TI DP83848C

DP83848C
DP83848C PHYTER Commercial Temperature Single Port 10/100 Mb/s Ethernet
Physical Layer Transceiver
Literature Number: SNOSAT2E
®
DP83848C PHYTER - Commercial Temperature
Single Port 10/100 Mb/s Ethernet Physical Layer Transceiver
General Description
Features
The DP83848C is a robust fully featured 10/100 single
port Physical Layer device offering low power consumption, including several intelligent power down
states. These low power modes increase overall product reliability due to decreased power dissipation. Supporting multiple intelligent power modes allows the
application to use the absolute minimum amount of
power needed for operation.
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The DP83848C includes a 25MHz clock out. This
means that the application can be designed with a
minimum of external parts, which in turn results in the
lowest possible total cost of the solution.
The DP83848C easily interfaces to twisted pair media
via an external transformer. Both MII and RMII are
supported ensuring ease and flexibility of design.
The DP83848C features integrated sublayers to support both 10BASE-T and 100BASE-TX Ethernet protocols, which ensures compatibility and interoperability
with all other standards based Ethernet solutions.
The DP83848C is offered in a small form factor (48 pin
LQFP) so that a minimum of board space is needed.
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Applications
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• High End Peripheral Devices
• Industrial Controls and Factory Automation
• General Embedded Applications
Low-power 3.3V, 0.18µm CMOS technology
Low power consumption < 270mW Typical
3.3V MAC Interface
Auto-MDIX for 10/100 Mb/s
Energy Detection Mode
25 MHz clock out
SNI Interface (configurable)
RMII Rev. 1.2 Interface (configurable)
MII Serial Management Interface (MDC and MDIO)
IEEE 802.3u MII
IEEE 802.3u Auto-Negotiation and Parallel Detection
IEEE 802.3u ENDEC, 10BASE-T transceivers and filters
IEEE 802.3u PCS, 100BASE-TX transceivers and filters
Integrated ANSI X3.263 compliant TP-PMD physical sublayer with adaptive equalization and Baseline Wander compensation
Error-free Operation up to 137 meters
Programmable LED support Link, 10 /100 Mb/s Mode, Activity, and Collision Detect
Single register access for complete PHY status
10/100 Mb/s packet BIST (Built in Self Test)
48-pin LQFP package (7mm) x (7mm)
DP83848C
10/100 Mb/s
25 MHz
Clock
Source
RJ-45
MII/RMII/SNI
Magnetics
MPU/CPU
Media Access Controller
System Diagram
10BASE-T
or
100BASE-TX
Status
LEDs
Typical Application
® is a registered trademark of National Semiconductor.
PHYTER
© 2008 National Semiconductor Corporation
www.national.com
1
DP83848C PHYTER® — Commercial Temperature Single Port 10/100 Mb/s Ethernet Physical Layer Transceiver
May 2008
DP83848C
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/SNI
MII/RMII/SNI INTERFACES
TX_DATA
RX_CLK
TX_CLK
MII
Registers
10BASE-T &
100BASE-TX
RX_DATA
10BASE-T &
100BASE-TX
Auto-Negotiation
State Machine
Transmit
Block
Receive
Block
Clock
Generation
ADC
DAC
Auto-MDIX
TD±
RD±
LED
Drivers
REFERENCE CLOCK
Figure 1. DP83848C Functional Block Diagram
www.national.com
2
LEDS
1.1 Serial Management Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
1.2 MAC Data Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
1.3 Clock Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
1.4 LED Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
1.5 Reset and Power Down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
1.6 Strap Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
1.7 10 Mb/s and 100 Mb/s PMD Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
1.8 Special Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
1.9 Power Supply Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
1.10 Package Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
2.0 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.1 Auto-Negotiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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16
17
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2.2 Auto-MDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
2.3 PHY Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
2.3.1 MII Isolate Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.4 LED Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
2.4.1 LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.4.2 LED Direct Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.5 Half Duplex vs. Full Duplex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
2.6 Internal Loopback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
2.7 BIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
3.0 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.1 MII Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
3.1.1 Nibble-wide MII Data Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.1.2 Collision Detect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.1.3 Carrier Sense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.2 Reduced MII Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
3.3 10 Mb Serial Network Interface (SNI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
3.4 802.3u MII Serial Management Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
3.4.1 Serial Management Register Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.4.2 Serial Management Access Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.4.3 Serial Management Preamble Suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.0 Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.1 100BASE-TX TRANSMITTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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26
4.2 100BASE-TX RECEIVER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.9 4B/5B Decoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.10 100BASE-TX Link Integrity Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.11 Bad SSD Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
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26
28
29
29
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30
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DP83848C
1.0 Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
DP83848C
4.3 10BASE-T TRANSCEIVER MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
31
31
31
31
32
32
32
32
32
5.0 Design Guidelines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.1
5.2
5.3
5.4
5.5
TPI Network Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
ESD Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Clock In (X1) Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Power Feedback Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Power Down/Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
5.5.1 Power Down Control Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.5.2 Interrupt Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.6 Energy Detect Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
6.0 Reset Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
6.1 Hardware Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
6.2 Software Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
7.0 Register Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7.1 Register Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
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) . . . . . . . . . . . . . . . . . . . . . . . . . .
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45
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48
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49
7.2 Extended Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
7.2.1 PHY Status Register (PHYSTS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.2 MII Interrupt Control Register (MICR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.3 MII Interrupt Status and Misc. Control Register (MISR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.4 False Carrier Sense Counter Register (FCSCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.5 Receiver Error Counter Register (RECR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.6 100 Mb/s PCS Configuration and Status Register (PCSR) . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.7 RMII and Bypass Register (RBR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.8 LED Direct Control Register (LEDCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.9 PHY Control Register (PHYCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.10 10Base-T Status/Control Register (10BTSCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.11 CD Test and BIST Extensions Register (CDCTRL1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.12 Energy Detect Control (EDCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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60
61
8.0 Electrical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
8.1 DC Specs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62
8.2 AC Specs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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64
65
66
66
67
67
68
69
70
70
10 Mb/s MII Transmit Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 Mb/s MII Receive Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 Mb/s Serial Mode Transmit Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 Mb/s Serial Mode 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
71
71
72
72
73
73
74
74
75
75
76
76
77
77
78
79
80
81
81
82
9.0 Physical Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
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DP83848C
8.2.11
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
8.2.29
8.2.30
DP83848C
List of Figures
Figure 1. DP83848C Functional Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Figure 2. PHYAD Strapping Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 3. AN Strapping and LED Loading Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 4. Typical MDC/MDIO Read Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 5. Typical MDC/MDIO Write Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 6. 100BASE-TX Transmit Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 7. 100BASE-TX Receive Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 8. EIA/TIA Attenuation vs. Frequency for 0, 50, 100, 130 & 150 meters of CAT 5 cable . . . . . . . . . . . 28
Figure 9. 100BASE-TX BLW Event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 10. 10BASE-T Twisted Pair Smart Squelch Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Figure 11. 10/100 Mb/s Twisted Pair Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 12. Crystal Oscillator Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 13. Power Feeback Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
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Table 1. Auto-Negotiation Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Table 2. PHY Address Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Table 3. LED Mode Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Table 4. Supported packet sizes at +/-50ppm +/-100ppm for each clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Table 5. Typical MDIO Frame Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Table 5. 4B5B Code-Group Encoding/Decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Table 6. 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Table 7. 25 MHz Oscillator Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Table 8. 50 MHz Oscillator Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Table 9. 25 MHz Crystal Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Table 10. Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Table 11. Register Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
Table 12. Basic Mode Control Register (BMCR), address 0x00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
Table 13. Basic Mode Status Register (BMSR), address 0x01 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Table 14. PHY Identifier Register #1 (PHYIDR1), address 0x02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Table 15. PHY Identifier Register #2 (PHYIDR2), address 0x03 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Table 16. Negotiation Advertisement Register (ANAR), address 0x04 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Table 17. Auto-Negotiation Link Partner Ability Register (ANLPAR) (BASE Page), address 0x05 . . . . . . . .46
Table 18. Auto-Negotiation Link Partner Ability Register (ANLPAR) (Next Page), address 0x05 . . . . . . . . .48
Table 19. Auto-Negotiate Expansion Register (ANER), address 0x06 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
Table 20. Auto-Negotiation Next Page Transmit Register (ANNPTR), address 0x07 . . . . . . . . . . . . . . . . . . .49
Table 21. PHY Status Register (PHYSTS), address 0x10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
Table 22. MII Interrupt Control Register (MICR), address 0x11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Table 23. MII Interrupt Status and Misc. Control Register (MISR), address 0x12 . . . . . . . . . . . . . . . . . . . . . .53
Table 24. False Carrier Sense Counter Register (FCSCR), address 0x14 . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Table 25. Receiver Error Counter Register (RECR), address 0x15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Table 26. 100 Mb/s PCS Configuration and Status Register (PCSR), address 0x16 . . . . . . . . . . . . . . . . . . . .55
Table 27. RMII and Bypass Register (RBR), addresses 0x17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Table 28. LED Direct Control Register (LEDCR), address 0x18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Table 29. PHY Control Register (PHYCR), address 0x19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Table 30. 10Base-T Status/Control Register (10BTSCR), address 0x1A . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58
Table 31. CD Test and BIST Extensions Register (CDCTRL1), address 0x1B . . . . . . . . . . . . . . . . . . . . . . . . .60
Table 32. Energy Detect Control (EDCR), address 0x1D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
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DP83848C
List of Tables
DGND
IOGND
X1
X2
IOVDD33
MDC
MDIO
RESET_N
LED_LINK/AN0
LED_SPEED/AN1
LED_ACT/COL/AN_EN
25MHz_OUT
36
35
34
33
32
31
30
29
28
27
26
25
37
24
RBIAS
RX_CLK
38
23
PFBOUT
RX_DV/MII_MODE
39
22
AVDD33
CRS/CRS_DV/LED_CFG
40
21
RESERVED
RX_ER/MDIX_EN
41
20
RESERVED
COL/PHYAD0
42
19
AGND
RXD_0/PHYAD1
43
18
PFBIN1
RXD_1/PHYAD2
44
17
TD +
RXD_2/PHYAD3
45
16
TD -
RXD_3/PHYAD4
46
15
AGND
IOGND
47
14
RD +
IOVDD33
48
13
RD -
9
10
11
12
RESERVED
RESERVED
RESERVED
6
TXD_3/SNI_MODE
8
5
TXD_2
RESERVED
4
TXD_1
RESERVED
3
TXD_0
7
2
TX_EN
o
PWR_DOWN/INT
DP83848C
1
PFBIN2
TX_CLK
DP83848C
Pin Layout
Top View
NS Package Number VBH48A
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8
The DP83848C pins are classified into the following interface categories (each interface is described in the sections
that follow):
All DP83848C 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 and Power Down
— Strap Options
— 10/100 Mb/s PMD Interface
— Special Connect Pins
— Power and Ground pins
Note: Strapping pin option. Please see Section 1.6 for strap
definitions.
Type: I
Type: O
Type: I/O
Type OD
Type: PD,PU
Type: S
Input
Output
Input/Output
Open Drain
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 for details.)
1.1 Serial Management Interface
Signal Name
Type
Pin #
Description
MDC
I
31
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
30
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
1
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.
SNI TRANSMIT CLOCK: 10 MHz Transmit clock output in 10 Mb
SNI mode. The MAC should source TX_EN and TXD_0 using this
clock.
TX_EN
I, PD
2
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].
SNI TRANSMIT ENABLE: Active high input indicates the presence of valid data on TXD_0.
TXD_0
I
TXD_1
4
TXD_2
TXD_3
3
5
S, I, PD
6
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.
SNI TRANSMIT DATA: Transmit data SNI input pin, TXD_0, that
accept data synchronous to the TX_CLK (10 MHz in 10 Mb/s SNI
mode).
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DP83848C
1.0 Pin Descriptions
DP83848C
Signal Name
RX_CLK
Type
Pin #
Description
O
38
MII RECEIVE CLOCK: Provides the 25 MHz recovered receive
clocks 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.
SNI RECEIVE CLOCK: Provides the 10 MHz recovered receive
clocks for 10 Mb/s SNI mode.
RX_DV
S, O, PD
39
MII RECEIVE DATA VALID: Asserted high to indicate that valid
data is present on the corresponding RXD[3:0]. MII mode by default with internal pulldown.
RMII Synchronous Receive Data Valid: This signal provides the
RMII Receive Data Valid indication independent of Carrier Sense.
This pin is not used in SNI mode.
RX_ER
S, O, PU
41
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 RXDV 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.
This pin is not used in SNI mode.
RXD_0
S, O, PD
43
RXD_1
44
RXD_2
45
RXD_3
46
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.
RMII RECEIVE DATA: 2-bits receive data signals, RXD[1:0], driven synchronously to the X1 clock, 50 MHz.
SNI RECEIVE DATA: Receive data signal, RXD_0, driven synchronously to the RX_CLK. RXD_0 contains valid data when CRS
is asserted. RXD[3:1] are not used in this mode.
CRS/CRS_DV
S, O, PU
40
MII CARRIER SENSE: Asserted high to indicate the receive medium is non-idle.
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.
SNI CARRIER SENSE: Asserted high to indicate the receive medium is non-idle. It is used to frame valid receive data on the
RXD_0 signal.
COL
S, O, PU
42
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.
SNI COLLISION DETECT: Asserted high to indicate detection of
a collision condition (simultaneous transmit and receive activity)
in 10 Mb/s SNI mode.
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10
Signal Name
X1
Type
Pin #
Description
I
34
CRYSTAL/OSCILLATOR INPUT: This pin is the primary clock
reference input for the DP83848C and must be connected to a 25
MHz 0.005% (+50 ppm) clock source. The DP83848C 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
O
33
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.
25MHz_OUT
O
25
25 MHz CLOCK OUTPUT:
In MII mode, this pin provides a 25 MHz clock output to the system.
In RMII mode, this pin provides a 50 MHz clock output to the system.
This allows other devices to use the reference clock from the
DP83848C without requiring additional clock sources.
1.4 LED Interface
See Table 3 for LED Mode Selection.
Signal Name
LED_LINK
Type
Pin #
Description
S, O, PU
28
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 and Mode 3, 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.
LED_SPEED
S, O, PU
27
SPEED LED: The LED is ON when device is in 100 Mb/s and OFF
when in 10 Mb/s. Functionality of this LED is independent of mode
selected.
LED_ACT/COL
S, O, PU
26
ACTIVITY LED: In Mode 1, this pin is the Activity LED which is
ON when activity is present on either Transmit or Receive.
COLLISION/DUPLEX LED: In Mode 2, this pin by default indicates Collision detection. For Mode 3, this LED output may be
programmed to indicate Full-duplex status instead of Collision.
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DP83848C
1.3 Clock Interface
DP83848C
1.5 Reset and Power Down
Signal Name
RESET_N
PWR_DOWN/INT
Type
Pin #
Description
I, PU
29
RESET: Active Low input that initializes or re-initializes the
DP83848C. 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.
I, OD, PU
7
See Section 5.5 for detailed description.
The default function of this pin is POWER DOWN.
POWER DOWN: The pin is an active low input in this mode and
should be asserted low to put the device in a Power Down mode.
INTERRUPT: The pin is an open drain output in this mode and will
be asserted low when an interrupt condition occurs. Although the
pin has a weak internal pull-up, some applications may require an
external pull-up resister. Register access is required for the pin to
be used as an interrupt mechanism. See Section 5.5.2 Interrupt
Mechanism for more details on the interrupt mechanisms.
1.6 Strap Options
The DP83848C uses many of the 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.
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.
Signal Name
Type
Pin #
Description
PHYAD0 (COL)
S, O, PU
42
PHYAD1 (RXD_0)
S, O, PD
43
PHY ADDRESS [4:0]: The DP83848C provides five PHY address pins, the state of which are latched into the PHYCTRL register at system Hardware-Reset.
PHYAD2 (RXD_1)
44
PHYAD3 (RXD_2)
45
PHYAD4 (RXD_3)
46
The DP83848C 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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12
AN_EN (LED_ACT/COL)
Type
Pin #
Description
S, O, PU
26
Auto-Negotiation Enable: When high, this enables Auto-Negotiation with the capability set by ANO and AN1 pins. When low, this
puts the part into Forced Mode with the capability set by AN0 and
AN1 pins.
AN_1 (LED_SPEED)
27
AN_0 (LED_LINK)
28
AN0 / AN1: These input pins control the forced or advertised operating mode of the DP83848C according to the following table.
The value on these pins is set by connecting the input pins to
GND (0) or VCC (1) through 2.2 kΩ resistors. These pins should
NEVER be connected directly to GND or VCC.
The value set at this input is latched into the DP83848C at Hardware-Reset.
The float/pull-down status of these pins are latched into the Basic
Mode Control Register and the Auto_Negotiation Advertisement
Register during Hardware-Reset.
The default is 111 since these pins have internal pull-ups.
AN_EN AN1
AN0
Forced Mode
0
0
0
10BASE-T, Half-Duplex
0
0
1
10BASE-T, Full-Duplex
0
1
0
100BASE-TX, Half-Duplex
0
1
1
100BASE-TX, Full-Duplex
AN_EN AN1
AN0
Advertised Mode
1
0
0
10BASE-T, Half/Full-Duplex
1
0
1
100BASE-TX, Half/Full-Duplex
1
1
0
10BASE-T Half-Duplex
100BASE-TX, Half-Duplex
1
1
1
10BASE-T, Half/Full-Duplex
100BASE-TX, Half/Full-Duplex
MII_MODE (RX_DV)
S, O, PD
SNI_MODE (TXD_3)
39
6
MII MODE SELECT: This strapping option pair determines the
operating mode of the MAC Data Interface. Default operation (No
pull-ups) will enable normal MII Mode of operation. Strapping
MII_MODE high will cause the device to be in RMII or SNI mode
of operation, determined by the status of the SNI_MODE strap.
Since the pins include internal pull-downs, the default values are
0.
The following table details the configurations:
LED_CFG (CRS)
S, O, PU
40
MII_MODE
SNI_MODE
MAC Interface
Mode
0
X
1
0
RMII Mode
1
1
10 Mb SNI Mode
MII 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)
S, O, PU
41
MDIX ENABLE: Default is to enable MDIX. This strapping option
disables Auto-MDIX. An external pull-down will disable AutoMDIX mode.
13
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DP83848C
Signal Name
DP83848C
1.7 10 Mb/s and 100 Mb/s PMD Interface
Signal Name
TD-, TD+
Type
Pin #
Description
I/O
16, 17
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
13, 14
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
Type
Pin #
Description
RBIAS
Signal Name
I
24
Bias Resistor Connection. A 4.87 kΩ 1% resistor should be connected from RBIAS to GND.
PFBOUT
O
23
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 18) and PFBIN2 (pin 37). See
Section 5.4 for proper placement pin.
PFBIN1
I
18
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
37
Note: Do not supply power to these pins other than from
PFBOUT.
RESERVED
I/O
RESERVED
I/O
8, 9, 10, 11, RESERVED: These pins must be left unconnected.
12
20, 21
RESERVED: These pins must be pulled-up through 2.2 kΩ resistors to AVDD33 supply.
1.9 Power Supply Pins
Signal Name
Pin #
Description
IOVDD33
32, 48
I/O 3.3V Supply
IOGND
35, 47
I/O Ground
DGND
36
Digital Ground
AVDD33
22
Analog 3.3V Supply
AGND
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15, 19
Analog Ground
14
VBH48A Pin # Pin Name
VBH48A Pin # Pin Name
1
TX_CLK
2
TX_EN
3
TXD_0
4
TXD_1
5
TXD_2
6
TXD_3/SNI_MODE
7
PWR_DOWN/INT
8
RESERVED
9
RESERVED
10
RESERVED
11
RESERVED
12
RESERVED
13
RD -
14
RD +
15
AGND
16
TD -
17
TD +
18
PFBIN1
19
AGND
20
RESERVED
21
RESERVED
22
AVDD33
23
PFBOUT
24
RBIAS
25
25MHz_OUT
26
LED_ACT/COL/AN_EN
27
LED_SPEED/AN1
28
LED_LINK/AN0
29
RESET_N
30
MDIO
31
MDC
32
IOVDD33
33
X2
34
X1
35
IOGND
36
DGND
37
PFBIN2
38
RX_CLK
39
RX_DV/MII_MODE
40
CRS/CRS_DV/LED_CFG
15
41
RX_ER/MDIX_EN
42
COL/PHYAD0
43
RXD_0/PHYAD1
44
RXD_1/PHYAD2
45
RXD_2/PHYAD3
46
RXD_3/PHYAD4
47
IOGND
48
IOVDD33
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DP83848C
1.10 Package Pin Assignments
DP83848C
2.0 Configuration
This section includes information on the various configuration options available with the DP83848C. The configuration options described below include:
—
—
—
—
—
—
Table 1. Auto-Negotiation Modes
Auto-Negotiation
PHY Address and LEDs
Half Duplex vs. Full Duplex
Isolate mode
Loopback mode
BIST
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 DP83848C 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 DP83848C can be controlled either by
internal register access or by the use of the AN_EN, AN1
and AN0 pins.
2.1.1 Auto-Negotiation Pin Control
The state of AN_EN, AN0 and AN1 determines whether the
DP83848C is forced into a specific mode or Auto-Negotiation will advertise a specific ability (or set of abilities) as
given in Table 1. These pins allow configuration options to
be selected without requiring internal register access.
The state of AN_EN, AN0 and AN1, 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.
AN_EN
AN1
AN0
0
0
0
10BASE-T, Half-Duplex
Forced Mode
0
0
1
10BASE-T, Full-Duplex
0
1
0
100BASE-TX, Half-Duplex
100BASE-TX, Full-Duplex
0
1
1
AN_EN
AN1
AN0
1
0
0
10BASE-T, Half/Full-Duplex
1
0
1
100BASE-TX, Half/Full-Duplex
1
1
0
10BASE-T Half-Duplex
Advertised Mode
100BASE-TX, Half-Duplex
1
1
1
10BASE-T, Half/Full-Duplex
100BASE-TX, Half/Full-Duplex
2.1.2 Auto-Negotiation Register Control
When Auto-Negotiation is enabled, the DP83848C 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 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.
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
DP83848C (only the 100BASE-T4 bit is not set since the
DP83848C does not support that function).
The BMSR also provides status on:
— Whether or not Auto-Negotiation is complete
— Whether or not the Link Partner is advertising that a remote fault has occurred
— Whether or not valid link has been established
— Support for Management Frame Preamble suppression
The Auto-Negotiation Advertisement Register (ANAR)
indicates the Auto-Negotiation abilities to be advertised by
the DP83848C. All available abilities are transmitted by
default, but any ability can be suppressed by writing to the
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16
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.
The Auto-Negotiation Expansion Register (ANER) indicates additional Auto-Negotiation status. The ANER provides status on:
— Whether or not a Parallel Detect Fault has occurred
— Whether or not the Link Partner supports the Next Page
function
— Whether or not the DP83848C supports the Next Page
function
— Whether or not the current page being exchanged by
Auto-Negotiation has been received
— Whether or not the Link Partner supports Auto-Negotiation
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 AutoNegotiation 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.
A renegotiation request from any entity, such as a management agent, will cause the DP83848C 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
DP83848C 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 DP83848C has been initialized upon power-up as a non-auto-negotiating device
(forced technology), and it is then required that Auto-Negotiation 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.
2.1.3 Auto-Negotiation Parallel Detection
The DP83848C 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 AutoNegotiation 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 10BASET PMAs recognize as valid link signals.
If the DP83848C completes Auto-Negotiation as a result of
Parallel Detection, bits 5 and 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.
2.1.6 Auto-Negotiation Complete Time
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.
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.
Note: Auto-MDIX will not work in a forced mode of operation.
17
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DP83848C
ANAR. Updating the ANAR to suppress an ability is one
way for a management agent to change (restrict) the technology that is used.
The 5 PHY address inputs pins are shared with the
RXD[3:0] pins and COL pin as shown below.
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).
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
42
PHYAD0
COL
43
PHYAD1
RXD_0
2.3.1 MII Isolate Mode
44
PHYAD2
RXD_1
45
PHYAD3
RXD_2
46
PHYAD4
RXD_3
The DP83848C 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 DP83848C 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 DP83848C or
port sharing an MDIO bus in a system must have a unique
physical address.
The DP83848C 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 2.3.1for
more information.
When in the MII isolate mode, the DP83848C 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 DP83848C 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.
COL
RXD_0
The DP83848C 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 DP83848C is in Isolate mode.
RXD_1
RXD_2
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.
RXD_3
PHYAD4= 0 PHYAD3 = 0 PHYAD2 = 0 PHYAD1 = 1 PHYAD0 = 1
2.2kΩ
DP83848C
2.3 PHY Address
VCC
Figure 2. PHYAD Strapping Example
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The DP83848C supports three configurable Light Emitting
Diode (LED) pins. The device supports three LED configurations: Link, Speed, Activity and Collision. Function are
multiplexed among the LEDs. The PHY Control Register
(PHYCR) for the LEDs can also be selected through
address 19h, bits [6:5].
See Table 3 for LED Mode selection.
Table 3. LED Mode Select
Mode
LED_CFG[1]
(bit 6)
LED_CFG[0]
(bit 5)
LED_LINK
LED_SPEED
LED_ACT/COL
ON for Good Link
ON in 100 Mb/s
ON for Activity
OFF for No Link
OFF in 10 Mb/s
OFF for No Activity
ON for Good Link
ON in 100 Mb/s
ON for Collision
BLINK for Activity
OFF in 10 Mb/s
OFF for No Collision
ON for Good Link
ON in 100 Mb/s
ON for Full Duplex
BLINK for Activity
OFF in 10 Mb/s
OFF for Half Duplex
or (pin40)
3
0
1
1
0
0
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.
The LED_LINK pin in Mode 1 will be OFF when no LINK is
present.
The LED_LINK pin in Mode 2 and Mode 3 will be ON to
indicate Link is good and BLINK to indicate activity is
present on either transmit or receive activity.
Specifically, when the LED outputs are used to drive LEDs
directly, the active state of each output driver is dependent
on the logic level sampled by the corresponding AN input
upon power-up/reset. For example, if a given AN input is
resistively pulled low then the corresponding output will be
configured as an active high driver. Conversely, if a given
AN 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 AN connections to
external components. In this example, the AN strapping
results in Auto-Negotiation with 10/100 Half/Full-Duplex
advertised.
The adaptive nature of the LED outputs helps to simplify
potential implementation issues of these dual purpose pins.
LED_ACT/COL
The LED_SPEED pin indicates 10 or 100 Mb/s data rate of
the port. The standard CMOS driver goes high when operating in 100 Mb/s operation. The functionality of this LED is
independent of mode selected.
The LED_ACT/COL pin in Mode 1 indicates the presence
of either transmit or receive activity. The LED will be ON for
Activity and OFF for No Activity. In Mode 2, this pin indicates the Collision status of the port. The LED will be ON
for Collision and OFF for No Collision.
AN_EN = 1
LED_LINK
2
don’t care
LED_SPEED
1
AN1 = 1
AN0 = 1
110Ω
2.2kΩ
110Ω
2.2kΩ
Since these LED pins are also used as strap options, the
polarity of the LED is dependent on whether the pin is
pulled up or down.
110Ω
In 10 Mb/s half duplex mode, the collision LED is based on
the COL signal.
2.2kΩ
The LED_ACT/COL pin in Mode 3 indicates the presence
of Duplex status for 10 Mb/s or 100 Mb/s operation. The
LED will be ON for Full Duplex and OFF for Half Duplex.
VCC
2.4.1 LEDs
Since the Auto-Negotiation (AN) strap options share the
LED output pins, the external components required for
strapping and LED usage must be considered in order to
avoid contention.
19
Figure 3. AN Strapping and LED Loading Example
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DP83848C
2.4 LED Interface
DP83848C
2.4.2 LED Direct Control
2.6 Internal Loopback
The DP83848C provides another option to directly control
any or all LED outputs through the LED Direct Control Register (LEDCR), address 18h. The register does not provide
read access to LEDs.
The DP83848C 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.
2.5 Half Duplex vs. Full Duplex
The DP83848C supports both half and full duplex operation at both 10 Mb/s and 100 Mb/s speeds.
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 DP83848C 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 DP83848C 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.
2.7 BIST
The DP83848C 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
All modes of operation (100BASE-TX and 10BASE-T) can received data is compared to the generated pseudo-ranrun either half-duplex or full-duplex. Additionally, other than dom data by the BIST Linear Feedback Shift Register
CRS and Collision reporting, all remaining MII signaling (LFSR) to determine the BIST pass/fail status.
remains the same regardless of the selected duplex mode.
The pass/fail status of the BIST is stored in the BIST status
It is important to understand that while Auto-Negotiation bit in the PHYCR register. The status bit defaults to 0 (BIST
with the use of Fast Link Pulse code words can interpret fail) and will transition on a successful comparison. If an
and configure to full-duplex operation, parallel detection error (mis-compare) occurs, the status bit is latched and is
can not recognize the difference between full and half- cleared upon a subsequent write to the Start/Stop bit.
duplex from a fixed 10 Mb/s or 100 Mb/s link partner over
twisted pair. As specified in the 802.3u specification, if a For transmit VOD testing, the Packet BIST Continuous
far-end link partner is configured to a forced full duplex Mode can be used to allow continuous data transmission,
100BASE-TX ability, the parallel detection state machine in setting BIST_CONT_MODE, bit 5, of CDCTRL1 (0x1Bh).
the partner would be unable to detect the full duplex capa- The number of BIST errors can be monitored through the
bility of the far-end link partner. This link segment would BIST Error Count in the CDCTRL1 (0x1Bh), bits [15:8].
negotiate to a half duplex 100BASE-TX configuration
(same scenario for 10 Mb/s).
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The DP83848C supports several modes of operation using
the MII interface pins. The options are defined in the following sections and include:
— MII Mode
— RMII Mode
— 10 Mb Serial Network Interface (SNI)
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.
In 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).
3.1 MII Interface
The DP83848C 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.
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).
If the DP83848C 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.
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.
3.1.3 Carrier Sense
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.
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.
3.2 Reduced MII Interface
The DP83848C incorporates the Reduced Media Independent Interface (RMII) as specified in the RMII specification
Clause 22 of the IEEE 802.3u specification defines the (rev1.2) from the RMII Consortium. This interface may be
Media Independent Interface. This interface includes a used to connect PHY devices to a MAC in 10/100 Mb/s
dedicated receive bus and a dedicated transmit bus. These systems using a reduced number of pins. In this mode,
two data buses, along with various control and status sig- data is transferred 2-bits at a time using the 50 MHz
nals, allow for the simultaneous exchange of data between RMII_REF clock for both transmit and receive. The followthe DP83848C and the upper layer agent (MAC).
ing pins are used in RMII mode:
The receive interface consists of a nibble wide data bus — TX_EN
RXD[3:0], a receive error signal RX_ER, a receive data — TXD[1:0]
valid flag RX_DV, and a receive clock RX_CLK for synchronous transfer of the data. The receive clock operates — RX_ER (optional for Mac)
at either 2.5 MHz to support 10 Mb/s operation modes or at — CRS_DV
25 MHz to support 100 Mb/s operational modes.
— RXD[1:0]
The transmit interface consists of a nibble wide data bus — X1 (RMII Reference clock is 50 MHz)
TXD[3:0], a transmit enable control signal TX_EN, and a
In addition, the RMII mode supplies an RX_DV signal
transmit clock TX_CLK which runs at either 2.5 MHz or 25
which allows for a simpler method of recovering receive
MHz.
data without having to separate RX_DV from the CRS_DV
Additionally, the MII includes the carrier sense signal CRS, indication. This is especially useful for systems which do
as well as a collision detect signal COL. The CRS signal not require CRS, such as systems that only support fullasserts to indicate the reception of data from the network duplex operation. This signal is also useful for diagnostic
or as a function of transmit data in Half Duplex mode. The testing where it may be desirable to loop Receive RMII
COL signal asserts as an indication of a collision which can data directly to the transmitter.
occur during half-duplex operation when both a transmit
Since the reference clock operates at 10 times the data
and receive operation occur simultaneously.
rate for 10 Mb/s operation, transmit data is sampled every
10 clocks. Likewise, receive data will be generated every
10th clock so that an attached device can sample the data
3.1.2 Collision Detect
every 10 clocks.
3.1.1 Nibble-wide MII Data Interface
For Half Duplex, a 10BASE-T or 100BASE-TX collision is RMII mode requires a 50 MHz oscillator be connected to
detected when the receive and transmit channels are the device X1 pin. A 50 MHz crystal is not supported.
active simultaneously. Collisions are reported by the COL
signal on the MII.
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DP83848C
3.0 Functional Description
DP83848C
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.
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.
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
3.3 10 Mb Serial Network Interface (SNI)
The DP83848C incorporates a 10 Mb Serial Network Interface (SNI) which allows a simple serial data interface for 10
Mb only devices. This is also referred to as a 7-wire interface. While there is no defined standard for this interface, it
is based on early 10 Mb physical layer devices. Data is
clocked serially at 10 MHz using separate transmit and
receive paths. The following pins are used in SNI mode:
—
—
—
—
—
—
—
TX_CLK
TX_EN
TXD[0]
RX_CLK
RXD[0]
CRS
COL
The DP83848C waits until it has received this preamble
sequence before responding to any other transaction.
Once the DP83848C 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.
The Start code is indicated by a <01> pattern. This assures
the MDIO line transitions from the default idle line state.
3.4 802.3u MII Serial Management Interface
3.4.1 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 DP83848C 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.
3.4.2 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.
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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 DP83848C 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 MDC clock cycles
should be used to re-sync the device if an invalid start,
opcode, or turnaround bit is detected.
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 DP83848C 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 DP83848C (PHY) for a typical register
read access.
For write transactions, the station management entity
writes data to the addressed DP83848C 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.
22
DP83848C
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>
MDC
MDIO
Z
Z
(STA)
Z
MDIO
Z
(PHY)
Z
Idle
0 1 1 0 0 1 1 0 0 0 0 0 0 0
Start
Opcode
(Read)
PHY Address
(PHYAD = 0Ch)
Z
Register Address
(00h = BMCR)
0 0 0 1 1 0 0 0 1 0 0 0 0 0 0 0 0
Register Data
TA
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
Register Data
Z
Idle
Figure 5. Typical MDC/MDIO Write Operation
3.4.3 Serial Management Preamble Suppression
The DP83848C 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 DP83848C requires a single initialization sequence of
32 bits of preamble following hardware/software reset. This
requirement is generally met by the mandatory pull-up
resistor on MDIO in conjunction with a continuous MDC, or
the management access made to determine whether Preamble Suppression is supported.
While the DP83848C 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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DP83848C
4.0 Architecture
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 block diagram in Figure 6. provides an overview of
each functional block within the 100BASE-TX transmit section.
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
4.1 100BASE-TX TRANSMITTER
where data conversion is not always required. The
The 100BASE-TX transmitter consists of several functional DP83848C implements the 100BASE-TX transmit state
blocks which convert synchronous 4-bit nibble data, as pro- machine diagram as specified in the IEEE 802.3u Stanvided by the MII, to a scrambled MLT-3 125 Mb/s serial dard, Clause 24.
data stream. Because the 100BASE-TX TP-PMD is integrated, the differential output pins, PMD Output Pair, can
be directly routed to the magnetics.
— 100BASE-TX Transmitter
— 100BASE-TX Receiver
— 10BASE-T Transceiver Module
TX_CLK
TXD[3:0] /
TX_EN
DIVIDE
BY 5
4B5B CODEGROUP
ENCODER &
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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DP83848C
Table 6.
5. 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.
25
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DP83848C
4.1.1 Code-group Encoding and Injection
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 5 for 4B to 5B code-group mapping details.
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.
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).
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).
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).
The 100BASE-TX transmit TP-PMD function within the
DP83848C is capable of sourcing only MLT-3 encoded
data. Binary output from the PMD Output Pair is not possible in 100 Mb/s mode.
4.2 100BASE-TX RECEIVER
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.
The Receive section consists of the following functional
blocks:
—
—
—
—
The scrambler is configured as a closed loop linear feed—
back 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 DP83848C 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
4.1.3 NRZ to NRZI Encoder
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.
4.2.1 Analog Front End
In addition to the Digital Equalization and Gain Control, the
DP83848C includes Analog Equalization and Gain Control
in the Analog Front End. The Analog Equalization reduces
the amount of Digital Equalization required in the DSP.
4.1.4 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
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4.2.2 Digital Signal Processor
The Digital Signal Processor includes Adaptive Equalization with Gain Control and Base Line Wander Compensation.
26
RX_CLK
DP83848C
RX_DV/CRS
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
SIGNAL
DETECT
DIGITAL
SIGNAL
PROCESSOR
ANALOG
FRONT
END
RD +/−
Figure 7. 100BASE-TX Receive Block Diagram
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DP83848C
4.2.2.1 Digital Adaptive Equalization and Gain Control
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.
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-
tive to ensure proper conditioning of the received signal
independent of the cable length.
The DP83848C 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.
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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DP83848C
4.2.2.2 Base Line Wander Compensation
Figure 9. 100BASE-TX BLW Event
The DP83848C is completely ANSI TP-PMD compliant and
includes Base Line Wander (BLW) compensation. The
BLW compensation block can successfully recover the TPPMD defined “killer” pattern.
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
BLW can generally be defined as the change in the aver- and fast link pulses per IEEE 802.3u Auto-Negotiation by
age DC content, relatively short period over time, of an AC the 100BASE-TX receiver do not cause the DP83848C to
coupled digital transmission over a given transmission assert signal detect.
medium. (i.e., copper wire).
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.
4.2.4 MLT-3 to NRZI Decoder
The DP83848C decodes the MLT-3 information from the
Digital Adaptive Equalizer block to binary NRZI data.
4.2.5 NRZI to NRZ
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.
In a typical application, the NRZI to NRZ decoder is
required in order to present NRZ formatted data to the
descrambler.
4.2.3 Signal Detect
The 100BASE-TX receiver includes a Serial to Parallel
converter which supplies 5-bit wide data symbols to the
PCS Rx state machine.
The signal detect function of the DP83848C is incorporated
to meet the specifications mandated by the ANSI FDDI TP-
4.2.6 Serial to Parallel
29
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DP83848C
4.2.7 Descrambler
4.2.10 100BASE-TX Link Integrity Monitor
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:
The 100 Base TX Link monitor ensures that a valid and stable link is established before enabling both the Transmit
and Receive PCS layer.
SD = ( UD ⊕ N )
UD = ( SD ⊕ N )
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.
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 code-groups within the 722 µs
period, the entire descrambler will be forced out of the current state of synchronization and reset in order to reacquire synchronization.
4.2.8 Code-group Alignment
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.
4.2.11 Bad SSD Detection
A Bad Start of Stream Delimiter (Bad SSD) is any transition
from consecutive idle code-groups to non-idle code-groups
which is not prefixed by the code-group pair /J/K.
If this condition is detected, the DP83848C 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.
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
DP83848C. This section focuses on the general 10BASE-T
system level operation.
4.3.1 Operational Modes
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.
The DP83848C has two basic 10BASE-T operational
modes:
— Half Duplex mode
— Full Duplex mode
Half Duplex Mode
4.2.9 4B/5B Decoder
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.
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In Half Duplex mode the DP83848C functions as a standard IEEE 802.3 10BASE-T transceiver supporting the
CSMA/CD protocol.
Full Duplex Mode
In Full Duplex mode the DP83848C is capable of simultaneously transmitting and receiving without asserting the
collision signal. The DP83848C's 10 Mb/s ENDEC is
designed to encode and decode simultaneously.
30
The smart squelch is responsible for determining when
valid data is present on the differential receive inputs. The
DP83848C 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.
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).
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
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.
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.
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.
>150 ns
<150 ns
VSQ+
VSQ+(reduced)
VSQ-(reduced)
VSQend of packet
start 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).
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.
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.
For 10 Mb/s Half Duplex operation, CRS is asserted during
either packet transmission or reception.
For 10 Mb/s Full Duplex operation, CRS is asserted only
during receive activity.
CRS is deasserted following an end of packet.
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.
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.
31
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DP83848C
4.3.2 Smart Squelch
DP83848C
4.3.6 Jabber Function
4.3.8 Transmit and Receive Filtering
The jabber function monitors the DP83848C'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.
External 10BASE-T filters are not required when using the
DP83848C, as the required signal conditioning is integrated into the device.
The Jabber function is only relevant in 10BASE-T mode.
4.3.9 Transmitter
Only isolation transformers and impedance matching resistors are required for the 10BASE-T transmit and receive
Once disabled by the Jabber function, the transmitter stays interface. The internal transmit filtering ensures that all the
disabled for the entire time that the ENDEC module's inter- harmonics in the transmit signal are attenuated by at least
nal transmit enable is asserted. This signal has to be de- 30 dB.
asserted for approximately 500 ms (the “unjab” time)
before the Jabber function re-enables the transmit outputs.
The encoder begins operation when the Transmit Enable
input (TX_EN) goes high and converts NRZ data to pre4.3.7 Automatic Link Polarity Detection and Correction emphasized Manchester data for the transceiver. For the
The DP83848C's 10BASE-T transceiver module incorpo- duration of TX_EN, the serialized Transmit Data (TXD) is
rates an automatic link polarity detection circuit. When encoded for the transmit-driver pair (PMD Output Pair).
three consecutive inverted link pulses are received, bad TXD must be valid on the rising edge of Transmit Clock
(TX_CLK). Transmission ends when TX_EN deasserts.
polarity is reported.
The last transition is always positive; it occurs at the center
A polarity reversal can be caused by a wiring error at either of the bit cell if the last bit is a one, or at the end of the bit
end of the cable, usually at the Main Distribution Frame cell if the last bit is a zero.
(MDF) or patch panel in the wiring closet.
The bad polarity condition is latched in the 10BTSCR register. The DP83848C'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.
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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.
32
DP83848C
5.0 Design Guidelines
5.1 TPI Network Circuit
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.
Pulse H1102
Pulse H2019
Pulse J0011D21
Pulse J0011D21B
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
49.9Ω
RJ45
1:1
0.1µF
T1
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
33
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DP83848C
5.2 ESD Protection
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.
See Section 8.0 for ESD rating.
capacitor values will vary with the crystal vendors; check
with the vendor for the recommended loads.
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.
Specification for 25 MHz crystal are listed in Table 9.
5.3 Clock In (X1) Requirements
The DP83848C supports an external CMOS level oscillator
source or a crystal resonator device.
X1
Oscillator
If an external clock source is used, X1 should be tied to the
clock source and X2 should be left floating.
X2
R1
Specifications for CMOS oscillators: 25 MHz in MII Mode
and 50 MHz in RMII Mode are listed in Table 6 and Table 8.
CL1
CL2
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
Figure 12. Crystal Oscillator Circuit
Table 6. 25
Table 7. 25 MHz Oscillator Specification
Parameter
Min
Frequency
Typ
Max
25
Units
Condition
MHz
Frequency
+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
Tolerance
Frequency
Stability
Symmetry
40%
60%
1 This
Duty Cycle
limit is provided as a guideline for component selection and to guaranteed by production testing.
Refer to AN-1548, “PHYTER 100 Base-TX Reference Clock Jitter Tolerance,“ for details on jitter performance.
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34
Parameter
Min
Typ
Frequency
Max
Units
50
Condition
MHz
Frequency
+50
ppm
Operational
Tolerance
Temperature
Frequency
+50
ppm
Operational
Temperature
Rise / Fall Time
6
nsec
20% - 80%
Jitter
8001
psec
Short term
Jitter
8001
psec
Long term
Stability
Symmetry
1
40%
60%
Duty Cycle
This limit is provided as a guideline for component selection and to guaranteed by production testing.
Refer to AN-1548, “PHYTER 100 Base-TX Reference Clock Jitter Tolerance,“ for details on jitter performance.
Table 9. 25 MHz Crystal Specification
Parameter
Min
Typ
Frequency
Max
25
Units
Condition
MHz
Frequency
+50
ppm
Operational Temperature
+50
ppm
1 year aging
40
pF
Tolerance
Frequency
Stability
Load Capacitance
25
5.4 Power Feedback Circuit
To ensure correct operation for the DP83848C, parallel
caps with values of 10 µF (Tantalum) and 0.1 µF should be
placed close to pin 23 (PFBOUT) of the device.
Pin 18 (PFBIN1) and pin 37 (PFBIN2) must be connected
to pin 23 (PFBOUT), each pin requires a small capacitor
(.1 µF). See Figure 13 below for proper connections.
The Power Down and Interrupt functions are multiplexed
on pin 7 of the device. By default, this pin functions as a
power down input and the interrupt function is disabled.
Setting bit 0 (INT_OE) of MICR (0x11h) will configure the
pin as an active low interrupt output.
5.5.1 Power Down Control Mode
Pin 23 (PFBOUT)
10 µF +
Pin 18 (PFBIN1)
Pin 37 (PFBIN2)
5.5 Power Down/Interrupt
.1 µF
.1 µF
.1 µF
The PWR_DOWN/INT pin can be asserted low to put the
device in a Power Down mode. This is equivalent to setting
bit 11 (Power Down) in the Basic Mode Control Register,
BMCR (0x00h). An external control signal can be used to
drive the pin low, overcoming the weak internal pull-up
resistor. Alternatively, the device can be configured to initialize into a Power Down state by use of an external pulldown resistor on the PWR_DOWN/INT pin. Since the
device will still respond to management register accesses,
setting the INT_OE bit in the MICR register will disable the
PWR_DOWN/INT input, allowing the device to exit the
Power Down state.
Figure 13. Power Feeback Connection
35
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DP83848C
Table 8. 50 MHz Oscillator Specification
DP83848C
5.5.2 Interrupt Mechanisms
The interrupt function is controlled via register access. All
interrupt sources are disabled by default. Setting bit 1
(INTEN) of MICR (0x11h) will enable interrupts to be output, dependent on the interrupt mask set in the lower byte
of the MISR (0x12h). The PWR_DOWN/INT pin is asynchronously asserted low when an interrupt condition
occurs. The source of the interrupt can be determined by
reading the upper byte of the MISR. One or more bits in the
MISR will be set, denoting all currently pending interrupts.
Reading of the MISR clears ALL pending interrupts.
When PWR_DOWN/INT pin asserts low, user would read
the MISR register to see if the ED_INT or LINK_INT bits
are set, i.e. which source caused the interrupt. After reading the MISR, the interrupt bits should clear and the
PWR_DOWN/INT pin will deassert.
5.6 Energy Detect Mode
When Energy Detect is enabled and there is no activity on
the cable, the DP83848C will remain in a low power mode
while monitoring the transmission line. Activity on the line
Example: To generate an interrupt on a change of link sta- will cause the DP83848C to go through a normal power up
tus or on a change of energy detect power state, the steps sequence. Regardless of cable activity, the DP83848C will
would be:
occasionally wake up the transmitter to put ED pulses on
the line, but will otherwise draw as little power as possible.
— Write 0003h to MICR to set INTEN and INT_OE
Energy detect functionality is controlled via register Energy
— Write 0060h to MISR to set ED_INT_EN and
Detect Control (EDCR), address 0x1Dh.
LINK_INT_EN
— Monitor PWR_DOWN/INT pin
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36
The DP83848C 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.
6.1 Hardware Reset
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 con-
figuration values will be re-latched into the device (similar
to the power-up/reset operation).
6.2 Software Reset
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 DP83848C.
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DP83848C
6.0 Reset Operation
DP83848C
7.0 Register Block
Table 10. Register Map
Offset
Access
Tag
Description
Hex
Decimal
00h
0
RW
BMCR
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
MICR
MII Interrupt Control Register
12h
18
RO
MISR
MII Interrupt Status Register
13h
19
RW
RESERVED
RESERVED
14h
20
RO
FCSCR
False Carrier Sense Counter Register
15h
21
RO
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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38
39
11h
12h
13h
14h
15h
16h
MII Interrupt Control Register
MII Interrupt Status and Misc. Control Register
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
MISR
MICR
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
ED_INT
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
LINK_IN
T
Reserved
Rx Err
Latch
BYP_4B
5B
Reserved
Reserved
Reserved
SPD_IN
T
Reserved
Polarity
Status
Reserved
Reserved
Reserved
Reserved
DUP_IN
T
Reserved
False
Carrier
Sense
Reserved
Descram
Lock
Reserved
CODE
Reserved
Code
T4
T4
VNDR_
MDL
Reserved
Page
Receive
Reserved
CODE
Reserved
Code
TX_FD
TX_FD
VNDR_
MDL
TQ_EN
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Jabber
Detect
Reserved
CODE
Reserved
Code
10
10
VNDR_
MDL
MDL_
REV
MDL_
REV
MDL_
REV
MDL_
REV
Reserved
AutoNeg
Complete
Reserved
CODE
PDF
Code
Reserved
Loopback Status
Reserved
CODE
LP_NP_
ABLE
Code
TINT
Duplex
Status
Reserved
CODE
NP_
ABLE
Code
INTEN
Speed
Status
Reserved
CODE
PAGE_
RX
Code
INT_OE
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
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
UNMSK_ UNMSK_ UNMSK_ UNMSK_ UNMSK_ UNMSK_ UNMSK_
ED
LINK
JAB
RF
ANC
FHF
RHF
Reserved
Remote
Fault
Reserved
CODE
Reserved
Code
10_FD
10_FD
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
MII Interrupt
Reserved
CODE
Reserved
Code
TX
TX
VNDR_
MDL
SD_FOR
SD_
DESC_T
CE_PMA OPTION
IME
Reserved
Reserved
Reserved
ANC_IN FHF_INT RHF_IN
T
T
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
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
DP83848C
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40
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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
10BT_S
ERIAL
MDIX_E
N
Reserved
Reserved
Reserved
Reserved
Reserved
REJECT
100
BASE T
ERROR
RANGE
BIST_fe
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
Bit 6
Reserved
Reserved
Bit 5
Reserved
Reserved
Reserved
Reserved
FORC_
LINK_10
Bit 3
Bit 2
Bit 1
Bit 0
Reserved
BIST_C
ONT_M
ODE
Reserved
Reserved
CDPattE
N_10
POLARITY
PHY
ADDR
Reserved
Reserved
Reserved
PHY
ADDR
Reserved
10Meg_
Patt_Ga
p
Reserved
PHY
ADDR
PHY
ADDR
Reserved
CDPattSel
Reserved
CDPattSel
HEART_ JABBER
DIS
_DIS
PHY
ADDR
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
Bit 4
RMII_RE RX_OVF RX_UNF RX_RD_ RX_RD_
V1_0
_STS
_STS
PTR[1]
PTR[0]
DRV_SP DRV_LN DRV_AC SPDLED LNKLED ACTLED
DLED
KLED
TLED
RMII_M
ODE
BIST_ BIST_ST BP_STR
LED_
LED_
STATUS
ART
ETCH CNFG[1] CNFG[0]
Reserved
Reserved
ERROR SQUELC SQUELC SQUELC LOOPBA
RANGE
H
H
H
CK_10_
DIS
FORCE_ PAUSE_ PAUSE_
MDIX
RX
TX
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
ERIAL
PHYCR
LEDCR
RBR
Table 11. Register Table
DP83848C
DP83848C
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
41
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DP83848C
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
Strap, 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
Strap, 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. This bit is OR’d with the input
from the PWR_DOWN/INT pin. When the active low
PWR_DOWN/INT pin is asserted, this bit will be set.
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
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
Strap, RW
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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DP83848C
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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DP83848C
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
14
100BASE-TX
1, RO/P
Description
100BASE-T4 Capable:
0 = Device not able to perform 100BASE-T4 mode.
Full Duplex
13
100BASE-TX
1 = Device able to perform 100BASE-TX in full duplex mode.
1, RO/P
Half Duplex
12
10BASE-T
100BASE-TX Full Duplex Capable:
100BASE-TX Half Duplex Capable:
1 = Device able to perform 100BASE-TX in half duplex mode.
1, RO/P
Full Duplex
10BASE-T Full Duplex Capable:
1 = Device able to perform 10BASE-T in full duplex mode.
11
10BASE-T
1, RO/P
10:7
RESERVED
0, RO
RESERVED: Write as 0, read as 0.
6
MF Preamble
1, RO/P
Preamble suppression Capable:
Half Duplex
10BASE-T Half Duplex Capable:
1 = Device able to perform 10BASE-T in half duplex mode.
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.
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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DP83848C
The PHY Identifier Registers #1 and #2 together form a unique identifier for the DP83848C. 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.
DP83848C
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
Strap, 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
Strap, 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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This register contains the advertised abilities of the Link Partner as received during Auto-Negotiation. The content
changes after the successful auto-negotiation if Next-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
RESERVED for Future IEEE use:
Write as 0, read as 0.
11
ASM_DIR
0, RO
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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DP83848C
7.1.6 Auto-Negotiation Link Partner Ability Register (ANLPAR) (BASE Page)
DP83848C
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
15:5
RESERVED
0, RO
RESERVED: Writes ignored, Read as 0.
Description
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.
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DP83848C
Table 19. Auto-Negotiate Expansion Register (ANER), address 0x06 (Continued)
DP83848C
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
MII Interrupt
0, RO
MII Interrupt Pending:
1 = Indicates that an internal interrupt is pending. Interrupt source
can be determined by reading the MISR Register (0x12h). Reading
the MISR will clear the Interrupt.
0= No interrupt pending.
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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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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DP83848C
Table 21. PHY Status Register (PHYSTS), address 0x10 (Continued)
DP83848C
7.2.2 MII Interrupt Control Register (MICR)
This register implements the MII Interrupt PHY Specific Control register. Sources for interrupt generation include: Energy
Detect State Change, Link State Change, Speed Status Change, Duplex Status Change, Auto-Negotiation Complete or
any of the counters becoming half-full. The individual interrupt events must be enabled by setting bits in the MII Interrupt Status and Event Control Register (MISR).
Table 22. MII Interrupt Control Register (MICR), address 0x11
Bit
Bit Name
Default
Description
15:3
Reserved
0, RO
Reserved: Write ignored, Read as 0
2
TINT
0, RW
Test Interrupt:
Forces the PHY to generate an interrupt to facilitate interrupt testing. Interrupts will continue to be generated as long as this bit remains set.
1 = Generate an interrupt
0 = Do not generate interrupt
1
INTEN
0, RW
Interrupt Enable:
Enable interrupt dependent on the event enables in the MISR register.
1 = Enable event based interrupts
0 = Disable event based interrupts
0
INT_OE
0, RW
Interrupt Output Enable:
Enable interrupt events to signal via the PWR_DOWN/INT pin by
configuring the PWR_DOWN/INT pin as an output.
1 = PWR_DOWN/INT is an Interrupt Output
0 = PWR_DOWN/INT is a Power Down Input
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This register contains event status and enables for the interrupt function. If an event has occurred since the last read of
this register, the corresponding status bit will be set. If the corresponding enable bit in the register is set, an interrupt
will be generated if the event occurs. The MICR register controls must also be set to allow interrupts. The status indications in this register will be set even if the interrupt is not enabled
Table 23. MII Interrupt Status and Misc. Control Register (MISR), address 0x12
15
Reserved
0, RO
14
ED_INT
0, RO/COR
RESERVED: Writes ignored, Read as 0
Energy Detect interrupt:
1 = Energy detect interrupt is pending and is cleared by the current
read.
0 = No energy detect interrupt pending.
13
LINK_INT
0, RO/COR
Change of Link Status interrupt:
1 = Change of link status interrupt is pending and is cleared by the
current read.
0 = No change of link status interrupt pending.
12
SPD_INT
0, RO/COR
Change of speed status interrupt:
1 = Speed status change interrupt is pending and is cleared by the
current read.
0 = No speed status change interrupt pending.
11
DUP_INT
0, RO/COR
Change of duplex status interrupt:
1 = Duplex status change interrupt is pending and is cleared by
the current read.
0 = No duplex status change interrupt pending.
10
ANC_INT
0, RO/COR
Auto-Negotiation Complete interrupt:
1 = Auto-negotiation complete interrupt is pending and is cleared
by the current read.
0 = No Auto-negotiation complete interrupt pending.
9
FHF_INT
0, RO/COR
False Carrier Counter half-full interrupt:
1 = False carrier counter half-full interrupt is pending and is
cleared by the current read.
0 = No false carrier counter half-full interrupt pending.
8
RHF_INT
0, RO/COR
Receive Error Counter half-full interrupt:
1 = Receive error counter half-full interrupt is pending and is
cleared by the current read.
0 = No receive error carrier counter half-full interrupt pending.
7
RESERVED
0, RO
RESERVED: Writes ignored, Read as 0
6
ED_INT_EN
0, RW
Enable Interrupt on energy detect event
5
LINK_INT_EN
0, RW
Enable Interrupt on change of link status
4
SPD_INT_EN
0, RW
Enable Interrupt on change of speed status
3
DUP_INT_EN
0, RW
Enable Interrupt on change of duplex status
2
ANC_INT_EN
0, RW
Enable Interrupt on Auto-negotiation complete event
1
FHF_INT_EN
0, RW
Enable Interrupt on False Carrier Counter Register half-full event
0
RHF_INT_EN
0, RW
Enable Interrupt on Receive Error Counter Register half-full event
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DP83848C
7.2.3 MII Interrupt Status and Misc. Control Register (MISR)
DP83848C
7.2.4 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 24. 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).
7.2.5 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 25. 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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DP83848C
7.2.6 100 Mb/s PCS Configuration and Status Register (PCSR)
Table 26. 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.
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DP83848C
7.2.7 RMII and Bypass Register (RBR)
This register configures the RMII Mode of operation. When RMII mode is disabled, the RMII functionality is bypassed.
Table 27. 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]
01, 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 values 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)
7.2.8 LED Direct Control Register (LEDCR)
This register provides the ability to directly control any or all LED outputs. It does not provide read access to LEDs.
Table 28. LED Direct Control Register (LEDCR), address 0x18
Bit
Bit Name
Default
Description
15:6
RESERVED
0, RO
RESERVED: Writes ignored, read as 0.
5
DRV_SPDLED
0, RW
1 = Drive value of SPDLED bit onto LED_SPD output
0 = Normal operation
4
DRV_LNKLED
0, RW
1 = Drive value of LNKLED bit onto LED_LNK output
0 = Normal operation
3
DRV_ACTLED
0, RW
1 = Drive value of ACTLED bit onto LED_ACT/COL output
2
SPDLED
0, RW
Value to force on LED_SPD output
1
LNKLED
0, RW
Value to force on LED_LNK output
0
ACTLED
0, RW
Value to force on LED_ACT/COL output
0 = Normal operation
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56
DP83848C
7.2.9 PHY Control Register (PHYCR)
Table 29. 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 LEDs will reflect the internal value.
1 = Bypass LED stretching.
0 = Normal operation.
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DP83848C
Table 29. PHY Control Register (PHYCR), address 0x19 (Continued)
Bit
Bit Name
Default
6
LED_CNFG[1]
0, RW
5
LED_CNFG[0]
Strap, RW
Description
LEDs Configuration
LED_CNFG[1]
LED_ CNFG[0]
Don’t care
Mode Description
1
Mode 1
0
0
Mode 2
1
0
Mode 3
In Mode 1, LEDs are configured as follows:
LED_LINK = ON for Good Link, OFF for No Link
LED_SPEED = ON in 100 Mb/s, OFF in 10 Mb/s
LED_ACT/COL = ON for Activity, OFF for No Activity
In Mode 2, LEDs are configured as follows:
LED_LINK = ON for good Link, BLINK for Activity
LED_SPEED = ON in 100 Mb/s, OFF in 10 Mb/s
LED_ACT/COL = ON for Collision, OFF for No Collision
Full Duplex, OFF for Half Duplex
In Mode 3, LEDs are configured as follows:
LED_LINK = ON for Good Link, BLINK for Activity
LED_SPEED = ON in 100 Mb/s, OFF in 10 Mb/s
LED_ACT/COL = ON for Full Duplex, OFF for Half Duplex
4:0
PHYADDR[4:0]
Strap, RW
PHY Address: PHY address for port.
7.2.10 10Base-T Status/Control Register (10BTSCR)
Table 30. 10Base-T Status/Control Register (10BTSCR), address 0x1A
Bit
Bit Name
Default
15
10BT_SERIAL
Strap, RW
Description
10Base-T Serial Mode (SNI)
1 = Enables 10Base-T Serial Mode
0 = Normal Operation
Places 10 Mb/s transmit and receive functions in Serial Network
Interface (SNI) Mode of operation. Has no effect on 100 Mb/s
operation.
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].
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58
DP83848C
Table 30. 10Base-T Status/Control Register (10BTSCR), address 0x1A
Bit
Bit Name
Default
7
LP_DIS
0, RW
Description
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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DP83848C
7.2.11 CD Test and BIST Extensions Register (CDCTRL1)
Table 31. CD Test and BIST Extensions Register (CDCTRL1), address 0x1B
Bit
Bit Name
Default
15:8
BIST_ERROR_CO
UNT
0, RO
RESERVED
0, RW
7:6
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.
5
4
BIST_CONT_MOD
E
0, RW
CDPATTEN_10
0, RW
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
2
10MEG_PATT_GA
P
0, RW
RESERVED:
Must be zero.
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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DP83848C
7.2.12 Energy Detect Control (EDCR)
Table 32. 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.
In managed applications, this bit can be set after clearing the Energy Detect interrupt to control the timing of changing the power
state.
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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DP83848C
8.0 Electrical Specifications
Note: All parameters are guaranteed by test, statistical analysis or design.
Absolute Maximum Ratings
Recommended Operating Conditions
Supply Voltage (VCC)
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)
92 °C
Max. die temperature (Tj)
150 °C
Lead Temp. (TL)
(Soldering, 10 sec.)
260 °C
ESD Rating
(RZAP = 1.5k, CZAP = 100 pF)
4.0 kV
267 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.
-65oC to 150°C
Max case temp for TA = 70°C
0 to 70 °C
Thermal Characteristic
Max
Units
Theta Junction to Case (Tjc)
28.7
°C / W
Theta Junction to Ambient (Tja) degrees Celsius/Watt - No Airflow @ 1.0W
83.6
°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
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
IOZ
I/O,
O
TRI-STATE
Leakage
VOUT = VCC
Vcc - 0.5
µA
1.05
V
+2
%
2.8
V
PMD Output
Pair
100M Transmit
Voltage
VTPTDsym
PMD Output
Pair
100M Transmit
Voltage Symmetry
VTPTD_10
PMD Output
Pair
10M Transmit
Voltage
CIN1
I
CMOS Input
Capacitance
5
pF
COUT1
O
CMOS Output
Capacitance
5
pF
SDTHon
PMD Input
Pair
2.2
100BASE-TX
Signal detect turnon threshold
1
+ 10
VTPTD_100
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0.95
V
2.5
1000
62
mV diff pk-pk
Pin Types
Parameter
Conditions
Min
Typ
Max
SDTHoff
PMD Input
Pair
100BASE-TX
Signal detect turnoff threshold
VTH1
PMD Input
Pair
10BASE-T Receive Threshold
Idd100
Supply
100BASE-TX
(Full Duplex)
81
mA
Idd10
Supply
10BASE-T
(Full Duplex)
92
mA
Idd
Supply
Power Down
Mode
14
mA
200
mV diff pk-pk
585
63
Units
mV
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DP83848C
Symbol
DP83848C
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
Dual Function Pins
Become Enabled As Outputs
Parameter
Description
output
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
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50
64
ns
DP83848C
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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DP83848C
8.2.3 MII Serial Management Timing
MDC
T2.3.1
T2.3.4
MDIO (output)
MDC
T2.3.2
Valid Data
MDIO (input)
Parameter
T2.3.3
Description
Notes
Min
Typ
Max
Units
30
ns
T2.3.1
MDC to MDIO (Output) Delay Time
0
T2.3.2
MDIO (Input) to MDC Setup Time
10
ns
T2.3.3
MDIO (Input) to MDC Hold Time
10
ns
T2.3.4
MDC Frequency
2.5
25
MHz
8.2.4 100 Mb/s MII Transmit Timing
T2.4.1
T2.4.1
TX_CLK
T2.4.3
T2.4.2
TXD[3:0]
TX_EN
Parameter
Valid Data
Min
Typ
T2.4.1
TX_CLK High/Low Time
Description
100 Mb/s Normal mode
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
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Notes
66
Max Units
24
ns
DP83848C
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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DP83848C
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.
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68
DP83848C
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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DP83848C
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
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70
DP83848C
8.2.11 10 Mb/s MII Transmit Timing
T2.11.1
T2.11.1
TX_CLK
T2.11.3
T2.11.2
TXD[3:0]
TX_EN
Parameter
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
T2.12.3
T2.12.2
RXD[3:0]
RX_DV
Parameter
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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DP83848C
8.2.13 10 Mb/s Serial Mode Transmit Timing
T2.13.2
T2.13.1
TX_CLK
T2.13.4
T2.13.3
TXD[0]
TX_EN
Parameter
Valid Data
Description
Notes
Min
Typ
Max Units
T2.13.1
TX_CLK High Time
10 Mb/s Serial mode
20
25
30
ns
T2.13.2
TX_CLK Low Time
10 Mb/s Serial mode
70
75
80
ns
T2.13.3
TXD_0, TX_EN Data Setup to TX_CLK rise
10 Mb/s Serial mode
25
ns
T2.13.4
TXD_0, TX_EN Data Hold from TX_CLK rise
10 Mb/s Serial mode
0
ns
8.2.14 10 Mb/s Serial Mode Receive Timing
T2.14.1
T2.14.1
RX_CLK
T2.14.2
RXD[0]
RX_DV
Parameter
Valid Data
Description
T2.14.1
RX_CLK High/Low Time
T2.14.2
RX_CLK fall to RXD_0, RX_DV Delay
Notes
10 Mb/s Serial mode
Min
Typ
Max
Units
35
50
65
ns
10
ns
-10
Note: RX_CLK may be held high 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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DP83848C
8.2.15 10BASE-T Transmit Timing (Start of Packet)
TX_CLK
TX_EN
TXD
T2.15.2
PMD Output Pair
T2.15.1
Parameter
T2.15.1
Description
Notes
Transmit Output Delay from the
Min
Typ
Max
Units
10 Mb/s MII mode
3.5
bits
10 Mb/s Serial mode
3.5
bits
Falling Edge of TX_CLK
T2.15.2
Transmit Output Delay from the
Rising Edge of TX_CLK
Note: 1 bit time = 100 ns in 10Mb/s.
8.2.16 10BASE-T Transmit Timing (End of Packet)
TX_CLK
TX_EN
0
PMD Output Pair
T2.16.1
0
T2.16.2
PMD Output Pair
Parameter
T2.16.1
1
1
Description
Notes
End of Packet High Time
Min
Typ
250
300
Max
Units
ns
250
300
ns
(with ‘0’ ending bit)
T2.16.2
End of Packet High Time
(with ‘1’ ending bit)
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DP83848C
8.2.17 10BASE-T Receive Timing (Start of Packet)
1st SFD bit decoded
1
0
1
0
1
0
1
0
1
0
1
1
TPRD±
T2.17.1
CRS
RX_CLK
T2.17.2
RX_DV
T2.17.3
0000
RXD[3:0]
Parameter
Preamble
Description
SFD
Notes
Min
Data
Typ
Max
Units
1000
ns
T2.17.1
Carrier Sense Turn On Delay (PMD
Input Pair to CRS)
630
T2.17.2
RX_DV Latency
10
bits
T2.17.3
Receive Data Latency
8
bits
Measurement shown from SFD
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.
8.2.18 10BASE-T Receive Timing (End of Packet)
1
0
1
IDLE
PMD Input Pair
RX_CLK
T2.18.1
CRS
Parameter
T2.18.1
Description
Notes
Carrier Sense Turn Off Delay
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74
Min
Typ
Max
Units
1.0
µs
DP83848C
8.2.19 10 Mb/s Heartbeat Timing
TX_EN
TX_CLK
T2.19.2
T2.19.1
COL
Parameter
Description
Notes
Min
Typ
Max
Units
T2.19.1
CD Heartbeat Delay
All 10 Mb/s modes
1200
ns
T2.19.2
CD Heartbeat Duration
All 10 Mb/s modes
1000
ns
8.2.20 10 Mb/s Jabber Timing
TXE
T2.20.1
T2.20.2
PMD Output Pair
COL
Parameter
Description
Notes
Min
Typ
Max
Units
T2.20.1
Jabber Activation Time
85
ms
T2.20.2
Jabber Deactivation Time
500
ms
75
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DP83848C
8.2.21 10BASE-T Normal Link Pulse Timing
T2.21.2
T2.21.1
Normal Link Pulse(s)
Parameter
Description
Notes
Min
Typ
Max
Units
T2.21.1
Pulse Width
100
ns
T2.21.2
Pulse Period
16
ms
Note: These specifications represent transmit timings.
8.2.22 Auto-Negotiation Fast Link Pulse (FLP) Timing
T2.22.2
T2.22.3
T2.22.1
T2.22.1
Fast Link Pulse(s)
clock
pulse
data
pulse
clock
pulse
T2.22.5
T2.22.4
FLP Burst
Parameter
FLP Burst
Description
Notes
Min
Typ
Max
Units
T2.22.1
Clock, Data Pulse Width
100
ns
T2.22.2
Clock Pulse to Clock Pulse
Period
125
µs
T2.22.3
Clock Pulse to Data Pulse
Period
62
µs
T2.22.4
Burst Width
2
ms
T2.22.5
FLP Burst to FLP Burst Period
16
ms
Data = 1
Note: These specifications represent transmit timings.
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76
DP83848C
8.2.23 100BASE-TX Signal Detect Timing
PMD Input Pair
T2.23.1
T2.23.2
SD+ internal
Parameter
Description
Notes
Min
Typ
Max
Units
T2.23.1
SD Internal Turn-on Time
1
ms
T2.23.2
SD Internal Turn-off Time
350
µs
Max
Units
240
ns
Note: The signal amplitude on PMD Input Pair must be TP-PMD compliant.
8.2.24 100 Mb/s Internal Loopback Timing
TX_CLK
TX_EN
TXD[3:0]
CRS
T2.24.1
RX_CLK
RX_DV
RXD[3:0]
Parameter
T2.24.1
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.
77
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DP83848C
8.2.25 10 Mb/s Internal Loopback Timing
TX_CLK
TX_EN
TXD[3:0]
CRS
T2.25.1
RX_CLK
RX_DV
RXD[3:0]
Parameter
T2.25.1
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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78
Typ
Max
Units
2
µs
DP83848C
8.2.26 RMII Transmit Timing
T2.26.1
X1
T2.26.2
TXD[1:0]
TX_EN
T2.26.3
Valid Data
T2.26.4
PMD Output Pair
Parameter
Symbol
Description
Notes
Min
50 MHz Reference Clock
Typ
T2.26.1
X1 Clock Period
T2.26.2
TXD[1:0], TX_EN, Data Setup
to X1 rising
4
ns
T2.26.3
TXD[1:0], TX_EN, Data Hold
from X1 rising
2
ns
T2.26.4
X1 Clock to PMD Output Pair From X1 Rising edge to first bit of symbol
Latency
79
20
Max Units
17
ns
bits
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DP83848C
8.2.27 RMII Receive Timing
PMD Input Pair
IDLE
(J/K)
Data
Data
(TR)
T2.27.4
T2.27.5
X1
T2.27.1
T2.27.2
T2.27.3
T2.27.2
T2.27.2
RX_DV
CRS_DV
T2.27.2
RXD[1:0]
RX_ER
Parameter
Description
Notes
Min
50 MHz Reference Clock
Typ
Max
20
Units
T2.27.1
X1 Clock Period
T2.27.2
RXD[1:0], CRS_DV, RX_DV,
and RX_ER output delay from
X1 rising
T2.27.3
CRS ON delay
From JK symbol on PMD Receive Pair to
initial assertion of CRS_DV
18.5
bits
T2.27.4
CRS OFF delay
From TR symbol on PMD Receive Pair to
initial deassertion of CRS_DV
27
bits
T2.27.5
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 why. 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.
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80
DP83848C
8.2.28 Isolation Timing
Clear bit 10 of BMCR
(return to normal operation
from Isolate mode)
T2.28.1
H/W or S/W Reset
(with PHYAD = 00000)
T2.28.2
MODE
NORMAL
ISOLATE
Max
Units
T2.28.1
Parameter
From software clear of bit 10 in
the BMCR register to the transition from Isolate to Normal Mode
Description
Notes
Min
Typ
100
µs
T2.28.2
From Deassertion of S/W or H/W
Reset to transition from Isolate to
Normal mode
500
µs
Max
Units
8.2.29 25 MHz_OUT Timing
X1
T2.29.2
T2.29.1
T2.29.1
25 MHz_OUT
Parameter
T2.29.1
T2.29.2
Description
Notes
25 MHz_OUT High/Low Time
25 MHz_OUT propagation delay
Min
Typ
MII mode
20
ns
RMII mode
10
ns
Relative to X1
8
ns
Note: 25 MHz_OUT characteristics are dependent upon the X1 input characteristics.
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DP83848C
8.2.30 100 Mb/s X1 to TX_CLK Timing
X1
T2.30.1
TX_CLK
Parameter
T2.30.1
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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82
DP83848C
Notes:
83
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DP83848C PHYTER® — Commercial Temperature Single Port 10/100 Mb/s Ethernet Physical Layer Transceiver
9.0 Physical Dimensions
inches (millimeters) unless otherwise noted
Lead Quad Frame Package (LQFP)
NS Package Number VBH48A
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