVE CLOCK: Provides the 25 MHz recovered receive
clock for 100 Mb/s mode and 2.5 MHz for 10 Mb/s mode.
Unused in RMII mode. The device uses the X1 reference clock input as the 50 MHz reference for both transmit and receive.
RX_DV
O, PD
32
MII RECEIVE DATA VALID: Asserted high to indicate that valid
data is present on the corresponding RXD[3:0].
RMII Synchronous Receive Data Valid: This signal provides the
RMII Receive Data Valid indication independent of Carrier Sense.
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DP83848M
1.0 Pin Descriptions
DP83848M
Signal Name
RX_ER
Type
Pin #
Description
S, O, PU
34
MII RECEIVE ERROR: Asserted high synchronously to RX_CLK
to indicate that an invalid symbol has been detected within a received packet in 100 Mb/s mode.
RMII RECEIVE ERROR: Assert high synchronously to X1 whenever it detects a media error and RX_DV is asserted in 100 Mb/s
mode.
This pin is not required to be used by a MAC, in either MII or RMII
mode, since the Phy is required to corrupt data on a receive error.
RXD_0
S, O, PD
36
MII RECEIVE DATA: Nibble wide receive data signals driven synchronously to the RX_CLK, 25 MHz for 100 Mb/s mode, 2.5 MHz
for 10 Mb/s mode). RXD[3:0] signals contain valid data when
RX_DV is asserted.
RXD_1
37
RXD_2
38
RXD_3
39
RMII RECEIVE DATA: 2-bits receive data signals, RXD[1:0], driven synchronously to the X1 clock, 50 MHz.
33
MII CARRIER SENSE: Asserted high to indicate the receive medium is non-idle.
CRS/CRS_DV
S, O, PU
RMII CARRIER SENSE/RECEIVE DATA VALID: This signal
combines the RMII Carrier and Receive Data Valid indications.
For a detailed description of this signal, see the RMII Specification.
COL
S, O, PU
35
MII COLLISION DETECT: Asserted high to indicate detection of
a collision condition (simultaneous transmit and receive activity)
in 10 Mb/s and 100 Mb/s Half Duplex Modes.
While in 10BASE-T Half Duplex mode with heartbeat enabled this
pin is also asserted for a duration of approximately 1µs at the end
of transmission to indicate heartbeat (SQE test).
In Full Duplex Mode, for 10 Mb/s or 100 Mb/s operation, this signal is always logic 0. There is no heartbeat function during 10
Mb/s full duplex operation.
RMII COLLISION DETECT: Per the RMII Specification, no COL
signal is required. The MAC will recover CRS from the CRS_DV
signal and use that along with its TX_EN signal to determine collision.
1.3 Clock Interface
Signal Name
X1
Type
Pin #
Description
I
28
CRYSTAL/OSCILLATOR INPUT: This pin is the primary clock
reference input for the DP83848M and must be connected to a 25
MHz 0.005% (+50 ppm) clock source. The DP83848M supports
either an external crystal resonator connected across pins X1 and
X2, or an external CMOS-level oscillator source connected to pin
X1 only.
RMII REFERENCE CLOCK: This pin is the primary clock reference input for the RMII mode and must be connected to a 50 MHz
0.005% (+50 ppm) CMOS-level oscillator source.
X2
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O
27
CRYSTAL OUTPUT: This pin is the primary clock reference output to connect to an external 25 MHz crystal resonator device.
This pin must be left unconnected if an external CMOS oscillator
clock source is used.
10
Type
Pin #
O
21
Description
25 MHz CLOCK OUTPUT:
This pin provides a 25 MHz clock output to the system. This allows other devices to use the reference clock from the DP83848M
without requiring additional clock sources.
RMII Mode: This pin provides a 50 MHz clock output to the system. For RMII mode, it is not recommended that the system clock
out be used as the reference clock to the MAC without first verifying the interface timing. See AN-1405 for more details.
1.4 LED Interface
See Table 3 for LED Mode Selection.
Signal Name
LED_LINK
Type
Pin #
Description
S, O, PU
22
LINK LED: In Mode 1, this pin indicates the status of the LINK.
The LED will be ON when Link is good.
LINK/ACT LED: In Mode 2, this pin indicates transmit and receive
activity in addition to the status of the Link. The LED will be ON
when Link is good. It will blink when the transmitter or receiver is
active.
1.5 Reset
Signal Name
RESET_N
Type
Pin #
Description
I, PU
23
RESET: Active Low input that initializes or re-initializes the
DP83848M. Asserting this pin low for at least 1 µs will force a reset process to occur. All internal registers will re-initialize to their
default states as specified for each bit in the Register Block section. All strap options are re-initialized as well.
1.6 Strap Options
A 2.2 kΩ resistor should be used for pull-down or pull-up
to change the default strap option. If the default option is
required, then there is no need for external pull-up or pull
down resistors. Since these pins may have alternate functions after reset is deasserted, they should not be connected directly to VCC or GND.
DP83848M uses many functional pins as strap options.
The values of these pins are sampled during reset and
used to strap the device into specific modes of operation.
The strap option pin assignments are defined below. The
functional pin name is indicated in parentheses.
Type
Pin #
Description
PHYAD0 (COL)
Signal Name
S, O, PU
35
PHYAD1 (RXD_0)
S, O, PD
36
PHY ADDRESS [4:0]: The DP83848M provides five PHY address pins, the state of which are latched into the PHYCTRL register at system Hardware-Reset.
PHYAD2 (RXD_1)
37
PHYAD3 (RXD_2)
38
PHYAD4 (RXD_3)
39
The DP83848M supports PHY Address strapping values 0
(<00000>) through 31 (<11111>). A PHY Address of 0 puts the
part into the MII Isolate Mode. The MII isolate mode must be selected by strapping Phy Address 0; changing to Address 0 by register write will not put the Phy in the MII isolate mode. Please refer
to section 2.3 for additional information.
PHYAD0 pin has weak internal pull-up resistor.
PHYAD[4:1] pins have weak internal pull-down resistors.
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DP83848M
Signal Name
25MHz_OUT
DP83848M
Signal Name
AN0 (LED_LINK)
Type
Pin #
Description
S, O, PU
22
This input pin controls the advertised operating mode of the
DP83848M according to the following table. The value on this pin
is set by connecting it to GND (0) or VCC (1) through 2.2 kΩ resistors. This pin should NEVER be connected directly to GND or
VCC.
The value set at this input is latched into the DP83848M at Hardware-Reset.
The float/pull-down status of this pin is latched into the Basic
Mode Control Register and the Auto-Negotiation Advertisement
Register during Hardware-Reset.
The default is 1 since this pin has an internal pull-up.
AN0
Advertised Mode
0
10BASE-T Half-Duplex
100BASE-TX, Half-Duplex
1
10BASE-T, Half/Full-Duplex
100BASE-TX, Half/Full-Duplex
MII_MODE (RX_DV)
S, O, PD
32
MII MODE SELECT: This strapping option determines the operating mode of the MAC Data Interface. Default operation (No pullup) will enable normal MII Mode of operation. Strapping
MII_MODE high will cause the device to be in RMII mode of operation. Since the pin includes an internal pull-down, the default value is 0.
The following table details the configuration:
MII_MODE
LED_CFG (CRS/CRS_DV)
S, O, PU
33
MAC Interface Mode
0
MII Mode
1
RMII Mode
LED CONFIGURATION: This strapping option determines the
mode of operation of the LED pins. Default is Mode 1. Mode 1 and
Mode 2 can be controlled via the strap option. All modes are configurable via register access.
SeeTable 3 for LED Mode Selection.
MDIX_EN (RX_ER)
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S, O, PU
34
MDIX ENABLE: Default is to enable MDIX. This strapping option
disables Auto-MDIX. An external pull-down will disable AutoMDIX mode.
12
Signal Name
TD-, TD+
Type
Pin #
Description
I/O
14, 15
Differential common driver transmit output (PMD Output Pair).
These differential outputs are automatically configured to either
10BASE-T or 100BASE-TX signaling.
In Auto-MDIX mode of operation, this pair can be used as the Receive Input pair.
These pins require 3.3V bias for operation.
RD-, RD+
I/O
11, 12
Differential receive input (PMD Input Pair). These differential inputs are automatically configured to accept either 100BASE-TX
or 10BASE-T signaling.
In Auto-MDIX mode of operation, this pair can be used as the
Transmit Output pair.
These pins require 3.3V bias for operation.
1.8 Special Connections
Signal Name
Type
Pin #
Description
RBIAS
I
20
Bias Resistor Connection. A 4.87 kΩ 1% resistor should be connected from RBIAS to GND.
PFBOUT
O
19
Power Feedback Output. Parallel caps, 10µ F (Tantalum preferred) and 0.1µF, should be placed close to the PFBOUT. Connect this pin to PFBIN1 (pin 16) and PFBIN2 (pin 30). See
Section 5.4 for proper placement pin.
PFBIN1
I
16
Power Feedback Input. These pins are fed with power from
PFBOUT pin. A small capacitor of 0.1µF should be connected
close to each pin.
PFBIN2
30
Note: Do not supply power to these pins other than from
PFBOUT.
RESERVED
I/O
8,9,10
RESERVED: These pins must be left unconnected.
1.9 Power Supply Pins
Signal Name
IOVDD33
Pin #
1, 26
Description
I/O 3.3V Supply
IOGND
40
I/O Ground
DGND
29
Digital Ground
AVDD33
18
Analog 3.3V Supply
AGND
13, 17
Analog Ground
13
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DP83848M
1.7 10 Mb/s and 100 Mb/s PMD Interface
DP83848M
1.10 Package Pin Assignments
Pin #
Pin Name
1
IO_VDD
2
TX_CLK
3
TX_EN
4
TXD_0
5
TXD_1
6
TXD_2
7
TXD_3
8
RESERVED
9
RESERVED
10
RESERVED
11
RD-
12
RD+
13
AGND
14
TD -
15
TD +
16
PFBIN1
17
AGND
18
AVDD33
19
PFBOUT
20
RBIAS
21
25MHz_OUT
22
LED_LINK/AN0
23
RESET_N
24
MDIO
25
MDC
26
IOVDD33
27
X2
28
X1
29
DGND
30
PFBIN2
31
RX_CLK
32
RX_DV/MII_MODE
33
CRS/CRS_DV/LED_CFG
34
RX_ER/MDIX_EN
35
COL/PHYAD0
36
RXD_0/PHYAD1
37
RXD_1/PHYAD2
38
RXD_2/PHYAD3
39
RXD_3/PHYAD4
40
IOGND
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14
This section includes information on the various configuration options available with the DP83848M. The configuration options described below include:
—
—
—
—
—
—
2.1.2 Auto-Negotiation Register Control
When Auto-Negotiation is enabled, the DP83848M transmits the abilities programmed into the Auto-Negotiation
Advertisement register (ANAR) at address 04h via FLP
Bursts. Any combination of 10 Mb/s, 100 Mb/s, HalfDuplex, and Full Duplex modes may be selected.
Auto-Negotiation
PHY Address and LED
Half Duplex vs. Full Duplex
Isolate mode
Loopback mode
BIST
Auto-Negotiation Priority Resolution:
— (1) 100BASE-TX Full Duplex (Highest Priority)
— (2) 100BASE-TX Half Duplex
— (3) 10BASE-T Full Duplex
— (4) 10BASE-T Half Duplex (Lowest Priority)
The Basic Mode Control Register (BMCR) at address 00h
provides control for enabling, disabling, and restarting the
Auto-Negotiation process. When Auto-Negotiation is disabled, the Speed Selection bit in the BMCR controls
switching between 10 Mb/s or 100 Mb/s operation, and
the Duplex Mode bit controls switching between full
duplex operation and half duplex operation. The Speed
Selection and Duplex Mode bits have no effect on the
mode of operation when the Auto-Negotiation Enable bit
is set.
2.1 Auto-Negotiation
The Auto-Negotiation function provides a mechanism for
exchanging configuration information between two ends
of a link segment and automatically selecting the highest
performance mode of operation supported by both
devices. Fast Link Pulse (FLP) Bursts provide the signalling used to communicate Auto-Negotiation abilities
between two devices at each end of a link segment. For
further detail regarding Auto-Negotiation, refer to Clause
28 of the IEEE 802.3u specification. The DP83848M supports four different Ethernet protocols (10 Mb/s Half
Duplex, 10 Mb/s Full Duplex, 100 Mb/s Half Duplex, and
100 Mb/s Full Duplex), so the inclusion of Auto-Negotiation ensures that the highest performance protocol will be
selected based on the advertised ability of the Link Partner. The Auto-Negotiation function within the DP83848M
can be controlled either by internal register access or by
the use of the AN0 pin.
The Link Speed can be examined through the PHY Status
Register (PHYSTS) at address 10h after a Link is
achieved.
The Basic Mode Status Register (BMSR) indicates the set
of available abilities for technology types, Auto-Negotiation ability, and Extended Register Capability. These bits
are permanently set to indicate the full functionality of the
DP83848M (only the 100BASE-T4 bit is not set since the
DP83848M does not support that function).
The BMSR also provides status on:
2.1.1 Auto-Negotiation Pin Control
— Completion of Auto-Negotiation
— Occurrence of a remote fault as advertised by the Link
Partner
— Establishment of a valid link
— Support for Management Frame Preamble suppression
The Auto-Negotiation Advertisement Register (ANAR)
indicates the Auto-Negotiation abilities to be advertised by
the DP83848M. All available abilities are transmitted by
default, but any ability can be suppressed by writing to the
ANAR. Updating the ANAR to suppress an ability is one
way for a management agent to change (restrict) the technology that is used.
The state of AN0 determines the specific mode advertised
by DP83848M as given in Table 1. The state of AN0, upon
power-up/reset, determines the state of bits [8:5] of the
ANAR register.
The Auto-Negotiation function selected at power-up or
reset can be changed at any time by writing to the Basic
Mode Control Register (BMCR) at address 0x00h.
Table 1. Auto-Negotiation Modes
AN0
0
Advertised Mode
10BASE-T Half-Duplex
The Auto-Negotiation Link Partner Ability Register
(ANLPAR) at address 05h is used to receive the base link
code word as well as all next page code words during the
negotiation. Furthermore, the ANLPAR will be updated to
either 0081h or 0021h for parallel detection to either 100
Mb/s or 10 Mb/s respectively.
100BASE-TX, Half-Duplex
1
10BASE-T, Half/Full-Duplex
100BASE-TX, Half/Full-Duplex
The Auto-Negotiation Expansion Register (ANER) indicates additional Auto-Negotiation status. The ANER provides status on:
—
—
—
—
Occurrence of a Parallel Detect Fault
Next Page function support by the Link Partner
Next page support function by DP83848M
Reception of the current page that is exchanged by
Auto-Negotiation
— Auto-Negotiation support by the Link Partner
15
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DP83848M
2.0 Configuration
DP83848M
2.1.3 Auto-Negotiation Parallel Detection
2.1.6 Auto-Negotiation Complete Time
The DP83848M supports the Parallel Detection function
as defined in the IEEE 802.3u specification. Parallel
Detection requires both the 10 Mb/s and 100 Mb/s receivers to monitor the receive signal and report link status to
the Auto-Negotiation function. Auto-Negotiation uses this
information to configure the correct technology in the
event that the Link Partner does not support Auto-Negotiation but is transmitting link signals that the 100BASE-TX
or 10BASE-T PMAs recognize as valid link signals.
Parallel detection and Auto-Negotiation take approximately 2-3 seconds to complete. In addition, Auto-Negotiation with next page should take approximately 2-3
seconds to complete, depending on the number of next
pages sent.
Refer to Clause 28 of the IEEE 802.3u standard for a full
description of the individual timers related to Auto-Negotiation.
If the DP83848M completes Auto-Negotiation as a result
of Parallel Detection, bit 5 or bit 7 within the ANLPAR register will be set to reflect the mode of operation present in
the Link Partner. Note that bits 4:0 of the ANLPAR will also
be set to 00001 based on a successful parallel detection
to indicate a valid 802.3 selector field. Software may
determine that negotiation completed via Parallel Detection by reading a zero in the Link Partner Auto-Negotiation
Able bit once the Auto-Negotiation Complete bit is set. If
configured for parallel detect mode and any condition
other than a single good link occurs then the parallel
detect fault bit will be set.
2.2 Auto-MDIX
When enabled, this function utilizes Auto-Negotiation to
determine the proper configuration for transmission and
reception of data and subsequently selects the appropriate MDI pair for MDI/MDIX operation. The function uses a
random seed to control switching of the crossover circuitry. This implementation complies with the corresponding IEEE 802.3 Auto-Negotiation and Crossover
Specifications.
Auto-MDIX is enabled by default and can be configured
via strap or via PHYCR (0x19h) register, bits [15:14].
Neither Auto-Negotiation nor Auto-MDIX is required to be
enabled in forcing crossover of the MDI pairs. Forced
crossover can be achieved through the FORCE_MDIX bit,
bit 14 of PHYCR (0x19h) register.
2.1.4 Auto-Negotiation Restart
Once Auto-Negotiation has completed, it may be restarted
at any time by setting bit 9 (Restart Auto-Negotiation) of
the BMCR to one. If the mode configured by a successful
Auto-Negotiation loses a valid link, then the Auto-Negotiation process will resume and attempt to determine the
configuration for the link. This function ensures that a valid
configuration is maintained if the cable becomes disconnected.
Note: Auto-MDIX will not work in a forced mode of operation.
A renegotiation request from any entity, such as a management agent, will cause the DP83848M to halt any
transmit data and link pulse activity until the
break_link_timer expires (~1500 ms). Consequently, the
Link Partner will go into link fail and normal Auto-Negotiation resumes. The DP83848M will resume Auto-Negotiation after the break_link_timer has expired by issuing FLP
(Fast Link Pulse) bursts.
2.1.5 Enabling Auto-Negotiation via Software
It is important to note that if the DP83848M has been initialized upon power-up as a non-auto-negotiating device
(forced technology), and it is then required that AutoNegotiation or re-Auto-Negotiation be initiated via software, bit 12 (Auto-Negotiation Enable) of the Basic Mode
Control Register (BMCR) must first be cleared and then
set for any Auto-Negotiation function to take effect.
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Since the PHYAD[0] pin has weak internal pull-up resistor
and PHYAD[4:1] pins have weak internal pull-down resistors, the default setting for the PHY address is 00001
(01h).
The 5 PHY address inputs pins are shared with the
RXD[3:0] pins and COL pin as shown below.
Refer to Figure 2 for an example of a PHYAD connection
to external components. In this example, the PHYAD
strapping results in address 00011 (03h).
Table 2. PHY Address Mapping
Pin #
PHYAD Function
RXD Function
35
PHYAD0
COL
36
PHYAD1
RXD_0
2.3.1 MII Isolate Mode
37
PHYAD2
RXD_1
38
PHYAD3
RXD_2
39
PHYAD4
RXD_3
The DP83848M can be put into MII Isolate mode by writing to bit 10 of the BMCR register or by strapping in Physical Address 0. It should be noted that selecting Physical
Address 0 via an MDIO write to PHYCR will not put the
device in the MII isolate mode.
The DP83848M can be set to respond to any of 32 possible PHY addresses via strap pins. The information is
latched into the PHYCR register (address 19h, bits [4:0])
at device power-up and hardware reset. The PHY
Address pins are shared with the RXD and COL pins.
Each DP83848M or port sharing an MDIO bus in a system
must have a unique physical address.
When in the MII isolate mode, the DP83848M does not
respond to packet data present at TXD[3:0], TX_EN inputs
and presents a high impedance on the TX_CLK, RX_CLK,
RX_DV, RX_ER, RXD[3:0], COL, and CRS outputs. When
in Isolate mode, the DP83848M will continue to respond to
all management transactions.
While in Isolate mode, the PMD output pair will not transmit packet data but will continue to source 100BASE-TX
scrambled idles or 10BASE-T normal link pulses.
The DP83848M supports PHY Address strapping values 0
(<00000>) through 31 (<11111>). Strapping PHY Address
0 puts the part into Isolate Mode. It should also be noted
that selecting PHY Address 0 via an MDIO write to
PHYCR will not put the device in Isolate Mode. See
Section 2.3.1 for more information.
The DP83848M can Auto-Negotiate or parallel detect to a
specific technology depending on the receive signal at the
PMD input pair. A valid link can be established for the
receiver even when the DP83848M is in Isolate mode.
COL
RXD_0
2.2kΩ
PHYAD0 = 1
PHYAD1 = 1
RXD_1
PHYAD2 = 0
RXD_2
PHYAD3 = 0
PHYAD4= 0
RXD_3
For further detail relating to the latch-in timing requirements of the PHY Address pins, as well as the other hardware configuration pins, refer to the Reset summary in
Section 6.0.
VCC
Figure 2. PHYAD Strapping Example
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DP83848M
2.3 PHY Address
LED_LINK
The DP83848M supports a configurable Light Emitting
Diode (LED) pin for configuring the link. The PHY Control
Register (PHYCR) for the LED can also be selected
through address 19h, bit [5].
See Table 3 for LED Mode selection.
Mode
LED_CFG[0]
(bit 5) or (pin33)
1
1
AN0 = 1
Table 3. LED Mode Select
LED_LINK
ON for Good Link
2
0
ON for Good Link
BLINK for Activity
The LED_LINK pin in Mode 1 indicates the link status of
the port. In 100BASE-T mode, link is established as a
result of input receive amplitude compliant with the TPPMD specifications which will result in internal generation
of signal detect. A 10 Mb/s Link is established as a result
of the reception of at least seven consecutive normal Link
Pulses or the reception of a valid 10BASE-T packet. This
will cause the assertion of LED_LINK. LED_LINK will
deassert in accordance with the Link Loss Timer as specified in the IEEE 802.3 specification.
VCC
Figure 3. AN0 Strapping and LED Loading Example
2.4.2 LED Direct Control
The LED_LINK pin in Mode 1 will be OFF when no LINK is
present.
The DP83848M provides another option to directly control
the LED output through the LED Direct Control Register
(LEDCR), address 18h. The register does not provide
read access to the LED.
The LED_LINK pin in Mode 2 will be ON to indicate Link is
good and BLINK to indicate activity is present on either
transmit or receive activity.
Since the LED_LINK pin is also used as a strap option,
the polarity of the LED is dependent on whether the pin is
pulled up or down.
2.4.1 LED
Since the Auto-Negotiation (AN0) strap option shares the
LED_LINK output pin, the external components required
for strapping and LED usage must be considered in order
to avoid contention.
Specifically, when the LED output is used to drive the LED
directly, the active state of the output driver is dependent
on the logic level sampled by the AN0 input upon powerup/reset. For example, if the AN0 input is resistively pulled
low then the corresponding output will be configured as an
active high driver. Conversely, if the AN0 input is resistively pulled high, then the corresponding output will be
configured as an active low driver.
Refer to Figure 3 for an example of AN0 connection to
external components. In this example, the AN0 strapping
results in Auto-Negotiation with 10/100 Half/Full-Duplex
advertised.
The adaptive nature of the LED output helps to simplify
potential implementation issues of this dual purpose pin.
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110Ω
OFF for No Link
2.2kΩ
DP83848M
2.4 LED Interface
18
dom data by the BIST Linear Feedback Shift Register
(LFSR) to determine the BIST pass/fail status.
The DP83848M supports both half and full duplex operation at both 10 Mb/s and 100 Mb/s speeds.
The pass/fail status of the BIST is stored in the BIST status bit in the PHYCR register. The status bit defaults to 0
(BIST fail) and will transition on a successful comparison.
If an error (mis-compare) occurs, the status bit is latched
and is cleared upon a subsequent write to the Start/Stop
bit.
Half-duplex relies on the CSMA/CD protocol to handle collisions and network access. In Half-Duplex mode, CRS
responds to both transmit and receive activity in order to
maintain compliance with the IEEE 802.3 specification.
Since the DP83848M is designed to support simultaneous
transmit and receive activity it is capable of supporting fullduplex switched applications with a throughput of up to
200 Mb/s per port when operating in 100BASE-TX mode.
Because the CSMA/CD protocol does not apply to fullduplex operation, the DP83848M disables its own internal
collision sensing and reporting functions and modifies the
behavior of Carrier Sense (CRS) such that it indicates
only receive activity. This allows a full-duplex capable
MAC to operate properly.
For transmit VOD testing, the Packet BIST Continuous
Mode can be used to allow continuous data transmission,
setting BIST_CONT_MODE, bit 5, of CDCTRL1 (0x1Bh).
The number of BIST errors can be monitored through the
BIST Error Count in the CDCTRL1 (0x1Bh), bits [15:8].
All modes of operation (100BASE-TX and 10BASE-T) can
run either half-duplex or full-duplex. Additionally, other
than CRS and Collision reporting, all remaining MII signaling remains the same regardless of the selected duplex
mode.
It is important to understand that while Auto-Negotiation
with the use of Fast Link Pulse code words can interpret
and configure to full-duplex operation, parallel detection
can not recognize the difference between full and halfduplex from a fixed 10 Mb/s or 100 Mb/s link partner over
twisted pair. As specified in the 802.3u specification, if a
far-end link partner is configured to a forced full duplex
100BASE-TX ability, the parallel detection state machine
in the partner would be unable to detect the full duplex
capability of the far-end link partner. This link segment
would negotiate to a half duplex 100BASE-TX configuration (same scenario for 10 Mb/s).
2.6 Internal Loopback
The DP83848M includes a Loopback Test mode for facilitating system diagnostics. The Loopback mode is
selected through bit 14 (Loopback) of the Basic Mode
Control Register (BMCR). Writing 1 to this bit enables MII
transmit data to be routed to the MII receive outputs.
Loopback status may be checked in bit 3 of the PHY Status Register (PHYSTS). While in Loopback mode the data
will not be transmitted onto the media. To ensure that the
desired operating mode is maintained, Auto-Negotiation
should be disabled before selecting the Loopback mode.
2.7 BIST
The DP83848M incorporates an internal Built-in Self Test
(BIST) circuit to accommodate in-circuit testing or diagnostics. The BIST circuit can be utilized to test the integrity of the transmit and receive data paths. BIST testing
can be performed with the part in the internal loopback
mode or externally looped back using a loopback cable
fixture.
The BIST is implemented with independent transmit and
receive paths, with the transmit block generating a continuous stream of a pseudo random sequence. The user can
select a 9 bit or 15 bit pseudo random sequence from the
PSR_15 bit in the PHY Control Register (PHYCR). The
received data is compared to the generated pseudo-ran-
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DP83848M
2.5 Half Duplex vs. Full Duplex
DP83848M
3.0 Functional Description
3.1.2 Collision Detect
The DP83848M supports two modes of operation using
the MII interface pins. The options are defined in the following sections and include:
For Half Duplex, a 10BASE-T or 100BASE-TX collision is
detected when the receive and transmit channels are
active simultaneously. Collisions are reported by the COL
signal on the MII.
— MII Mode
— RMII Mode
The modes of operation can be selected by strap options
or register control. For RMII mode, it is required to use the
strap option, since it requires a 50 MHz clock instead of
the normal 25 MHz.
If the DP83848M is transmitting in 10 Mb/s mode when a
collision is detected, the collision is not reported until
seven bits have been received while in the collision state.
This prevents a collision being reported incorrectly due to
noise on the network. The COL signal remains set for the
duration of the collision.
In the each of these modes, the IEEE 802.3 serial management interface is operational for device configuration
and status. The serial management interface of the MII
allows for the configuration and control of multiple PHY
devices, gathering of status, error information, and the
determination of the type and capabilities of the attached
PHY(s).
If a collision occurs during a receive operation, it is immediately reported by the COL signal.
When heartbeat is enabled (only applicable to 10 Mb/s
operation), approximately 1µs after the transmission of
each packet, a Signal Quality Error (SQE) signal of
approximately 10 bit times is generated (internally) to indicate successful transmission. SQE is reported as a pulse
on the COL signal of the MII.
3.1 MII Interface
3.1.3 Carrier Sense
The DP83848M incorporates the Media Independent
Interface (MII) as specified in Clause 22 of the IEEE
802.3u standard. This interface may be used to connect
PHY devices to a MAC in 10/100 Mb/s systems. This section describes the nibble wide MII data interface.
Carrier Sense (CRS) is asserted due to receive activity,
once valid data is detected via the squelch function during
10 Mb/s operation. During 100 Mb/s operation CRS is
asserted when a valid link (SD) and two non-contiguous
zeros are detected on the line.
The nibble wide MII data interface consists of a receive
bus and a transmit bus each with control signals to facilitate data transfer between the PHY and the upper layer
(MAC).
For 10 or 100 Mb/s Half Duplex operation, CRS is
asserted during either packet transmission or reception.
For 10 or 100 Mb/s Full Duplex operation, CRS is
asserted only due to receive activity.
CRS is deasserted following an end of packet.
3.1.1 Nibble-wide MII Data Interface
Clause 22 of the IEEE 802.3u specification defines the
Media Independent Interface. This interface includes a
dedicated receive bus and a dedicated transmit bus.
These two data buses, along with various control and status signals, allow for the simultaneous exchange of data
between the DP83848M and the upper layer agent
(MAC).
3.2 Reduced MII Interface
The DP83848T incorporates the Reduced Media Independent Interface (RMII) as specified in the RMII specification
(rev1.2) from the RMII Consortium. This interface may be
used to connect PHY devices to a MAC in 10/100 Mb/s
systems using a reduced number of pins. In this mode,
data is transferred 2-bits at a time using the 50 MHz
RMII_REF clock for both transmit and receive. The following pins are used in RMII mode:
The receive interface consists of a nibble wide data bus
RXD[3:0], a receive error signal RX_ER, a receive data
valid flag RX_DV, and a receive clock RX_CLK for synchronous transfer of the data. The receive clock operates
at either 2.5 MHz to support 10 Mb/s operation modes or
at 25 MHz to support 100 Mb/s operational modes.
— TX_EN
— TXD[1:0]
The transmit interface consists of a nibble wide data bus
TXD[3:0], a transmit enable control signal TX_EN, and a
transmit clock TX_CLK which runs at either 2.5 MHz or 25
MHz.
— RX_ER (optional for Mac)
— CRS_DV
— RXD[1:0]
Additionally, the MII includes the carrier sense signal
CRS, as well as a collision detect signal COL. The CRS
signal asserts to indicate the reception of data from the
network or as a function of transmit data in Half Duplex
mode. The COL signal asserts as an indication of a collision which can occur during half-duplex operation when
both a transmit and receive operation occur simultaneously.
— X1 (RMII Reference clock is 50 MHz)
In addition, the RMII mode supplies an RX_DV signal
which allows for a simpler method of recovering receive
data without having to separate RX_DV from the CRS_DV
indication. This is especially useful for systems which do
not require CRS, such as systems that only support fullduplex operation. This signal is also useful for diagnostic
testing where it may be desirable to loop Receive RMII
data directly to the transmitter.
Since the reference clock operates at 10 times the data
rate for 10 Mb/s operation, transmit data is sampled every
10 clocks. Likewise, receive data will be generated every
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The elasticity buffer will force Frame Check Sequence
errors for packets which overrun or underrun the FIFO.
Underrun and Overrun conditions can be reported in the
RMII and Bypass Register (RBR). The following table indicates how to program the elasticity buffer fifo (in 4-bit
increments) based on expected max packet size and
clock accuracy. It assumes both clocks (RMII Reference
clock and far-end Transmitter clock) have the same accuracy.
RMII mode requires a 50 MHz oscillator be connected to
the device X1 pin. A 50 MHz crystal is not supported.
To tolerate potential frequency differences between the 50
MHz reference clock and the recovered receive clock, the
receive RMII function includes a programmable elasticity
buffer. The elasticity buffer is programmable to minimize
propagation delay based on expected packet size and
clock accuracy. This allows for supporting a range of
packet sizes including jumbo frames.
Table 4. Supported packet sizes at +/-50ppm +/-100ppm for each clock
Start Threshold
RBR[1:0]
Latency Tolerance
Recommended Packet Size
at +/- 50ppm
Recommended Packet Size
at +/- 100ppm
1 (4-bits)
2 bits
2400 bytes
1200 bytes
2 (8-bits)
6 bits
7200 bytes
3600 bytes
3 (12-bits)
10 bits
12000 bytes
6000 bytes
0 (16-bits)
14 bits
16800 bytes
8400 bytes
MDC clock cycles should be used to re-sync the device if
an invalid start, opcode, or turnaround bit is detected.
3.3 802.3u MII Serial Management Interface
The DP83848M waits until it has received this preamble
sequence before responding to any other transaction.
Once the DP83848M serial management port has been
initialized no further preamble sequencing is required until
after a power-on/reset, invalid Start, invalid Opcode, or
invalid turnaround bit has occurred.
3.3.1 Serial Management Register Access
The serial management MII specification defines a set of
thirty-two 16-bit status and control registers that are
accessible through the management interface pins MDC
and MDIO. The DP83848M implements all the required
MII registers as well as several optional registers. These
registers are fully described in Section 7.0. A description
of the serial management access protocol follows.
The Start code is indicated by a <01> pattern. This
assures the MDIO line transitions from the default idle line
state.
Turnaround is defined as an idle bit time inserted between
the Register Address field and the Data field. To avoid
contention during a read transaction, no device shall
actively drive the MDIO signal during the first bit of Turnaround. The addressed DP83848M drives the MDIO with
a zero for the second bit of turnaround and follows this
with the required data. Figure 4 shows the timing relationship between MDC and the MDIO as driven/received by
the Station (STA) and the DP83848M (PHY) for a typical
register read access.
3.3.2 Serial Management Access Protocol
The serial control interface consists of two pins, Management Data Clock (MDC) and Management Data Input/Output (MDIO). MDC has a maximum clock rate of 25 MHz
and no minimum rate. The MDIO line is bi-directional and
may be shared by up to 32 devices. The MDIO frame format is shown below in Table 5.
For write transactions, the station management entity
writes data to the addressed DP83848M thus eliminating
the requirement for MDIO Turnaround. The Turnaround
time is filled by the management entity by inserting <10>.
Figure 5 shows the timing relationship for a typical MII
register write access.
The MDIO pin requires a pull-up resistor (1.5 kΩ) which,
during IDLE and turnaround, will pull MDIO high. In order
to initialize the MDIO interface, the station management
entity sends a sequence of 32 contiguous logic ones on
MDIO to provide the DP83848M with a sequence that can
be used to establish synchronization. This preamble may
be generated either by driving MDIO high for 32 consecutive MDC clock cycles, or by simply allowing the MDIO
pull-up resistor to pull the MDIO pin high during which
time 32 MDC clock cycles are provided. In addition, 32
Table 5. Typical MDIO Frame Format
MII Management
Serial Protocol
<idle><start><op code><device addr><reg addr><turnaround><data><idle>
Read Operation
<idle><01><10><AAAAA><RRRRR><Z0><xxxx xxxx xxxx xxxx><idle>
Write Operation
<idle><01><01><AAAAA><RRRRR><10><xxxx xxxx xxxx xxxx><idle>
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DP83848M
10th clock so that an attached device can sample the data
every 10 clocks.
DP83848M
MDC
MDIO
Z
Z
(STA)
Z
MDIO
Z
(PHY)
Z
0 1 1 0 0 1 1 0 0 0 0 0 0 0
Idle
Start
Opcode
(Read)
PHY Address
(PHYAD = 0Ch)
Register Address
(00h = BMCR)
Z
0 0 0 1 1 0 0 0 1 0 0 0 0 0 0 0 0
TA
Register Data
Z
Idle
Figure 4. Typical MDC/MDIO Read Operation
MDC
MDIO
Z
Z
(STA)
Z
Idle
0 1 0 1 0 1 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Start
Opcode
(Write)
PHY Address
(PHYAD = 0Ch)
Register Address
(00h = BMCR)
TA
Figure 5. Typical MDC/MDIO Write Operation
3.3.3 Serial Management Preamble Suppression
The DP83848M supports a Preamble Suppression mode
as indicated by a one in bit 6 of the Basic Mode Status
Register (BMSR, address 01h.) If the station management
entity (i.e. MAC or other management controller) determines that all PHYs in the system support Preamble Suppression by returning a one in this bit, then the station
management entity need not generate preamble for each
management transaction.
The DP83848M requires a single initialization sequence of
32 bits of preamble following hardware/software reset.
This requirement is generally met by the mandatory pullup resistor on MDIO in conjunction with a continuous
MDC, or the management access made to determine
whether Preamble Suppression is supported.
While the DP83848M requires an initial preamble
sequence of 32 bits for management initialization, it does
not require a full 32-bit sequence between each subsequent transaction. A minimum of one idle bit between
management transactions is required as specified in the
IEEE 802.3u specification.
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22
Register Data
Z
Idle
The block diagram in Figure 6. provides an overview of
each functional block within the 100BASE-TX transmit
section.
This section describes the operations within each transceiver module, 100BASE-TX and 10BASE-T. Each operation consists of several functional blocks and described in
the following:
The Transmitter section consists of the following functional blocks:
— Code-group Encoder and Injection block
— Scrambler block (bypass option)
— NRZ to NRZI encoder block
— Binary to MLT-3 converter / Common Driver
The bypass option for the functional blocks within the
100BASE-TX transmitter provides flexibility for applications where data conversion is not always required. The
DP83848M implements the 100BASE-TX transmit state
machine diagram as specified in the IEEE 802.3u Standard, Clause 24.
— 100BASE-TX Transmitter
— 100BASE-TX Receiver
— 10BASE-T Transceiver Module
4.1 100BASE-TX TRANSMITTER
The 100BASE-TX transmitter consists of several functional blocks which convert synchronous 4-bit nibble data,
as provided by the MII, to a scrambled MLT-3 125 Mb/s
serial data stream. Because the 100BASE-TX TP-PMD is
integrated, the differential output pins, PMD Output Pair,
can be directly routed to the magnetics.
TX_CLK
TXD[3:0] /
TX_EN
DIVIDE
BY 5
4B5B CODE-GROUP
ENCODER &
INJECTOR
5B PARALLEL
TO SERIAL
125MHZ CLOCK
SCRAMBLER
MUX
BP_SCR
100BASE-TX
LOOPBACK
MLT[1:0]
NRZ TO NRZI
ENCODER
BINARY
TO MLT-3 /
COMMON
DRIVER
PMD OUTPUT PAIR
Figure 6. 100BASE-TX Transmit Block Diagram
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DP83848M
4.0 Architecture
DP83848M
Table 6. 4B5B Code-Group Encoding/Decoding
DATA CODES
0
11110
0000
1
01001
0001
2
10100
0010
3
10101
0011
4
01010
0100
5
01011
0101
6
01110
0110
7
01111
0111
8
10010
1000
9
10011
1001
A
10110
1010
B
10111
1011
C
11010
1100
D
11011
1101
E
11100
1110
F
11101
1111
IDLE AND CONTROL CODES
H
00100
HALT code-group - Error code
I
11111
Inter-Packet IDLE - 0000 (Note 1)
J
11000
First Start of Packet - 0101 (Note 1)
K
10001
Second Start of Packet - 0101 (Note 1)
T
01101
First End of Packet - 0000 (Note 1)
R
00111
Second End of Packet - 0000 (Note 1)
INVALID CODES
V
00000
V
00001
V
00010
V
00011
V
00101
V
00110
V
01000
V
01100
Note: Control code-groups I, J, K, T and R in data fields will be mapped as invalid codes, together with RX_ER asserted.
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24
The 100BASE-TX transmit TP-PMD function within the
DP83848M is capable of sourcing only MLT-3 encoded
data. Binary output from the PMD Output Pair is not possible in 100 Mb/s mode.
The code-group encoder converts 4-bit (4B) nibble data
generated by the MAC into 5-bit (5B) code-groups for
transmission. This conversion is required to allow control
data to be combined with packet data code-groups. Refer
to Table 6 for 4B to 5B code-group mapping details.
4.2 100BASE-TX RECEIVER
The code-group encoder substitutes the first 8-bits of the
MAC preamble with a J/K code-group pair (11000 10001)
upon transmission. The code-group encoder continues to
replace subsequent 4B preamble and data nibbles with
corresponding 5B code-groups. At the end of the transmit
packet, upon the deassertion of Transmit Enable signal
from the MAC, the code-group encoder injects the T/R
code-group pair (01101 00111) indicating the end of the
frame.
The 100BASE-TX receiver consists of several functional
blocks which convert the scrambled MLT-3 125 Mb/s
serial data stream to synchronous 4-bit nibble data that is
provided to the MII. Because the 100BASE-TX TP-PMD is
integrated, the differential input pins, RD±, can be directly
routed from the AC coupling magnetics.
See Figure 7 for a block diagram of the 100BASE-TX
receive function. This provides an overview of each functional block within the 100BASE-TX receive section.
After the T/R code-group pair, the code-group encoder
continuously injects IDLEs into the transmit data stream
until the next transmit packet is detected (reassertion of
Transmit Enable).
The Receive section consists of the following functional
blocks:
—
—
—
—
—
—
—
—
—
—
—
4.1.2 Scrambler
The scrambler is required to control the radiated emissions at the media connector and on the twisted pair cable
(for 100BASE-TX applications). By scrambling the data,
the total energy launched onto the cable is randomly distributed over a wide frequency range. Without the scrambler, energy levels at the PMD and on the cable could
peak beyond FCC limitations at frequencies related to
repeating 5B sequences (i.e., continuous transmission of
IDLEs).
The scrambler is configured as a closed loop linear feedback shift register (LFSR) with an 11-bit polynomial. The
output of the closed loop LFSR is X-ORd with the serial
NRZ data from the code-group encoder. The result is a
scrambled data stream with sufficient randomization to
decrease radiated emissions at certain frequencies by as
much as 20 dB. The DP83848M uses the PHY_ID (pins
PHYAD [4:0]) to set a unique seed value.
Analog Front End
Digital Signal Processor
Signal Detect
MLT-3 to Binary Decoder
NRZI to NRZ Decoder
Serial to Parallel
Descrambler
Code Group Alignment
4B/5B Decoder
Link Integrity Monitor
Bad SSD Detection
4.2.1 Analog Front End
In addition to the Digital Equalization and Gain Control,
the DP83848M includes Analog Equalization and Gain
Control in the Analog Front End. The Analog Equalization
reduces the amount of Digital Equalization required in the
DSP.
4.1.3 NRZ to NRZI Encoder
4.2.2 Digital Signal Processor
After the transmit data stream has been serialized and
scrambled, the data must be NRZI encoded in order to
comply with the TP-PMD standard for 100BASE-TX transmission over Category-5 Unshielded twisted pair cable.
The Digital Signal Processor includes Adaptive Equalization with Gain Control and Base Line Wander Compensation.
4.1.4 Binary to MLT-3 Convertor
The Binary to MLT-3 conversion is accomplished by converting the serial binary data stream output from the NRZI
encoder into two binary data streams with alternately
phased logic one events. These two binary streams are
then fed to the twisted pair output driver which converts
the voltage to current and alternately drives either side of
the transmit transformer primary winding, resulting in a
MLT-3 signal.
The 100BASE-TX MLT-3 signal sourced by the PMD Output Pair common driver is slew rate controlled. This
should be considered when selecting AC coupling magnetics to ensure TP-PMD Standard compliant transition
times (3 ns < Tr < 5 ns).
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DP83848M
4.1.1 Code-group Encoding and Injection
DP83848M
RX_DV/CRS
RX_CLK
RXD[3:0] / RX_ER
4B/5B DECODER
SERIAL TO
PARALLEL
CODE GROUP
ALIGNMENT
RX_DATA VALID
SSD DETECT
LINK
INTEGRITY
MONITOR
DESCRAMBLER
NRZI TO NRZ
DECODER
MLT-3 TO BINARY
DECODER
DIGITAL
SIGNAL
PROCESSOR
ANALOG
FRONT
END
RD +/−
Figure 7. 100BASE-TX Receive Block Diagram
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26
SIGNAL
DETECT
tive to ensure proper conditioning of the received signal
independent of the cable length.
When transmitting data at high speeds over copper
twisted pair cable, frequency dependent attenuation
becomes a concern. In high-speed twisted pair signalling,
the frequency content of the transmitted signal can vary
greatly during normal operation based primarily on the
randomness of the scrambled data stream. This variation
in signal attenuation caused by frequency variations must
be compensated to ensure the integrity of the transmission.
The DP83848M utilizes an extremely robust equalization
scheme referred as ‘Digital Adaptive Equalization.’
The Digital Equalizer removes ISI (inter symbol interference) from the receive data stream by continuously adapting to provide a filter with the inverse frequency response
of the channel. Equalization is combined with an adaptive
gain control stage. This enables the receive 'eye pattern'
to be opened sufficiently to allow very reliable data recovery.
In order to ensure quality transmission when employing
MLT-3 encoding, the compensation must be able to adapt
to various cable lengths and cable types depending on the
installed environment. The selection of long cable lengths
for a given implementation, requires significant compensation which will over-compensate for shorter, less attenuating lengths. Conversely, the selection of short or
intermediate cable lengths requiring less compensation
will cause serious under-compensation for longer length
cables. The compensation or equalization must be adap-
The curves given in Figure 8 illustrate attenuation at certain frequencies for given cable lengths. This is derived
from the worst case frequency vs. attenuation figures as
specified in the EIA/TIA Bulletin TSB-36. These curves
indicate the significant variations in signal attenuation that
must be compensated for by the receive adaptive equalization circuit.
Figure 8. EIA/TIA Attenuation vs. Frequency for 0, 50,
100, 130 & 150 meters of CAT 5 cable
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DP83848M
4.2.2.1 Digital Adaptive Equalization and Gain Control
DP83848M
4.2.2.2 Base Line Wander Compensation
Figure 9. 100BASE-TX BLW Event
The DP83848M is completely ANSI TP-PMD compliant
and includes Base Line Wander (BLW) compensation.
The BLW compensation block can successfully recover
the TP-PMD defined “killer” pattern.
4.2.4 MLT-3 to NRZI Decoder
The DP83848M decodes the MLT-3 information from the
Digital Adaptive Equalizer block to binary NRZI data.
BLW can generally be defined as the change in the average DC content, relatively short period over time, of an AC
coupled digital transmission over a given transmission
medium. (i.e., copper wire).
4.2.5 NRZI to NRZ
In a typical application, the NRZI to NRZ decoder is
required in order to present NRZ formatted data to the
descrambler.
BLW results from the interaction between the low frequency components of a transmitted bit stream and the
frequency response of the AC coupling component(s)
within the transmission system. If the low frequency content of the digital bit stream goes below the low frequency
pole of the AC coupling transformers then the droop characteristics of the transformers will dominate resulting in
potentially serious BLW.
4.2.6 Serial to Parallel
The 100BASE-TX receiver includes a Serial to Parallel
converter which supplies 5-bit wide data symbols to the
PCS Rx state machine.
The digital oscilloscope plot provided in Figure 9 illustrates the severity of the BLW event that can theoretically
be generated during 100BASE-TX packet transmission.
This event consists of approximately 800 mV of DC offset
for a period of 120 µs. Left uncompensated, events such
as this can cause packet loss.
4.2.3 Signal Detect
The signal detect function of the DP83848M is incorporated to meet the specifications mandated by the ANSI
FDDI TP-PMD Standard as well as the IEEE 802.3
100BASE-TX Standard for both voltage thresholds and
timing parameters.
Note that the reception of normal 10BASE-T link pulses
and fast link pulses per IEEE 802.3u Auto-Negotiation by
the 100BASE-TX receiver do not cause the DP83848M to
assert signal detect.
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28
Signal detect must be valid for 395us to allow the link
monitor to enter the 'Link Up' state, and enable the transmit and receive functions.
A serial descrambler is used to de-scramble the received
NRZ data. The descrambler has to generate an identical
data scrambling sequence (N) in order to recover the original unscrambled data (UD) from the scrambled data (SD)
as represented in the equations:
4.2.11 Bad SSD Detection
SD = ( UD ⊕ N )
UD = ( SD ⊕ N )
A Bad Start of Stream Delimiter (Bad SSD) is any transition from consecutive idle code-groups to non-idle codegroups which is not prefixed by the code-group pair /J/K.
Synchronization of the descrambler to the original scrambling sequence (N) is achieved based on the knowledge
that the incoming scrambled data stream consists of
scrambled IDLE data. After the descrambler has recognized 12 consecutive IDLE code-groups, where an
unscrambled IDLE code-group in 5B NRZ is equal to five
consecutive ones (11111), it will synchronize to the receive
data stream and generate unscrambled data in the form of
unaligned 5B code-groups.
If this condition is detected, the DP83848M will assert
RX_ER and present RXD[3:0] = 1110 to the MII for the
cycles that correspond to received 5B code-groups until at
least two IDLE code groups are detected. In addition, the
False Carrier Sense Counter register (FCSCR) will be
incremented by one.
Once at least two IDLE code groups are detected, RX_ER
and CRS become de-asserted.
In order to maintain synchronization, the descrambler
must continuously monitor the validity of the unscrambled
data that it generates. To ensure this, a line state monitor
and a hold timer are used to constantly monitor the synchronization status. Upon synchronization of the descrambler the hold timer starts a 722 µs countdown. Upon
detection of sufficient IDLE code-groups (58 bit times)
within the 722 µs period, the hold timer will reset and
begin a new countdown. This monitoring operation will
continue indefinitely given a properly operating network
connection with good signal integrity. If the line state monitor does not recognize sufficient unscrambled IDLE codegroups within the 722 µs period, the entire descrambler
will be forced out of the current state of synchronization
and reset in order to re-acquire synchronization.
4.3 10BASE-T TRANSCEIVER MODULE
The 10BASE-T Transceiver Module is IEEE 802.3 compliant. It includes the receiver, transmitter, collision, heartbeat, loopback, jabber, and link integrity functions, as
defined in the standard. An external filter is not required
on the 10BASE-T interface since this is integrated inside
the DP83848M. This section focuses on the general
10BASE-T system level operation.
4.3.1 Operational Modes
The DP83848M has two basic 10BASE-T operational
modes:
— Half Duplex mode
— Full Duplex mode
4.2.8 Code-group Alignment
The code-group alignment module operates on unaligned
5-bit data from the descrambler (or, if the descrambler is
bypassed, directly from the NRZI/NRZ decoder) and converts it into 5B code-group data (5 bits). Code-group alignment occurs after the J/K code-group pair is detected.
Once the J/K code-group pair (11000 10001) is detected,
subsequent data is aligned on a fixed boundary.
Half Duplex Mode
In Half Duplex mode the DP83848M functions as a standard IEEE 802.3 10BASE-T transceiver supporting the
CSMA/CD protocol.
4.2.9 4B/5B Decoder
Full Duplex Mode
The code-group decoder functions as a look up table that
translates incoming 5B code-groups into 4B nibbles. The
code-group decoder first detects the J/K code-group pair
preceded by IDLE code-groups and replaces the J/K with
MAC preamble. Specifically, the J/K 10-bit code-group
pair is replaced by the nibble pair (0101 0101). All subsequent 5B code-groups are converted to the corresponding
4B nibbles for the duration of the entire packet. This conversion ceases upon the detection of the T/R code-group
pair denoting the End of Stream Delimiter (ESD) or with
the reception of a minimum of two IDLE code-groups.
In Full Duplex mode the DP83848M is capable of simultaneously transmitting and receiving without asserting the
collision signal. The DP83848M's 10 Mb/s ENDEC is
designed to encode and decode simultaneously.
4.2.10 100BASE-TX Link Integrity Monitor
The 100 Base TX Link monitor ensures that a valid and
stable link is established before enabling both the Transmit and Receive PCS layer.
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DP83848M
4.2.7 Descrambler
DP83848M
4.3.2 Smart Squelch
within 150 ns. Finally the signal must again exceed the
original squelch level within a 150 ns to ensure that the
input waveform will not be rejected. This checking procedure results in the loss of typically three preamble bits at
the beginning of each packet.
The smart squelch is responsible for determining when
valid data is present on the differential receive inputs. The
DP83848M implements an intelligent receive squelch to
ensure that impulse noise on the receive inputs will not be
mistaken for a valid signal. Smart squelch operation is
independent of the 10BASE-T operational mode.
Only after all these conditions have been satisfied will a
control signal be generated to indicate to the remainder of
the circuitry that valid data is present. At this time, the
smart squelch circuitry is reset.
The squelch circuitry employs a combination of amplitude
and timing measurements (as specified in the IEEE 802.3
10BSE-T standard) to determine the validity of data on the
twisted pair inputs (refer to Figure 10).
Valid data is considered to be present until the squelch
level has not been generated for a time longer than 150
ns, indicating the End of Packet. Once good data has
been detected, the squelch levels are reduced to minimize
the effect of noise causing premature End of Packet
detection.
The signal at the start of a packet is checked by the smart
squelch and any pulses not exceeding the squelch level
(either positive or negative, depending upon polarity) will
be rejected. Once this first squelch level is overcome correctly, the opposite squelch level must then be exceeded
<150 ns
>150 ns
<150 ns
VSQ+
VSQ+(reduced)
VSQ-(reduced)
VSQ-
start of packet
end of packet
Figure 10. 10BASE-T Twisted Pair Smart Squelch Operation
4.3.3 Collision Detection and SQE
4.3.4 Carrier Sense
When in Half Duplex, a 10BASE-T collision is detected
when the receive and transmit channels are active simultaneously. Collisions are reported by the COL signal on
the MII. Collisions are also reported when a jabber condition is detected.
Carrier Sense (CRS) may be asserted due to receive
activity once valid data is detected via the squelch function.
The COL signal remains set for the duration of the collision. If the PHY is receiving when a collision is detected it
is reported immediately (through the COL pin).
For 10 Mb/s Full Duplex operation, CRS is asserted only
during receive activity.
For 10 Mb/s Half Duplex operation, CRS is asserted during either packet transmission or reception.
CRS is deasserted following an end of packet.
When heartbeat is enabled, approximately 1 µs after the
transmission of each packet, a Signal Quality Error (SQE)
signal of approximately 10-bit times is generated to indicate successful transmission. SQE is reported as a pulse
on the COL signal of the MII.
4.3.5 Normal Link Pulse Detection/Generation
The link pulse generator produces pulses as defined in
the IEEE 802.3 10BASE-T standard. Each link pulse is
nominally 100 ns in duration and transmitted every 16 ms
in the absence of transmit data.
The SQE test is inhibited when the PHY is set in full
duplex mode. SQE can also be inhibited by setting the
HEARTBEAT_DIS bit in the 10BTSCR register.
Link pulses are used to check the integrity of the connection with the remote end. If valid link pulses are not
received, the link detector disables the 10BASE-T twisted
pair transmitter, receiver and collision detection functions.
When the link integrity function is disabled
(FORCE_LINK_10 of the 10BTSCR register), a good link
is forced and the 10BASE-T transceiver will operate
regardless of the presence of link pulses.
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DP83848M
4.3.6 Jabber Function
The jabber function monitors the DP83848M's output and
disables the transmitter if it attempts to transmit a packet
of longer than legal size. A jabber timer monitors the
transmitter and disables the transmission if the transmitter
is active for approximately 85 ms.
Once disabled by the Jabber function, the transmitter
stays disabled for the entire time that the ENDEC module's internal transmit enable is asserted. This signal has
to be de-asserted for approximately 500 ms (the “unjab”
time) before the Jabber function re-enables the transmit
outputs.
The Jabber function is only relevant in 10BASE-T mode.
4.3.7 Automatic Link Polarity Detection and
Correction
The DP83848M's 10BASE-T transceiver module incorporates an automatic link polarity detection circuit. When
three consecutive inverted link pulses are received, bad
polarity is reported.
A polarity reversal can be caused by a wiring error at
either end of the cable, usually at the Main Distribution
Frame (MDF) or patch panel in the wiring closet.
The bad polarity condition is latched in the 10BTSCR register. The DP83848M's 10BASE-T transceiver module
corrects for this error internally and will continue to decode
received data correctly. This eliminates the need to correct
the wiring error immediately.
4.3.8 Transmit and Receive Filtering
External 10BASE-T filters are not required when using the
DP83848M, as the required signal conditioning is integrated into the device.
Only isolation transformers and impedance matching
resistors are required for the 10BASE-T transmit and
receive interface. The internal transmit filtering ensures
that all the harmonics in the transmit signal are attenuated
by at least 30 dB.
4.3.9 Transmitter
The encoder begins operation when the Transmit Enable
input (TX_EN) goes high and converts NRZ data to preemphasized Manchester data for the transceiver. For the
duration of TX_EN, the serialized Transmit Data (TXD) is
encoded for the transmit-driver pair (PMD Output Pair).
TXD must be valid on the rising edge of Transmit Clock
(TX_CLK). Transmission ends when TX_EN deasserts.
The last transition is always positive; it occurs at the center of the bit cell if the last bit is a one, or at the end of the
bit cell if the last bit is a zero.
4.3.10 Receiver
The decoder detects the end of a frame when no additional mid-bit transitions are detected. Within one and a
half bit times after the last bit, carrier sense is de-asserted.
Receive clock stays active for five more bit times after
CRS goes low, to guarantee the receive timings of the
controller.
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DP83848M
5.0 Design Guidelines
5.1 TPI Network Circuit
Pulse H1102
Pulse H2019
Pulse J0011D21
Pulse J0011D21B
Figure 11 shows the recommended circuit for a 10/100
Mb/s twisted pair interface. To the right is a partial list of
recommended transformers. It is important that the user
realize that variations with PCB and component characteristics requires that the application be tested to ensure that
the circuit meets the requirements of the intended application.
Vdd
RDVdd
COMMON MODE CHOKES
MAY BE REQUIRED.
49.9Ω
0.1µF
1:1
49.9Ω
RD+
RD-
0.1µF*
RD+
TD-
TD-
TD+
0.1µF*
Vdd
RJ45
49.9Ω
1:1
0.1µF
NOTE: CENTER TAP IS PULLED TO VDD
49.9Ω
*PLACE CAPACITORS CLOSE TO THE
TRANSFORMER CENTER TAPS
TD+
All values are typical and are +/- 1%
PLACE RESISTORS AND
CAPACITORS CLOSE TO
THE DEVICE.
Figure 11. 10/100 Mb/s Twisted Pair Interface
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T1
32
capacitor values will vary with the crystal vendors; check
with the vendor for the recommended loads.
Typically, ESD precautions are predominantly in effect
when handling the devices or board before being installed
in a system. In those cases, strict handling procedures
need be implemented during the manufacturing process
to greatly reduce the occurrences of catastrophic ESD
events. After the system is assembled, internal components are less sensitive from ESD events.
The oscillator circuit is designed to drive a parallel resonance AT cut crystal with a minimum drive level of 100µW
and a maximum of 500µW. If a crystal is specified for a
lower drive level, a current limiting resistor should be
placed in series between X2 and the crystal.
As a starting point for evaluating an oscillator circuit, if the
requirements for the crystal are not known, CL1 and CL2
should be set at 33 pF, and R1 should be set at 0Ω.
See Section 8.0 for ESD rating.
Specification for 25 MHz crystal are listed in Table 8.
5.3 Clock In (X1) Recommendations
The DP83848M supports an external CMOS level oscillator source or a crystal resonator device.
X2
X1
Oscillator
If an external clock source is used, X1 should be tied to
the clock source and X2 should be left floating.
R1
The CMOS oscillator specifications for MII Mode are listed
in Table 7. 25 MHz Oscillator Specification. For RMII
Mode, the CMOS oscillator specifications are listed in
Table 8. 50 MHz Oscillator Specification. For RMII mode,
it is not recommended that the system clock out, Pin 21,
be used as the reference clock to the MAC without first
verifying the interface timing. See AN-1405 for more
details.
CL1
CL2
Figure 12. Crystal Oscillator Circuit
Crystal
A 25 MHz, parallel, 20 pF load crystal resonator should be
used if a crystal source is desired. Figure 12 shows a typical connection for a crystal resonator circuit. The load
Table 7. 25 MHz Oscillator Specification
Parameter
Min
Frequency
Typ
Max
25
Units
Condition
MHz
+50
ppm
Operational Temperature
+50
ppm
1 year aging
Rise / Fall Time
6
nsec
20% - 80%
Jitter
8001
psec
Short term
Jitter
8001
psec
Long term
Frequency
Tolerance
Frequency
Stability
Symmetry
40%
60%
Duty Cycle
1. This limit is provided as a guideline for component selection and not guaranteed by production testing. Refer to AN1548, “PHYTER 100 Base-TX Reference Clock Jitter Tolerance,” for details on jitter performance.
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DP83848M
5.2 ESD Protection
DP83848M
Table 8. 50 MHz Oscillator Specification
Parameter
Min
Frequency
Typ
Max
50
Units
Condition
MHz
+50
ppm
Operational Temperature
+50
ppm
1 year aging
Rise / Fall Time
6
nsec
20% - 80%
Jitter
8001
psec
Short term
Jitter
8001
psec
Long term
Frequency
Tolerance
Frequency
Stability
Symmetry
40%
60%
Duty Cycle
1. This limit is provided as a guideline for component selection and not guaranteed by production testing. Refer to AN1548, “PHYTER 100 Base-TX Reference Clock Jitter Tolerance,” for details on jitter performance.
Table 9. 25 MHz Crystal Specification
Parameter
Min
Frequency
Typ
Max
25
Units
MHz
Frequency
+50
ppm
Operational Temperature
+50
ppm
1 year aging
40
pF
Tolerance
Frequency
Stability
Load Capacitance
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Condition
25
34
6.0 Reset Operation
To ensure correct operation for the DP83848M, parallel
caps with values of 10 µF (Tantalum) and 0.1 µF should
be placed close to pin 19 (PFBOUT) of the device.
The DP83848M includes an internal power-on reset
(POR) function and does not need to be explicitly reset for
normal operation after power up. If required during normal
operation, the device can be reset by a hardware or software reset.
Pin 16 (PFBIN1) and pin 30 (PFBIN2) must be connected
to pin 19 (PFBOUT), each pin requires a small capacitor
(0.1 µF). See Figure 13 below for proper connections.
6.1 Hardware Reset
Pin 19 (PFBOUT)
10 µF
+
A hardware reset is accomplished by applying a low pulse
(TTL level), with a duration of at least 1 µs, to the
RESET_N. This will reset the device such that all registers
will be reinitialized to default values and the hardware
configuration values will be re-latched into the device
(similar to the power-up/reset operation).
0.1µF
Pin 16 (PFBIN1)
0.1 µF
-
Pin 30 (PFBIN2)
6.2 Software Reset
0.1 µF
A software reset is accomplished by setting the reset bit
(bit 15) of the Basic Mode Control Register (BMCR). The
period from the point in time when the reset bit is set to the
point in time when software reset has concluded is
approximately 1 µs.
The software reset will reset the device such that all registers will be reset to default values and the hardware configuration values will be maintained. Software driver code
must wait 3 µs following a software reset before allowing
further serial MII operations with the DP83848M.
Figure 13. Power Feeback Connection
5.5 Power Down
The device can be put in a Power Down mode by setting
bit 11 (Power Down) in the Basic Mode Control Register,
BMCR (0x00h).
5.6 Energy Detect Mode
When Energy Detect is enabled and there is no activity on
the cable, the DP83848M will remain in a low power mode
while monitoring the transmission line. Activity on the line
will cause the DP83848M to go through a normal power
up sequence. Regardless of cable activity, the DP83848M
will occasionally wake up the transmitter to put ED pulses
on the line, but will otherwise draw as little power as possible. Energy detect functionality is controlled via register
Energy Detect Control (EDCR), address 0x1Dh.
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DP83848M
5.4 Power Feedback Circuit
DP83848M
7.0 Register Block
Table 10. Register Map
Offset
Hex
Decimal
00h
0
Access
RW
Tag
BMCR
Description
Basic Mode Control Register
01h
1
RO
BMSR
Basic Mode Status Register
02h
2
RO
PHYIDR1
PHY Identifier Register #1
03h
3
RO
PHYIDR2
PHY Identifier Register #2
04h
4
RW
ANAR
Auto-Negotiation Advertisement Register
05h
5
RW
ANLPAR
Auto-Negotiation Link Partner Ability Register (Base Page)
05h
5
RW
ANLPARNP
Auto-Negotiation Link Partner Ability Register (Next Page)
06h
6
RW
ANER
Auto-Negotiation Expansion Register
07h
7
RW
ANNPTR
Auto-Negotiation Next Page TX
08h-Fh
8-15
RW
RESERVED
RESERVED
Extended Registers
10h
16
RO
PHYSTS
PHY Status Register
11h
17
RW
RESERVED
RESERVED
12h
18
RO
RESERVED
RESERVED
13h
19
RW
RESERVED
RESERVED
14h
20
RW
FCSCR
False Carrier Sense Counter Register
15h
21
RW
RECR
Receive Error Counter Register
16h
22
RW
PCSR
PCS Sub-Layer Configuration and Status Register
17h
23
RW
RBR
RMII and Bypass Register
18h
24
RW
LEDCR
LED Direct Control Register
19h
25
RW
PHYCR
PHY Control Register
1Ah
26
RW
10BTSCR
10Base-T Status/Control Register
1Bh
27
RW
CDCTRL1
CD Test Control Register and BIST Extensions Register
1Ch
28
RW
RESERVED
RESERVED
1Dh
29
RW
EDCR
Energy Detect Control Register
1Eh-1Fh
30-31
RW
RESERVED
RESERVED
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36
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11h
12h
13h
14h
15h
16h
RESERVED
RESERVED
RESERVED
False Carrier Sense Counter Register
Receive Error Counter Register
PCS Sub-Layer Configuration and Status
Register
06h
Auto-Negotiation Expansion Register
10h
05h
Auto-Negotiation Link Partner Ability Register Next Page
PHY Status Register
05h
Auto-Negotiation Link Partner Ability Register (Base Page)
08-0fh
04h
Auto-Negotiation Advertisement Register
RESERVED
03h
PHY Identifier Register 2
07h
02h
PHY Identifier Register 1
Auto-Negotiation Next Page TX Register
01h
Basic Mode Status Register
Addr
00h
Register Name
Basic Mode Control Register
Tag
Next
Page Ind
OUI LSB
Reserved
PCSR
RECR
FCSCR
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
PHYSTS Reserved
Reserved
ANNPTR Next
Page Ind
Reserved
ANNext
LPARNP Page Ind
ANER
AutoNeg
Enable
100Base 100Base 10BaseT
-TX FDX -TX HDX
FDX
Speed
Selection
10BaseT
HDX
Power
Down
Reserved
Isolate
Bit 9
Reserved
Restart
AutoNeg
Bit 8
Reserved
Duplex
Mode
Bit 7
Reserved
Collision
Test
MF Preamble
Suppress
Reserved
Bit 6
AutoNeg
Complete
Reserved
Bit 5
Remote
Fault
Reserved
Bit 4
AutoNeg
Ability
Reserved
Bit 3
Link
Status
Reserved
Bit 2
Jabber
Detect
Reserved
Bit 1
Extended Capability
Reserved
Bit 0
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
MDI-X
mode
Reserved
Reserved
Reserved
ACK
ACK
Reserved
Reserved
ACK2
Reserved
ACK2
Reserved
Reserved
Reserved
TOG_TX
Reserved
Toggle
ASM_DI
R
ASM_DI
R
Reserved
CODE
Reserved
Code
PAUSE
PAUSE
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Rx Err
Latch
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Polarity
Status
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
False
Carrier
Sense
TQ_EN
Reserved
Reserved
Reserved
Reserved
Reserved
Signal
Detect
EXTENDED REGISTERS
Reserved
Message
Page
Reserved
Message
Page
Remote
Fault
Remote
Fault
OUI LSB OUI LSB OUI LSB OUI LSB OUI LSB
Reserved
Reserved
Reserved
Reserved
Reserved
Page
Receive
Reserved
CODE
Reserved
Code
TX_FD
TX_FD
VNDR_
MDL
Reserved
Reserved
Reserved
Remote
Fault
Reserved
CODE
Reserved
Code
10_FD
10_FD
VNDR_
MDL
Reserved
Reserved
Reserved
Jabber
Detect
Reserved
CODE
Reserved
Code
10
10
VNDR_
MDL
MDL_
REV
MDL_
REV
MDL_
REV
MDL_
REV
Reserved
Reserved
Reserved
AutoNeg
Complete
Reserved
CODE
PDF
Code
Reserved
Reserved
Reserved
Loopback Status
Reserved
CODE
LP_NP_
ABLE
Code
Reserved
Reserved
Reserved
Duplex
Status
Reserved
CODE
NP_
ABLE
Code
Reserved
Reserved
Reserved
Speed
Status
Reserved
CODE
PAGE_
RX
Code
Reserved
Reserved
Reserved
Link
Status
Reserved
CODE
LP_AN_
ABLE
Code
Protocol Protocol Protocol Protocol Protocol
Selection Selection Selection Selection Selection
Protocol Protocol Protocol Protocol Protocol
Selection Selection Selection Selection Selection
VNDR_
MDL
RXERCNT
Reserved
RXERCNT
FORCE_
100_OK
RXERCNT
Reserved
RXERCNT
Reserved
RXERCNT
RXERCNT
RXERCNT
NRZI_ SCRAM_
DE
BYPASS BYPASS SCRAM_
BYPASS
RXERCNT
FCSCNT FCSCNT FCSCNT FCSCNT FCSCNT FCSCNT FCSCNT FCSCNT
Reserved
Reserved
Reserved
Reserved
Reserved
CODE
Reserved
Code
TX
TX
VNDR_
MDL
SD_FOR
SD_
DESC_T
CE_PMA OPTION
IME
Reserved
Reserved
Reserved
Reserved
Reserved
Descram
Lock
Reserved
CODE
Reserved
Code
T4
T4
VNDR_
MDL
OUI MSB OUI MSB OUI MSB OUI MSB OUI MSB OUI MSB OUI MSB OUI MSB OUI MSB OUI MSB OUI MSB OUI MSB OUI MSB OUI MSB OUI MSB OUI MSB
100Base
-T4
Loopback
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10
Reset
ANLPAR Next
Page Ind
ANAR
PHYIDR
2
PHYIDR
1
BMSR
BMCR
Table 11. Register Table
DP83848M
37
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38
18h
19h
1Ah
1Bh
1Ch
1Dh
1Eh-1Fh
LED Direct Control Register
PHY Control Register
10Base-T Status/Control Register
CD Test Control and BIST Extensions Register
RESERVED
Energy Detect Control Register
RESERVED
Addr
17h
Register Name
RMII and Bypass Register
Tag
Reserved
MDIX_E
N
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
FORCE_ PAUSE_ PAUSE_
MDIX
RX
TX
Reserved
Reserved
PSR_15
Reserved
Reserved
Bit 9
Bit 8
Reserved
Reserved
Reserved
EDCR
Reserved
Reserved
ED_EN
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
ED_AUT ED_AUT ED_MAN ED_BUR ED_PW
O_UP
O_DOW
ST_DIS R_STAT
N
E
Reserved
Bit 7
Reserved
Reserved
Reserved
Reserved
Bit 6
Reserved
Reserved
FORC_
LINK_10
Reserved
Reserved
Reserved
Bit 5
Reserved
BIST_C
ONT_M
ODE
Reserved
LED_
CNFG[0]
Reserved
ODE
RMII_M
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reserved
CDPattE
N_10
POLARITY
PHY
ADDR
DRV_LN
KLED
V1_0
Reserved
Reserved
Reserved
PHY
ADDR
Reserved
_STS
Reserved
10Meg_
Patt_Ga
p
Reserved
PHY
ADDR
Reserved
_STS
PHY
ADDR
Reserved
PTR[0]
Reserved
CDPattSel
Reserved
CDPattSel
HEART_ JABBER
DIS
_DIS
PHY
ADDR
LNKLED
PTR[1]
RMII_RE RX_OVF RX_UNF RX_RD_ RX_RD_
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
ED_ERR ED_DAT ED_ERR ED_ERR ED_ERR ED_ERR ED_DAT ED_DAT ED_DAT ED_DAT
_MET
A_MET _COUNT _COUNT _COUNT _COUNT A_COUN A_COUN A_COUN A_COUN
T
T
T
T
Reserved
Reserved
LP_DIS
BIST_ BIST_ST BP_STR
STATUS
ART
ETCH
Reserved
Reserved
SQUELC SQUELC SQUELC LOOPBA
H
H
H
CK_10_
DIS
BIST_fe
Reserved
Reserved
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10
Reserved
CDCTRL BIST_ER BIST_ER BIST_ER BIST_ER BIST_ER BIST_ER BIST_ER BIST_ER
1
ROR_C ROR_C ROR_C
ROR_C ROR_C ROR_C
ROR_C ROR_C
OUNT
OUNT OUNT
OUNT
OUNT OUNT
OUNT
OUNT
10BT_S
CR
PHYCR
LEDCR
RBR
Table 11. Register Table
DP83848M
DP83848M
7.1 Register Definition
In the register definitions under the ‘Default’ heading, the following definitions hold true:
— RW=Read Write access
—
—
—
—
—
—
—
—
SC=Register sets on event occurrence and Self-Clears when event ends
RW/SC =Read Write access/Self Clearing bit
RO=Read Only access
COR = Clear on Read
RO/COR=Read Only, Clear on Read
RO/P=Read Only, Permanently set to a default value
LL=Latched Low and held until read, based upon the occurrence of the corresponding event
LH=Latched High and held until read, based upon the occurrence of the corresponding event
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DP83848M
7.1.1 Basic Mode Control Register (BMCR)
Table 12. Basic Mode Control Register (BMCR), address 0x00
Bit
Bit Name
Default
15
Reset
0, RW/SC
Description
Reset:
1 = Initiate software Reset / Reset in Process.
0 = Normal operation.
This bit, which is self-clearing, returns a value of one until the reset
process is complete. The configuration is re-strapped.
14
Loopback
0, RW
Loopback:
1 = Loopback enabled.
0 = Normal operation.
The loopback function enables MII transmit data to be routed to the MII
receive data path.
Setting this bit may cause the descrambler to lose synchronization and
produce a 500 µs “dead time” before any valid data will appear at the
MII receive outputs.
13
Speed Selection
RW
Speed Select:
When auto-negotiation is disabled writing to this bit allows the port
speed to be selected.
1 = 100 Mb/s.
0 = 10 Mb/s.
12
Auto-Negotiation
Enable
RW
Auto-Negotiation Enable:
Strap controls initial value at reset.
1 = Auto-Negotiation Enabled - bits 8 and 13 of this register are ignored when this bit is set.
0 = Auto-Negotiation Disabled - bits 8 and 13 determine the port speed
and duplex mode.
11
Power Down
0, RW
Power Down:
1 = Power down.
0 = Normal operation.
Setting this bit powers down the PHY. Only the register block is enabled during a power down condition.
10
Isolate
0, RW
Isolate:
1 = Isolates the Port from the MII with the exception of the serial management.
0 = Normal operation.
9
Restart AutoNegotiation
0, RW/SC
Duplex Mode
Strap, RW
Restart Auto-Negotiation:
1 = Restart Auto-Negotiation. Re-initiates the Auto-Negotiation process. If Auto-Negotiation is disabled (bit 12 = 0), this bit is ignored. This
bit is self-clearing and will return a value of 1 until Auto-Negotiation is
initiated, whereupon it will self-clear. Operation of the Auto-Negotiation
process is not affected by the management entity clearing this bit.
0 = Normal operation.
8
Duplex Mode:
When auto-negotiation is disabled writing to this bit allows the port Duplex capability to be selected.
1 = Full Duplex operation.
0 = Half Duplex operation.
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40
DP83848M
Table 12. Basic Mode Control Register (BMCR), address 0x00 (Continued)
Bit
Bit Name
Default
7
Collision Test
0, RW
Description
Collision Test:
1 = Collision test enabled.
0 = Normal operation.
When set, this bit will cause the COL signal to be asserted in response
to the assertion of TX_EN within 512-bit times. The COL signal will be
de-asserted within 4-bit times in response to the de-assertion of
TX_EN.
6:0
RESERVED
0, RO
RESERVED: Write ignored, read as 0.
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DP83848M
7.1.2 Basic Mode Status Register (BMSR)
Table 13. Basic Mode Status Register (BMSR), address 0x01
Bit
Bit Name
Default
15
100BASE-T4
0, RO/P
Description
100BASE-T4 Capable:
0 = Device not able to perform 100BASE-T4 mode.
14
100BASE-TX
1, RO/P
Full Duplex
13
100BASE-TX
1 = Device able to perform 100BASE-TX in full duplex mode.
1, RO/P
Half Duplex
12
10BASE-T
10BASE-T
100BASE-TX Half Duplex Capable:
1 = Device able to perform 100BASE-TX in half duplex mode.
1, RO/P
Full Duplex
11
100BASE-TX Full Duplex Capable:
10BASE-T Full Duplex Capable:
1 = Device able to perform 10BASE-T in full duplex mode.
1, RO/P
Half Duplex
10BASE-T Half Duplex Capable:
1 = Device able to perform 10BASE-T in half duplex mode.
10:7
RESERVED
0, RO
RESERVED: Write as 0, read as 0.
6
MF Preamble
1, RO/P
Preamble suppression Capable:
Suppression
1 = Device able to perform management transaction with preamble
suppressed, 32-bits of preamble needed only once after reset, invalid
opcode or invalid turnaround.
0 = Normal management operation.
5
Auto-Negotiation Complete
0, RO
Auto-Negotiation Complete:
1 = Auto-Negotiation process complete.
0 = Auto-Negotiation process not complete.
4
Remote Fault
0, RO/LH
Remote Fault:
1 = Remote Fault condition detected (cleared on read or by reset).
Fault criteria: Far End Fault Indication or notification from Link Partner of Remote Fault.
0 = No remote fault condition detected.
3
Auto-Negotiation Ability
1, RO/P
Auto Negotiation Ability:
1 = Device is able to perform Auto-Negotiation.
0 = Device is not able to perform Auto-Negotiation.
2
Link Status
0, RO/LL
Link Status:
1 = Valid link established (for either 10 or 100 Mb/s operation).
0 = Link not established.
The criteria for link validity is implementation specific. The occurrence
of a link failure condition will causes the Link Status bit to clear. Once
cleared, this bit may only be set by establishing a good link condition
and a read via the management interface.
1
Jabber Detect
0, RO/LH
Jabber Detect: This bit only has meaning in 10 Mb/s mode.
1 = Jabber condition detected.
0 = No Jabber.
This bit is implemented with a latching function, such that the occurrence of a jabber condition causes it to set until it is cleared by a read
to this register by the management interface or by a reset.
0
Extended Capability
1, RO/P
Extended Capability:
1 = Extended register capabilities.
0 = Basic register set capabilities only.
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7.1.3 PHY Identifier Register #1 (PHYIDR1)
Table 14. PHY Identifier Register #1 (PHYIDR1), address 0x02
Bit
Bit Name
15:0
OUI_MSB
Default
Description
<0010 0000 0000 OUI Most Significant Bits: Bits 3 to 18 of the OUI (080017h) are
0000>, RO/P
stored in bits 15 to 0 of this register. The most significant two bits
of the OUI are ignored (the IEEE standard refers to these as bits 1
and 2).
7.1.4 PHY Identifier Register #2 (PHYIDR2)
Table 15. PHY Identifier Register #2 (PHYIDR2), address 0x03
Bit
Bit Name
15:10
OUI_LSB
Default
Description
<0101 11>, RO/P OUI Least Significant Bits:
Bits 19 to 24 of the OUI (080017h) are mapped from bits 15 to 10
of this register respectively.
9:4
VNDR_MDL
<00 1001>, RO/P Vendor Model Number:
The six bits of vendor model number are mapped from bits 9 to 4
(most significant bit to bit 9).
3:0
MDL_REV
<0000>, RO/P
Model Revision Number:
Four bits of the vendor model revision number are mapped from
bits 3 to 0 (most significant bit to bit 3). This field will be incremented
for all major device changes.
7.1.5 Auto-Negotiation Advertisement Register (ANAR)
This register contains the advertised abilities of this device as they will be transmitted to its link partner during Auto-Negotiation. Any writes to this register prior to completion of Auto-Negotiation (as indicated in the Basic Mode Status Register
(address 0x01) Auto-Negotiation complete bit, BMSR[5]) should be followed by a renegotiation. This will ensure that the
new values are properly used in the Auto-Negotiation.
Table 16. Negotiation Advertisement Register (ANAR), address 0x04
Bit
Bit Name
Default
15
NP
0, RW
Description
Next Page Indication:
0 = Next Page Transfer not desired.
1 = Next Page Transfer desired.
14
RESERVED
0, RO/P
13
RF
0, RW
RESERVED by IEEE: Writes ignored, Read as 0.
Remote Fault:
1 = Advertises that this device has detected a Remote Fault.
0 = No Remote Fault detected.
12
RESERVED
0, RW
RESERVED for Future IEEE use: Write as 0, Read as 0
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DP83848M
The PHY Identifier Registers #1 and #2 together form a unique identifier for the DP83848M. The Identifier consists of a
concatenation of the Organizationally Unique Identifier (OUI), the vendor's model number and the model revision number. A PHY may return a value of zero in each of the 32 bits of the PHY Identifier if desired. The PHY Identifier is intended
to support network management. National's IEEE assigned OUI is 080017h.
DP83848M
Table 16. Negotiation Advertisement Register (ANAR), address 0x04 (Continued)
Bit
Bit Name
Default
11
ASM_DIR
0, RW
Description
Asymmetric PAUSE Support for Full Duplex Links:
The ASM_DIR bit indicates that asymmetric PAUSE is supported.
Encoding and resolution of PAUSE bits is defined in IEEE 802.3
Annex 28B, Tables 28B-2 and 28B-3, respectively. Pause resolution status is reported in PHYCR[13:12].
1 = Advertise that the DTE (MAC) has implemented both the optional MAC control sublayer and the pause function as specified in
clause 31 and annex 31B of 802.3u.
0= No MAC based full duplex flow control.
10
PAUSE
0, RW
PAUSE Support for Full Duplex Links:
The PAUSE bit indicates that the device is capable of providing the
symmetric PAUSE functions as defined in Annex 31B.
Encoding and resolution of PAUSE bits is defined in IEEE 802.3
Annex 28B, Tables 28B-2 and 28B-3, respectively. Pause resolution status is reported in PHYCR[13:12].
1 = Advertise that the DTE (MAC) has implemented both the optional MAC control sublayer and the pause function as specified in
clause 31 and annex 31B of 802.3u.
0= No MAC based full duplex flow control.
9
T4
0, RO/P
100BASE-T4 Support:
1= 100BASE-T4 is supported by the local device.
0 = 100BASE-T4 not supported.
8
TX_FD
Strap, RW
100BASE-TX Full Duplex Support:
1 = 100BASE-TX Full Duplex is supported by the local device.
0 = 100BASE-TX Full Duplex not supported.
7
TX
Strap, RW
100BASE-TX Support:
1 = 100BASE-TX is supported by the local device.
0 = 100BASE-TX not supported.
6
10_FD
RW
10BASE-T Full Duplex Support:
1 = 10BASE-T Full Duplex is supported by the local device.
0 = 10BASE-T Full Duplex not supported.
5
10
RW
10BASE-T Support:
1 = 10BASE-T is supported by the local device.
0 = 10BASE-T not supported.
4:0
Selector
<00001>, RW
Protocol Selection Bits:
These bits contain the binary encoded protocol selector supported
by this port. <00001> indicates that this device supports IEEE
802.3u.
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44
This register contains the advertised abilities of the Link changes after the successful auto-negotiation if NextPartner as received during Auto-Negotiation. The content pages are supported.
Table 17. Auto-Negotiation Link Partner Ability Register (ANLPAR) (BASE Page), address 0x05
Bit
Bit Name
Default
15
NP
0, RO
Description
Next Page Indication:
0 = Link Partner does not desire Next Page Transfer.
1 = Link Partner desires Next Page Transfer.
14
ACK
0, RO
Acknowledge:
1 = Link Partner acknowledges reception of the ability data word.
0 = Not acknowledged.
The Auto-Negotiation state machine will automatically control the
this bit based on the incoming FLP bursts.
13
RF
0, RO
Remote Fault:
1 = Remote Fault indicated by Link Partner.
0 = No Remote Fault indicated by Link Partner.
12
RESERVED
0, RO
11
ASM_DIR
0, RO
RESERVED for Future IEEE use:
Write as 0, read as 0.
ASYMMETRIC PAUSE:
1 = Asymmetric pause is supported by the Link Partner.
0 = Asymmetric pause is not supported by the Link Partner.
10
PAUSE
0, RO
PAUSE:
1 = Pause function is supported by the Link Partner.
0 = Pause function is not supported by the Link Partner.
9
T4
0, RO
100BASE-T4 Support:
1 = 100BASE-T4 is supported by the Link Partner.
0 = 100BASE-T4 not supported by the Link Partner.
8
TX_FD
0, RO
100BASE-TX Full Duplex Support:
1 = 100BASE-TX Full Duplex is supported by the Link Partner.
0 = 100BASE-TX Full Duplex not supported by the Link Partner.
7
TX
0, RO
100BASE-TX Support:
1 = 100BASE-TX is supported by the Link Partner.
0 = 100BASE-TX not supported by the Link Partner.
6
10_FD
0, RO
10BASE-T Full Duplex Support:
1 = 10BASE-T Full Duplex is supported by the Link Partner.
0 = 10BASE-T Full Duplex not supported by the Link Partner.
5
10
0, RO
10BASE-T Support:
1 = 10BASE-T is supported by the Link Partner.
0 = 10BASE-T not supported by the Link Partner.
4:0
Selector
<0 0000>, RO
Protocol Selection Bits:
Link Partner’s binary encoded protocol selector.
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DP83848M
7.1.6 Auto-Negotiation Link Partner Ability Register (ANLPAR) (BASE Page)
DP83848M
7.1.7 Auto-Negotiation Link Partner Ability Register (ANLPAR) (Next Page)
Table 18. Auto-Negotiation Link Partner Ability Register (ANLPAR) (Next Page), address 0x05
Bit
Bit Name
Default
15
NP
0, RO
Description
Next Page Indication:
1 = Link Partner desires Next Page Transfer.
0 = Link Partner does not desire Next Page Transfer.
14
ACK
0, RO
Acknowledge:
1 = Link Partner acknowledges reception of the ability data word.
0 = Not acknowledged.
The Auto-Negotiation state machine will automatically control the
this bit based on the incoming FLP bursts. Software should not attempt to write to this bit.
13
MP
0, RO
Message Page:
1 = Message Page.
0 = Unformatted Page.
12
ACK2
0, RO
Acknowledge 2:
1 = Link Partner does have the ability to comply to next page message.
0 = Link Partner does not have the ability to comply to next page
message.
11
Toggle
0, RO
Toggle:
1 = Previous value of the transmitted Link Code word equalled 0.
0 = Previous value of the transmitted Link Code word equalled 1.
10:0
CODE
<000 0000 0000>, Code:
RO
This field represents the code field of the next page transmission.
If the MP bit is set (bit 13 of this register), then the code shall be
interpreted as a “Message Page,” as defined in annex 28C of
Clause 28. Otherwise, the code shall be interpreted as an “Unformatted Page,” and the interpretation is application specific.
7.1.8 Auto-Negotiate Expansion Register (ANER)
This register contains additional Local Device and Link Partner status information.
Table 19. Auto-Negotiate Expansion Register (ANER), address 0x06
Bit
Bit Name
Default
Description
15:5
RESERVED
0, RO
RESERVED: Writes ignored, Read as 0.
4
PDF
0, RO
Parallel Detection Fault:
1 = A fault has been detected via the Parallel Detection function.
0 = A fault has not been detected.
3
LP_NP_ABLE
0, RO
Link Partner Next Page Able:
1 = Link Partner does support Next Page.
0 = Link Partner does not support Next Page.
2
NP_ABLE
1, RO/P
Next Page Able:
1 = Indicates local device is able to send additional “Next Pages”.
1
PAGE_RX
0, RO/COR
Link Code Word Page Received:
1 = Link Code Word has been received, cleared on a read.
0 = Link Code Word has not been received.
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Bit
Bit Name
Default
0
LP_AN_ABLE
0, RO
Description
Link Partner Auto-Negotiation Able:
1 = indicates that the Link Partner supports Auto-Negotiation.
0 = indicates that the Link Partner does not support Auto-Negotiation.
7.1.9 Auto-Negotiation Next Page Transmit Register (ANNPTR)
This register contains the next page information sent by this device to its Link Partner during Auto-Negotiation.
Table 20. Auto-Negotiation Next Page Transmit Register (ANNPTR), address 0x07
Bit
Bit Name
Default
15
NP
0, RW
Description
Next Page Indication:
0 = No other Next Page Transfer desired.
1 = Another Next Page desired.
14
RESERVED
0, RO
RESERVED: Writes ignored, read as 0.
13
MP
1, RW
Message Page:
1 = Message Page.
0 = Unformatted Page.
12
ACK2
0, RW
Acknowledge2:
1 = Will comply with message.
0 = Cannot comply with message.
Acknowledge2 is used by the next page function to indicate that Local Device has the ability to comply with the message received.
11
TOG_TX
0, RO
Toggle:
1 = Value of toggle bit in previously transmitted Link Code Word
was 0.
0 = Value of toggle bit in previously transmitted Link Code Word
was 1.
Toggle is used by the Arbitration function within Auto-Negotiation
to ensure synchronization with the Link Partner during Next Page
exchange. This bit shall always take the opposite value of the Toggle bit in the previously exchanged Link Code Word.
10:0
CODE
<000 0000 0001>, This field represents the code field of the next page transmission.
RW
If the MP bit is set (bit 13 of this register), then the code shall be
interpreted as a "Message Page”, as defined in annex 28C of IEEE
802.3u. Otherwise, the code shall be interpreted as an "Unformatted Page”, and the interpretation is application specific.
The default value of the CODE represents a Null Page as defined
in Annex 28C of IEEE 802.3u.
47
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DP83848M
Table 19. Auto-Negotiate Expansion Register (ANER), address 0x06 (Continued)
DP83848M
7.2 Extended Registers
7.2.1 PHY Status Register (PHYSTS)
This register provides a single location within the register set for quick access to commonly accessed information.
Table 21. PHY Status Register (PHYSTS), address 0x10
Bit
Bit Name
Default
Description
15
RESERVED
0, RO
RESERVED: Write ignored, read as 0.
14
MDI-X mode
0, RO
MDI-X mode as reported by the Auto-Negotiation logic:
This bit will be affected by the settings of the MDIX_EN and
FORCE_MDIX bits in the PHYCR register. When MDIX is enabled, but not forced, this bit will update dynamically as the
Auto-MDIX algorithm swaps between MDI and MDI-X configurations.
1 = MDI pairs swapped
(Receive on TPTD pair, Transmit on TPRD pair)
0 = MDI pairs normal
(Receive on TRD pair, Transmit on TPTD pair)
13
Receive Error Latch
0, RO/LH
Receive Error Latch:
This bit will be cleared upon a read of the RECR register.
1 = Receive error event has occurred since last read of RXERCNT
(address 0x15, Page 0).
0 = No receive error event has occurred.
12
Polarity Status
0, RO
Polarity Status:
This bit is a duplication of bit 4 in the 10BTSCR register. This bit will
be cleared upon a read of the 10BTSCR register, but not upon a
read of the PHYSTS register.
1 = Inverted Polarity detected.
0 = Correct Polarity detected.
11
False Carrier Sense
Latch
0, RO/LH
False Carrier Sense Latch:
This bit will be cleared upon a read of the FCSR register.
1 = False Carrier event has occurred since last read of FCSCR (address 0x14).
0 = No False Carrier event has occurred.
10
Signal Detect
0, RO/LL
100Base-TX unconditional Signal Detect from PMD.
9
Descrambler Lock
0, RO/LL
100Base-TX Descrambler Lock from PMD.
8
Page Received
0, RO
Link Code Word Page Received:
This is a duplicate of the Page Received bit in the ANER register,
but this bit will not be cleared upon a read of the PHYSTS register.
1 = A new Link Code Word Page has been received. Cleared on
read of the ANER (address 0x06, bit 1).
0 = Link Code Word Page has not been received.
7
RESERVED
0, RO
RESERVED: Writes ignored, read as 0.
6
Remote Fault
0, RO
Remote Fault:
1 = Remote Fault condition detected (cleared on read of BMSR (address 01h) register or by reset). Fault criteria: notification from Link
Partner of Remote Fault via Auto-Negotiation.
0 = No remote fault condition detected.
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48
Bit
Bit Name
Default
5
Jabber Detect
0, RO
Description
Jabber Detect: This bit only has meaning in 10 Mb/s mode
This bit is a duplicate of the Jabber Detect bit in the BMSR register,
except that it is not cleared upon a read of the PHYSTS register.
1 = Jabber condition detected.
0 = No Jabber.
4
Auto-Neg Complete
0, RO
Auto-Negotiation Complete:
1 = Auto-Negotiation complete.
0 = Auto-Negotiation not complete.
3
Loopback Status
0, RO
Loopback:
1 = Loopback enabled.
0 = Normal operation.
2
Duplex Status
0, RO
Duplex:
This bit indicates duplex status and is determined from Auto-Negotiation or Forced Modes.
1 = Full duplex mode.
0 = Half duplex mode.
Note: This bit is only valid if Auto-Negotiation is enabled and complete and there is a valid link or if Auto-Negotiation is disabled and
there is a valid link.
1
Speed Status
0, RO
Speed10:
This bit indicates the status of the speed and is determined from
Auto-Negotiation or Forced Modes.
1 = 10 Mb/s mode.
0 = 100 Mb/s mode.
Note: This bit is only valid if Auto-Negotiation is enabled and complete and there is a valid link or if Auto-Negotiation is disabled and
there is a valid link.
0
Link Status
0, RO
Link Status:
This bit is a duplicate of the Link Status bit in the BMSR register,
except that it will not be cleared upon a read of the PHYSTS register.
1 = Valid link established (for either 10 or 100 Mb/s operation)
0 = Link not established.
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DP83848M
Table 21. PHY Status Register (PHYSTS), address 0x10 (Continued)
DP83848M
7.2.2 False Carrier Sense Counter Register (FCSCR)
This counter provides information required to implement the “False Carriers” attribute within the MAU managed object
class of Clause 30 of the IEEE 802.3u specification.
Table 22. False Carrier Sense Counter Register (FCSCR), address 0x14
Bit
Bit Name
Default
15:8
RESERVED
0, RO
7:0
FCSCNT[7:0]
0, RO / COR
Description
RESERVED: Writes ignored, Read as 0
False Carrier Event Counter:
This 8-bit counter increments on every false carrier event. This
counter sticks when it reaches its max count (FFh).
7.2.3 Receiver Error Counter Register (RECR)
This counter provides information required to implement the “Symbol Error During Carrier” attribute within the PHY managed object class of Clause 30 of the IEEE 802.3u specification.
Table 23. Receiver Error Counter Register (RECR), address 0x15
Bit
Bit Name
Default
15:8
RESERVED
0, RO
7:0
RXERCNT[7:0]
0, RO / COR
Description
RESERVED: Writes ignored, Read as 0
RX_ER Counter:
When a valid carrier is present and there is at least one occurrence
of an invalid data symbol, this 8-bit counter increments for each receive error detected. This event can increment only once per valid
carrier event. If a collision is present, the attribute will not increment. The counter sticks when it reaches its max count.
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50
DP83848M
7.2.4 100 Mb/s PCS Configuration and Status Register (PCSR)
Table 24. 100 Mb/s PCS Configuration and Status Register (PCSR), address 0x16
Bit
Bit Name
Default
15:13
RESERVED
<00>, RO
12
RESERVED
0
Description
RESERVED: Writes ignored, Read as 0.
RESERVED:
Must be zero.
11
RESERVED
0
10
TQ_EN
0, RW
RESERVED:
Must be zero.
100Mbs True Quiet Mode Enable:
1 = Transmit True Quiet Mode.
0 = Normal Transmit Mode.
9
SD FORCE PMA
0, RW
Signal Detect Force PMA:
1 = Forces Signal Detection in PMA.
0 = Normal SD operation.
8
SD_OPTION
1, RW
Signal Detect Option:
1 = Enhanced signal detect algorithm.
0 = Reduced signal detect algorithm.
7
DESC_TIME
0, RW
Descrambler Timeout:
Increase the descrambler timeout. When set this should allow the
device to receive larger packets (>9k bytes) without loss of synchronization.
1 = 2ms
0 = 722us (per ANSI X3.263: 1995 (TP-PMD) 7.2.3.3e)
6
RESERVED
0
RESERVED:
Must be zero.
5
FORCE_100_OK
0, RW
Force 100Mb/s Good Link:
1 = Forces 100Mb/s Good Link.
0 = Normal 100Mb/s operation.
4
RESERVED
0
RESERVED:
Must be zero.
3
RESERVED
0
2
NRZI_BYPASS
0, RW
RESERVED:
Must be zero.
NRZI Bypass Enable:
1 = NRZI Bypass Enabled.
0 = NRZI Bypass Disabled.
1
RESERVED
0
0
RESERVED
0
RESERVED:
Must be zero.
RESERVED:
Must be zero.
51
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DP83848M
7.2.5 RMII and Bypass Register (RBR)
This register configures the RMII Mode of operation. When RMII mode is disabled, the RMII functionality is bypassed.
Table 25. RMII and Bypass Register (RBR), addresses 0x17
Bit
Bit Name
Default
15:6
RESERVED
0, RO
5
RMII_MODE
Strap, RW
Description
RESERVED: Writes ignored, Read as 0.
Reduced MII Mode:
0 = Standard MII Mode
1 = Reduced MII Mode
4
RMII_REV1_0
0, RW
Reduce MII Revision 1.0:
0 = (RMII revision 1.2) CRS_DV will toggle at the end of a packet
to indicate deassertion of CRS.
1 = (RMII revision 1.0) CRS_DV will remain asserted until final data
is transferred. CRS_DV will not toggle at the end of a packet.
3
RX_OVF_STS
0, RO
RX FIFO Over Flow Status:
0 = Normal
1 = Overflow detected
2
RX_UNF_STS
0, RO
RX FIFO Under Flow Status:
0 = Normal
1 = Underflow detected
1:0
ELAST_BUF[1:0]
1, RW
Receive Elasticity Buffer. This field controls the Receive Elasticity Buffer which allows for frequency variation tolerance between
the 50MHz RMII clock and the recovered data. The following value
indicate the tolerance in bits for a single packet. The minimum setting allows for standard Ethernet frame sizes at +/-50ppm accuracy
for both RMII and Receive clocks. For greater frequency tolerance
the packet lengths may be scaled (i.e. for +/-100ppm, the packet
lengths need to be divided by 2).
00 = 14 bit tolerance (up to 16800 byte packets)
01 = 2 bit tolerance (up to 2400 byte packets)
10 = 6 bit tolerance (up to 7200 byte packets)
11 = 10 bit tolerance (up to 12000 byte packets)
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52
This register provides the ability to directly control the LED output. It does not provide read access to the LED.
Table 26. LED Direct Control Register (LEDCR), address 0x18
Bit
Bit Name
Default
15:6
RESERVED
0, RO
5
RESERVED
0
Description
RESERVED: Writes ignored, read as 0.
RESERVED:
Must be zero.
4
DRV_LNKLED
0, RW
1 = Drive value of LNKLED bit onto LED_LINK output
0 = Normal operation
3
RESERVED
0
2
RESERVED
0
RESERVED:
Must be zero.
RESERVED:
Must be zero.
1
LNKLED
0, RW
0
RESERVED
0
Value to force on LED_LNK output
RESERVED:
Must be zero.
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DP83848M
7.2.6 LED Direct Control Register (LEDCR)
DP83848M
7.2.7 PHY Control Register (PHYCR)
Table 27. PHY Control Register (PHYCR), address 0x19
Bit
Bit Name
Default
15
MDIX_EN
Strap, RW
Description
Auto-MDIX Enable:
1 = Enable Auto-neg Auto-MDIX capability.
0 = Disable Auto-neg Auto-MDIX capability.
The Auto-MDIX algorithm requires that the Auto-Negotiation Enable bit in the BMCR register to be set. If Auto-Negotiation is not
enabled, Auto-MDIX should be disabled as well.
14
FORCE_MDIX
0, RW
Force MDIX:
1 = Force MDI pairs to cross.
(Receive on TPTD pair, Transmit on TPRD pair)
0 = Normal operation.
13
PAUSE_RX
0, RO
Pause Receive Negotiated:
Indicates that pause receive should be enabled in the MAC. Based
on ANAR[11:10] and ANLPAR[11:10] settings.
This function shall be enabled according to IEEE 802.3 Annex 28B
Table 28B-3, “Pause Resolution”, only if the Auto-Negotiated Highest Common Denominator is a full duplex technology.
12
PAUSE_TX
0, RO
Pause Transmit Negotiated:
Indicates that pause transmit should be enabled in the MAC. Based
on ANAR[11:10] and ANLPAR[11:10] settings.
This function shall be enabled according to IEEE 802.3 Annex 28B
Table 28B-3, “Pause Resolution”, only if the Auto-Negotiated Highest Common Denominator is a full duplex technology.
11
BIST_FE
0, RW/SC
BIST Force Error:
1 = Force BIST Error.
0 = Normal operation.
This bit forces a single error, and is self clearing.
10
PSR_15
0, RW
BIST Sequence select:
1 = PSR15 selected.
0 = PSR9 selected.
9
BIST_STATUS
0, LL/RO
BIST Test Status:
1 = BIST pass.
0 = BIST fail. Latched, cleared when BIST is stopped.
For a count number of BIST errors, see the BIST Error Count in the
CDCTRL1 register.
8
BIST_START
0, RW
BIST Start:
1 = BIST start.
0 = BIST stop.
7
BP_STRETCH
0, RW
Bypass LED Stretching:
This will bypass the LED stretching and the LED will reflect the internal value.
1 = Bypass LED stretching.
0 = Normal operation.
6
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RESERVED
0
RESERVED: Must be zero.
54
DP83848M
Table 27. PHY Control Register (PHYCR), address 0x19 (Continued)
Bit
Bit Name
Default
5
LED_CNFG[0]
Strap, RW
Description
LED Configuration
LED_ CNFG[0]
Mode Description
1
Mode 1
0
Mode2
In Mode 1, LEDs are configured as follows:
LED_LINK = ON for Good Link, OFF for No Link
In Mode 2, LEDs are configured as follows:
LED_LINK = ON for good Link, BLINK for Activity
4:0
PHYADDR[4:0]
Strap, RW
PHY Address: PHY address for port.
55
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DP83848M
7.2.8 10Base-T Status/Control Register (10BTSCR)
Table 28. 10Base-T Status/Control Register (10BTSCR), address 0x1A
Bit
Bit Name
Default
15
RESERVED
0, RW
Description
RESERVED:
Must be zero.
14:12
RESERVED
0, RW
RESERVED:
Must be zero.
11:9
SQUELCH
100, RW
Squelch Configuration:
Used to set the Squelch ‘ON’ threshold for the receiver.
Default Squelch ON is 330mV peak.
8
LOOPBACK_10_D
IS
0, RW
In half-duplex mode, default 10BASE-T operation loops Transmit
data to the Receive data in addition to transmitting the data on the
physical medium. This is for consistency with earlier 10BASE2 and
10BASE5 implementations which used a shared medium. Setting
this bit disables the loopback function.
This bit does not affect loopback due to setting BMCR[14].
7
LP_DIS
0, RW
Normal Link Pulse Disable:
1 = Transmission of NLPs is disabled.
0 = Transmission of NLPs is enabled.
6
FORCE_LINK_10
0, RW
Force 10Mb Good Link:
1 = Forced Good 10Mb Link.
0 = Normal Link Status.
5
RESERVED
0, RW
RESERVED:
Must be zero.
4
POLARITY
RO/LH
10Mb Polarity Status:
This bit is a duplication of bit 12 in the PHYSTS register. Both bits
will be cleared upon a read of 10BTSCR register, but not upon a
read of the PHYSTS register.
1 = Inverted Polarity detected.
0 = Correct Polarity detected.
3
RESERVED
0, RW
RESERVED:
Must be zero.
2
RESERVED
1, RW
RESERVED:
Must be set to one.
1
HEARTBEAT_DIS
0, RW
Heartbeat Disable: This bit only has influence in half-duplex 10Mb
mode.
1 = Heartbeat function disabled.
0 = Heartbeat function enabled.
When the device is operating at 100Mb or configured for full
duplex operation, this bit will be ignored - the heartbeat function is disabled.
0
JABBER_DIS
0, RW
Jabber Disable:
Applicable only in 10BASE-T.
1 = Jabber function disabled.
0 = Jabber function enabled.
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56
DP83848M
7.2.9 CD Test and BIST Extensions Register (CDCTRL1)
Table 29. CD Test and BIST Extensions Register (CDCTRL1), address 0x1B
Bit
Bit Name
Default
15:8
BIST_ERROR_CO
UNT
0, RO
7:6
RESERVED
0, RW
5
BIST_CONT_MOD
E
0, RW
CDPATTEN_10
0, RW
Description
BIST ERROR Counter:
Counts number of errored data nibbles during Packet BIST. This
value will reset when Packet BIST is restarted. The counter sticks
when it reaches its max count.
RESERVED:
Must be zero.
4
Packet BIST Continuous Mode:
Allows continuous pseudo random data transmission without any
break in transmission. This can be used for transmit VOD testing.
This is used in conjunction with the BIST controls in the PHYCR
Register (0x19h). For 10Mb operation, jabber function must be disabled, bit 0 of the 10BTSCR (0x1Ah), JABBER_DIS = 1.
CD Pattern Enable for 10Mb:
1 = Enabled.
0 = Disabled.
3
RESERVED
0, RW
RESERVED:
Must be zero.
2
10MEG_PATT_GA
P
0, RW
Defines gap between data or NLP test sequences:
1 = 15 µs.
0 = 10 µs.
1:0
CDPATTSEL[1:0]
00, RW
CD Pattern Select[1:0]:
If CDPATTEN_10 = 1:
00 = Data, EOP0 sequence
01 = Data, EOP1 sequence
10 = NLPs
11 = Constant Manchester 1s (10MHz sine wave) for harmonic distortion testing.
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DP83848M
7.2.10 Energy Detect Control (EDCR)
Table 30. Energy Detect Control (EDCR), address 0x1D
Bit
Bit Name
Default
15
ED_EN
0, RW
Description
Energy Detect Enable:
Allow Energy Detect Mode.
When Energy Detect is enabled and Auto-Negotiation is disabled
via the BMCR register, Auto-MDIX should be disabled via the PHYCR register.
14
ED_AUTO_UP
1, RW
Energy Detect Automatic Power Up:
Automatically begin power up sequence when Energy Detect Data
Threshold value (EDCR[3:0]) is reached. Alternatively, device
could be powered up manually using the ED_MAN bit (ECDR[12]).
13
ED_AUTO_DOWN
1, RW
Energy Detect Automatic Power Down:
Automatically begin power down sequence when no energy is detected. Alternatively, device could be powered down using the
ED_MAN bit (EDCR[12]).
12
ED_MAN
0, RW/SC
Energy Detect Manual Power Up/Down:
Begin power up/down sequence when this bit is asserted. When
set, the Energy Detect algorithm will initiate a change of Energy Detect state regardless of threshold (error or data) and timer values.
11
ED_BURST_DIS
0, RW
Energy Detect Bust Disable:
Disable bursting of energy detect data pulses. By default, Energy
Detect (ED) transmits a burst of 4 ED data pulses each time the CD
is powered up. When bursting is disabled, only a single ED data
pulse will be send each time the CD is powered up.
10
ED_PWR_STATE
0, RO
Energy Detect Power State:
Indicates current Energy Detect Power state. When set, Energy
Detect is in the powered up state. When cleared, Energy Detect is
in the powered down state. This bit is invalid when Energy Detect
is not enabled.
9
ED_ERR_MET
0, RO/COR
Energy Detect Error Threshold Met:
No action is automatically taken upon receipt of error events. This
bit is informational only and would be cleared on a read.
8
ED_DATA_MET
0, RO/COR
Energy Detect Data Threshold Met:
The number of data events that occurred met or surpassed the Energy Detect Data Threshold. This bit is cleared on a read.
7:4
ED_ERR_COUNT
0001, RW
Energy Detect Error Threshold:
Threshold to determine the number of energy detect error events
that should cause the device to take action. Intended to allow averaging of noise that may be on the line. Counter will reset after approximately 2 seconds without any energy detect data events.
3:0
ED_DATA_COUNT
0001, RW
Energy Detect Data Threshold:
Threshold to determine the number of energy detect events that
should cause the device to take actions. Intended to allow averaging of noise that may be on the line. Counter will reset after approximately 2 seconds without any energy detect data events.
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DP83848M
8.0 Electrical Specifications
Note: All parameters are guaranteed by test, statistical analysis or design.
Absolute Maximum Ratings
Supply Voltage (VCC)
Recommended Operating Conditions
Supply voltage (VCC)
-0.5 V to 4.2 V
3.3 Volts +.3V
DC Input Voltage (VIN)
-0.5V to VCC + 0.5V
Commercial - Ambient Temperature (TA)
DC Output Voltage (VOUT)
-0.5V to VCC + 0.5V
Power Dissipation (PD)
Storage Temperature (TSTG)
-65oC to 150°C
Max case temp
147.7 °C
Max. die temperature (Tj)
150 °C
Lead Temp. (TL)
(Soldering, 10 sec.)
260 °C
ESD Rating
(RZAP = 1.5k, CZAP = 120 pF)
4.0 kV
0 to 70°C
264 mW
Absolute maximum ratings are those values beyond which
the safety of the device cannot be guaranteed. They are
not meant to imply that the device should be operated at
these limits.
Thermal Characteristic
Max
Units
Theta Junction to Case (Tjc)
8.8
°C / W
Theta Junction to Ambient (Tja) degrees Celsius/Watt - No Airflow @ 1.0W
31.7
°C / W
Note: This is done with a JEDEC (2 layer 2 oz CU.) thermal test board
8.1 DC Specs
Symbol
Pin Types
Parameter
Conditions
Min
Typ
Max
Units
VIH
I
I/O
Input High Voltage Nominal VCC
VIL
I
I/O
Input Low Voltage
0.8
V
IIH
I
I/O
Input High Current VIN = VCC
10
µA
IIL
I
I/O
Input Low Current VIN = GND
10
µA
VOL
O,
I/O
Output Low
Voltage
IOL = 4 mA
0.4
V
VOH
O,
I/O
Output High
Voltage
IOH = -4 mA
VledOL
LED
Output Low
Voltage
IOL = 2.5 mA
VledOH
LED
Output High
Voltage
IOH = -2.5 mA
IOZ
I/O,
O
TRI-STATE
Leakage
VOUT = VCC
VTPTD_100
PMD Output Pair
100M Transmit
Voltage
VTPTDsym
PMD Output Pair
100M Transmit
Voltage Symmetry
VTPTD_10
PMD Output Pair
10M Transmit
Voltage
2.0
Vcc - 0.5
V
0.4
Vcc - 0.5
0.95
2.2
59
V
V
V
1
2.5
+ 10
µA
1.05
V
+2
%
2.8
V
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DP83848M
Symbol
Pin Types
Parameter
Conditions
Min
Typ
Max
Units
CIN1
I
CMOS Input
Capacitance
5
pF
COUT1
O
CMOS Output
Capacitance
5
pF
SDTHon
PMD Input Pair
100BASE-TX
Signal detect turnon threshold
SDTHoff
PMD Input Pair
100BASE-TX
Signal detect turnoff threshold
VTH1
PMD Input Pair
10BASE-T Receive Threshold
Idd100
Supply
Idd10
Supply
1000
200
mV diff pk-pk
585
100BASE-TX
(Full Duplex)
IOUT = 0 mA
10BASE-T
(Full Duplex)
IOUT = 0 mA
mV
81
mA
92
mA
See Note1
See
Note1
1. Refer to application note AN-1540, “Power Measurement of Ethernet Physical Layer Products”
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mV diff pk-pk
60
DP83848M
8.2 AC Specs
8.2.1 Power Up Timing
Vcc
X1 clock
T2.1.1
Hardware
RESET_N
32 clocks
MDC
T2.1.2
Latch-In of Hardware
Configuration Pins
T2.1.3
input
output
Dual Function Pins
Become Enabled As Outputs
Parameter
Description
Notes
Min
Typ
Max
Units
T2.1.1
Post Power Up Stabilization
MDIO is pulled high for 32-bit serial mantime prior to MDC preamble for agement initialization
register accesses
X1 Clock must be stable for a min. of
167ms at power up.
167
ms
T2.1.2
Hardware Configuration Latch- Hardware Configuration Pins are dein Time from power up
scribed in the Pin Description section
167
ms
X1 Clock must be stable for a min. of
167ms at power up.
T2.1.3
Hardware Configuration pins
transition to output drivers
50
ns
Note: In RMII Mode, the minimum Post Power up Stabilization and Hardware Configuration Latch-in times are 84 ms.
61
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DP83848M
8.2.2 Reset Timing
Vcc
X1 clock
T2.2.1
T2.2.4
Hardware
RESET_N
32 clocks
MDC
T2.2.2
Latch-In of Hardware
Configuration Pins
T2.2.3
input
Dual Function Pins
Become Enabled As Outputs
Parameter
Description
output
Notes
Min
Typ
Max
Units
T2.2.1
Post RESET Stabilization time MDIO is pulled high for 32-bit serial manprior to MDC preamble for reg- agement initialization
ister accesses
3
µs
T2.2.2
Hardware Configuration Latch- Hardware Configuration Pins are dein Time from the Deassertion scribed in the Pin Description section
of RESET (either soft or hard)
3
µs
T2.2.3
Hardware Configuration pins
transition to output drivers
50
ns
T2.2.4
RESET pulse width
X1 Clock must be stable for at min. of 1us
during RESET pulse low time.
1
µs
Note: It is important to choose pull-up and/or pull-down resistors for each of the hardware configuration pins that provide
fast RC time constants in order to latch-in the proper value prior to the pin transitioning to an output driver.
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DP83848M
8.2.3 MII Serial Management Timing
MDC
T2.3.4
T2.3.1
MDIO (output)
MDC
T2.3.2
Valid Data
MDIO (input)
Parameter
T2.3.3
Description
Notes
Min
T2.3.1
MDC to MDIO (Output) Delay Time
0
T2.3.2
MDIO (Input) to MDC Setup Time
10
T2.3.3
MDIO (Input) to MDC Hold Time
10
T2.3.4
MDC Frequency
Typ
Max
Units
30
ns
ns
ns
2.5
25
MHz
8.2.4 100 Mb/s MII Transmit Timing
T2.4.1
T2.4.1
TX_CLK
T2.4.2
TXD[3:0]
TX_EN
Parameter
T2.4.3
Valid Data
Min
Typ
T2.4.1
TX_CLK High/Low Time
Description
100 Mb/s Normal mode
Notes
16
20
T2.4.2
TXD[3:0], TX_EN Data Setup to TX_CLK
100 Mb/s Normal mode
10
ns
T2.4.3
TXD[3:0], TX_EN Data Hold from TX_CLK 100 Mb/s Normal mode
0
ns
63
Max Units
24
ns
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DP83848M
8.2.5 100 Mb/s MII Receive Timing
T2.5.1
T2.5.1
RX_CLK
T2.5.2
RXD[3:0]
RX_DV
RX_ER
Valid Data
Parameter
Description
Notes
Min
Typ
Max
Units
20
24
ns
30
ns
T2.5.1
RX_CLK High/Low Time
100 Mb/s Normal mode
16
T2.5.2
RX_CLK to RXD[3:0], RX_DV, RX_ER Delay 100 Mb/s Normal mode
10
Note: RX_CLK may be held low or high for a longer period of time during transition between reference and recovered
clocks. Minimum high and low times will not be violated.
8.2.6 100BASE-TX Transmit Packet Latency Timing
TX_CLK
TX_EN
TXD
PMD Output Pair
Parameter
T2.6.1
T2.6.1
IDLE
(J/K)
Description
TX_CLK to PMD Output Pair
Latency
Notes
100 Mb/s Normal mode
DATA
Min
Typ
6
Max
Units
bits
Note: For Normal mode, latency is determined by measuring the time from the first rising edge of TX_CLK occurring after
the assertion of TX_EN to the first bit of the “J” code group as output from the PMD Output Pair. 1 bit time = 10 ns in 100
Mb/s mode.
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DP83848M
8.2.7 100BASE-TX Transmit Packet Deassertion Timing
TX_CLK
TX_EN
TXD
T2.7.1
PMD Output Pair
Parameter
T2.7.1
DATA
DATA
(T/R)
(T/R)
Description
TX_CLK to PMD Output Pair
Deassertion
Notes
100 Mb/s Normal mode
IDLE
IDLE
Min
Typ
6
Max
Units
bits
Note: Deassertion is determined by measuring the time from the first rising edge of TX_CLK occurring after the deassertion of TX_EN to the first bit of the “T” code group as output from the PMD Output Pair. 1 bit time = 10 ns in 100 Mb/s mode.
65
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DP83848M
8.2.8 100BASE-TX Transmit Timing (tR/F & Jitter)
T2.8.1
+1 rise
90%
10%
PMD Output Pair
10%
+1 fall
90%
T2.8.1
-1 fall
-1 rise
T2.8.1
T2.8.1
T2.8.2
PMD Output Pair
eye pattern
Parameter
T2.8.1
T2.8.2
T2.8.2
Description
Notes
Min
Typ
Max
Units
3
4
5
ns
100 Mb/s tR and tF Mismatch
500
ps
100 Mb/s PMD Output Pair
Transmit Jitter
1.4
ns
100 Mb/s PMD Output Pair tR
and tF
Note: Normal Mismatch is the difference between the maximum and minimum of all rise and fall times
Note: Rise and fall times taken at 10% and 90% of the +1 or -1 amplitude
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DP83848M
8.2.9 100BASE-TX Receive Packet Latency Timing
PMD Input Pair
IDLE
Data
(J/K)
T2.9.1
CRS
T2.9.2
RXD[3:0]
RX_DV
RX_ER
Parameter
Description
Notes
Min
Typ
Max
Units
T2.9.1
Carrier Sense ON Delay
100 Mb/s Normal mode
20
bits
T2.9.2
Receive Data Latency
100 Mb/s Normal mode
24
bits
Note: Carrier Sense On Delay is determined by measuring the time from the first bit of the “J” code group to the assertion
of Carrier Sense.
Note: 1 bit time = 10 ns in 100 Mb/s mode
Note: PMD Input Pair voltage amplitude is greater than the Signal Detect Turn-On Threshold Value.
8.2.10 100BASE-TX Receive Packet Deassertion Timing
PMD Input Pair
DATA
IDLE
(T/R)
T2.10.1
CRS
Parameter
T2.10.1
Description
Carrier Sense OFF Delay
Notes
100 Mb/s Normal mode
Min
Typ
24
Max
Units
bits
Note: Carrier Sense Off Delay is determined by measuring the time from the first bit of the “T” code group to the deassertion of Carrier Sense.
Note: 1 bit time = 10 ns in 100 Mb/s mode
67
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DP83848M
8.2.11 10 Mb/s MII Transmit Timing
T2.11.1
T2.11.1
TX_CLK
T2.11.2
TXD[3:0]
TX_EN
Parameter
T2.11.3
Valid Data
Description
Notes
Min
Typ
Max Units
200
210
T2.11.1
TX_CLK High/Low Time
10 Mb/s MII mode
190
ns
T2.11.2
TXD[3:0], TX_EN Data Setup to TX_CLK fall
10 Mb/s MII mode
25
ns
T2.11.3
TXD[3:0], TX_EN Data Hold from TX_CLK rise
10 Mb/s MII mode
0
ns
Note: An attached Mac should drive the transmit signals using the positive edge of TX_CLK. As shown above, the MII
signals are sampled on the falling edge of TX_CLK.
8.2.12 10 Mb/s MII Receive Timing
T2.12.1
T2.12.1
RX_CLK
T2.12.2
RXD[3:0]
RX_DV
Parameter
T2.12.3
Valid Data
Description
Notes
Min
Typ
Max
Units
160
200
240
ns
T2.12.1
RX_CLK High/Low Time
T2.12.2
RX_CLK to RXD[3:0], RX_DV Delay
10 Mb/s MII mode
100
ns
T2.12.3
RX_CLK rising edge delay from RXD[3:0],
RX_DV Valid
10 Mb/s MII mode
100
ns
Note: RX_CLK may be held low for a longer period of time during transition between reference and recovered clocks.
Minimum high and low times will not be violated.
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DP83848M
8.2.13 10BASE-T Transmit Timing (Start of Packet)
TX_CLK
TX_EN
TXD
PMD Output Pair
T2.13.1
Parameter
T2.13.1
Description
Notes
Transmit Output Delay from the
Min
10 Mb/s MII mode
Typ
Max
3.5
Units
bits
Falling Edge of TX_CLK
Note: 1 bit time = 100 ns in 10Mb/s.
8.2.14 10BASE-T Transmit Timing (End of Packet)
TX_CLK
TX_EN
0
PMD Output Pair
T2.14.1
0
T2.14.2
PMD Output Pair
Parameter
T2.14.1
1
1
Description
Notes
End of Packet High Time
Min
Typ
Max
Units
250
300
ns
250
300
ns
(with ‘0’ ending bit)
T2.14.2
End of Packet High Time
(with ‘1’ ending bit)
69
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DP83848M
8.2.15 10BASE-T Receive Timing (Start of Packet)
1st SFD bit decoded
1
0
1
0
1
0
1
0
1
0
1
1
TPRD±
T2.15.1
CRS
RX_CLK
T2.15.2
RX_DV
T2.15.3
0000
RXD[3:0]
Parameter
Preamble
Description
SFD
Notes
T2.15.1
Carrier Sense Turn On Delay (PMD
Input Pair to CRS)
T2.15.2
RX_DV Latency
T2.15.3
Receive Data Latency
Min
Measurement shown from SFD
Data
Typ
Max
Units
630
1000
ns
10
bits
8
bits
Note: 10BASE-T RX_DV Latency is measured from first bit of preamble on the wire to the assertion of RX_DV
Note: 1 bit time = 100 ns in 10 Mb/s mode.
8.2.16 10BASE-T Receive Timing (End of Packet)
1
0
1
IDLE
PMD Input Pair
RX_CLK
T2.16.1
CRS
Parameter
T2.16.1
Description
Notes
Carrier Sense Turn Off Delay
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70
Min
Typ
Max
Units
1.0
µs
DP83848M
8.2.17 10 Mb/s Heartbeat Timing
TX_EN
TX_CLK
T2.17.1
T2.17.2
COL
Parameter
Description
Notes
Min
Typ
Max
Units
T2.17.1
CD Heartbeat Delay
All 10 Mb/s modes
1200
ns
T2.17.2
CD Heartbeat Duration
All 10 Mb/s modes
1000
ns
8.2.18 10 Mb/s Jabber Timing
TXE
T2.18.1
T2.18.2
PMD Output Pair
COL
Parameter
Description
Notes
Min
Typ
Max
Units
T2.18.1
Jabber Activation Time
85
ms
T2.18.2
Jabber Deactivation Time
500
ms
71
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DP83848M
8.2.19 10BASE-T Normal Link Pulse Timing
T2.19.2
T2.19.1
Normal Link Pulse(s)
Parameter
Description
Notes
Min
Typ
Max
Units
T2.19.1
Pulse Width
100
ns
T2.19.2
Pulse Period
16
ms
Note: These specifications represent transmit timings.
8.2.20 Auto-Negotiation Fast Link Pulse (FLP) Timing
T2.20.2
T2.20.3
T2.20.1
T2.20.1
Fast Link Pulse(s)
clock
pulse
data
pulse
clock
pulse
T2.20.5
T2.20.4
FLP Burst
Parameter
FLP Burst
Description
Notes
Min
Typ
Max
Units
T2.20.1
Clock, Data Pulse Width
100
ns
T2.20.2
Clock Pulse to Clock Pulse
Period
125
µs
T2.20.3
Clock Pulse to Data Pulse
Period
62
µs
T2.20.4
Burst Width
2
ms
T2.20.5
FLP Burst to FLP Burst Period
16
ms
Data = 1
Note: These specifications represent transmit timings.
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DP83848M
8.2.21 100BASE-TX Signal Detect Timing
PMD Input Pair
T2.21.1
T2.21.2
SD+ internal
Parameter
Description
Notes
Min
Typ
Max
Units
T2.21.1
SD Internal Turn-on Time
1
ms
T2.21.2
SD Internal Turn-off Time
350
µs
Max
Units
240
ns
Note: The signal amplitude on PMD Input Pair must be TP-PMD compliant.
8.2.22 100 Mb/s Internal Loopback Timing
TX_CLK
TX_EN
TXD[3:0]
CRS
T2.22.1
RX_CLK
RX_DV
RXD[3:0]
Parameter
T2.22.1
Description
TX_EN to RX_DV Loopback
Notes
Min
100 Mb/s internal loopback mode
Typ
Note1: Due to the nature of the descrambler function, all 100BASE-TX Loopback modes will cause an initial “dead-time”
of up to 550 µs during which time no data will be present at the receive MII outputs. The 100BASE-TX timing specified is
based on device delays after the initial 550µs “dead-time”.
Note2: Measurement is made from the first rising edge of TX_CLK after assertion of TX_EN.
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DP83848M
8.2.23 10 Mb/s Internal Loopback Timing
TX_CLK
TX_EN
TXD[3:0]
CRS
T2.23.1
RX_CLK
RX_DV
RXD[3:0]
Parameter
T2.23.1
Description
TX_EN to RX_DV Loopback
Notes
Min
10 Mb/s internal loopback mode
Note: Measurement is made from the first rising edge of TX_CLK after assertion of TX_EN.
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74
Typ
Max
Units
2
µs
DP83848M
8.2.24 RMII Transmit Timing
T2.24.1
X1
T2.24.2
TXD[1:0]
TX_EN
T2.24.3
Valid Data
T2.24.4
PMD Output Pair
Parameter
Symbol
Description
Notes
Min
50 MHz Reference Clock
Typ
T2.24.1
X1 Clock Period
T2.24.2
TXD[1:0], TX_EN, Data Setup
to X1 rising
4
ns
T2.24.3
TXD[1:0], TX_EN, Data Hold
from X1 rising
2
ns
T2.24.4
X1 Clock to PMD Output Pair From X1 Rising edge to first bit of symbol
Latency
75
20
Max Units
17
ns
bits
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DP83848M
8.2.25 RMII Receive Timing
PMD Input Pair
IDLE
Data
(J/K)
Data
(TR)
T2.25.5
T2.25.4
X1
T2.25.1
T2.25.2
T2.25.2
T2.25.3
T2.25.2
RX_DV
CRS_DV
T2.25.2
RXD[1:0]
RX_ER
Parameter
Description
Notes
Min
50 MHz Reference Clock
Typ
Max
20
Units
T2.25.1
X1 Clock Period
T2.25.2
RXD[1:0], CRS_DV, RX_DV,
and RX_ER output delay from
X1 rising
T2.25.3
CRS ON delay
From JK symbol on PMD Receive Pair to
initial assertion of CRS_DV
18.5
bits
T2.25.4
CRS OFF delay
From TR symbol on PMD Receive Pair to
initial deassertion of CRS_DV
27
bits
T2.25.5
RXD[1:0] and RX_ER latency
From symbol on Receive Pair. Elasticity
buffer set to default value (01)
38
bits
2
ns
14
ns
Note: Per the RMII Specification, output delays assume a 25pF load.
Note: CRS_DV is asserted asynchronously in order to minimize latency of control signals through the Phy. CRS_DV may
toggle synchronously at the end of the packet to indicate CRS deassertion.
Note: RX_DV is synchronous to X1. While not part of the RMII specification, this signal is provided to simplify recovery of
receive data.
Note: CRS ON delay is measured from the first bit of the JK symbol on the PMD Input Pair to initial assertion of CRS_DV.
Note: CRS OFF delay is measured from the first bit of the TR symbol on the PMD Input Pair to initial de-assertion of
CRS_DV.
Note: Receive Latency is measured from the first bit of the symbol pair on the PMD Input Pair. Typical values are with the
Elasticity Buffer set to the default value (01).
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DP83848M
8.2.26 Isolation Timing
Clear bit 10 of BMCR
(return to normal operation
from Isolate mode)
T2.26.1
H/W or S/W Reset
(with PHYAD = 00000)
T2.26.2
MODE
ISOLATE
Parameter
Description
Notes
NORMAL
Min
Typ
Max
Units
T2.26.1
From software clear of bit 10 in
the BMCR register to the transition from Isolate to Normal Mode
100
µs
T2.26.2
From Deassertion of S/W or H/W
Reset to transition from Isolate to
Normal mode
500
µs
Max
Units
8.2.27 25 MHz_OUT Timing
X1
T2.27.1
T2.27.2
T2.27.1
25 MHz_OUT
Parameter
T2.27.1
T2.27.2
Description
Notes
25 MHz_OUT High/Low Time
25 MHz_OUT propagation delay
Min
Typ
MII mode
20
RMII mode
10
Relative to X1
ns
8
ns
Note: 25 MHz_OUT characteristics are dependent upon the X1 input characteristics.
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DP83848M
8.2.28 100 Mb/s X1 to TX_CLK Timing
X1
T2.28.1
TX_CLK
Parameter
T2.28.1
Description
Notes
X1 to TX_CLK delay
100 Mb/s Normal mode
Min
0
Typ
Max
Units
5
ns
Note: X1 to TX_CLK timing is provided to support devices that use X1 instead of TX_CLK as the reference for transmit
Mll data.
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78
DP83848M
Notes
79
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DP83848M PHYTER® Mini - Commercial Temperature Single 10/100 Ethernet Transceiver
Physical Dimensions inches (millimeters) unless otherwise noted
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