DP8573AVNOPB - NATIONAL SEMICONDUCTOR

DP83843

DP83843 PHYTER

Literature Number: SNLS021A

DP83843BVJE PHYTER

July 1999

DP83843BVJE PHYTER

General Description

TheDP83843BVJEisafullfeaturePhysicalLayerdevice

withintegratedPMDsublayerstosupportboth10BASE-T

and 100BASE-X Ethernet protocols.

ThisVLSIdeviceisdesignedforeasyimplementationof

10/100Mb/sEthernetLANs.ItinterfacesdirectlytoTwisted

Pairmediathroughanexternaltransformerortoﬁber

mediaviaindustrystandardelectrical/opticalﬁberPMD

transceivers.Thisdevicealsointerfacesdirectlytothe

MAClayerthroughtheIEEE802.3ustandardMediaInde-

pendentInterface(MII),ensuringinteroperabilitybetween

products from different vendors.

TheDP83843isdesignedwithNationalSemiconductor's

advancedCMOSprocess.Itssystemarchitectureisbased

ontheintegrationofseveralofNational'sindustryproven

core technologies:

—IEEE 802.3 ENDEC with AUI/10BASE-T transceiver

module to provide the 10 Mb/s functions

—ClockRecovery/GeneratorModulesfromNational'sFast

Ethernet and FDDI products

—FDDI Stream Cipher scrambler/descrambler for

TP-PMD

—100BASE-Xphysicalcodingsub-layer(PCS)andcontrol

logicthatintegratesthecoremodulesintoadualspeed

Ethernet physical layer controller

—ANSI X3T12 Compliant TP-PMD Transceiver

technology with Baseline Wander (BLW) compensation

System Diagram

ThunderLAN® is a registered trademark of Texas Instruments.

TWISTER™ is a trademark of National Semiconductor Corporation.

TRI-STATE® is a registered trademark of National Semiconductor Corporation.

10 AND/OR 100 Mb/s

ETHERNET MAC OR

100Mb/s REPEATER DP83843

10/100 Mb/s

ETHERNET PHYSICAL LAYER

STATUS

LEDS

MAGNETICS

RJ-45 10BASE-T

100BASE-TX

MII

10BASE-T or

CONTROLLER

100BASE-TX

100BASE-FX/

CLOCK

25 MHz

AUI

Features

—IEEE 802.3 ENDEC with AUI/10BASE-T transceivers

and built-in filters

—IEEE 802.3u 100BASE-TX compatible - directly drives

standard Category 5 UTP, no need for external

100BASE-TX transceiver

—Fully Integrated and fully compliant ANSI X3.263 TP-

PMD physical sublayer which includes adaptive equal-

ization and BLW compensation

—IEEE802.3u100BASE-FXcompatible-connectsdirect-

ly to industry standard Electrical/Optical transceivers

—IEEE 802.3u Auto-Negotiation for automatic speed se-

lection

—IEEE 802.3u compatible Media Independent Interface

(MII) with Serial Management Interface

—Integrated high performance 100 Mb/s clock recovery

circuitry requiring no external filters

—Full Duplex support for 10 and 100 Mb/s data rates

—MII Serial 10 Mb/s mode

—Fully configurable node/switch and 100Mb/s repeater

modes

—Programmableloopbackmodesforflexiblesystemdiag-

nostics

—Flexible LED support

—Single register access to complete PHY status

—MDIO interrupt support

—Individualized scrambler seed for 100BASE-TX applica-

tions using multiple PHYs

—Low power consumption for multi-port applications

—Small footprint 80-pin PQFP package

Obsolete

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Block Diagram

SERIAL

MANAGEMENT

MII

TX_CLK

TXD[3:0]

TX_ER

TX_EN

MDIO

MDC

COL

CRS

RX_ER

RX_DV

RXD[3:0]

RX_CL

MII INTERFACE/CONTROL

RX_EN

TRANSMIT CHANNELS &

100 MB/S 10 MB/S

NRZ TO

MANCHESTER

ENCODER

STATE MACHINES

TRANSMIT

FILTER

LINK PULSE

GENERATOR

4B/5B

ENCODER

SCRAMBLER

PARALLEL TO

SERIAL

NRZ TO NRZI

ENCODER

BINARY TO

MLT-3

ENCODER

10/100 COMMON

RECEIVE CHANNELS &

100 MB/S 10 MB/S

MANCHESTER

TO NRZ

DECODER

STATE MACHINES

RECEIVE

FILTER

LINK PULSE

DETECTOR

4B/5B

DECODER

DESCRAMBLER

SERIAL TO

PARALLEL

NRZI TO NRZ

DECODER

MLT-3 TO

10/100 COMMON

AUTO-NEGOTIATION

STATE MACHINE

FAR-END-FAULT

STATE MACHINE

REGISTERS

AUTO

100BASE-X

10BASE-T

MII

NODE/RPTR

PCS CONTROL

PHY ADDRESS

NEGOTIATION

CLOCK

RECOVERY

CLOCK

RECOVERY

CODE GROUP

ALIGNMENT

SMART

SQUELCH

RX_DATA

RX_CLK

RX_DATA

RX_CLK

TX_DATA TX_DATA TX_CLK

SYSTEM CLOCK

REFERENCE FXSD/CD+/−

TPRD+/−TPTD+/−

OUTPUT DRIVER

FXTD/AUITD+/−

INPUT BUFFER

BINARY

DECODER

ADAPTIVE

AND

BLW

COMP.

FXRD/AUIRD+/−

LED

DRIVERS

LEDS

HARDWARE

CONFIGURATION

PINS

TXAR100

(REPEATER,

SERIAL10, SYMBOL,

AN0, AN1,FXEN

PHYAD[4:0])

GENERATION

Obsolete

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Table of Contents
0 Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1 MII Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
2 10 Mb/s and 100 Mb/s PMD Interface . . . . . . . . . .6
3 Clock Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
4 Device Configuration Interface  . . . . . . . . . . . . . . .8
5 LED Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
6 PHY Address Interface  . . . . . . . . . . . . . . . . . . . .11
7 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
8 Power And Ground Pins  . . . . . . . . . . . . . . . . . . .12
9 Special Connect Pins . . . . . . . . . . . . . . . . . . . . . .12
0 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . .13
1 802.3u MII  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
2 100BASE-TX TRANSMITTER . . . . . . . . . . . . . . .15
3 100BASE-TX RECEIVER  . . . . . . . . . . . . . . . . . .18
4 10BASE-T TRANSCEIVER MODULE . . . . . . . . .22
5 100 BASE-FX  . . . . . . . . . . . . . . . . . . . . . . . . . . .24
6 AUI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
0  Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
1 Auto-Negotiation  . . . . . . . . . . . . . . . . . . . . . . . . .28
2 PHY Address and LEDs  . . . . . . . . . . . . . . . . . . .30
3 Half Duplex vs. Full Duplex  . . . . . . . . . . . . . . . . .31
4 100 Mb/s Symbol Mode . . . . . . . . . . . . . . . . . . . .32
5 100BASE-FX Mode . . . . . . . . . . . . . . . . . . . . . . .32
6 10 Mb/s Serial Mode  . . . . . . . . . . . . . . . . . . . . . .32
7 10 Mb/s AUI Mode . . . . . . . . . . . . . . . . . . . . . . . .32
8 Repeater vs. Node . . . . . . . . . . . . . . . . . . . . . . . .33
9 Isolate Mode  . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
10 Loopback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
0 Clock Architecture  . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
1 Clock Generation Module (CGM)  . . . . . . . . . . . .34
2 100BASE-X Clock Recovery Module . . . . . . . . . .36
3 10 Mb/s Clock Recovery Module . . . . . . . . . . . . .36
4 Reference Clock Connection Options  . . . . . . . . .36
0 Reset Operation  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
1 Power-up / Reset . . . . . . . . . . . . . . . . . . . . . . . . .37
2 Hardware Reset . . . . . . . . . . . . . . . . . . . . . . . . . .37
3 Software Reset  . . . . . . . . . . . . . . . . . . . . . . . . . .37
0 DP83843 Application  . . . . . . . . . . . . . . . . . . . . . . . . . .38
1 Typical Node Application . . . . . . . . . . . . . . . . . . .38
2 Power And Ground Filtering  . . . . . . . . . . . . . . . .38
3 Power Plane Considerations . . . . . . . . . . . . . . . .38
0 User Information  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
1 Link LED While in Force 100Mb/s Good Link . . . 42
2 False Link Indication When in Forced 10Mb/s  . . 42
3 10Mb/s Repeater Mode  . . . . . . . . . . . . . . . . . . . 42
4 Resistor Value Modifications  . . . . . . . . . . . . . . . 42
5 Magnetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
6 Next Page Toggle Bit Initialization  . . . . . . . . . . . 43
7 Base Page to Next Page Initial FLP Burst Spacing
43
8 100Mb/s FLP Exchange Followed by Quiet . . . . 43
9 Common Mode Capacitor for EMI improvement 44
10 BAD_SSD Event Lockup  . . . . . . . . . . . . . . . . . . 44
0 Register Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
1 Register Definitions  . . . . . . . . . . . . . . . . . . . . . . 45
0 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . 63
1 DC Electrical Specification . . . . . . . . . . . . . . . . . 64
2 CGM Clock Timing  . . . . . . . . . . . . . . . . . . . . . . 66
3 MII Serial Management AC Timing  . . . . . . . . . . 66
4 100 Mb/s AC Timing . . . . . . . . . . . . . . . . . . . . . . 67
5 10 Mb/s AC Timing . . . . . . . . . . . . . . . . . . . . . . . 74
6 Auto-Negotiation Fast Link Pulse (FLP) Timing 80
7 100BASE-X Clock Recovery Module (CRM) Timing
80
8 Reset Timing  . . . . . . . . . . . . . . . . . . . . . . . . . . 82
9 Loopback Timing  . . . . . . . . . . . . . . . . . . . . . . . 83
10 Isolation Timing  . . . . . . . . . . . . . . . . . . . . . . . . 84
0 Test Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
1 FXTD/AUITD+/- Outputs (sourcing AUI levels)  . 85
2 FXTD/AUITD+/- Outputs (sourcing PECL) . . . . . 85
3 CMOS Outputs (MII and LED)  . . . . . . . . . . . . . . 85
4 TPTD+/- Outputs (sourcing 10BASE-T) . . . . . . . 85
5 TPTD+/- Outputs (sourcing 100BASE-TX) . . . . . 85
6 Idd Measurement Conditions  . . . . . . . . . . . . . . . 85
0 Package Dimensions inches (millimeters) unless other-
wise noted  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Obsolete

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Connection Diagram

LED_RX/PHYAD[2]

LED_LINK/PHYAD[3]

LED_FDPOL/PHYAD[4]

MDC

IO_VSS3

IO_VDD3

CRS/SYMBOL

RX_EN

TX_ER

TX_EN

MDIO

TX_CLK

IO_VSS5

IO_VDD5

TXD[0]

TXD[1]

TXD[2]

TXD[3]

COL/FXEN

IO_VSS4

CD_GND1

CD_VDD0

TPTD+

TPTD-

SUB_GND2

TR_AGND

TW_AGND

TW_AVDD

TR_AVDD

TPRD-

SUB_GND1

TXAR100

TPRD+

CD_GND0

THIN/REPEATER

SERIAL10

CD_VDD1

VCM_CAP

BGREF

RXD[2]

RXD[3]

RESET

PCS_VSS

PCS_VDD

AN1

AN0

SPEED10

IO_VDD1

IO_VDD2

IO_VSS2

IO_VSS1

RXD[0]

RXD[1]

RX_DV

RX_ER

RX_CLK

TWREF

CPTW_DVSS

CPTW_DVDD

CP_AVDD

FXSD+/CD+

FXSD-/CD-

CP_AGND

AUIFX_VDD

AUIFX_GND

FXTD+/AUITD+

FXRD-/AUIRD-

FXRD+/AUIRD+

FXTD-/AUITD-

ATP_GND

LED_TX/PHYAD[1]

LED_COL/PHYAD[0]

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41

DP83843BVJE

PHYTER

Order Number DP83843BVJE

NS Package Number VJE80

Obsolete

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1.0 Pin Descriptions

The DP83843 pins are classiﬁed into the following interface

categories. Each interface is described in the sections that

follow.

— MII INTERFACE

— 10/100 Mb/s PMD INTERFACE

— CLOCK INTERFACE

— DEVICE CONFIGURATION INTERFACE

— LED INTERFACE

— PHY ADDRESS INTERFACE

— RESET

— POWER AND GROUND PINS

— SPECIAL CONNECT PINS

1.1 MII Interface

Signal Name Type Pin # Description

MDC I 35 MANAGEMENT DATA CLOCK: Synchronous clock to the MDIO management data in-

put/output serial interface which may be asynchronous to transmit and receive clocks.

The maximum clock rate is 2.5 MHz. There is no minimum clock rate.

MDIO I/O, Z 34 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 kΩpul-

lup resistor.

CRS

(SYMBOL) I/O, Z 22 CARRIER SENSE: This pin is asserted high to indicate the presence of carrier due to

receive or transmit activities in 10BASE-T or 100BASE-X Half Duplex modes.

In Repeater or Full Duplex mode, this pin is asserted high to indicate the presence of

carrier due only to receive activity.

In Symbol mode this pin indicates the signal detect status of the TP-PMD (active high).

COL

(FXEN) I/O, Z 21 COLLISION DETECT: Asserted high to indicate detection of collision condition (asser-

tion of CRS due to 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 (bit 7, register 18h), this

pin is also asserted for a duration of approximately 1 µs at the end of transmission to

indicate heartbeat (SQE test). During Repeater mode the heartbeat function is disabled.

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.

TX_CLK O, Z 33 TRANSMIT CLOCK: Transmit clock output from the DP83843:

25 MHz nibble transmit clock derived from Clock Generator Module's (CGM) PLL in

100BASE-TX mode.

2.5 MHz transmit clock in 10BASE-T Nibble mode.

10 MHz transmit clock in 10BASE-T Serial mode.

TXD[3]

TXD[2]

TXD[1]

TXD[0]

I28

TRANSMIT DATA: Transmit data MII input pins that accept nibble data during normal

nibble-wide MII operation at either 2.5 MHz (10BASE-T mode) or 25 MHz (100BASE-X

mode).

In 10 Mb/s Serial mode, the TXD[0] pin is used as the serial data input pin, and TXD[3:1]

are ignored.

TX_EN I 25 TRANSMIT ENABLE: Active high input indicates the presence of valid nibble data on

TXD[3:0] for both 100 Mb/s or 10 Mb/s nibble mode.

In 10 Mb/s Serial mode, active high indicates the presence of valid 10 Mb/s data on

TXD[0].

TX_ER

(TXD[4]) I24TRANSMIT ERROR: In 100 Mb/s mode, when this signal is high and TX_EN is active

the HALT symbol is substituted for the actual data nibble.

In 10 Mb/s mode, this input is ignored.

In Symbol mode (Symbol=0), TX_ER becomes the TXD [4] pin which is the MSB for the

transmit 5-bit data symbol.

RX_CLK O, Z 18 RECEIVE CLOCK: Provides the recovered receive clock for different modes of opera-

tion:

25 MHz nibble clock in 100 Mb/s mode

2.5 MHz nibble clock in 10 Mb/s nibble mode

10 MHz receive clock in 10 Mb/s serial mode

Obsolete

1.0 Pin Descriptions (Continued)

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1.2 10 Mb/s and 100 Mb/s PMD Interface

RXD[3]

RXD[2]

RXD[1]

RXD[0]

O, Z 12

RECEIVE DATA: Nibble wide receive data (synchronous to RX_CLK, 25 MHz for

100BASE-X mode, 2.5 MHz for 10BASE-T nibble mode). Data is driven on the falling

edge of RX_CLK.

In 10 Mb/s serial mode, the RXD[0] pin is used as the data output pin which is also

clocked out on the falling edge of RX_CLK. During 10 Mb/s serial mode RXD[3:1] pins

become don't cares.

RX_EN I 23 RECEIVE ENABLE: Active high enable for receive signals RXD[3:0], RX_CLK, RX_DV

and RX_ER. A low on this input places these output pins in the TRI-STATE mode. For

normal operation in a node or switch application, this pin should be pulled high. For op-

eration in a repeater application, this pin may be connected to a repeater controller.

RX_ER

(RXD[4]) O, Z 19 RECEIVE ERROR: Asserted high to indicate that an invalid symbol has been detected

within a received packet in 100 Mb/s mode.

In Symbol mode (Symbol = 0), RX_ER becomes RXD[4] which is the MSB for the re-

ceive 5-bit data symbol.

RX_DV O, Z 20 RECEIVEDATAVALID:AssertedhightoindicatethatvaliddataispresentonRXD[3:0]

for nibble mode and RXD[0] for serial mode. Data is driven on the falling edge of

RX_CLK.

This pin is not meaningful during Symbol mode.

Signal Name Type Pin # Description

TPTD-

TPTD+ O

(MLT-3

10BASE-T)

74 TRANSMIT DATA: Differential common output driver. This differential output

is configurable to either 10BASE-T or 100BASE-TX signaling:

10BASE-T: Transmission of Manchester encoded 10BASE-T packet data as

well as Link Pulses (including Fast Link Pulses for Auto-Negotiation purpos-

es.)

100BASE-TX: Transmission of ANSI X3T12 compliant MLT-3 data.

The DP83843 will automatically configure this common output driver for the

proper signal type as a result of either forced configuration or Auto-Negotia-

tion.

TPRD-

TPRD+ I

(MLT-3

10BASE-T)

67 RECEIVE DATA: Differential common input buffer. This differential input can

be configured to accept either 100BASE-TX or 10BASE-T signaling:

10BASE-T:ReceptionofManchester encoded10BASE-Tpacketdataaswell

as normal Link Pulses (including Fast Link Pulses for Auto-Negotiation pur-

poses.)

100BASE-TX: Reception of ANSI X3T12 compliant scrambled MLT-3 data.

The DP83843 will automatically configure this common input buffer to accept

the proper signal type as a result of either forced configuration or Auto-Nego-

tiation.

FXTD-/AUITD-

FXTD+/AUITD+ O

(PECL

AUI)

43 100BASE-FX or 10 Mb/s AUI TRANSMIT DATA: This configurable output

driver supports either 125 Mb/s PECL, for 100BASE-FX applications, or

10 Mb/s AUI signaling.

When configured as a 100BASE-FX transmitter this output sources

100BASE-FX standard compliant binary data for direct connection to an opti-

cal transceiver. This differential output is enabled only during 100BASE-FX

device configuration (see pin definition for FXEN.)

When configured as an AUI driver this output sources AUI compatible

Manchester encoded data to support typical 10BASE2 or 10BASE5 products.

Obsolete

1.0 Pin Descriptions (Continued)

7 www.national.com

FXRD-/AUIRD-

FXRD+/AUIRD+ I

(PECL

AUI)

50 100BASE-FX or 10 Mb/s AUI RECEIVE DATA: This configurable input buff-

er supports either 125 Mb/s PECL, for 100BASE-FX applications, or 10 Mb/s

AUI signaling.

When configured as a 100BASE-FX receiver this input accepts 100BASE-FX

standard compliant binary data direct from an optical transceiver. This differ-

entialinput isenabledonly during 100BASE-FXdevice configuration (seethe

pin definition for FXEN).

When configured as an AUI buffer this input receives AUI compatible

Manchester data to support typical 10BASE2 or 10BASE5 products.

FXSD-/CD-

FXSD+/CD+ I

(PECL

AUI)

48 SIGNAL DETECT or AUI COLLISION DETECT: Thisconfigurable inputbuff-

er supports either 125 Mb/s PECL, for 100BASE-FX applications, or 10 Mb/s

AUI signaling.

When configured as a 100BASE-FX receiver this input accepts indication

from the 100BASE-FX PMD transceiver upon detection of a receive signal

from the fiber media. This pin is only active during 100BASE-FX opera-

tion(see the pin definition for FXEN).

When configured as an AUI buffer this input receives AUI compatible

Manchester data to support typical 10BASE2 or 10BASE5 products.

THIN

(REPEATER) I/O, Z 63 THIN AUI MODE: This output allows for control of an external CTI coaxial

transceiver connected through the AUI. This pin is controlled by writing to bit

3 of the 10BTSCR register (address 18h). The THIN pin may also be used as

a user configurable output control pin.

TXAR100 I

(current

reference)

78 100 Mb/s TRANSMIT AMPLITUDE REFERENCE CONTROL: Reference

current allowing adjustment of the TPTD+/− output amplitude during

100BASE-TX operation.

By placing a resistor between this pin and ground or VCC, a reference current

is set up which dictates the output amplitude of the 100BASE-TX MLT-3

transmit signal. Connecting a resistor to VCC will increase the transmit ampli-

tude while connecting a resistor to ground will decrease the transmit ampli-

tude. While the value of the resistor should be evaluated on a case by case

bases, the DP83843 was designed to produce an amplitude close to the re-

quired range of 2V pk-pk differential ±5% as measured across TD+/− while

driving a typical 100Ωdifferential load without a resistor connected to this pin.

Therefore this pin is allowed to float in typical applications.

This current reference is only recognized during 100BASE-TX operation and

has no effect during100BASE-FX,10BASE-T, or AUI modes of operation.

TWREF I 60 TWISTERREFERENCE RESISTOR: Externalreferencecurrentadjustment,

viaa resistor toTW_AGND,whichcontrols theTP-PMDreceiverequalization

levels. The value of this resistor is 70k ± 1%.

BGREF I

(current

reference)

61 BANDGAP REFERENCE: External current reference resistor for internal

bandgap circuitry. The value of this resistor is 4.87k ± 1%.

VCM_CAP I 66 COMMON MODE BYPASS CAPACITOR: External capacitor to improve

common mode filtering for the receive signal. It is recommended that a

.0033µF in parallel with a .10µF capacitor be used, see Figure 23.

Signal Name Type Pin # Description

Obsolete

1.0 Pin Descriptions (Continued)

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1.3 Clock Interface

1.4 Device Configuration Interface

Signal Name Type Pin # Description

X1 I 9 CRYSTAL/OSCILLATOR INPUT: This pin is the primary clock reference input for

the DP83843 and must be connected to a 25 MHz 0.005% (50 ppm) clock source.

TheDP83843devicesupportseitheran external crystalresonatorconnectedacross

pins X1 and X2, or an external CMOS-level oscillator source connected to pin X1

only. For 100 Mb/s repeater applications, X1 should be tied to the common 25 MHz

transmit clock reference. Refer to section 4.4 for further detail relating to the clock

requirements of the DP83843. Refer to section 4.0 for clock source specifications.

X2 O 8 CRYSTAL/OSCILLATOR OUTPUT PIN: This pin is used in conjunction with the X1

pin to connect to an external 25 MHz crystal resonator device. This pin must be left

unconnected if an external CMOS oscillator clock source is utilized. For more infor-

mation see the definition for pin X1. Refer to section 2.8 for further detail.

Signal Name Type Pin # Description

AN0 I

(3-level) 4AN0: This is a three level input pin (1, M, 0) that works in conjunction with the AN1

pin to control the forced or advertised operating mode of the DP83843 according to

the following table. The value on this pin is set by connecting the input pin to GND

(0), VCC (1), or leaving it unconnected (M.) The unconnected state, M, refers to the

mid-level (VCC/2) set by internal resistors. The value set at this input is latched into

the DP83843 at power-up/reset.

AN1 I

(3-level) 3AN1: This is a three-level input pin (i.e., 1, M, 0) that works in conjunction with the

AN0 pin to control the forced or advertised operating mode of the DP83843 accord-

ing to the table given in the AN0 pin description above. The value on this pin is set

by connecting the input pin to GND (0), VCC (1), or leaving it unconnected (M.) The

value at this input is latched into the DP83843 at power-up, hardware or software

reset.

AN1 AN0 Forced Mode

0 M 10BASE-T, Half-Duplex without Auto-Negotiation

1 M 10BASE-T, Full Duplex without Auto-Negotiation

M 0 100BASE-X, Half-Duplex without Auto-Negotiation

M 1 100BASE-X, Full Duplex without Auto-Negotiation

AN1 AN0 Advertised Mode

M M Allcapable(i.e.Half-Duplex&FullDuplex for10BASE-Tand

100BASE-TX) advertised via Auto-Negotiation

0 0 10BASE-T, Half-Duplex & Full Duplex advertised via Auto-

Negotiation

0 1 100BASE-TX, Half-Duplex & Full Duplex advertised via

Auto-Negotiation

1 0 10BASE-T& 100BASE-TX, Half-Duplexadvertisedvia Auto-

Negotiation

1 1 10 BASE-T, Half-Duplex advertised via Auto-Negotiation

Obsolete

1.0 Pin Descriptions (Continued)

9 www.national.com

REPEATER

(THIN) I/O 63 REPEATER/NODE MODE: Selects 100 Mb/s Repeater mode when set high and

node mode when set low. When set in Repeater mode the DP83843 only supports

100 Mb/s data rates. In Repeater mode (or Node mode with Full Duplex conﬁg-

ured), the Carrier Sense (CRS) output from the DP83843 is asserted due to

receive activity only. In Half Duplex Node mode, CRS is asserted due to either

receive or transmit activity. During repeater mode the heartbeat function(SQE) is

forced off.

The Carrier Integrity Monitor (CIM) function is automatically enabled when this pin

is set high (repeater mode) and disabled when this pin is set low (node mode) in

order to facilitate 802.3u CIM requirements.

There is an internal pullup resistor for this pin which is active during the power-

up/reset period. If this pin is left ﬂoating externally, then the device will conﬁgure to

100 Mb/s Repeater mode as a result of power-up/reset. This pin must be externally

pulled low (typically 10 kΩ) in order to conﬁgure the DP83843 for Node operation.

The value of this input is latched into the DP83843 at power-up, hardware or soft-

ware reset.

SYMBOL/

(CRS) I/O, Z 22 SYMBOL MODE: This active low input allows 100 Mb/s transmit and receive data

streams to bypass all of the transmit and receive operations when set low. Note

that the PCS signals (CRS, RX_DV, RX_ER, and COL) have no meaning during

this mode. During Symbol operation, pins RX_ER/RXD[4] and TX_ER/TXD[4] are

used as the MSB of the 5 bit RX and TX data symbols.

There is an internal pullup resistor for this pin which is active during the power-

up/reset period. If this pin is left ﬂoating externally, then the device will conﬁgure to

normal mode as a result of power-up/reset. This pin must be externally pulled low

(typically 10 kΩ) in order to conﬁgure the DP83843 for Symbol mode operation.

In Symbol mode this pin will indicate the signal detect status of the TP-PMD (active

high).

This mode has no effect on 10Mb/s operation. The value at this input is latched into

the DP83843 at power-up, hardware or software reset.

SERIAL10 I 69 10BASE-T SERIAL/NIBBLE SELECT: With this active low input selected, transmit

and receive data are exchanged serially at a 10 MHz clock rate on the least signiﬁ-

cant bits of the nibble-wide MII data buses, pins TXD[0] and RXD[0] respectively.

This mode is intended for use with the DP83843 connected to a MAC using a 10

Mb/s serial interface. Serial operation is not supported in 100 Mb/s mode, therefore

this input is ignored during 100 Mb/s operation.

There is an internal pullup resistor for this pin which is active during the power-

up/reset period. If this pin is left ﬂoating externally, then the device will conﬁgure to

normal mode as a result of power-up/reset. This pin must be externally pulled low

(typically 10 kΩ) in order to conﬁgure the DP83843 for Serial MII operation when

running at 10 Mb/s.

The value at this input is latched into the DP83843 at power-up, hardware or soft-

ware reset.

FXEN/

(COL) I/O, Z 21 FIBER ENABLE: This active low input allows 100 Mb/s transmit and receive data

streams to bypass the scrambler and descrambler circuits when selected. All PCS

signaling remains active and unaffected during this mode. During this mode, the

internal 100 Mb/s transceiver is disabled, and NRZI data is transmitted and

received via the FXTD/AUITD+/− and FXRD/AUIRD+/− pins.

There is an internal pullup resistor for this pin which is active during the power-

up/reset period. If this pin is left ﬂoating externally, then the device will conﬁgure to

normal mode as a result of power-up/reset. This pin must be externally pulled low

(typically 10 kΩ) in order to conﬁgure the DP83843 for 100BASE-FX operation.

The value at this input is latched into the DP83843 at power-up, hardware or soft-

ware reset.

Signal Name Type Pin # Description

Obsolete

1.0 Pin Descriptions (Continued)

10 www.national.com

1.5 LED Interface

These outputs can be used to drive LEDs directly, or can

be used to provide status information to a network man-

agement device. Refer to section 2.2 for a description of

how to generate LED indication of 100 Mb/s mode. The

active state of each LED output driver is dependent on the

logic level sampled by the corresponding PHY address

input upon power-up/reset. For example, if a given PHYAD

input is resistively pulled low then the corresponding LED

output will be conﬁgured as an active high driver. Con-

versely, if a given PHYAD input is resistively pulled high

then the corresponding LED output will be conﬁgured as an

active low driver (refer to section 5.0.1 for further details).

Note that these outputs are standard CMOS voltage

drivers and not open-drain.

Signal Name Type Pin # Description

LED_COL

(PHYAD[0]) I/O 42 COLLISION LED: Indicates the presence of collision activity for 10 Mb/s and 100

Mb/s Half Duplex operation. This LED has no meaning for 10 Mb/s or 100 Mb/s Full

Duplex operation and will remain deasserted. During 10 Mb/s half duplex mode this

pin will be asserted after data transmission due to the heartbeat function.

The DP83843 incorporates a “monostable” function on the LED_COL output. This

ensures that even collisions generate adequate LED ON time (approximately 50

ms) for visibility.

LED_TX

(PHYAD[1]) I/O 41 TRANSMIT LED: Indicates the presence of transmit activity for 10 Mb/s and 100

Mb/s operation.

If bit 7 (LED_Trans_MODE) of the PHYCTRL register (address 19h) is set high,

then the LED_TX pin function is changed to indicate the status of the Disconnect

function as defined by the state of bit 4 (CIM_STATUS) in the 100 Mb/s PCS con-

figuration & status register (address 16h). See register definition for complete de-

scription of alternative operation.

TheDP83843 incorporates a“monostable”function on theLED_TXoutput.This en-

sures that even minimum size packets generate adequate LED ON time (approxi-

mately 50 ms) for visibility.

LED_RX

(PHYAD[2]) I/O 40 RECEIVE LED: Indicates the presence of any receive activity for 10 Mb/s and 100

Mb/s operation. See register definitions(PHYCTRL register and PCSR register) for

complete descriptions of alternative operation.

TheDP83843incorporatesa“monostable”functionontheLED_RX output. This en-

sures that even minimum size packets generate adequate LED active time (approx-

imately 50 ms) for visibility.

LED_LINK

(PHYAD[3]) I/O 39 LINK LED: Indicates good link status for 10 Mb/s and 100 Mb/s operation.

In 100BASE-T mode, link is established as a result of input receive amplitude com-

pliant with TP-PMD specifications which will result in internal generation of Signal

Detect as well as an internal signal from the Clock Recovery Module (cypher &

sync). LED_LINK will assert after these internal signals have remained asserted for

a minimum of 500µs. Once Link is established, then cipher & sync are no longer

sampled and the Link will remain valid as long as Signal Detect is valid. LED_LINK

will deassert immediately following the deassertion of the internal Signal Detect.

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 which will cause

the assertion of LED_LINK. LED_LINK will deassert in accordance with the Link

Loss Timer as specified in IEEE 802.3.

In 100BASE-FX mode, link is established as a result of the assertion of the Signal

detectinputtotheDP83843.LED_LINKwillassertafterSignalDetecthasremained

asserted for a minimum of 500µS. LED_LINK will deassert immediately following

the deassertion of signal detect.

The link function is disabled during AUI operation and LED_LINK is asserted.

LED_FDPOL

(PHYAD[4]) I/O 38 FULL DUPLEX LED: Indicates Full Duplex mode status for 10 Mb/s or 100 Mb/s

operation. This pin can be configured to indicate Polarity status for 10 Mb/s opera-

tion. If bit 6 (LED_DUP_MODE) in the PHYCTRL Register (address 19h) is deas-

serted, the LED_FDPOL pin function is changed to indicate Polarity status for 10

Mb/s operation.

The DP83843 automatically compensates for 10BASE-T polarity inversion.

10BASE-T polarity inversion is indicated by the assertion of LED_FDPOL.

SPEED10 O 5 SPEED 10 Mb/s: Indicates 10 Mb/s operation when high. Indicates 100 Mb/s oper-

ation when low. This pin can be used to drive peripheral circuitry such as an LED

indicator.

Obsolete

1.0 Pin Descriptions (Continued)

11 www.national.com

1.6 PHY Address Interface

The DP83843 PHYAD[4:0] inputs provide up to 32 unique

PHY address options. An address selection of all zeros

(00000) will result in a PHY isolation condition as a

result of power-on/reset, as speciﬁed in IEEE 802.3u.

1.7 Reset

Signal Name Type Pin # Description

PHYAD[0]

(LED_COL) I/O 42 PHY ADDRESS [0]: PHYaddress sensing pinformultiple PHY applications.PHY

address sensing is achieved by strapping a pull-up/pull-down resistor (typically 10

kΩ) to this pin as required.

The pull-up/pull-down status of this pin is latched into the PHYCTRL register (ad-

dress 19h, bit 0) during power up/reset.

PHYAD[1]

(LED_TX) I/O 41 PHY ADDRESS [1]: PHY address sensing pin for multiple PHY applications. PHY

address sensing is achieved by strapping a pull-up/pull-down resistor (typically 10

kΩ) to this pin as required.

The pull-up/pull-down status of this pin is latched into the PHYCTRL register (ad-

dress 19h, bit 1) during power up/reset.

PHYAD[2]

(LED_RX) I/O 40 PHY ADDRESS [2]: PHYaddress sensing pinformultiple PHY applications.PHY

address sensing is achieved by strapping a pull-up/pull-down resistor (typically 10

kΩ) to this pin as required.

The pull-up/pull-down status of this pin is latched into the PHYCTRL register (ad-

dress 19h, bit 2) during power up/reset.

PHYAD[3]

(LED_LINK) I/O 39 PHY ADDRESS [3]: PHYaddress sensing pinformultiple PHY applications.PHY

address sensing is achieved by strapping a pull-up/pull-down resistor (typically 10

kΩ) to this pin as required.

The pull-up/pull-down status of this pin is latched into the PHYCTRL register (ad-

dress 19h, bit 3) during power up/reset.

PHYAD[4]

(LED_FDPOL) I/O 38 PHY ADDRESS [4]: PHYaddress sensing pinformultiple PHY applications.PHY

address sensing is achieved by strapping a pull-up/pull-down resistor (typically 10

kΩ) to this pin as required.

The pull-up/pull-down status of this pin is latched into the PHYCTRL register (ad-

dress 19h, bit 4) during power up/reset.

Signal Name Type Pin # Description

RESET I 1 RESET: Active high input that initializes or reinitializes the DP83843. Asserting this

pin will force a reset process to occur which will result in all internal registers reini-

tializing to their default states as specified for each bit in section 7.0, and all strap-

ping options are reinitialized. Refer to section 5.0 for further detail regarding reset.

Obsolete

1.0 Pin Descriptions (Continued)

12 www.national.com

1.8 Power And Ground Pins

The power (VCC) and ground (GND) pins of the DP83843

are grouped in pairs into three categories--TTL/CMOS

Input pairs, Transmit/Receive supply pairs, and Internal

supply pairs. This grouping allows for optimizing the layout

and ﬁltering of the power and ground supplies to this

device.

1.9 Special Connect Pins

Signal Name Pin # Description

TTL/CMOS INPUT/OUTPUT SUPPLY PAIRS

IO_VDD1

IO_VSS1 6

7TTL Input/Output Supply #1

IO_VDD2

IO_VSS2 16

17 TTL Input/Output Supply #2

IO_VDD3

IO_VSS3 26

27 TTL Input /Output Supply #3

IO_VSS4 32 TTL Input/Output Supply #4

IO_VDD5

IO_VSS5 36

37 TTL Input/ Output Supply #5

PCS_VDD

PCS_VSS 10

11 Physical Coding Sublayer Supply

TRANSMIT/RECEIVE SUPPLY PAIRS

AUIFX_VDD

AUIFX_GND 46

45 AUI Power Supply

TR_AVDD

TR_AGND 79

80 10 Mb/s Supply

TW_AVDD

TW_AGND 68

64 100 Mb/s Power Supply

CD_VDD0

CD_GND0 72

71 Common Driver Supply

CD_VDD1

CD_GND1 76

75 Common Driver Supply

INTERNAL SUPPLY PAIRS

CP_AVDD

CP_AGND 52

51 CRM/CGM Supply

CPTW_DVDD

CPTW_DVSS 54

53 CRM/CGM Supply

ATP_GND 57 100BASE-T PMD Supply

SUB_GND1,

SUB_GND2 70

77 100BASE-T PMD Supply

Signal Name Type Pin # Description

NC 2,55,56,

58,59,

NO CONNECT: These pins are reserved for future use. Leave them unconnected

(floating).

Obsolete

13 www.national.com

2.0 Functional Description

2.1 802.3u MII

The DP83843 incorporates the Media Independent Inter-

face (MII) as speciﬁed in clause 22 of the IEEE 802.3u

standard. This interface may be used to connect PHY

devices to a 10/100 Mb/s MAC or a 100 Mb/s repeater con-

troller. This section describes both the serial MII manage-

ment interface as well as the nibble wide MII data interface.

The management interface of the MII allows the conﬁgura-

tion and control of multiple PHY devices, the gathering of

status and error information, and the determination of the

type and abilities of the attached PHY(s).

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

or repeater).

The DP83843 supports the TI ThunderLAN® MII interrupt

function. For further information please contact your local

National sales representative.

2.1.1 Serial Management Register Access

The serial MII speciﬁcation deﬁnes a set of thirty-two 16-bit

status and control registers that are accessible through the

serial management data interface pins MDC and MDIO.

The DP83843 implements all the required MII registers as

well as several optional registers. These registers are fully

described in Section 7. A description of the serial manage-

ment access protocol follows.

2.1.2 Serial Management Access Protocol

The serial control interface consists of two pins, Manage-

ment Data Clock (MDC) and Management Data Input/Out-

put (MDIO). MDC has a maximum clock rate of 2.5 MHz

and no minimum rate. The MDIO line is bi-directional and

may be shared by up to 32 devices. The MDIO frame for-

mat is shown in Table 1.

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 (SME) sends a sequence of 32 contiguous logic

ones on MDIO to provide the DP83843 with a sequence

that can be used to establish synchronization. This pream-

ble 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 if an invalid start, op

code, or turnaround bit is detected.

The DP83843 waits until it has received this preamble

sequence before responding to any other transaction.

Once the DP83843 serial management port has initialized

no further preamble sequencing is required until after a

power-on/reset has occurred.

The Start code is indicated by a <01> pattern. This assures

the MDIO line transitions from the default idle line state.

Turnaround is an idle bit time inserted between the Regis-

ter Address ﬁeld and the Data ﬁeld. To avoid contention, no

device actively drives the MDIO signal during the ﬁrst bit of

Turnaround during a read transaction. The addressed

DP83843 drives the MDIO with a zero for the second bit of

turnaround and follows this with the required data. Figure 2

shows the timing relationship between MDC and the MDIO

as driven/received by the Station Management Entity and

the DP83843 (PHY) for a typical register read access.

Table 1. 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>

Figure 1. Typical MDC/MDIO Write Operation

Figure 2. Typical MDC/MDIO Read Operation

MDC

MDIO

00011110000000

(SME)

Idle Start Opcode

(Write) PHY Address

(PHYAD = 0Ch) Register Address

(00h = BMCR) TA Register Data

Z0 0 0 000 00000000Z

Idle

1000

MDC

MDIO

00011 110000000

(SME)

Idle Start Opcode

(Read) PHY Address

(PHYAD = 0Ch) Register Address

(00h = BMCR) TA Register Data

MDIO

(PHY)

Z0 0 011000100000000Z

Idle

Obsolete

2.0 Functional Description (Continued)

14 www.national.com

For write transactions, the Station Management Entity

writes data to an addressed DP83843 eliminating the

requirement for MDIO Turnaround. The Turnaround time is

ﬁlled by the management entity inserting <10> for these

two bits. Figure 1 shows the timing relationship for a typical

MII register write access.

2.1.3 Preamble Suppression

The DP83843 supports a Preamble Suppression mode as

indicated by a one in bit 6 of the Basic Mode Status Regis-

ter (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 DP83843 requires a single initialization sequence of

32 bits of preamble following power-up/hardware 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 Pre-

amble Suppression is supported.

While the DP83843 requires an initial preamble sequence

of 32 bits for management initialization, it does not require

a full 32 bit sequence between each subsequent transac-

tion. A

minimum of one idle bit between management

transactions is required

as speciﬁed in IEEE 802.3u.

2.1.4 PHY Address Sensing

The DP83843 can be set to respond to any of the possible

32 PHY addresses. Each DP83843 connected to a com-

mon serial MII must have a unique address. It should be

noted that while an address selection of all zeros <00000>

will result in PHY Isolate mode, this will not effect serial

management access.

The DP83843 provides ﬁve PHY address pins, the state of

which are latched into the PHYCTRL register (address

19h) at system power-up/reset. These pins are described

in Section 2.8. For further detail relating to the latch-in tim-

ing requirements of the PHY address pins, as well as the

other hardware conﬁguration pins, refer to Section 3.10.

2.1.5 Nibble-wide MII Data Interface

Clause 22 of the IEEE 802.3u speciﬁcation deﬁnes the

Media Independent Interface. This interface includes a

dedicated receive bus and a dedicated transmit bus. These

two data buses, along with various control and indicate sig-

nals, allow for the simultaneous exchange of data between

the DP83843 and the upper layer agent (MAC or repeater).

The receive interface consists of a nibble wide data bus

RXD[3:0], a receive error signal RX_ER, a receive data

valid ﬂag RX_DV, and a receive clock RX_CLK for synchro-

nous transfer of the data. The receive clock can operate at

either 2.5 MHz to support 10 Mb/s operation modes or at

25 MHz to support 100 Mb/s operational modes.

The transmit interface consists of a nibble wide data bus

TXD[3:0], a transmit error ﬂag TX_ER, a transmit enable

control signal TX_EN, and a transmit clock TX_CLK which

runs at either 2.5 MHz or 25 MHz.

Additionally, the MII includes the carrier sense signal CRS,

as well as a collision detect signal COL. The CRS signal

asserts to indicate the reception of data from the network

or as a function of transmit data in Half Duplex mode. The

COL signal asserts as an indication of a collision which can

occur during half-duplex operation when both a transmit

and receive operation occur simultaneously.

2.1.6 Collision Detect

For Half Duplex, a 10BASE-T or 100BASE-X collision is

detected when the receive and transmit channels are

active simultaneously. Collisions are reported by the COL

signal on the MII.

If the DP83843 is transmitting in 10 Mb/s mode when a col-

lision 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 dura-

tion of the collision.

If a collision occurs during a receive operation, it is immedi-

ately reported by the COL signal.

When heartbeat is enabled (only applicable to 10 Mb/s

operation), approximately 1 µs after the transmission of

each packet, a Signal Quality Error (SQE) signal of approx-

imately 10 bit times is generated (internally) to indicate

successful transmission. SQE is reported as a pulse on the

COL signal of the MII.

2.1.7 Carrier Sense

Carrier Sense (CRS) may be asserted due to receive activ-

ity, once valid data is detected via the Smart Squelch func-

tion during 10 Mb/s operation.

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

due to receive activity.

CRS is deasserted following an end of packet.

In Repeater mode (pin 63/bit 9, register address 19h), CRS

is only asserted due to receive activity.

2.1.8 MII Isolate Mode

A 100BASE-X PHY connected to the mechanical MII inter-

face speciﬁed in IEEE 802.3u is required to have a default

value of one in bit 10 of the Basic Mode Control Register

(BMCR, address 00h). The DP83843 will set this bit to one

if the PHY Address is set to 00000 upon power-up/hard-

ware reset. Otherwise, the DP83843 will set this bit to zero

upon power-up/hardware reset.

With bit 10 in the BMCR set to one, the DP83843 does not

respond to packet data present at TXD[3:0], TX_EN, and

TX_ER inputs and presents a high impedance on the

TX_CLK, RX_CLK, RX_DV, RX_ER, RXD[3:0], COL, and

CRS outputs. The DP83843 will continue to respond to all

serial management transactions over the MII.

While in Isolate mode, the TPTD+/− and FXTD/AUITD+/−

outputs are dependent on the current state of Auto-Negoti-

ation. The DP83843 can Auto-Negotiate or parallel detect

to a speciﬁc technology depending on the receive signal at

the TPRD+/− inputs. A valid link can be established for

either TPRD or FXRD/AUI even when the DP83843 is in

Isolate mode.

It is recommended that the user have a basic understand-

ing of clause 22 of the 802.3u standard.

Obsolete

2.0 Functional Description (Continued)

15 www.national.com

2.2 100BASE-TX TRANSMITTER

The 100BASE-TX transmitter consists of several functional

blocks which convert synchronous 4-bit nibble data, as pro-

vided by the MII, to a scrambled MLT-3 125 Mb/s serial data

stream. Because the 100BASE-TX TP-PMD is integrated,

the differential output pins, TPTD+/−, can be directly routed

to the AC coupling magnetics.

The block diagram in Figure 3 provides an overview of

each functional block within the 100BASE-TX transmit sec-

tion.

The Transmitter section consists of the following functional

blocks:

— Code-groupEncoderandInjectionblock(bypassoption)

— 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-X transmitter provides ﬂexibility for applications

such as 100 Mb/s repeaters where data conversion is not

always required. The DP83843 implements the 100BASE-

X transmit state machine diagram as speciﬁed in the IEEE

802.3u Standard, Clause 24.

– Code-group Encoding and Injection

Figure 1. 100BASE-TX Transmit Block Diagram

CODE-GROUP

ENCODER &

INJECTOR

SCRAMBLER

NRZ TO NRZI

ENCODER

PARALLEL

TO SERIAL

TPTD +/−

TX_CLK TXD[3:0] /

TX_ER

100BASE-X

LOOPBACK

MUX

BINARY

TO MLT-3 /

COMMON

DRIVER

25MHZ

BP_4B5B

BP_TX

BP_SCR

Obsolete

2.0 Functional Description (Continued)

16 www.national.com

The code-group encoder converts 4 bit (4B) nibble data

generated by the MAC into 5 bit (5B) code-groups for trans-

mission. This conversion is required to allow control data to

be combined with packet data code-groups. Refer to Table

2 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 transmit. 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 or Repeater, the code-group encoder injects

the T/R code-group pair (01101 00111) indicating the end

of 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).

The DP83843 also incorporates a special injection function

which allows for ﬁxed transmission of special repeating pat-

terns for testing purposes. These special patterns are not

delimited with Start of Stream Delimiter (SSD) or End of

Stream Delimiter (ESD) code-groups and should not be

enabled during normal network connectivity.

These patterns, selectable via bits [8:7] of PCRS (address

16h), include:

8=0, 7=0: Normal operation (injection disabled)

8=0, 7=1: Transmit repeating FEFI pattern

8=1, 7=0: Transmit repeating 1.28 µs period squarewave

8=1, 7=1: Transmit repeating 160 ns period squarewave

Note that these patterns will be routed through the transmit

scrambler and become scrambled (and therefore poten-

tially less useful) unless the scrambler is bypassed via bit

12 of LBR (address 17h). It should be noted that if the

scrambler is bypassed by forcing the FXEN pin (and subse-

quently resetting the device) the TPTD+/− outputs will

become disabled and the test pattern data will be routed to

the FXTD/AUITD+/− outputs. Additionally, the test patterns

will not be generated if the DP83843 is in symbol mode.

2.2.1 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 distrib-

uted over a wide frequency range. Without the scrambler,

energy levels at the PMD and on the cable could peak

beyond FCC limitations at frequencies related to repeating

5B sequences (i.e., continuous transmission of IDLEs).

The scrambler is conﬁgured as a closed loop linear feed-

back shift register (LFSR) with an 11-bit polynomial. The

output of the closed loop LFSR is combined with the NRZ

5B data from the code-group encoder via an X-OR logic

function. The result is a scrambled data stream with sufﬁ-

cient randomization to decrease radiated emissions at cer-

tain frequencies by as much as 20 dB. The DP83843 uses

the PHYID as determined by the PHYAD [4:0] pins to set a

unique seed value for the scrambler so that the total energy

produced by a multi-PHY application (i.e. repeater) distrib-

utes the energy out of phase across the spectrum and

helps to reduce overall electro-magnetic radiation.

The scrambler is automatically bypassed when the

DP83843 is placed in FXEN mode via hardware or, alterna-

tively, controlled by bit 12 of LBR (address 17h) via soft-

ware.

2.2.2 NRZ to NRZI Encoder

After the transmit data stream has been scrambled and

serialized, the data must be NRZI encoded in order to com-

ply with the TP-PMD standard for 100BASE-TX transmis-

sion over Category-5 unshielded twisted pair cable. There

is no ability to bypass this block within the DP83843.

2.2.3 Binary to MLT-3 Convertor / Common Driver

The Binary to MLT-3 conversion is accomplished by con-

verting the serial binary datastream 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

these streams to current sources and alternately drives

either side of the transmit transformer primary winding

resulting in a minimal current (20 mA max) MLT-3 signal.

Refer to Figure 4 .

Figure 1. Binary to MLT-3 conversion

binary_in binary_plus

binary_minus

binary_in

binary_plus

binary_minus

COMMON

DRIVER MLT-3

differential MLT-3

Obsolete

2.0 Functional Description (Continued)

17 www.national.com

Table 2. 4B5B Code-Group Encoding/Decoding

Name PCS 5B Code-group MII 4B Nibble Code

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 0110 or 0101 (Note 2)

V 00001 0110 or 0101 (Note 2)

V 00010 0110 or 0101 (Note 2)

V 00011 0110 or 0101 (Note 2)

V 00101 0110 or 0101 (Note 2)

V 00110 0110 or 0101 (Note 2)

V 01000 0110 or 0101 (Note 2)

V 01100 0110 or 0101 (Note 2)

V 10000 0110 or 0101 (Note 2)

V 11001 0110 or 0101 (Note 2)

Note 1: Control code-groups I, J, K, T and R in data fields will be mapped as invalid codes, together with RX_ER asserted.

Note 2: Normally, invalid codes (V) are mapped to 6h on RXD[3:0] with RX_ER asserted. If the CODE_ERR bit in the PCS (bit 3, register address 16h)

is set, the invalid codes are mapped to 5h on RXD[3:0] with RX_ER asserted. Refer to Section 4.14 for further detail.

Obsolete

2.0 Functional Description (Continued)

18 www.national.com

The 100BASE-TX MLT-3 signal sourced by the TPTD+/−

common driver output pins is slow rate controlled. This

should be considered when selecting AC coupling magnet-

ics to ensure TP-PMD compliant transition times (3 ns < Tr

< 5ns).

The 100BASE-TX transmit TP-PMD function within the

DP83843 is capable of sourcing only MLT-3 encoded data.

Binary output from the TPTD+/− outputs is not possible in

100 Mb/s mode.

2.2.4 TX_ER

Assertion of the TX_ER input while the TX_EN input is also

asserted will cause the DP83843 to substitute HALT code-

groups for the 5B data present at TXD[3:0]. However, the

SSD (/J/K/) and ESD (/T/R/) will not be substituted with

Halt code-groups. As a result, the assertion of TX_ER

while TX_EN is asserted will result in a frame properly

encapsulated with the /J/K/ and /T/R/ delimiters which con-

tains HALT code-groups in place of the data code-groups.

2.2.5 TXAR100

The transmit amplitude of the signal presented at the

TPTD+/− output pins can be controlled by varying the value

of resistance between TXAR100 and system GND. This

TXAR100 resistor sets up a reference current that deter-

mines the ﬁnal output current at TPTD+/−.

For 100ΩCategory-5 UTP cable implementations, the

TXAR100 resistor may be omitted as the DP83843 was

designed to source a nominal 2V pk-pk differential transmit

amplitude with this pin left ﬂoating. Setting the transmit

amplitude to 2V pk-pk differential (MLT-3) as measured

across the RJ45-8 transmit pins is critical for complying

with the IEEE/ANSI TP-PMD speciﬁcation of 2.0V pk-pk

differential ±5%.

2.3 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 pro-

vided to the MII. Because the 100BASE-TX TP-PMD is

integrated, the differential input pins, TPRD+/−, can be

directly routed to the AC coupling magnetics.

See Figure 5 for a block diagram of the 100BASE-TX

receive function. This provides an overview of each func-

tional block within the 100BASE-TX receive section.

The Receive section consists of the following functional

blocks:

— Input and BLW Compensation

— Signal Detect

— Digital Adaptive Equalization

— MLT-3 to Binary Decoder

— Clock Recovery Module

— NRZI to NRZ Decoder

— Serial to Parallel

— DESCRAMBLER (bypass option)

— Code Group Alignment

— 4B/5B Decoder (bypass option)

— Link Integrity Monitor

— Bad SSD Detection

The bypass option for the functional blocks within the

100BASE-X receiver provides ﬂexibility for applications

such as 100 Mb/s repeaters where data conversion is not

always required.

2.3.1 Input and Base Line Wander Compensation

Unlike the DP83223V TWISTER™, the DP83843 requires

no external attenuation circuitry at its receive inputs,

TPRD+/−. The DP83843 accepts TP-PMD compliant wave-

forms directly, requiring only a 100Ωtermination plus a

simple 1:1 transformer. The DP83843 also requires exter-

nal capacitance to VCC at the VCM_CAP pin (refer to Fig-

ure 23). This establishes a solid common mode voltage

that is needed since the TPRD pins are used in both 10

Mb/s and 100 Mb/s modes.

The DP83843 is completely ANSI TP-PMD compliant

because it compensates for baseline wander. The BLW

compensation block can successfully recover the TP-PMD

deﬁned “killer” pattern and pass it to the digital adaptive

equalization block.

Baseline wander can generally be deﬁned as the change in

the average DC content, over time, of an AC coupled digital

transmission over a given transmission medium. (i.e. cop-

per wire).

Baseline wander results from the interaction between the

low frequency components of a bit stream being transmit-

ted and the frequency response of the AC coupling compo-

nent(s) within the transmission system. If the low frequency

content of the digital bit stream goes below the low fre-

quency pole of the AC coupling transformers then the

droop characteristics of the transformers will dominate

resulting in potentially serious baseline wander.

It is interesting to note that the probability of a baseline wan-

der event serious enough to corrupt data is very low. In fact,

it is reasonable to virtually bound the occurrence of a base-

line wander event serious enough to cause bit errors to a

legal but premeditated, artificially constructed bit sequence

loaded into the original MAC frame. Several studies have

been conducted to evaluate the probability of various base-

line wander events for FDDI transmission over copper. Con-

tact the X3.263 ANSI group for further information.

2.3.2 Signal Detect

The signal detect function of the DP83843 is incorporated

to meet the speciﬁcations mandated by the ANSI FDDI TP-

PMD Standard as well as the IEEE 802.3 100BASE-TX

Standard for both voltage thresholds and timing parame-

ters.

Note that the reception of Normal 10BASE-T link pulses

and fast link pulses per IEEE 802.3u Auto-Negotiation by

the 100BASE-X receiver do not cause the DP83843 to

assert signal detect.

While signal detect is normally generated and processed

entirely within the DP83843, it can be observed directly on

the CRS pin (pin 22) while the DP83843 is conﬁgured for

Symbol mode. Refer to Section 3.4 for further detail regard-

ing Symbol mode operation.

2.3.3 Digital Adaptive Equalization

When transmitting data at high speeds over copper twisted

pair cable, frequency dependent attenuation becomes a

concern. In high speed twisted pair signalling, the fre-

quency content of the transmitted signal can vary greatly

during normal operation based primarily on the random-

ness of the scrambled data stream. This variation in signal

Obsolete

2.0 Functional Description (Continued)

19 www.national.com

Figure 1. Receive Block Diagram

4B/5B

DECODER

DESCRAMBLER

DIGITAL

ADAPTIVE

EQUALIZATION

MLT-3 TO

BINARY

DECODER

TPRD +/−

RX_CLK RXD[3:0] / RX_ER

INPUT

&BLW

COMPEN-

SATION

BP_4B5B

BP_SCR

BP_RX

SIGNAL

DETECT

NRZI TO NRZ

DECODER

CODE GROUP

ALIGNMENT

SERIAL TO

PARALLEL

MUX

CLOCK

RECOVERY

MODULE

DATA

CLOCK

RX_DATA

VALID SSD

DETECT

CARRIER

INTEGRITY

MONITOR

LINK INTEG-

RITY MONITOR

Obsolete

2.0 Functional Description (Continued)

20 www.national.com

attenuation caused by frequency variations must be com-

pensated for 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 compensa-

tion which will over-compensate for shorter, less attenuat-

ing lengths. Conversely, the selection of short or

intermediate cable lengths requiring less compensation will

cause serious under-compensation for longer length

cables. Therefore, the compensation or equalization must

be adaptive to ensure proper conditioning of the received

signal independent of the cable length.

The DP83843 utilizes an extremely robust equalization

scheme referred to herein as ‘Digital Adaptive Equaliza-

tion.’ Existing designs use an adaptive equalization scheme

that determines the approximate cable length by monitor-

ing signal attenuation at certain frequencies. This attenua-

tion value was compared to the internal receive input

reference voltage. This comparison would indicate that

amount of equalization to use. Although this scheme is

used successfully on the DP83223V TWISTER, it is sensi-

tive to transformer mismatch, resistor variation and process

induced offset. The DP83223V also required an external

attenuation network to help match the incoming signal

amplitude to the internal reference.

Digital Adaptive Equalization is based on an advanced dig-

itally controlled signal tracking technique. This method

uses peak tracking with digital over-sampling and digitally

controlled feedback loops to regenerate the receive signal.

This technique does not depend on input amplitude varia-

tions to set the equalization factor. As a result it maintains

constant jitter performance for any cable length up to 150

meters of CAT-5. Digital Adaptive Equalization allows for

very high tolerance to signal amplitude variations.

The curves given in Figure 6 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 sig-

niﬁcant variations in signal attenuation that must be com-

pensated for by the receive adaptive equalization circuit.

Figure 7 represents a scrambled IDLE transmitted over

zero meters of cable as measured at the AII (Active Input

Interface) of the receiver. Figure 8 and Figure 9 represent

the signal degradation over 50 and 100 Meters of CAT-5

cable respectively, also measured at the AII. These plots

show the extreme degradation of signal integrity and indi-

cate the requirement for a robust adaptive equalizer.

The DP83843 provides the added ﬂexibility of controlling

the type of receive equalization required for a given imple-

mentation. This is done through TW_EQSEL (bits [13:12]

of the PHYCTRL register, address 19h). While digital adap-

tive equalization is the preferred method of cable compen-

sation for 100BASE-TX, the ability to switch the equalizer

completely off or to a ﬁxed maximum is provided. This fea-

ture is intended as a test mode only and, if enabled, will

inhibit normal performance of the DP83843.

2.3.4 MLT-3 to NRZI Decoder

The DP83843 decodes the MLT-3 information from the Dig-

ital Adaptive Equalizer block to binary NRZI data. The rela-

tionship of binary to MLT-3 data is shown in Figure 4.

2.3.5 Clock Recovery Module

The Clock Recovery Module (CRM) accepts 125 Mb/s

NRZI data from the MLT-3 to NRZI decoder. The CRM locks

onto the 125 Mb/s data stream and extracts a 125 MHz ref-

erence clock. The extracted and synchronized clock and

data are used as required by the synchronous receive

operations as generally depicted in Figure 5.

The CRM is implemented using an advanced digital Phase

Locked Loop (PLL) architecture that replaces sensitive

analog circuits. Using digital PLL circuitry allows the

DP83843 to be manufactured and speciﬁed to tighter toler-

ances.

For further information relating to the 100BASE-X clock

recovery module, refer to Section 4.3.

Figure 1. EIA/TIA Attenuation vs Frequency for 0, 50,

100 meters of CAT-5 cable

Figure 2. MLT-3 Signal Measured at AII after 0 meters of

CAT-5 cable

100M

50M

enuation (dB)

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

22.00

2ns/div

Obsolete

2.0 Functional Description (Continued)

21 www.national.com

2.3.6 NRZI to NRZ

In a typical application, the NRZI to NRZ decoder is

required in order to present NRZ formatted data to the

descrambler (or to the code-group alignment block, if the

descrambler is bypassed, or directly to the PCS, if the

receiver is bypassed).

The receive data stream is in NRZI format, therefore, the data

must be decoded to NRZ before further processing.

2.3.7 Serial to Parallel

The 100BASE-X receiver includes a Serial to Parallel con-

verter which supplies 5 bit wide data symbols to the

Descrambler. Converting to parallel helps to decrease

latency through the device, as well as performing the

required function for ultimately providing data to the nibble-

wide interface of the MII.

2.3.8 Descrambler

A 5-bit parallel (code-group wide) descrambler is used to

descramble the receive NRZ data. To reverse the data

scrambling process, 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:

Synchronization of the descrambler to the original scram-

bling sequence (N) is achieved based on the knowledge

that the incoming scrambled data stream consists of

scrambled IDLE data. After the descrambler has recog-

nized 12 consecutive IDLE code-groups, where an 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 synchroniza-

tion status. Upon synchronization of the descrambler the

hold timer starts a 722 µs countdown. Upon detection of

sufﬁcient IDLE code-groups within the 722 µs period, the

hold timer will reset and begin a new countdown. This mon-

itoring 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 re-acquire synchro-

nization.

The value of the time-out for this timer may be modiﬁed

from 722 sto 2 ms by setting bit 12 of the PCSR (address

16h) to one. The 2 ms option allows applications with Maxi-

mum Transmission Units (packet sizes) larger than IEEE

802.3 speciﬁcations to maintain descrambler synchroniza-

tion (i.e. switch or router applications).

Additionally, this timer may be disabled entirely by setting

bit 11 of the PCSR (address 16h) to one. The disabling of

the time-out timer is not recommended as this will eventu-

ally result in a lack of synchronization between the transmit

scrambler and the receive descrambler which will corrupt

data. The descrambler time-out counter may be reset by bit

13 of the PCSR.

2.3.9 Code-group Alignment

The code-group alignment module operates on unaligned

5-bit data from the descrambler (or, if the descrambler is

bypassed, directly from the NRZI/NRZ decoder) and con-

verts it into 5B code-group data (5 bits). Code-group align-

ment 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.

2.3.10 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

Figure 1. MLT-3 Signal Measured at AII after 50 meters

of CAT-5 cable

Figure 2. MLT-3 Signal Measured at AII after 100 meters

of CAT-5 cable

2ns/div

UD SD N⊕()=

SD UD N⊕()=

Obsolete

2.0 Functional Description (Continued)

22 www.national.com

the MAC preamble. Speciﬁcally, the J/K 10-bit code-group

pair is replaced by the nibble pair (0101 0101). All subse-

quent 5B code-groups are converted to the corresponding

4B nibbles for the duration of the entire packet. This con-

version 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.

2.3.11 100BASE-X Link Integrity Monitor

The 100BASE-X Link Integrity Monitor function (LIM)

allows the receiver to ensure that reliable data is being

received. Without reliable data reception, the LIM will halt

both transmit and receive operations until such time that a

valid link is detected (i.e. good link).

If Auto-Negotiation is not enabled, then a valid link will be

indicated once SD+/− is asserted continuously for 500 µs.

If Auto-Negotiation is enabled, then Auto-Negotiation will

further qualify a valid link as follows:

— The descrambler must receive a minimum of 12 IDLE

code groups for proper link initialization.

— The Auto-Negotiation must determine that the

100BASE-X function should be enabled.

A valid link for a non-Auto-Negotiating application is indi-

cated by either the Link LED output or by reading bit 2 of

the Basic Mode Status Register BMSR (address 01h). For

a truly qualiﬁed valid link indication as a result of Auto-

Negotiation, bit 2 of the BMSR register (address 01h) must

be read.

2.3.12 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 DP83843 will assert

RX_ER and present RXD[3:0] = 1110 to the MII for the

cycles that correspond to received 5B code-groups. In

order to exit this state the PHYTER must receive at least

two IDLE code groups and the PHYTER cannot receive a

single IDLE code group at any time. In addition, the False

Carrier Event Counter (address 14h) will be incremented

by one. Once the PHYTER exits this state, RX_ER and

CRS become de-asserted.

When bit 11 of the LBR register is one (BP_RX), RXD[3:0]

and RX_ER/RXD[4] are not modiﬁed.

2.3.13 Carrier Integrity Monitor

The Carrier Integrity Monitor function (CIM) protects the

repeater from transient conditions that would otherwise

cause spurious transmission due to a faulty link. This func-

tion is required for repeater applications and is not speci-

ﬁed for node applications.

The REPEATER pin (pin 63) determines the default state of

bit 5 of the PCS register (Carrier Integrity Monitor Disable,

address 16h) to automatically enable or disable the CIM

function as required for IEEE 802.3 compliant applications.

After power-up/reset, software may enable or disable this

function independent of Repeater or Node mode.

If the CIM determines that the link is unstable, the

DP83843 will not propagate the received data or control

signaling to the MII and will ignore data transmitted via the

MII. The DP83843 will continue to monitor the receive

stream for valid carrier events.

Detection of an unstable link condition will cause bit 4 of

the PCS register (address 16h) to be set to one. This bit is

cleared to zero upon a read operation once a stable link

condition is detected by the CIM. Upon detection of a sta-

ble link, the DP83843 will resume normal operations.

The Disconnect Counter (address 13h) increments each

time the CIM determines that the link is unstable.

2.4 10BASE-T TRANSCEIVER MODULE

The 10BASE-T Transceiver Module is IEEE 802.3 compli-

ant. It includes the receiver, transmitter, collision, heart-

beat, 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

DP83843. Due to the complexity and scope of the

10BASE-T Transceiver block and various sub-blocks, this

section focuses on the general system level operation.

2.4.1 Operational Modes

The DP83843 has 2 basic 10BASE-T operational modes:

Half Duplex mode

Full Duplex mode

Half Duplex Mode

In Half Duplex mode the DP83843 functions as a standard

IEEE 802.3 10BASE-T transceiver supporting the

CSMA/CD protocol.

Full Duplex Mode

In Full Duplex mode the DP83843 is capable of simulta-

neously transmitting and receiving without asserting the

collision signal. The DP83843's 10 Mb/s ENDEC is

designed to encode and decode simultaneously.

2.4.2 Oscillator Module Operation

A 25 MHz crystal or can-oscillator with the following speciﬁ-

cations is recommended for driving the X1 input.

1. CMOS output with a 50ppm frequency tolerance.

2. 35-65% duty cycle (max).

3. Two TTL load output drive.

Additional output drive may be necessary if the oscillator

must also drive other components. When using a clock

oscillator it is still recommended that the designer connect

the oscillator output to the X1 pin and leave X2 ﬂoating.

2.4.3 Smart Squelch

The smart squelch is responsible for determining when

valid data is present on the differential receive inputs

(TPRD+/−). The DP83843 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

10BASE-T standard) to determine the validity of data on

the twisted pair inputs (refer to Figure 10).

The signal at the start of 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 cor-

rectly, the opposite squelch level must then be exceeded

within 150 ns. Finally the signal must exceed the original

squelch level within a further 150 ns to ensure that the

Obsolete

2.0 Functional Description (Continued)

23 www.national.com

input waveform will not be rejected. The checking proce-

dure 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 squelch level

has not been generated for a time longer than 150ns, indi-

cating the End of Packet. Once good data has been

detected the squelch levels are reduced to minimize the

effect of noise causing premature End of Packet detection.

The receive squelch threshold level can be lowered for use

in longer cable applications. This is achieved by setting the

LS_SEL bit in the 10BTSCR (bit 6, register 18h). Collision

Detection

For 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.

If the ENDEC is transmitting when a collision is detected,

the collision is not reported until seven bits have been

received while in the collision state. This prevents a colli-

sion being reported incorrectly due to noise on the network.

The COL signal remains set for the duration of the collision.

If the ENDEC is receiving when a collision is detected it is

reported immediately (through the COL).

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 (inter-

nally) to indicate successful transmission. SQE is reported

as a pulse on the COL signal of the MII.

2.4.4 Carrier Sense

Carrier Sense (CRS) may be asserted due to receive activ-

ity once valid data is detected via the smart squelch func-

tion.

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

due to receive activity.

CRS is deasserted following an end of packet.

In Repeater mode, CRS is only asserted due to receive

activity.

2.4.5 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 nomi-

nally 100 ns in duration and is transmitted every 16 ms ±8

ms, in the absence of transmit data.

Link pulse is 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 trans-

mitter, receiver and collision detection functions.

When the link integrity function is disabled, the 10BASE-T

transceiver will operate regardless of the presence of link

pulses.

2.4.6 Jabber Function

The jabber function monitors the DP83843's output and

disables the transmitter if it attempts to transmit a packet of

longer than legal size. A jabber timer monitors the transmit-

ter and disables the transmission if the transmitter is active

for approximately 20-30 ms.

Once disabled by the Jabber function, the transmitter stays

disabled for the entire time that the ENDEC module's inter-

nal transmit enable is asserted. This signal has to be de-

asserted for approximately 400-600 ms (the “unjab” time)

before the Jabber function re-enables the transmit outputs.

The Jabber function is only meaningful in 10BASE-T mode.

2.4.7 Status Information

10BASE-T Status Information is available on the LED out-

put pins of the DP83843. Transmit activity, receive activity,

link status, link polarity and collision activity information is

output to the ﬁve LED output pins (LED_RX, LED_TX,

LED_LINK, LED_FDPOL, and LED_COL). Additionally, the

active high SPEED10 output will assert to indicate 10 Mb/s

operation.

If required, the LED outputs can be used to provide digital

status information to external circuitry.

The link LED output indicates good link status for both 10

and 100 Mb/s modes. In Half Duplex 10BASE-T mode,

LED_LINK indicates link status.

The link integrity function can be disabled. When disabled,

the transceiver will operate regardless of the presence of

link pulses and the link LED will stay asserted continuously.

2.4.8 Automatic Link Polarity Detection

The DP83843's 10BASE-T transceiver module incorpo-

rates an automatic link polarity detection circuit. When

seven consecutive link pulses or three consecutive receive

Figure 1. 10BASE-T Twisted Pair Smart Squelch Operation

<150ns <150ns >150ns

start of packet end of packet

Vsq +

Vsq -

Vsq +

reduced

Vsq -

reduced

Twisted Pair Squelch Operation

Obsolete

2.0 Functional Description (Continued)

24 www.national.com

packets with inverted End-of-Packet pulses are received,

bad polarity is reported.

A polarity reversal can be caused by a wiring error at either

end of the cable, usually at the Main Distribution Frame

(MDF) or patch panel in the wiring closet.

The bad polarity condition is latched and the LED_ FDPOL

output is asserted. The DP83843'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.

2.4.9 10BASE-T Internal Loopback

When the 10MB_ENDEC_LB bit in the LBR (bit 4, register

address 17h) is set, 10BASE-T transmit data is looped

back in the ENDEC to the receive channel. The transmit

drivers and receive input circuitry are disabled in trans-

ceiver loopback mode, isolating the transceiver from the

network.

Loopback is used for diagnostic testing of the data path

through the transceiver without transmitting on the network

or being interrupted by receive trafﬁc. This loopback func-

tion causes the data to loopback just prior to the 10BASE-T

output driver buffers such that the entire transceiver path is

tested.

2.4.10 Transmit and Receive Filtering

External 10BASE-T ﬁlters are not required when using the

DP83843 as the required signal conditioning is integrated.

Only isolation/step-up transformers and impedance match-

ing resistors are required for the 10BASE-T transmit and

receive interface. The internal transmit ﬁltering ensures

that all the harmonics in the transmit signal are attenuated

by at least 30 dB.

2.4.11 Encoder/Decoder (ENDEC) Module

The ENDEC module consists of essentially four functions:

The oscillator generates the 10 MHz transmit clock signal

for system timing from an external 25 MHz oscillator.

The Manchester encoder accepts NRZ data from the con-

troller or repeater, encodes the data to Manchester, and

transmits it differentially to the transceiver, through the dif-

ferential transmit driver.

The Manchester decoder receives Manchester data from

the transceiver, converts it to NRZ data and recovers clock

pulses for synchronous data transfer to the controller or

repeater.

The collision monitor indicates to the controller the pres-

ence of a valid 10 Mb/s collision signal.

2.4.12 Manchester Encoder

The encoder begins operation when the Transmit Enable

input (TX_EN) goes high and converts the NRZ data to

pre-emphasized Manchester data for the transceiver. For

the duration of TX_EN remaining high, the Transmit Data

(TPTD+/−) is encoded for the transmit-driver pair

(TPTD+/−). TXD must be valid on the rising edge of Trans-

mit Clock (TX_CLK). Transmission ends when TX_EN

deasserts. The last transition is always positive; it occurs at

the center of the bit cell if the last bit is a one, or at the end

of the bit cell if the last bit is a zero.

2.4.13 Manchester Decoder

The decoder consists of a differential receiver and a PLL to

separate a Manchester encoded data stream into internal

clock signals and data. The differential input must be exter-

nally terminated with either a differential 100ohm termina-

tion network to accommodate UTP cable.

The decoder detects the end of a frame when no more 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 or

repeater.

2.5 100 BASE-FX

The DP83843 is fully capable of supporting 100BASE-FX

applications. 100BASE-FX is similar to 100BASE-TX with

the exceptions being the PMD sublayer, lack of data scram-

bling, and signaling medium and connectors. Chapter 26 of

the IEEE 802.3u speciﬁcation deﬁnes the interface to this

PMD sublayer.

The DP83843 can be conﬁgured for 100BASE-FX opera-

tion either through hardware or software. Conﬁguration

through hardware is accomplished by forcing the FXEN pin

(pin 21) to a logic low level prior to power-up/reset. Conﬁg-

uration through software is accomplished by setting bits 9:7

of the LBR register to <011>, enabling FEFI (bit 14 of regis-

ter PCSR(16h)), bypassing the scrambler (bit 12 of register

LBR(17h)) and disabling Auto-Negotiation. In addition, set-

ting the FX_EN bit of the PHYCTRL register (bit 5, address

19h) accomplishes the same function as forcing the FXEN

pin (pin 21) to a logic low. In 100BASE-FX mode, the FX

interface is enabled along with the Far End Fault Indication

(FEFI) and Bypass Scrambler functions. Auto-Negotiation

must be disabled in order for 100BASE-FX operation to

work properly.

The diagram in Figure 11 is a block diagram representation

of the FX interface and the alternative data paths for trans-

mit, receive and signal detect.

Obsolete

2.0 Functional Description (Continued)

25 www.national.com

2.5.1 FX Interface

When the FX interface is enabled the internal 100BASE-TX

transceiver is disabled. As deﬁned by the 802.3u speciﬁca-

tion, PMD_SIGNAL_indicate (signal detect function),

PMD_UNITDATA.indicate (receive function), and

PMD_UNIT_DATA.request (transmit function) are sup-

ported by the FXSD+/−, FXRD+/−, and FXTD+/− pins

respectively.

Transmit

The DP83843 transmits NRZI data on the FXTD+/− pins.

This data is transmitted at PECL signal levels. 100BASE-

FX requires no scrambling/de-scrambling, so the scrambler

is bypassed in the transmit path. All other PMA and PCS

functions remain unaffected.

Receive

The DP83843 receives NRZI data on the FXRD+/− pins.

This data is accepted at PECL signal levels. 100BASE-FX

requires no scrambling/de-scrambling, so the de-scrambler

is bypassed in the receive path. All other PMA and PCS

functions remain unaffected.

Signal Detect

The DP83843 receives signal detect information on the

FXSD+/− pins. This data is accepted at PECL signal levels.

Signal detect indicates that a signal with the proper ampli-

tude is present at the PMD sublayer.

2.5.2 Far End Fault Indication

Auto-Negotiation provides a mechanism for transferring

information from the Local Station to the Link Partner that a

remote fault has occurred for 100BASE-TX. As Auto-Nego-

tiation is not currently speciﬁed for operation over ﬁber, the

Far End Fault Indication function (FEFI) provides some

degree of communication between link partners in support

of 100BASE-FX operation.

A remote fault is an error in the link that one station can

detect while the other cannot. An example of this is a dis-

connected ﬁber at a station’s transmitter. This station will

be receiving valid data and detect that the link is good via

the Link Integrity Monitor, but will not be able to detect that

its transmission is not propagating to the other station.

A 100BASE-FX station that detects such a remote fault

(through the deassertion of signal detect) may modify its

transmitted IDLE stream from all ones to a group of 84

ones followed by a single zero (i.e. 16 IDLE code groups

followed by a single Data 0 code group). This is referred to

as the FEFI IDLE pattern. Transmission of the FEFI IDLE

pattern will continue until FXSD+/− is re-asserted.

If three or more FEFI IDLE patterns are detected by the

DP83843, then bit 4 of the Basic Mode Status register

(address 01h) is set to one until read by management. It is

also set in bit 7 of the PHY Status register (address 10h).

The ﬁrst FEFI IDLE pattern may contain more than 84 ones

as the pattern may have started during a normal IDLE

transmission which is actually quite likely. However, since

FEFI is a repeating pattern, this will not cause a problem

with the FEFI function. It should be noted receipt of the

FEFI IDLE pattern will not cause CRS to assert.

To enable Fiber mode without FEFI, set bits 9:7 of the LBR

PCSR(16h)), bypass the scrambler (bit 12 of register

Figure 1. 100Base-FX Block Diagram

NRZ TO NRZI

ENCODER

BINARY

TO MLT-3 /

COMMON

DRIVER

PECL

DRIVER

FXTD

TPRD+/−

INPUT &BLW COMP

FULL ADAPT. EQUALIZ.

MLT-3 TO BINARY DEC.

SIGNAL

DETECT

CLOCK

RECOVERY

MODULE

PECL

INPUTS

FXSDFXRD

NORMAL TX DATA

W/ SCRAMBLER BYPASSED NORMAL RX DATA TO

DESCRAMBLER BYPASS NORMAL

SIGNAL DETECT

TPTD+/−

Obsolete

2.0 Functional Description (Continued)

26 www.national.com

LBR(17h)) and disable Auto-Negotiation. Without FEFI

enabled the DP83843 will not send the FEFI idle pattern.

Additionally, upon detection of Far End Fault, all receive

and transmit MII activity is disabled/ignored (MII serial

management is unaffected).

This function is optional for 100BASE-FX compliance and

should be disabled for 100BASE-TX compliance. If Auto-

Negotiation is enabled (bit 12 of the BMCR) then FEFI is

automatically disabled. FEFI is automatically enabled when

the DP83843 is conﬁgured for 100BASE-FX operation.

2.5.3 Software Enable

The FX functions can also be set via software. The FX-

interface is set by bit 5 of the PHYCTRL register (address

19h). The FEFI_EN function is set by bit 14 of register 16h.

The bypass scrambler and de-scrambler function is set by

bit 11 of the loopback and bypass register (address 17h).

2.5.4 FX Interface Considerations

The termination and signal routing for the high-speed

PECL signals are critical. The following diagram shows a

typical thevenin termination circuit.

Chapter 26 of the 802.3u 100BASE-X document includes

references to the three most common types of 125 Mb/s

optical transceiver connectors available. The DP83843 may

be used with any of these three connectors.

It is important to note that the typical 9-pin low cost ﬁber

transceiver utilizes a single-ended PECL output for Signal

Detect indication. Since the DP83843 incorporates stan-

dard differential PECL inputs for Signal Detect, the FXSD-

input (pin 47) can be externally biased as depicted in

Figure 12 to ensure proper operation.

Optionally, the proper bias potential for FXSD- can be gen-

erated by the DP83843 internally. This is accomplished by

setting bit 15 of register 16 (PCSR). This option eliminates

the requirement for additional external passive components

which would otherwise be required for the proper biasing of

FXSD- in an application where only a single-ended SD sig-

nal is available.

2.6 AUI

The DP83843 is capable of operating in 10BASE-2 and

10BASE-5 applications. This is done by utilizing the AUI

(Attachment Unit Interface) pins of the DP83843. The AUI

interface is completely IEEE 802.3 compliant. See

Figure 14 for an example of a typical AUI connector setup.

AUI mode is selected by bit 5 (AUI_SEL) of the 10BASE-T

Control and Status register (10BTSCR). It can also be acti-

vated by the Autoswitch feature explained below.

Autoswitch overrides the AUI_SEL bit. The Status of the

port, either AUI or TP mode, is displayed in bit 12

(AUI_TPI) of the 10BTSCR register.

2.6.1 AUI Block Diagram

The pins at the AUI interface are AUIRD+/−, AUITD+/−, and

AUICD+/−. They provide the Read, Transmit and Collision

Detect functions respectively. See Figure 13 for a block dia-

gram of the AUI interface. The AUI interface includes the

PLL Decoder, Collision Decoder and Manchester Encoder

and Driver.

The PLL Decoder receives Manchester data from the

transceiver, converts it to NRZ data and clock pulses and

sends it to the controller.

The collision decoder indicates to the MII the presence of a

valid 10 MHz collision signal to the PLL.

Figure 1. Typical DP83843 to Optical Transceiver Interfaces

9-pin Optical Transceiver

DP83843 100BASE-FX

FXRD+/-

FXTD+/-

FXSD+/-

RX_DATA+/-

Signal_Detect +

TX_DATA+/-

VCC

130Ω

PECL Thevenin Termination

130Ω

130Ω130Ω

115Ω

370Ω

82Ω

82Ω82Ω90Ω

90Ω

Figure 1. AUI Block Diagram

PLL

AUIRD+/- AUICD+/- AUITD+/-

Decoder Collision

Decoder

Manchester

Encoder

& Driver

MII Interface/Control

rx_clk rx_data

crs col_

detect tx_data tx_clk

Obsolete

2.0 Functional Description (Continued)

27 www.national.com

The Manchester encoder accepts NRZ data from the MII,

encodes the data to Manchester and sends it to the driver.

The driver transmits the data differentially to the trans-

ceiver.

2.6.2 AUI/TP Autoswitch

The DP83843 has an autoswitching feature that allows

switching between the AUI and TP operation. The AUI/TPI

autoswitch feature (AUTOSW_EN) is enabled by bit 9 of

the 10BASE-T Control and Status Register (10BTSCR). If

AUTOSW_EN is asserted (default is de-asserted) and the

DP83843 is in 10 Mb/s mode it automatically activates the

TPI interface (10 Mb/s data is transmitted and received at

the TPTD+/− and TPRD+/− pins respectively). If there is an

absence of link pulses, the transceiver will switch to AUI

mode. Similarly, when the transceiver starts detecting link

pulses it will switch to TP mode. The switching from one

mode to the next is only done after the current packet has

been transmitted or received. If the twisted pair output is

jabbering and gets into link fail state, then the switch to AUI

mode is only done after the jabbering is done, including the

time it takes to unjab (unjab time).

2.6.3 Ethernet Cable Configuration / THIN Output

The DP83843 offers the choice of Thick Ethernet

(10BASE5) and Thin Ethernet (10BASE-2). The type of

cabling used is controlled through bit 3 of the 10BTSCR

output signal which can be used to disable/enable an exter-

nal DC-DC converter which is required for 10BASE-2 appli-

cations to provide electrical isolation. This enables a

10BASE-2 and10BASE-5 common interface application.

Figure 1. AUI Typical Setup

15 Pin D AUI Connector

100uH

39Ω

.01uf

AUITD AUIRD AUICD

200Ω200Ω

Obsolete

28 www.national.com

3.0 Configuration

This section includes information on the various conﬁgura-

tion options available with the DP83843. The conﬁguration

options described herein include:

— Auto-Negotiation

— PHY Address and LEDs

— Half Duplex vs Full Duplex

— 100M Symbol mode

— 100BASE-FX mode

— 10M serial MII mode

— 10M AUI Mode

— Repeater vs. Node

— Isolate mode

— Loopback mode

3.1 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 per-

formance mode of operation supported by both devices.

Fast Link Pulse (FLP) Bursts provide the signaling 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 DP83843 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 high-

est performance protocol will be selected based on the

ability of the Link Partner. The Auto-Negotiation function

within the DP83843 can be controlled either by internal

3.1.1 Auto-Negotiation Pin Control

The state of AN0 and AN1 determines whether the

DP83843 is forced into a speciﬁc mode or Auto-Negotiation

will advertise a speciﬁc ability (or set of abilities) as given in

Table 3. Pins AN0 and AN1 are implemented as three-level

control pins which are conﬁgured by connecting them to

VCC, GND, or by leaving them unconnected (refer to

Figure 15). These pins allow conﬁguration options to be

selected without requiring internal register access.

It should be noted that due to the internal resistor networks

depicted in Figure 15, the AN0 or AN1 should be con-

nected directly to either VCC or GND, depending on the

requirements. These pins should never be resistively tied to

VCC or GND as this will interfere with the internal pull-up

and pull-down resistors resulting in improper Auto-Negotia-

tion behavior.

The state of AN0 and AN1, upon power-up/reset, deter-

mines the state of bit 9 in the PHYSTS register (address

10h) as well as bits [8:5] of the ANAR register (address

04h).

Upon power-up/reset the DP83843 uses default register

values, which enables Auto-Negotiation and advertises the

full set of abilities (10 Mb/s Half Duplex, 10 Mb/s Full

Duplex, 100 Mb/s Half Duplex, and 100 Mb/s Full Duplex)

unless subsequent software accesses modify the mode.

The status of Auto-Negotiation as a function of hardware

conﬁguration via the AN0 and AN1 pins is reﬂected in bit 9

of the PHYSTS register (address 10h).

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 00h.

3.1.2 Auto-Negotiation Register Control

When Auto-Negotiation is enabled, the DP83843 transmits

the abilities programmed into the Auto-Negotiation Adver-

tisement register (ANAR) at address 04h via FLP Bursts.

Any combination of 10 Mb/s, 100 Mb/s, Half-Duplex, and

Full Duplex modes may be selected. The default setting of

bits [8:5] in the ANAR and bit 9 in the PHYSTS register

(address 10h) are determined at power-up or hard reset by

the state of the AN0 and AN1 pins.

The BMCR provides software with a mechanism to control

the operation of the DP83843. However, the AN0 and AN1

pins do not affect the contents of the BMCR and cannot be

used by software to obtain status of the mode selected.Bits

1 & 2 of the PHYSTS register (address 10h) are only valid

if Auto-Negotiation is disabled or after Auto-Negotiation is

complete.

The contents of the ANLPAR register are used to automati-

cally conﬁgure to the highest performance protocol

between the local and far-end ports. Software can deter-

mine which mode has been conﬁgured by Auto-Negotiation

by comparing the contents of the ANAR and ANLPAR reg-

isters and then selecting the technology whose bit is set in

both the ANAR and ANLPAR of highest priority relative to

the following list.

Figure 15. 3 Level Hardware Configuration Pin Control

DECODER

GND

OUT

VIN

VCC VHVIN A B OUT

0V L L L

VCC /2 L H M

VCC H H H

Obsolete

3.0 Configuration (Continued)

29 www.national.com

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 of enabling, disabling, and restarting of the

Auto-Negotiation function. When Auto-Negotiation is dis-

abled the Speed Selection bit in the BMCR (bit 13, register

address 00h) controls switching between 10 Mb/s or 100

Mb/s operation, while the Duplex Mode bit (bit 8, register

address 00h) controls switching between full duplex opera-

tion 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 (bit 12, register

address 00h) is set.

The Basic Mode Status Register (BMSR) at address 01h

indicates the set of available abilities for technology types

(bits 15 to 11, register address 01h), Auto-Negotiation abil-

ity (bit 3, register address 01h), and Extended Register

Capability (bit 0, register address 01h). These bits are per-

manently set to indicate the full functionality of the

DP83843 (only the 100BASE-T4 bit is not set since the

DP83843 does not support that function, while it does sup-

port all the other functions).

The BMSR also provides status on:

— Whether Auto-Negotiation is complete (bit 5, register ad-

dress 01h)

— Whether the Link Partner is advertising that a remote

fault has occurred (bit 4, register address 01h)

— Whether a valid link has been established (bit 2, register

address 01h)

— Support for Management Frame Preamble suppression

(bit 6, register address 01h)

The Auto-Negotiation Advertisement Register (ANAR) at

address 04h indicates the Auto-Negotiation abilities to be

advertised by the DP83843. All available abilities are trans-

mitted by default, but any ability can be suppressed by writ-

ing to the ANAR. Updating the ANAR to suppress an ability

is one way for a management agent to change (force) the

technology that is used.

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.

If Next Page is NOT being used, then the ANLPAR will

store the base link code word (link partner's abilities) and

retain this information from the time the page is received,

as indicated by a 1 in bit 1 of the Auto-Negotiation Expan-

sion Register (ANER, register address 06h), through the

end of the negotiation and beyond.

When using the next page operation, the DP83843 cannot

wait for Auto-Negotiation to complete in order to read the

ANLPAR because the register is used to store both the

Table 3. Auto-Negotiation Mode Select

AN1

(Pin 3) AN0

(Pin 4) Action Mode

FORCED MODES

0 M PHYSTS (10h) Bit 9 = 0, Bit 1 = 1, Bit 2 = 0

ANAR (04h) [8:0] = 021h 10BASE-T, Half-Duplex without Auto-Negotiation

1 M PHYSTS (10h) Bit 9 = 0, Bit 1 = 1, Bit 2 = 1

ANAR (04h) [8:0] = 041h 10BASE-T, Full Duplex without Auto-Negotiation

M 0 PHYSTS (10h) Bit 9 = 0, Bit 1 = 0, Bit 2 = 0

ANAR (04h) [8:0] = 081h 100BASE-X, Half-Duplex without Auto-Negotia-

tion

M 1 PHYSTS (10h) Bit 9 = 0, Bit1 = 0, Bit 2 = 1

ANAR (04h) [8:0] = 101h 100BASE-X, Full Duplex without Auto-Negotia-

tion

ADVERTISED MODES

M M PHYSTS (10h) Bit 9 = 1

ANAR (04h) [8:0] = 1E1h All capable (i.e. Half-Duplex & Full Duplex for

10BASE-T and 100BASE-TX) advertised via

Auto-Negotiation

0 0 PHYSTS (10h) Bit 9 = 1

ANAR (04h) [8:0] = 061h 10BASE-T, Half-Duplex & Full Duplex advertised

via Auto-Negotiation

0 1 PHYSTS (10h) Bit 9 = 1

ANAR (04h) [8:0] = 181h 100BASE-TX, Half-Duplex & Full Duplex adver-

tised via Auto-Negotiation

1 0 PHYSTS (10h) Bit 9 = 1

ANAR (04h) [8:0] = 0A1h 10BASE-T & 100BASE-TX, Half-Duplex adver-

tised via Auto-Negotiation

1 1 PHYSTS (10h) Bit 9 = 1

ANAR (04h) [8:0] = 021h 10 BASE-T, Half-Duplex advertised via Auto-Ne-

gotiation.

Note: “M” indicates logic mid level (Vcc/2), “1” indicates logic high level, “0” indicates logic low level.

Obsolete

3.0 Configuration (Continued)

30 www.national.com

base and next pages. Software must be available to per-

form several functions. The ANER (register 6) must have a

page received (bit 1), once the DP83843 receives the ﬁrst

page, software must store it in memory if it wants to keep

the information. Auto-Negotiation keeps a copy of the base

page information but it is no longer accessible by software.

After reading the base page information, software needs to

write to ANNPTR (register 7) to load the next page informa-

tion to be sent. Continue to poll the page received bit in the

ANER and when active read the ANLPAR. The contents of

the ANLPAR will tell if the partner has further pages to be

sent. As long as the partner has more pages to send, soft-

ware must write to the next page transmit register and load

another page.

The Auto-Negotiation Expansion Register (ANER) at

address 06h indicates additional Auto-Negotiation status.

The ANER provides status on:

— Whether a Parallel Detect Fault has occurred (bit 4, reg-

ister address 06h)

— Whether the Link Partner supports the Next Page func-

tion (bit 3, register address 06h)

— Whether the DP83843 supports the Next Page function

(bit2, register address06h).The DP83843doessupport

the Next Page function.

— Whether the current page being exchanged by Auto-Ne-

gotiation has been received (bit1, register address 06h)

— Whether the Link Partner supports Auto-Negotiation (bit

0, register address 06h)

The Auto-Negotiation Next Page Transmit Register

(ANNPTR) at address 07h contains the next page code

word to be sent. See Table 13 for a bit description of this

3.1.3 Auto-Negotiation Parallel Detection

The DP83843 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 moni-

tor the receive signal and report link status to the Auto-

Negotiation function. Auto-Negotiation uses this informa-

tion to conﬁgure the correct technology in the event that the

Link Partner does not support Auto-Negotiation yet is

transmitting link signals that the 100BASE-X or 10BASE-T

PMAs recognize as valid link signals.

The Auto-Negotiation function will only accept a valid link

signal for the purpose of Parallel Detection from PMAs

which have a corresponding bit set in the Auto-Negotiation

Advertisement register, (ANAR register bits 5 and 7,

address 04h.) This allows the DP83843 to be conﬁgured

for 100 Mb/s only, 10 Mb/s only, or 10 Mb/s & 100 Mb/s

CSMA/CD operation depending on the advertised abilities.

The state of these bits may be modiﬁed via the AN0 and

AN1 pins or by writing to the ANAR. For example, if bit 5 is

zero, and bit 7 is one in the ANAR (i.e. 100 Mb/s CSMA/CD

only), and the Link Partner is 10BASE-T without Auto-

Negotiation, then Auto-Negotiation will not complete since

the advertised abilities and the detected abilities have no

common mode. This operation allows the DP83843 to be

used in single mode (i.e. repeater) applications as well as

dual mode applications (i.e. 10/100 nodes or switches).

If the DP83843 completes Auto-Negotiation as a result of

Parallel Detection, without Next Page operation, bits 5 and

7 within the ANLPAR register (register address 05h) will be

set to reﬂect the mode of operation present in the Link Part-

ner. 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 (bit 0,

bit (bit 5, register address 01h) is set. If conﬁgured for par-

allel detect mode and any condition other than a single

good link occurs then the parallel detect fault bit will set (bit

4, register 06h).

3.1.4 Auto-Negotiation Restart

Once Auto-Negotiation has completed, it may be restarted

at any time by setting bit 9 of the BMCR to one. If the mode

conﬁgured by a successful Auto-Negotiation loses a valid

link, then the Auto-Negotiation process will resume and

attempt to determine the conﬁguration for the link. This

function ensures that a valid conﬁguration is maintained if

the cable becomes disconnected.

A renegotiation request from any entity, such as a manage-

ment agent, will cause the DP83843 to halt any transmit

data and link pulse activity until the break_link_timer

expires (~1500ms). Consequently, the Link Partner will go

into link fail and normal Auto-Negotiation resumes. The

DP83843 will resume Auto-Negotiation after the

break_link_timer has expired by issuing FLP (Fast Link

Pulse) bursts.

3.1.5 Enabling Auto-Negotiation via Software

It is important to note that if the DP83843 has been initial-

ized upon power-up as a non-auto-negotiating device

(forced technology), and it is then required that Auto-Nego-

tiation or re-Auto-Negotiation be initiated via software, bit

12 of the Basic Mode Control Register (address 00h) must

ﬁrst be cleared and then set for any Auto-Negotiation func-

tion to take effect.

3.1.6 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 com-

plete, depending on the number of next pages sent.

Refer to chapter 28 of the IEEE 802.3u standard for a full

description of the individual timers related to Auto-Negotia-

tion.

Auto-Negotiation Next Page Support

The DP83843 supports the optional Auto-Negotiation Next

Page protocol. The ANNPTR register (address 07h) allows

for the conﬁguration and transmission of Next Page. Refer

to clause 28 of the IEEE 802.3u standard for detailed infor-

mation regarding the Auto-Negotiation Next Page function.

3.2 PHY Address and LEDs

The DP83843 maps the 5 PHY address input pins onto the

5 LED output pins as:

LED_COL <=> PHYAD[0]

LED_TX <=> PHYAD[1]

LED_RX <=> PHYAD[2]

LED_LINK <=> PHYAD[3]

LED_FDPOL <=> PHYAD[4]

The DP83843 can be set to respond to any of 32 possible

PHY addresses. Each DP83843 connected to a common

serial MII must have a unique address. It should be noted

Obsolete

3.0 Configuration (Continued)

31 www.national.com

that while an address selection of all zeros <00000> will

result in PHY Isolate mode, this will not effect serial man-

agement access.

The state of each of the PHYAD inputs are latched into the

PHYCTRL register bits [4:0] (address 19h) at system

power-up/reset depending on whether a pull-up or pull-

down resistor has been installed for each pin. For further

detail relating to the latch-in timing requirements of the

PHY Address pins, as well as the other hardware conﬁgu-

ration pins, refer to the Reset summary in Section 5.

Since the PHYAD strap options share the LED output pins,

the external components required for strapping and LED

usage must be considered in order to avoid contention.

Additionally, the sensing and auto polarity feature of the

LED must be taken into account.

Speciﬁcally, these LED outputs can be used to drive LEDs

directly, or can be used to provide status information to a

network management device. The active state of each LED

output driver is dependent on the logic level sampled by the

corresponding PHYAD input upon power-up / reset. For

example, if a given PHYAD input is resistively pulled low

(nominal 10 kΩresistor recommended) then the corre-

sponding LED output will be conﬁgured as an active high

driver. Conversely, if a given PHYAD input is resistively

pulled high, then the corresponding LED output will be con-

ﬁgured as an active low driver. Refer to Figure 16 for an

example of LED & PHYAD connection to external compo-

nents where, in this example, the PHYAD strapping results

in address 00011 or hex 03h or decimal 3.

The adaptive nature of the LED outputs helps to simplify

potential implementation issues of these dual purpose

pins.

Refer to the PHYCTRL register (address 19h) bits [8:6] for

further information regarding LED operations and conﬁgu-

ration.

3.3 Half Duplex vs. Full Duplex

The DP83843 supports both half and full duplex operation

at both 10 Mb/s and 100 Mb/s speeds.

Half-duplex is the standard, traditional mode of operation

which 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

compliant to the IEEE 802.3 speciﬁcation.

Since the DP83843 is architected to support simultaneous

transmit and receive activity it is capable of supporting full-

duplex switched applications with an aggregate throughput

of up to 200 Mb/s when operating in 100BASE-X mode.

Because the CSMA/CD protocol does not apply to full-

duplex operation, the DP83843 simply disables its own

internal collision sensing and reporting functions and modi-

ﬁes the behavior of Carrier Sense (CRS) such that it indi-

cates only receive activity to allow the full-duplex capable

MAC to operate properly.

All modes of operation (100BASE-TX, 100BASE-FX,

10BASE-T (both nibble and serial)) can run full-duplex

although it should be noted that full-duplex operation does

not apply to typical repeater implementations or AUI appli-

cations. Additionally, other than CRS and Collision report-

ing, all remaining MII signaling remains the same

regardless of the selected duplex mode.

Figure 16. PHYAD Strapping and LED Loading Example

LED_COL/PHYAD[0]

LED_TX/PHYAD[1]

LED_RX/PHYAD[2]

LED_LINK/PHYAD[3]

LED_FDPOL/PHYAD[4]

VCC VCC

1κΩ

10 κΩ

1 κΩ

10 κΩ

1 κΩ

10 κΩ

1 κΩ

10 κΩ

1κΩ

Obsolete

3.0 Configuration (Continued)

32 www.national.com

It is important to understand that while full Auto-Negotiation

with the use of Fast Link Pulse code words can interpret

and conﬁgure to support full-duplex, parallel detection can

not recognize the difference between full and half-duplex

from a ﬁxed 10 Mb/s or 100 Mb/s link partner over twisted

pair. Therefore, as speciﬁed in 802.3u, if a far-end link part-

ner is transmitting forced full duplex 100BASE-TX for

example, the parallel detection state machine in the receiv-

ing station would be unable to detect the full duplex capa-

bility of the far-end link partner and would negotiate to a

half duplex 100BASE-TX conﬁguration (same scenario for

10 Mb/s).

3.4 100 Mb/s Symbol Mode

In Symbol mode, all of the conditioning blocks in the trans-

mit and receive sections of the 100BASE-X section are

bypassed. The 100BASE-X serial data received at the

RD+/− inputs of the DP83843 are recovered by the inte-

grated PMD receiver, shifted into 5-bit parallel words and

presented to the MII receive outputs RXD[3:0] and

RX_ER/RXD[4]. All data, including Idles, passes through

the DP83843 unaltered other than for serial/parallel conver-

sions.

Similarly, the TX_ER input pin is conﬁgured as the new

MSB (TXD[4]) to support the unaligned 5 bit transmit data.

All data, including Idles, passes through the DP83843 unal-

tered other than for serial/parallel conversions.

While in Symbol mode RX_DV and COL are held low and

TX_ER is used as the ﬁfth bit and no longer functions as

TX_ER. Additionally, the CRS output reports the state of

signal detect as generated internally for 100BASE-TX and

externally for 100BASE-FX.

Symbol mode can be used for those applications where the

system design requires only the integrated PMD, clock

recovery, and clock generation functions of the DP83843.

This is accomplished either by conﬁguring the CRS/SYM-

BOL pin (pin 22) of the DP83843 to a logic low level prior to

power-up/reset or by setting bits 10 and 11 (BP_TX and

BP_RX respectively) of the LBR register (address 17h)

through the serial MII port. Symbol mode only applies to

100BASE-X operation.

3.5 100BASE-FX Mode

The DP83843 will allow 100BASE-FX functionality by

bypassing the scrambler and descrambler and routing the

PECL serial transmit and receive data through the separate

FXTD/AUITD outputs and FXRD/AUIRD inputs respec-

tively. Additionally, the signal detect indication from the opti-

cal transceiver is handled by the FXSD inputs. Placing the

DP83843 in 100BASE-FX mode disables the TPTD and

TPRD transmit and receive pin pairs.

Conﬁguring the DP83843 for 100BASE-FX mode can be

accomplished either through hardware conﬁguration or via

software.

The hardware conﬁguration is set simply by tying the

COL/FXEN pin (21) to a logic low level prior to power-

on/reset. The software setting is accomplished by setting

the BP_SCR bit (bit 12) of the LBR register (address 17h)

via MII serial management.

The DP83843 can support either half-duplex or full-duplex

operation while in 100BASE-FX mode. Additionally, all MII

signaling remains identical to that of 100BASE-TX opera-

tion.

Please refer to Section 2.2 for more information regarding

100BASE-FX operation.

3.6 10 Mb/s Serial Mode

The DP83843 allows for serial MII operation. In this mode,

the transmit and receive MII data transactions occur seri-

ally at a 10 MHz clock rate on the least signiﬁcant bits

(RXD[0] and TXD[0]) of the MII data pins. This mode is

intended for use with a MAC based on a 10 Mb/s serial

interface.

While the MII control signals (CRS, RX_DV, TX_DV, and

TX_EN) as well as RX_EN and Collision are still used dur-

ing 10 Mb/s Serial mode, some of the timing parameters

are different. Refer to Section 8 for AC timing details.

Both 10BASE-T and AUI can be conﬁgured for Serial

mode. Serial mode is not supported for 100 Mb/s opera-

tion.

Serial mode can be selected via hardware by forcing the

SERIAL10 pin (pin 69) to a logic low level prior to power-

up/reset. The state of the SERIAL10 pin is latched into bits

11 and 12 of the 10BTSCR register (address 18h) as a

result of power-up/reset. These bits can be written through

software to control serial mode operation.

While in 10 Mb/s serial mode, RXD[3:1] will be placed in

TRI-STATE mode and RX_DV asserts coincident with CRS.

3.7 10 Mb/s AUI Mode

Placing the DP83843 in AUI mode enables the

FXTD/AUITD, FXRD/AUIRD, and FXSD/CD pin pairs to

allow for any AUI compliant external transceivers to be con-

nected to the AUI interface. Placing the DP83843 in 10

Mb/s AUI mode disables the TPTD and TPRD transmit and

receive pin pairs.

The DP83843 also incorporates a THIN output control pin

for use with traditional AUI based CTI transceivers. This

output follows the state of bit 3 in the 10BTSCR register

accessible through the serial MII.

The AUI/TP autoswitching allows transceiver autoswitching

between the AUI and TP outputs. At power up, the

autoswitch function is deselected in the 10BTSCR register

(bit 9 = 0) and the current mode, AUI or TP, is reported by

the bit 13 of the 10BTSCR register (low for TPI and high for

AUI).

When the auto-switch function is enabled (bit 9 = 1), it

allows the transceiver to automatically switch between TPI

and AUI I/O’s. If there is an absence of link pulses, the

transceiver switches to AUI mode. Similarly, when the

transceiver starts detecting link pulses, it switches to TP

mode. Switching from one mode to the other is done only

after the current packet has been transmitted or received. If

the twisted pair output is jabbering and it gets into link fail

state, then the switch to AUI mode is done only after the

jabbering has stopped, including the time it takes to unjab

(unjab time). Also, if TPI mode is selected, transmit packet

data are driven only by the TPI outputs and the AUI trans-

mit outputs remain idle. Similar behavior applies when AUI

mode is selected. The only difference in AUI mode is that

the TP drivers continue to send link pulses; however, no

packet data is transmitted. The TPI receive circuitry and

the Link Integrity state machine are always active to enable

this algorithm to function as described above.

Obsolete

3.0 Configuration (Continued)

33 www.national.com

3.8 Repeater vs. Node

The DP83843 Carrier Sense (CRS) operation depends on

the value of the Repeater bit in the PHYCTRL register (bit

9, address 19h). When set high, the CRS output (pin 22) is

asserted for receive activity only. When set low, the CRS

output is asserted for either receive or transmit activity. The

default value for this bit is set by the THIN/REPEATER pin

(pin 63) at power-up/reset.

There is an internal pullup resistor for this pin which is

active during the power-up/reset period. If this pin is left

ﬂoating externally, then the device will conﬁgure to

Repeater mode as a result of power-up/reset. This pin

must be externally pulled low (typically 10 kΩ) in order to

conﬁgure the DP83843 for node operation.

When the repeater mode of operation is selected during

100 Mb/s operation, there are two parameters that are

directly effected.

First, CRS will only respond to receive activity.

Second, in compliance with the 802.3 standard, the Carrier

Integrity Monitor (CIM) function is automatically enabled for

detection and reporting of bad start of stream delimiters

(whereas in node mode the CIM is disabled).

The Dp83843 does not support 10Mb/s repeater applica-

tions.

3.9 Isolate Mode

An IEEE 802.3u compliant PHY connected to the mechani-

cal MII interface is required to have a default value of one in

bit 10 of the Basic Mode Control Register (BMCR, address

00h.) The DP83843 will set this bit to one if the PHY

Address is set to 00000 upon power-up/hardware reset.

Otherwise, the DP83843 will set this bit to zero upon

power-up/hardware reset. Refer to Section 2.4.2 for infor-

mation relating to the requirements for selecting a given

PHYAD.

With bit 10 in the BMCR set to one the DP83843 does not

respond to packet data present at TXD[3:0], TX_EN, and

TX_ER inputs and presents a high impedance on the

TX_CLK, RX_CLK, RX_DV, RX_ER, RXD[3:0], COL, and

CRS outputs. The DP83843 will continue to respond to all

management transactions.

While in Isolate mode, the TD+/− outputs will not transmit

packet data but will continue to source 100BASE-TX

scrambled idles or 10BASE-T normal link pulses.

3.10 Loopback

The DP83843 includes a Loopback Test mode for easy

board diagnostics. The Loopback mode is selected through

bit 14 (‘Loopback’) of the Basic Mode Control Register

(BMCR). The status of this mode may be checked in bit 3

of the PHY Status Register. Writing 1 to this bit enables MII

transmit data to be routed to the MII receive outputs. In

Loopback mode the data will not be transmitted on to the

media. This occurs for either 10 Mb/s or 100 Mb/s data.

Normal 10BASE-T, 10BASE-2, or 10BASE-5 operation, in

order to be standard compliant, also loops back the MII

transmit data to the MII receive data. However the data is

also allowed to be transmitted out the AUI or TP ports

(depending on the mode).

In 100 Mb/s Loopback mode the data is routed through the

PCS and PMA layers into the PMD sublayer before it is

looped back. Therefore, in addition to serving as a board

diagnostic, this mode serves as quick functional veriﬁcation

of the device.

In addition to Loopback mode, there are many other test

modes that serve similar loopback functions. These modes

are mutually exclusive with Loopback mode, enabling

Loopback mode disables the following test modes:

— CP_Loop(bits9:7)oftheLoopbackandBypassRegister

(LBR). These bits control the 100 Mb/s loopback func-

tions in more depth. A write of either a 0 or 1 to ‘Loop-

back’ causes these bits to be set to <000> which is

normal operation. At reset if FXEN is true then this will

default to, <011> which is Normal Fiber operation, other-

wise it will default to <000>. The other modes are ex-

plained in the LBR definition table.

— Dig_Loop (bit 6) of the LBR. Digital loopback is used to

place the digital portions of the DP83843 into loopback

prior to the signals entering the analog sections. A write

of eithera0or1to‘Loopback’ causes this bits to be set

to 0 which is digital loopback disabled.

Bit 5 and Bit 4 of the LBR are automatically enabled in

Loopback mode. They are TWISTER (100 Mb/s) loopback

and TREX (10 Mb/s) loopback modes respectively.

Obsolete

34 www.national.com

4.0 Clock Architecture

The DP83843 incorporates a sophisticated Clock Genera-

tion Module (CGM) design which allows full operation sup-

porting all modes with a single 25 MHz (±50 ppm) CMOS

level reference clock. As depicted in Figure 17, the single

25 MHz reference serves both the 100 Mb/s and 10 Mb/s

mode clocking requirements.

The DP83843 also incorporates Clock Recovery circuitry

(CRM) which extracts the 125 MHz clock from the 125

Mb/s receive datastream present during 100BASE-TX and

100BASE-FX applications (Figure 17).

The 10 Mb/s receive clock requirements are handled by a

PLL which is tuned to extract a clock from either 10BASE-T

or AUI receive Manchester encoded data streams

(Figure 17).

4.1 Clock Generation Module (CGM)

For 100 Mb/s operation, the external 25 MHz reference is

routed to a 250 MHz voltage controlled oscillator. The high

frequency output from the oscillator is divided by two and

serves to clock out the 125Mb/s serial bit stream for

100BASE-TX and 100BASE-FX applications. The 125

MHz clock is also routed to a counter where it is divided by

5 to produce the 25 MHz TX_CLK signal for the transmit

MII. Additionally, a set of phase related 250 MHz clock sig-

nals are routed to the Clock Recovery Module (CRM)

which act as a frequency reference to ensure proper opera-

tion.

For 10 Mb/s operation, the external 25 MHz reference is

routed to a 100 MHz voltage controlled oscillator. The high

frequency output from the oscillator is divided by ﬁve and

serves to clock out the 10BASE-T or AUI serial bit stream

for 10 Mb/s applications. The 100 MHz clock is also routed

to a counter where it is divided by either eight or two to pro-

duce the 2.5 MHz or 10 MHz TX_CLK signal for the trans-

mit MII. Additionally, a set of phase related 100 MHz clock

signals are routed to the Clock Recovery Module (CRM)

which act as a frequency reference to ensure proper opera-

tion.

Figure 17. Clock Generation Module BLOCK DIAGRAM

VCO

(250 MHz)

25 MHz

input

Divide

by 2

Divide by 5 25 MHz

125 MHz serial

transmit clock

Ref Clock to CRM

VCO

(100 MHz) Divide

by 5 20 MHz 10BASE-T

transmit clock

Ref Clock to CRM

2.5 MHz or 10 MHz

MII TX_CLK

Divide

by 8

or 2

100M CLOCKING

10M CLOCKING

MII TX_CLK

Obsolete

4.0 Clock Architecture (Continued)

35 www.national.com

Figure 18. 100BASE-X Clock Recovery Module block diagram

Figure 19. 10M Manchester Clock Recovery Module block diagram

25 MHz

Phase

Detector

Divide by 2

Phase Error

Processor

Digital Loop

Filter

Phase to

Frequency

Converter

Frequency

Controlled

Oscillator

Deserializer

Frequency

Reference

From CGM

125Mb/s

Serial Data

Input

RX_CLK

RXD [4:0]

Phase

Detector

& CRS Filter Phase

Selector

Clk Gen

Serial /

Nibble

MUX Deserializer

CRS

10 MHz

RX_CLK

RXD[0]

Serial Data

RXD[3:0]

2.5 MHz

RX_CLK

10 Mb/s

Serial Data

Input Frequency

Reference

From CGM

Obsolete

4.0 Clock Architecture (Continued)

36 www.national.com

4.2 100BASE-X Clock Recovery Module

The diagram in Figure 18 illustrates a high level block archi-

tecture of the 100BASE-X Clock Recovery circuit. The

125Mb/s serial binary receive data stream that has been

recovered by the integrated TP-PMD receiver is routed to

the input of the phase detector. A loop consisting of the

phase detector, phase error processor, digital loop ﬁlter,

phase to frequency converter, and the frequency controlled

oscillator then works to synthesize a 125 MHz clock based

on the receive data stream. This clock is used to latch the

serial data into the deserializer where the data is then con-

verted to 5-bit code groups for processing by descrambler,

code-group alignment, and code-group decoder functional

blocks.

4.3 10 Mb/s Clock Recovery Module

The diagram in Figure 19 illustrates a high level block archi-

tecture of the 10 Mb/s Clock Recovery circuit. The 10 Mb/s

serial Manchester receive data stream, from either the

10BASE-T or AUI inputs, is routed to the input of the phase

detector. A loop consisting of the phase detector, digital

loop ﬁlter, phase selector, and the frequency generator

then works to synthesize a 20 MHz clock based on the

receive data stream. This clock is used to latch the serial

data into the deserializer where the data is then optionally

converted to 4-bit code groups for presentation to the MII

as nibble wide data clocked out at 2.5 MHz. Optionally, the

deserializer can be bypassed and the 10 Mb/s data is

clocked out serially at 10 MHz.

As a function of the Phase Detector, upon recognizing an

incoming 10 Mb/s datastream, Carrier Sense (CRS) is gen-

erated for use by the MAC.

4.4 Reference Clock Connection Options

The two basic options for connecting the DP83843 to an

external reference clock consist of the use of either an

oscillator or a crystal. Figure 20 and 21 illustrate the rec-

ommended connection for the two typical options.

Figure 20. Oscillator Reference Clock Connection Diagram

Figure 21. Xtal Reference Clock Connection Diagram

25 MHz

Osc 50ppm

n/c

33pF

25 MHz

Xtal 50ppm

Obsolete

37 www.national.com

5.0 Reset Operation

The DP83843 can be reset either by hardware or software.

A hardware reset may be accomplished either by asserting

the RESET pin during normal operation, or upon powering

up the device. A software reset is accomplished by setting

the reset bit in the Basic Mode Control Register.

While either the hardware or software reset can be imple-

mented at any time after device initialization, providing a

hardware reset, as described in Section 6.2 must be

implemented upon device power-up/initialization.

Omitting the hardware reset operation during the

device power-up/initialization sequence can result in

improper device operation.

Depending on the crystal starting up time, it is recom-

mended to wait 20 ms after the supply has reached its

proper value before initiating a hardware reset.

5.1 Power-up / Reset

When VCC is ﬁrst applied to the DP83843 it takes some

amount of time for power to actually reach the nominal 5V

potential. This initial power-up time can be referred to as a

VCC ramp when VCC is “ramping” from 0V to 5V. When the

initial VCC ramp reaches approximately 4V, the DP83843

begins an internal reset operation which must be allowed

sufﬁcient time, relative to the assertion and deassertion of

the RESET pin, to reset the device. There are two methods

for guaranteeing successful reset upon device power-up.

The ﬁrst method accounts for those designs that utilize a

special power up circuit which, through hardware, will

assert the RESET pin upon power-up. In this case, the

deassertion (falling edge) of the RESET pin must not occur

until at least 500 µs after the time at which the VCC ramp

initially reached the 4V point.

The second method accounts for those applications which

produce a reset pulse sometime after the initial power-up of

the device. In this case, it is recommended that a positive

pulse, with a duration of at least 1 µs, be applied to the

RESET pin no sooner than 500 µs after the point in time

where the initial VCC ramp reached 4V.

In both methods described above, it is important to note

that the logic levels present at each of the hardware conﬁg-

uration pins of the DP83843 (see list below) are also

latched into the device as a function of the reset operation

(either hardware or software). These hardware conﬁgura-

tion values are guaranteed to be latched into the DP83843

2µs after the deassertion of the RESET pin.

The hardware conﬁguration values latched into the

DP83843 during the reset operation are dependent on the

logic levels present at the device pins shown in Table 4

upon power-up.

During the power-up/ reset operation the LED1 through

LED5 pins are undeﬁned, the SPEED10 will be asserted.

The 25 MHz clock reference must be applied for reset to

take effect.

5.2 Hardware Reset

A hardware reset is accomplished by applying a positive

pulse (TTL level), with a duration of at least 1 µs, to the

RESET pin of the DP83843 during normal operation. This

will reset the device such that all registers will be reset to

default values and the hardware conﬁguration values will

be re-latched into the device (similar to the power-up/reset

operation).

5.3 Software Reset

A software reset is accomplished by setting the reset bit (bit

15) of the Basic Mode Control register (address 00h). This

bit is self clearing and, when set, will return a value of “1”

until the software reset operation has completed. The

period from the point in time when the reset bit is set to the

point in time when software reset has concluded is approx-

imately 5 µs.

The software reset will reset the device such that all regis-

ters will be reset to default values and the hardware conﬁg-

uration values will be re-latched into the device (similar to

the power-up/reset operation). Driver code should wait 500

µs following a software reset before allowing further serial

MII operations with the DP83843.

Table 4. Latched pins at Reset

Pin # Primary Function Latched in at Reset

21 COL FXEN

22 CRS SYMBOL

38 LED_FDPOL PHYAD4

39 LED_LINK PHYAD3

40 LED_RX PHYAD2

41 LED_TX PHYAD1

42 LED_COL PHYAD0

63 THIN REPEATER

69 SERIAL10 SERIAL10

Obsolete

38 www.national.com

6.0 DP83843 Application

6.1 Typical Node Application

Figure 22 illustrates a typical implementation of a 10/100

Mb/s node application. This is given only to indicate the

major circuit elements of such a design. It is not intended to

be a full circuit diagram. For detailed system level applica-

tion information please contact your local National sales

representative.

6.2 Power And Ground Filtering

Sufﬁcient ﬁltering between the DP83843 power and ground

pins placed as near to these pins as possible is recom-

mended. Figure 23 suggests one option for device noise ﬁl-

tering including special consideration for the sensitive

analog power pins.

6.3 Power Plane Considerations

The recommendations for power plane considerations pro- vided herein represent a more simpliﬁed approach when

compared to earlier recommendations. By reducing the

number of instances of plane partitioning within a given

Figure 22. Typical Implementation of 10/100 Mb/s Node Application

TXD0 (31)

TXD1 (30)

TXD2 (29)

TXD3 (28)

TX_ER (24)

TX_EN (25)

TX_CLK (33)

MDC (35)

MDIO (34)

RXD0 (15)

RXD1 (14)

RXD2 (13)

RXD3 (12)

RX_ER (19)

RX_DV (20)

RX_CLK (18)

CRS/SYMBOL (22)

COL/FXEN (21)

AN0 (4)

AN1 (3)

X1 (9)

X2 (8)

THIN/REPEATER (63)

RESET (1)

SPEED10 (5)

SERIAL10 (69)

(74) TPTD+

(73) TPTD-

(67) TPRD+

(65) TPRD-

(78) TXAR100

(43) FXTD+/AUITD+

(44) FXTD-/AUITD-

(50) FXRD+/AUIRD+

(49) FXRD-/AUIRD-

(48) FXSD+/CD+

(47) FXSD-/CD-

(60) TWREF

(61) BGREF

(66) VCM_CAP

(42) LED_COL/PHYAD0

(41) LED_TX/PHYAD1

(40) LED_RX/PHYAD2

(39) LED_LINK/PHYAD3

(38) LED_FDPOL/PHYAD4

NC (2)

NC (55)

NC (56)

NC (58)

NC (59)

NC (62)

RX_EN (23)

DP83843

33pF

25MHz Xtal

50ppm

Active High Reset

Input (500us min)

GND GND

Floating conﬁgures

the device for full

Auto-Negotiation NC

10KΩ

VDD

Management

{

Receive

{

Transmit

MII

10KΩ

1.5KΩ

49.9 Ω

TBD

This cap is an optional component for

control of transmit transition time. An

RJ45-8

49.9Ω49.9Ω

0.1uF

4.87KΩ

TWAGND

GND

TW_AVDD

directly to the

This point should be tied

GND

VCC

GND

VDD

1KΩ

10KΩ10KΩ

10KΩ

This conﬁguration results

in a PHY address of 00001

0.0033uF

TW_AVDD power pin

69.8KΩ

inital value of 10pF is suggested.

GND

Optional 10pF Cap

connected to the center

tap of the receive

transformer

49.9 Ω

GND

Optional 10pF Cap

connected to the center

tap of the transmit

transformer

--TX+

--TX-

100pF

GND

49.9Ω

3kV

--RX+

--RX-

GND

100pF

49.9Ω

3kV

Obsolete

6.0 DP83843 Application (Continued)

39 www.national.com

system design, empirical data has shown a resultant

improvement (reduction) in radiated emissions testing.

Additionally, by eliminating power plane partitioning within

the system VCC and system ground domains, speciﬁc

impedance controlled signal routing can remain uninter-

rupted.

Figure 24 illustrates a way of creating isolated power

sources using beads on surface traces. No power or

ground plane partitioning is implied or required.

By placing chassis ground on the top and bottom layers,

additional EMI shielding is created around the 125Mb/s sig-

nal traces that must be routed between the magnetics and

the RJ45-8 media connector. The example in Figure 24

assumes the use of Micro-Strip impedance control tech-

niques for trace routing.

Figure 23. Power and Ground Filtering for the DP83843

= FERRITE BEAD TDK # HF70ACB-321611T

ALL CAPS ARE 16V CERAMIC

DP83843

CD_GND0(#71),

TR_AVDD(#79)

TW_AGND(#64)

TW_AVDD(#68)

CD_VDD0(#72),

CPTW_DVDD(#54)

CP_AVDD(#52)

CP_AGND(#51)

AUIFX_VDD(#46)

AUIFX_GND(#45)

TR_AGND(#80)

VCC

GND

0.1UF

VCC

0.1UF

GND

CPTW_DVSS(#53)

VCC

VCC 0.1UF

0.001UF

0.1UF

0.0033UF

GND

ALTHOUGH THE FB’S TO GND REDUCE NOISE ON

THESE TWO CRITICAL PINS, THEY MAY INCREASE

EMI EMISSIONS. THEREFORE, DEPENDING ON

YOUR APPLICATION THEY MAY OR MAY NOT BE

A BENEFIT. GND

IO_VSS1(#7),

VCC FB

VCC

ATP_GND(#57)

GND

0.1UF

0.001UF

GND

VCC

0.0033UF

SUB_GND1(#70)

SUB_GND2(#77)

GND

10UF

CD_GND1(#75),

PCS_VSS(#11)

CD_VDD1(#76),

PCS_VDD(#10)

IO_VDD1(#6),

IO_VDD2(#16),

IO_VDD3(#26),

IO_VDD5(#36)

IO_VSS2(#17),

IO_VSS3(#27),

IO_VSS4(#32),

IO_VSS5(#37)

26ΩAT 100MHZ

Obsolete

6.0 DP83843 Application (Continued)

40 www.national.com

Figure 24. Typical plane layout recommendation for DP83843

Layer 1 (top)

Layer 2

Layer 3

Layer 4 (bottom)

Chassis

Ground

System Ground

Ground

Plane:

VCC

Planes:

Chassis

Ground

Plane:

DP83843 Magnetics RJ45

System

DP83843 Magnetics RJ45

System

VCC

DP83843 Magnetics RJ45

RJ45

Chassis Ground

DP83843 Magnetics

Signal Routing

Ground

System

VCC Signal Routing

Signal Routing

System VCC

Obsolete

6.0 DP83843 Application (Continued)

41 www.national.com

6.3.1 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 can

be implemented during the manufacturing process to

greatly reduce the occurrences of catastrophic ESD

events. After the system is assembled, internal compo-

nents are usually relatively immune from ESD events.

In the case of an installed Ethernet system however, the

network interface pins are still susceptible to external ESD

events. For example, a category 5 cable being dragged

across a carpet has the potential of developing a charge

well above the typical 2kV ESD rating of a semiconductor

device.

For applications where high reliability is required, it is rec-

ommended that additional ESD protection diodes be added

as shown below. There are numerous dual series con-

nected diode pairs that are available speciﬁcally for ESD

protection. The level of protection will vary dependent upon

the diode ratings. The primary parameter that affects the

level of ESD protection is peak forward surge current. Typi-

cal speciﬁcations for diodes intended for ESD protection

range from 500mA (Motorola BAV99LT1 single pair diodes)

to 12A (STM DA108S1 Quad pair array).

Since performance is dependent upon components used,

board impedance characteristics, and layout, the circuit

should be completely tested to ensure performance to the

required levels.

Figure 25. Typical DP83843 Network Interface with additional ESD protection

RJ-45

DP83843 10/100

TX±

RX±

Vcc

Pin 1

Pin 2

Pin 3

Pin 6

Diodes placed on the

device side of the isola-

tion transformer

Obsolete

42 www.national.com

7.0 User Information

7.1 Link LED While in Force 100Mb/s Good Link

Type:

Information Hardware

Problem:

The Good Link LED (LED_LINK pin 39) will not assert

when the DP83843BVJE is programmed to force good link

in 100Mb/s mode. However, as long as the DP83843BVJE

is conﬁgured for forced 100BASE-X operation and good

link is forced for 100M operation, it will still be able to trans-

mit data even though the good link LED is not lit.

Description:

When the DP83843BVJE is conﬁgured for forced good link

in 100Mb/s mode, by setting bit 6 of the PCS register

(address 16h), the LINK_LED pin will not assert unless an

internal state machine term, referred to as Cipher_In_Sync

(aka CIS), is asserted. The assertion of CIS is based on

the receive descrambler either being bypassed or becom-

ing synchronized with the receive scrambled data stream.

As long as the DP83843BVJE is conﬁgured for forced

100BASE-X operation however, setting bit 6 of the PCS

Solution / Workaround:

In order to assert the Link LED while in Forced Good Link

100Mb/s mode, the user may select one of two options:

1: After setting bit 6 of the PCS register (address 16h), the

user may connect the DP83843BVJE to a known good far-

end link partner that is transmitting valid scrambled IDLEs.

This will assert the internal CIS term and, in turn, assert

the Link LED.

2: After setting bit 6 of the PCS register (address 16h), the

user may then assert bit 12 of the LBR register (address

17h) to bypass the scrambler/descrambler. This will assert

the internal CIS term and, in turn, assert the Link LED. The

user should then clear bit 12 of the LBR register (address

17h) to re-engage the scrambler/descrambler to allow for

normal scrambled operation while in forced good link

100Mb/s mode.

7.2 False Link Indication When in Forced 10Mb/s

Type:

Informational Hardware

Problem:

The DP83843BVJE will indicate valid link status when

forced to 10Mb/s (without Auto-Negotiation) while receiving

100BASE-TX scrambled Idles.

Description:

The DP83843BVJE can incorrectly identify 100BASE-TX

scrambled Idles being received as valid 10BASE-T energy

and consequently indicate a valid link by the assertion of

the Link LED as well as by setting the Link Status bit (bit 2)

in the BMSR (reg 01h).

Solution / Workaround:

Do not force 10Mb/s operation. Instead, use Auto-Negotia-

tion to advertise 10BASE-T full and/or half duplex (as

desired) via the ANAR register (reg 04h)

By using Auto-Negotiation and only specifying 10BASE-T

(either half or full duplex), the DP83843BVJE will recognize

the scrambled idles as a valid 100Mb/s stream, but it will

not complete the negotiation since it is not advertising

100Mb/s capability. In an application in which the user only

desires 10Mb/s operation and is being sent 100Mb/s sig-

nals, then the correct operation is to never complete the

negotiation.

7.3 10Mb/s Repeater Mode

Type:

Urgent Hardware

Problem:

The DP83843BVJE is not designed to support the use of

certain AUI attachments in repeater applications nor will it

directly support 10Mb/s repeater applications while in

10Mb/s serial or nibble mode.

Description:

When implementing repeater applications which include a

Coaxial Transceiver Interface (CTI) connected to the

DP83843 AUI interface, CRS will be asserted due to trans-

mit data because the transmit data is looped back to the

receive channel at the CTI transceiver. The assertion of

CRS during transmit will result in undue collisions at the

repeater controller.

Additionally, because there is no way to guarantee phase

alignment of the 10MHz TX_CLK between multiple

PHYTERs in a serial 10M repeater application (same is

true for 2.5MHz TX_CLK in 10Mb/s nibble mode), assum-

ing each PHYTER is referenced to a single 25MHz X1

clock signal, it is impossible to meet the input set and hold

requirements across all ports during a transmit operation.

Solution:

It is not recommended that the DP83843BVJE be used for

AUI repeater applications where the transmit data is looped

back to the receive channel at the transceiver. (i.e. CTI).

Additionally, 10M serial and nibble repeater applications

are not currently directly supported.

7.4 Resistor Value Modifications

Type:

Urgent Hardware

Problem:

To ensure optimal performance, the DP83843BVJE band-

gap reference and receive equalization reference resistor

values require updating.

Description:

The internal bandgap reference of the DP83843BVJE is

slightly offset which results in an offset in various IEEE

conformance parameters such as VOD.

The internal adaptive equalization reference bias is also

slightly offset which can result in slightly reduced maximum

cable length performance.

Solution / Workaround:

In order to set the proper internal bandgap reference, it is

recommended that the value of the resistor connected to

the BGREF pin (pin 61) be set to 4.87KΩ(1/10th Watt

resistor with a 1% tolerance is recommended). This resis-

tor should be connected between the BGREF pin and

TW_AGND.

In order to ensure maximum cable length performance for

100BASE-TX operation, it is recommended that a 70KΩ

Obsolete

43 www.national.com

resistor be placed between the TWREF pin (pin 60) and

TW_AGND. (1/10th Watt resistor with a 1% tolerance is

recommended)

7.5 Magnetics

Type:

Informational Hardware

Problem:

N/A

Description:

The DP83843BVJE has been extensively tested with the

following single package magnetics:

Valor PT4171 and ST6118

Bel Fuse S558-5999-39

Pulse H1086

Solution / Workaround:

Please note that one of the most important parameters that

is directly affected by the magnetics is 100BASE-TX Out-

put Transition Timing. Even with the Valor PT4171S mag-

netics, it is possible, depending on the system design,

layout, and associated parasitics, the output transition

times may need to be further controlled.

In order to help control the output transition time of the

100BASE-TX transmit signal, the user may wish to place a

capacitive load across the TPTD+/- pins as close to these

pins as possible. However, because every system is differ-

ent, it is suggested that the system designer experiment

with the capacitive value in order to obtain the desired

results.

Note that the board layout, the magnetics, and the output

signal of the DP83843BVJE each contribute to the ﬁnal rise

and fall times as measured across the RJ45-8 transmit

pins. It should be noted that excessive capacitive loading

across the TPTD+/- pins may result in improper transmit

return loss performance at high frequencies (up to 80MHz).

Finally, when performing 100Mb/s transmit return loss

measurements, it is recommended that the DP83843BVJE

be placed in True Quiet mode as described here:

In order to conﬁgure the PHYTER for "True Quiet" opera-

tion, the following software calls should occur via the serial

MII management port following normal initialization of the

device:

- Write 01h to register 1Fh (this enables the extended

- Write 02h to register 05h (this disables the NRZI

encoder, required for True Quiet)

- write 00h to register 1Fh (this exits the extended register

set)

- Set bit 9 of register 16h (this enables TX_QUIET which

stops transmitting 100M IDLEs))

7.6 Next Page Toggle Bit Initialization

Type:

Urgent Software

Problem:

The DP83843BVJE's Next Page Toggle bit initializes to 0

independent of the value programmed in bit 11 of the

Advertised Abilities Register (ANAR), Reg 4h

Description:

The Next Page Toggle bit is used only in Next Page opera-

tions, and is used to distinguish one page from another.

The AutoNegotiation speciﬁcation indicates that the toggle

bit should take on an initial value equal to that of bit 11 in

the ANAR, Reg 4h.

The DP83843BVJE incorrectly initializes this bit to 0, inde-

pendent of the setting of bit 11 in the ANAR. Note that this

bit is a RESERVED bit in the 802.3 speciﬁcation, and

defaults to 0 for all combinations of strap options.

If the user were to program both the Next Page bit, bit 15,

and the RESERVED bit, bit 11, to a logic 1 to perform a

next page type negotiation, and the partner node also sup-

ported next page operation, then the negotiation would not

complete due to the initial wrong polarity of the toggle bit.

Solution / Workaround:

Do not set RESERVED bit 11 (reg 04h) to a logic 1 if you

plan to perform next page operations.

7.7 Base Page to Next Page Initial FLP Burst

Spacing

Type:

Informational Hardware

Problem:

In performing Next Page Negotiation, the FLP burst spac-

ing on the initial burst when changing from the Base Page

to the Next Page can be as long as 28ms. The 802.3u

speciﬁcation, Clause 28 sets a maximum of 22.3ms. Thus,

there is a potential violation of 5.7ms.

Description:

This anomaly is due to the handshake between the arbitra-

tion and transmit state machines within the device. All other

FLP burst to burst spacings, either base page or next page,

will be in the range of 13ms to 15ms.

Note that the violating burst causes NO functional prob-

lems for either base page or next page exchange. This is

due to the fact that the nlp_test_max_timer in the receive

state machine has a minimum speciﬁcation of 50ms, and

the nlp_test_min_timer has a minimum speciﬁcation of

5ms. Thus, even if the transmitter waits 28ms vs. 22.3ms

between FLP bursts, the nlp_test_max_timer will not have

come close to expiring. (50 + 5 - 28) = 27ms slack time.

Solution.

NOT APPLICABLE, Not a functional problem

7.8 100Mb/s FLP Exchange Followed by Quiet

Type:

Informational Hardware

Problem:

The scenario is when the DP83843BVJE and another sta-

tion are BOTH using AutoNegotiation AND advertising

100mb full or half. If both units complete the FLP exchange

properly, but the partner does NOT send any idles (a

FAULT condition), then the DP83843BVJE will get into a

state in which it constantly sends 100mb idles and looks for

100mb idles from the partner.

Obsolete

44 www.national.com

Description:

The symptoms of this problem include:

will be cleared on read of this register (bit 1 = 1, then bit 1 =

0 if read twice)

Solution / Workaround:

The workarounds include (these are mutually exclusive):

1. Provide a 100mb data stream to the DP83843BVJE (fix

the problem)

2. Force 10mb mode by writing 0000h (half10) or 0100

(full10) to Register 0. This is a logical progression since

the 100mb side of the partner logic is down.

3. If you want to run AutoNegotiation again, with reduced

capabilities or all capabilities:

Turn off AutoNegotiation by writing a 0000h to Register 0.

(Need to do this to clear the DP83843 from sending idles.)

Change the capabilities to the desired conﬁguration by writ-

ing to Register 4 (0061 for full10/half10, or 0021 for half10

only, etc.)

Enable AutoNegotiation by writing a 1200 to Register 0.

(This restarts AutoNegotiation as well)

7.9 Common Mode Capacitor for EMI

improvement

Type:

Informational Hardware

Problem:

As with any high-speed design it is always practical to take

precautions regarding the design and layout of a system to

attempt to ensure acceptable EMI performance.

Description:

In an attempt to improve the EMI performance of a

DP83843BVJE based PCI Node Card, a 10pF capacitor

was installed from the center-tap of the primary winding of

the transmit transformer to gnd. This common mode capac-

itive ﬁltering improved (reduced) the EMI emissions by sev-

eral dB at critical frequencies when tested in an FCC

certiﬁed open ﬁeld test site.

Solution / Workaround:

It is recommended that the footprint for a typical ceramic

chip cap be included on all new DP83843BVJE based

designs to allow for the experimentation of EMI improve-

ment. Again, a component footprint for the 10pF capacitor

should be installed from the center-tap of the primary wind-

ing of the transmit transformer to system gnd. The inclusion

of this capacitor should have no deleterious effect on the

differential signalling of the transmitted signal. In fact,

because of the unique current source transmitter of the

DP83843BVJE, this center-tap cap has been shown to

actually improve some of the signal characteristics such as

rise/fall times and transmit return loss.

When including this component in a given design, it is rec-

ommended that it be connected from the transmit trans-

former primary center-tap directly to ground with an

absolute minimum of routing (preferably just an immediate

via to the ground plane).

7.10 BAD_SSD Event Lockup

Type:

Urgent Hardware

Problem:

When the PHYTER receives a particular invalid data

sequence, it can get stuck in the RX_DATA state with an

invalid alignment. It will not recover until the link is broken

or software intervenes. The required data sequence looks

like a bad_ssd event (I,J, followed by symbol with MSB=0),

followed eventually by a good IJK pattern before seeing 10

consecutive idle bits. The data pattern also has to show up

on a speciﬁc alignment.

Description:

Root cause is that the transition from BAD_SSD state to

the CARRIER_DET state, which can only occur if there is a

single IDLE between packets, does not cause a re-loading

of the data alignment. If the Bad SSD event which pre-

ceded this met certain conditions deﬁned above, then the

alignment logic is in an invalid state and the state machine

will not be able to detect an end of frame condition.

Solution:

There is no workaround available. Since the data pattern

should never occur on a normally operating network, it has

been decided that no corrective action is required for the

current product.

Obsolete

45 www.national.com

8.0 Register Block

8.1 Register Definitions

In the register deﬁnitions under the ‘Default’ heading, the following deﬁnitions hold true:

— RW = Read/Write; Register bit is able to be read and written to by software

— RO = Read Only; Register bit is able to be read but not written to by software

— L(H) = Latch/Hold; Register bit is latched and held until read by software based upon the occurrence of the correspond-

ing event

— SC = Self Clear; Register bit will clear itself after the event has occurred without software intervention

— P = Permanent; Register bit is permanently set to the default value and no action will cause the bit to change

Table 5. Register Block - Phyter Register Map

Offset Access Tag Description

00h RW BMCR Basic Mode Control Register

01h RO BMSR Basic Mode Status Register

02h RO PHYIDR1 PHY Identifier Register #1

03h RO PHYIDR2 PHY Identifier Register #2

04h RW ANAR Auto-Negotiation Advertisement Register

05h RW ANLPAR Auto-Negotiation Link Partner Ability Register

06h RW ANER Auto-Negotiation Expansion Register

07h RW ANNPTR Auto-Negotiation Next Page TX

08h-0Fh Reserved Reserved

10h RO PHYSTS PHY Status Register

11h RW MIPSCR MII Interrupt PHY Specific Control Register

12h RO MIPGSR MII Interrupt PHY Generic Status Register

13h RW DCR Disconnect Counter Register

14h RW FCSCR False Carrier Sense Counter Register

15h RW RECR Receive Error Counter Register

16h RW PCSR PCS Sub-Layer Configuration and Status Register

17h RW LBR Loopback and Bypass Register

18h RW 10BTSCR 10BASE-T Status & Control Register

19h RW PHYCTRL PHY Control Register

1Ah-1Fh Reserved Reserved

Obsolete

46 www.national.com

8.0 Register Block (Continued)

Table 6. Basic Mode Control Register (BMCR) Address 00h

Bit Bit Name Default Description

15 Reset 0, RW/SC Reset:

1 = Initiate software Reset / Reset in Process

0 = Normal operation

This bit sets the status and control registers of the PHY to their

defaultstates.Thisself-clearingbitreturnsavalueofoneuntilthe

reset process is complete (approximately 1.2 ms for reset dura-

tion). Reset is finished once the Auto-Negotiation process has

begun or the device has entered its forced mode.

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 synchroniza-

tion 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:

1 = 100 Mb/s

0 = 10 Mb/s

Link speed is selected by this bit or by Auto-Negotiation if bit 12

ofthis registerisset (in whichcase, the valueofthis bitisignored)

At reset, this bit is set according to the strap configuration of the

AN0 and AN1 pins. After reset, this bit may be written to by soft-

ware.

12 Auto-Negotiation En-

able Strap, RW Auto-Negotiation Enable:

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 link

speed and mode.

At reset, this bit is set according to the strap configuration of the

AN0 and AN1 pins. After reset, this bit may be written to by soft-

ware.

11 Power Down 0, RW Power Down:

1 = Power Down

0 = Normal Operation

Setting this bit configures the PHYTER for minimum power re-

quirements.While in Power Down mode, the PHYTER is not ca-

pable of transmitting or receiving data on an active network.

Additionally, the PHYTER is not capable of "Wake-on-LAN" and

will not react to receive data while in Power Down mode. Power

Downmodeis usefulforscenarioswhereminimumsystempower

is desired (ie. Green PCs) but can only be used in systems that

have control over the PHYTER via Serial MII management.

Obsolete

47 www.national.com

8.0 Register Block (Continued)

10 Isolate Strap, RW Isolate:

1 = Isolates the DP83843 from the MII with the exception of the

serial management. When this bit is asserted, the DP83843 does

not respond to TXD[3:0], TX_EN, and TX_ER inputs, and it pre-

sents a high impedance on its TX_CLK, RX_CLK, RX_DV,

RX_ER, RXD[3:0], COL and CRS outputs.

0 = Normal operation

If the PHY address is set to “00000” at power-up/reset the isolate

bit will be set to one, otherwise it defaults to 0. After reset this bit

may be written to by software.

9 Restart Auto-Negoti-

ation 0, RW/SC Restart Auto-Negotiation:

1 = Restart Auto-Negotiation. Re-initiates the Auto-Negotiation

process. If Auto-Negotiation is disabled (bit 12 of this register

cleared), this bit has no function and should be cleared. This bit

is self-clearing and will return a value of 1 until Auto-Negotiation

is initiated by the Device, whereupon it will self-clear. Operation

of the Auto-Negotiation process is not affected by the manage-

ment entity clearing this bit.

0 = Normal operation

8 Duplex Mode Strap, RW Duplex Mode:

1 = Full Duplex operation. Duplex selection is allowed when Auto-

Negotiation is disabled (bit 12 of this register is cleared).

0 = Half Duplex operation

AtresetthisbitissetbyeitherAN0orAN1.Afterresetthisbitmay

be written to by software.

7 Collision Test 0, RW Collision Test:

1 = Collision test enabled

0 = Normal operation

When set, this bit will cause the COL signal to be asserted in re-

sponse to the assertion of TX_EN within 512BT. The COL signal

will be de-asserted within 4BT in response to the de-assertion of

TX_EN.

6:0 Reserved 0, RO Reserved: Write ignored, read as zero

Table 7. Basic Mode Status Register (BMSR) Address 01h

Bit Bit Name Default Description

15 100BASE-T4 0, RO/P 100BASE-T4 Capable:

1 = Device able to perform in 100BASE-T4 mode

0 = Device not able to perform in 100BASE-T4 mode

The PHYTER is NOT capable of supporting 100BASE-T4 and

this bit is permanently set to 0.

14 100BASE-TX Full

Duplex 1, RO/P 100BASE-TX Full Duplex Capable:

1 = Device able to perform 100BASE-TX in full duplex mode

0 = Device not able to perform 100BASE-TX in full duplex mode

13 100BASE-TX Half

Duplex 1, RO/P 100BASE-TX Half Duplex Capable:

1 = Device able to perform 100BASE-TX in half duplex mode

0 = Device not able to perform 100BASE-TX in half duplex mode

Table 6. Basic Mode Control Register (BMCR) Address 00h (Continued)

Bit Bit Name Default Description

Obsolete

48 www.national.com

8.0 Register Block (Continued)

12 10BASE-T Full Du-

plex 1, RO/P 10BASE-T Full Duplex Capable:

1 = Device able to perform 10BASE-T in full duplex mode

0 = Device not able to perform 10BASE-T in full duplex mode

11 10BASE-T Half Du-

plex 1, RO/P 10BASE-T Half Duplex Capable:

1 = Device able to perform 10BASE-T in half duplex mode

0 = Device not able to perform 10BASE-T in half duplex mode

10:7 Reserved 0, RO Reserved: Write as 0, read as 0

6 Preamble

Suppression 1, RO/P Preamble suppression Capable:

1 = Device able to perform management transaction with pream-

ble suppressed*

0 = Device not able to perform management transaction with pre-

amble suppressed

* Need minimum of 32 bits of preamble after reset.

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 conditiondetected(clearedonread or byachip

reset). Fault criteria is Far End Fault Isolation or notification from

Link Partner of Remote Fault.

0 = No remote fault condition detected

3 Auto-Negotiation

Ability 1, RO/P Auto Conﬁguration Ability:

1 = Device is able to perform Auto-Negotiation

0 = Device is not able to perform Auto-Negotiation

2 Link Status 0, RO/L 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 link

status bit is implemented with a latching function, so that the oc-

currence of a link failure condition causes the Link Status bit to

become cleared and remain cleared until it is read via the man-

agement interface.

1 Jabber Detect 0, RO/L Jabber Detect:

1 = Jabber condition detected

0 = No Jabber

This bit is implemented with a latching function so that the occur-

rence of a jabber condition causes it to become set until it is

cleared by a read to this register by the management interface or

by a Device Reset. This bit only has meaning in 10 Mb/s mode.

0 Extended Capability 1, RO/P Extended Capability:

1 = Extended register capable

0 = Basic register capable only

Table 7. Basic Mode Status Register (BMSR) Address 01h (Continued)

Bit Bit Name Default Description

Obsolete

49 www.national.com

8.0 Register Block (Continued)

The PHY Identiﬁer Registers #1 and #2 together form a unique identiﬁer for the DP83843. The Identiﬁer consists of a

concatenation of the Organizationally Unique Identiﬁer (OUI), the vendor's model number and the model revision num-

ber. 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.

This register contains the advertised abilities of this device as they will be transmitted to its Link Partner during Auto-

Negotiation.

Table 8. PHY Identiﬁer Register #1 (PHYIDR1) Address 02h

Bit Bit Name Default Description

15:0 OUI_MSB <00 1000 0000

0000 00>, RO/P OUI Most Significant Bits: This registerstoresbits3to18ofthe

OUI (080017h) to bits 15 to 0 of this register respectively. The

most significant two bits of the OUI are ignored (the IEEE stan-

dard refers to these as bits 1 and 2).

Table 9. PHY Identiﬁer Register #2 (PHYIDR2) Address 03h

Bit Bit Name Default Description

15:10 OUI_LSB <01 0111>,

RO/P OUI Least Signiﬁcant Bits:

Bits 19 to 24 of the OUI (080017h) are mapped to bits 15 to 10

of this register respectively.

9:4 VNDR_MDL <00 0001>,

RO/P Vendor Model Number:

Six bits of vendor model number mapped to bits 9 to 4 (most sig-

nificant bit to bit 9).

3:0 MDL_REV <0000>, RO/P Model Revision Number:

Four bits of vendor model revision number mapped to bits 3 to 0

(most significant bit to bit 3). This field will be incremented for all

major device changes.

Table 10. Auto-Negotiation Advertisement Register (ANAR) Address 04h

Bit Bit Name Default Description

15 NP 0, RW Next Page Indication:

0 = Next Page Transfer not desired

1 = Next Page Transfer desired

14 Reserved 0, RO/P Reserved by IEEE: Writes ignored, Read as 0

13 RF 0, RW Remote Fault:

1 = Advertises that this device has detected a Remote Fault

0 = No Remote Fault detected

12:11 Reserved 0, RW Reserved for Future IEEE use: Write as 0, Read as 0

10 FDFC 0, RW Full Duplex Flow Control:

1 = Advertise that the DTE(MAC) has implemented both the op-

tional 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

At reset, this bit is set by AN0/AN1. After reset, this bit may be

written to by software.

Obsolete

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8.0 Register Block (Continued)

Advertised abilities of the Link Partner as received during Auto-Negotiation.

7 TX Strap, RW 100BASE-TX Support:

1 = 100BASE-TX is supported by the local device

0 = 100BASE-TX not supported

At reset, this bit is set by AN0/AN1. After reset, this bit may be

written to by software.

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

At reset, this bit is set by AN0/AN1. After reset, this bit may be

written to by software.

5 10 Strap, RW 10BASE-T Support:

1 = 10BASE-T is supported by the local device

0 = 10BASE-T not supported

At reset, this bit is set by AN0/AN1. After reset, this bit may be

written to by software.

4:0 Selector <00001>, RW Protocol Selection Bits:

These bits contain the binary encoded protocol selector support-

edbythisnode.<00001>indicatesthatthisdevicesupportsIEEE

802.3 CSMA/CD.

Table 11. Auto-Negotiation Link Partner Ability Register (ANLPAR) Address 05h

Bit Bit Name Default Description

15 NP 0, RO 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 Device's Auto-Negotiation state machine will automatically

control the use of this bit from the incoming FLP bursts. Software

should not attempt to write to this bit.

13 RF 0, RO Remote Fault:

1 = Remote Fault indicated by Link Partner

0 = No Remote Fault indicated by Link Partner

12:10 Reserved 0, RO Reserved for Future IEEE use: Write as 0, read as 0

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

Table 10. Auto-Negotiation Advertisement Register (ANAR) Address 04h (Continued)

Bit Bit Name Default Description

Obsolete

51 www.national.com

8.0 Register Block (Continued)

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 <00000>, RO Protocol Selection Bits:

Link Partners’s binary encoded protocol selector.

Table 11. Auto-Negotiation Link Partner Ability Register (ANLPAR) Address 05h

Bit Bit Name Default Description

Obsolete

52 www.national.com

8.0 Register Block (Continued)

This register also contains the Link Partner Next Page contents.

15 NP X RO Next Page Indication:

0 = Link Partner does not desire another Next Page Transfer

1 = Link Partner desires another Next Page Transfer

14 ACK X, RO Acknowledge:

1 = Link Partner acknowledges reception of the ability data word

0 = Not acknowledged

The Device's Auto-Negotiation state machine will automatically

control the use of this bit from the incoming FLP bursts. Software

should not attempt to write to this bit.

13 MP X, RO Message Page:

1 = Message Page

0 = Unformatted Page

12 ACK2 X, RO Acknowledge 2:

0 = Link Partner does not have the ability to comply to next page

message

1 = Link Partner has the ability to comply to next page message

11 TOGGLE X, RO Toggle:

0 = Previous value of the transmitted Link Code word equalled

logic one

1 = Previous value of the transmitted Link Code word equalled

logic zero

10:0 CODE XXX, RW Thisfieldrepresentsthecodefieldofthenextpagetransmission.

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 "Un-

formatted Page," and the interpretation is application specific.

Table 12. Auto-Negotiation Expansion Register (ANER) Address 06h

Bit Bit Name Default Description

15:5 Reserved 0, RO Reserved: Writes ignored, Read as 0.

4 PDF 0, RO Parallel Detection Fault:

1 = A fault has been detected via the Parallel Detection function

0 = A fault has not been detected via the Parallel Detection func-

tion

3 LP_NP_ABLE 0, RO Link Partner Next Page Able:

Status indicating if the Link Partner supports Next Page negotia-

tion. A one indicates that the Link Partner does support Next

Page.

2 NP_ABLE 1, RO/P Next Page Able:

Indicates if this node is able to send additional “Next Pages.”

1 PAGE_RX 0, RO/L Link Code Word Page Received:

This bit is set when a new Link Code Word Page has been re-

ceived. Cleared on read of this register.

0 LP_AN_ABLE 0, RO Link Partner Auto-Negotiation Able:

A one in this bit indicates that the Link Partner supports Auto-Ne-

gotiation.

Table 11. Auto-Negotiation Link Partner Ability Register (ANLPAR) Address 05h

Bit Bit Name Default Description

Obsolete

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8.0 Register Block (Continued)

This register contains the next page information sent by this device to its Link Partner during Auto-Negotiation.

Table 13. Auto-Negotiation Next Page Transmit Register (ANNPTR) Address 07h

Bit Bit Name Default Description

15 NP 0, RW 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

a device has the ability to comply with the message received.

11 TOG_TX 1, RO Toggle:

1 = Previous value of transmitted Link Code Word equalled logic

0 = Previous value of transmitted Link Code Word equalled logic

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. The ini-

tial value is the inverse of bit 11 in the base Link Code Word

(ANAR), which makes the default value of TOG_TX = 1.

10:0 CODE 001, RW Thisfield 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 "Un-

formatted Page," and the interpretation is application specific.

Thedefault value oftheCODE representsaNullPage as defined

in annex 28C of Clause 28.

Obsolete

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8.0 Register Block (Continued)

This register provides a single location within the register set for quick access to commonly accessed information.

Table 14. PHY Status Register (PHYSTS) Address 10h

Bit Bit Name Default Description

15 Receive Error Latch 0, RO/L Receive Error Latch:

1 = Receive error event has occurred since last read of RXER-

CNT

0 = No receive error event has occurred

14 CIM Latch 0, RO/L Carrier Integrity Monitor Latch:

1 = Carrier Integrity Monitor has found an isolate event since last

read of DCR

0 = No Carrier Integrity Monitor isolate event has occurred

13 False Carrier Sense

Latch 0, RO/L False Carrier Sense Latch:

1 = False Carrier event has occurred since last read of FCSCR

0 = No False Carrier event has occurred

12 Reserved 0, RO Reserved: Write ignored, read as 0.

11 Device Ready 0, RO Device Ready:

This bit signifies that the device is now ready to transmit data.

1 = Device Ready

0 = Device not Ready

10 Page Received 0, RO/L Link Code Word Page Received:

This bit is set when a new Link Code Word Page has been re-

ceived. Cleared on read of the ANER register.

9 Auto-Negotiation En-

abled Strap, RO Auto-Negotiation Enabled:

1 = Auto-Negotiation Enabled.

0 = Auto-Negotiation Disabled.

8 MII Interrupt 0, RO/L MII Interrupt Pending:

Indicatesthataninternalinterruptis pendingandisclearedbythe

current read. A read of this bit will clear the bit in the MIPGSR

(12h) also.

7 Remote Fault 0, RO/L Remote Fault:

1 = Remote Fault condition detected (cleared on read of BMSR

or notification from Link Partner of Remote Fault.

0 = No remote fault condition detected

6 Jabber Detect 0, RO/L Jabber Detect:

1 = Jabber condition detected

0 = No Jabber

This bit is implemented with a latching function so that the occur-

rence of a jabber condition causes it to become set until it is

cleared by a read to the BMSR register by the management inter-

face or by a Device reset. This bit only has meaning in 10 Mb/s

mode.

5 NWAY Complete 0, RO Auto-Negotiation Complete:

1 = Auto-Negotiation complete

0 = Auto-Negotiation not complete

4 Reset Status 0, RO Reset Status:

0 = Normal operation

1 = Reset in progress

Obsolete

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8.0 Register Block (Continued)

This register implements the MII Interrupt PHY Speciﬁc Control register. Sources for interrupt generation include: Link

State Change, Jabber Event, Remote Fault, Auto-Negotiation Complete or any of the counters becoming half-full. Note

that the TINT bit operates independently of the INTEN bit. In other words, INTEN does not need to be active to generate

the test interrupt.

This register implements the MII Interrupt PHY Generic Status Register.

3 Loopback Status 0, RO Loopback:

1 = Loopback enabled

0 = Normal operation

2 Duplex Status RO Duplex:

This bit indicates duplex status and is determined from Auto-Ne-

gotiation or Forced Modes.

1 = Running in Full duplex mode

0 = Running in Half duplex mode

Note: This bit is only valid if Auto-Negotiation is enabled and

completeandthereisavalid linkorifAuto-Negotiationisdisabled

and there is a valid link.

1 Speed Status RO Speed10:

This bit indicates the status of the speed and is determined from

Auto-Negotiation or Forced Modes.

1 = Running in 10Mb/s mode

0 = Running in 100 Mb/s mode

Note: This bit is only valid if Auto-Negotiation is enabled and

completeandthereisavalid linkorifAuto-Negotiationisdisabled

and there is a valid link.

0 Link Status 0, RO 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.

Table 15. MII Interrupt PHY Speciﬁc Control Register (MIPSCR) Address 11h

Bit Bit Name Default Description

15:2 Reserved 0, RO Reserved: Writes ignored, Read as 0

1 INTEN 0, RW Interrupt Enable:

1 = Enable event based interrupts

0 = Disable event based interrupts

0 TINT 0, RW Test Interrupt:

Forces the PHY to always generate an interrupt to allow testing

of the interrupt.

1 = Generate an interrupt at the end of each access

0 = Do not generate interrupt

Table 16. MII Interrupt PHY Generic Status Register (MIPGSR) Address 12h

Bit Bit Name Default Description

15 MINT 0, RO/COR MII Interrupt Pending:

Indicatesthat an interrupt ispendingandis cleared by thecurrent

read. A read of this will also clear the MII Interrupt bit (8) of the

PHYSTS (10h) register.

14:0 Reserved 0, RO Reserved: Writes ignored, Read as 0

Table 14. PHY Status Register (PHYSTS) Address 10h (Continued)

Bit Bit Name Default Description

Obsolete

56 www.national.com

8.0 Register Block (Continued)

This counter provides information required to implement the isolates attribute within the Repeater Port managed object

class of Clause 30 of the IEEE 802.3 speciﬁcation.

This counter provides information required to implement the FalseCarriers attribute within the MAU managed object class

of Clause 30 of the IEEE 802.3 speciﬁcation.

This counter provides information required to implement the aSymbolErrorDuringCarrier attribute within the PHY man-

aged object class of Clause 30 of the IEEE 802.3 speciﬁcation.

Table 17. Disconnect Counter Register (DCR) Address 13h

Bit Bit Name Default Description

15:0 DCNT[15:0] <0000h>, RW /

COR Disconnect Counter:

This 16 bit counter increments for each isolate event. Each time

the CIM detects a transition from the False Carrier state to the

Link Unstable state of the Carrier Integrity State Machine, the

counter increments. This counter rolls over when it reaches its

max count (FFFFh).

Table 18. False Carrier Sense Counter Register (FCSCR) Address 14h

Bit Bit Name Default Description

15:0 FCSCNT[15:0] <0000h>, RW /

COR False Carrier Event Counter:

This16bitcounterincrementsforeachfalsecarrierevent.Afalse

carrier event occurs when carrier sense is asserted without J/K

symbol detection. This counter rolls over when it reaches its max

count (FFFFh).

Table 19. Receive Error Counter Register (RECR) Address 15h

Bit Bit Name Default Description

15:0 RXERCNT[15:0] <0000h>, RW /

COR RX_ER Counter:

This 16 bit counter is incremented for each receive error detect-

ed. The counter is incremented when valid carrier is present and

there is at least one occurrence of an invalid data symbol. This

event can increment only once per valid carrier event. If a colli-

sion is present, this attribute will not increment. This counter rolls

over when it reaches its max count (FFFFh).

Table 20. 100 Mb/s PCS Conﬁguration and Status Register (PCSR) Address 16h

Bit Bit Name Default Description

15 Single_SD 0, RW SIngle Ended Signal Detect Enable:

1=Single Ended SD mode enabled

0=Single Ended SD mode disabled

14 FEFI_EN Strap, RW Far End Fault Indication Mode:

1 = FEFI mode enabled

0 = FEFI mode disabled

Note: If Auto-Negotiation is enabled, bit 12 of BMCR, this bit is

RO and forced to zero. Additionally, if FX_EN is set to a one then

this bit is RO and forced to a one.

13 DESCR_TO_RST 0, RW Reset Descrambler Time-Out Counter:

1 = Reset Time-Out Counter

0 = Normal operation

Obsolete

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8.0 Register Block (Continued)

12 DESCR_TO_SEL 0, RW Descrambler Time-out Select:

1 = Descrambler Timer set to 2 ms

0 = Descrambler Timer set to 722 µs

The Descrambler Timer selects the interval over which a mini-

mum number of IDLES are required to be received to maintain

descrambler synchronization. The default time of 722 µs sup-

ports 100BASE-X compliant applications.

A timer time-out indicates a loss of descrambler synchronization

which cause the descrambler to restart its operation by immedi-

ately looking for IDLES.

The 2 ms option allows applications with Maximum Transmission

Units (packet sizes) larger than IEEE 802.3 to maintain descram-

bler synchronization (i.e., Token Ring/Fast-Ethernet switch/rout-

er applications).

11 DESCR_TO_DIS 0, RW Descrambler Time-out Disable:

1 = Time-out Counter in the descrambler section of the receiver

disabled

0 = Time-out Counter enabled

10 LD_SCR_SD 0, RW Load Scrambler Seed:

1 = Load Scrambler Seed continuously

0 = Normal operation

9 TX_QUIET 0, RW 100 Mps Transmit True Quiet Mode:

1 = Transmit True Quiet mode

0 = Normal mode

8:7 TX_PATTERN[1:0] <00>, RW 100 Mps Transmit Test Pattern:

<00> = Normal operation

<01> = Send FEFI pattern

<10> = Send 1.28 µsperiod pattern (640 ns high/low time)

<11> = Send 160 ns period pattern (80 ns high/low time)

6 F_LINK_100 0, RW Force Good Link in 100 Mb/s:

1 = Force 100 Mb/s Good Link status

0 = Normal 100 Mb/s operation

This bit is useful for diagnostic purposes.

5 CIM_DIS Strap, RW Carrier Integrity Monitor Disable:

1 = Carrier Integrity Monitor function disabled (Node/Switch oper-

ation)

0 = Carrier Integrity Monitor function enabled (Repeater opera-

tion)

The THIN/REPEATER determines the default state of this bit to

automatically enable or disable the CIM function as required for

IEEE 802.3 compliant applications. The value latched into this bit

at power-on/reset is the compliment of the value forced on the

THIN/REPEATER input. After power-on/reset, software may en-

able or disable this function independent of repeater or

node/switch mode.

Table 20. 100 Mb/s PCS Conﬁguration and Status Register (PCSR) Address 16h (Continued)

Bit Bit Name Default Description

Obsolete

58 www.national.com

8.0 Register Block (Continued)

4 CIM_STATUS 0, RO Carrier Integrity Monitor Status:

This bit indicates the status of the Carrier Integrity Monitor func-

tion. This status is optionally muxed out through the TX_LED pin

when the LED_TXRX_MODE bits (8:7) of the PHYCTRL register

(address 19h) are set to either <10> or <01>.

1 = Unstable link condition detected

0 = Unstable link condition not detected

3 CODE_ERR 0, RW Code Errors:

1 = Forces code errors to be reported with the value 5h on

RXD[3:0] and with RX_ER set to 1.

0 = Forces code errors to be reported with the value of 6h on

RXD[3:0] and with RX_ER set to 1.

2 PME_ERR 0, RW Premature End Errors:

1 = Forces premature end errors to be reported with the value 4h

on RXD[3:0] and with RX_ER set to 1.

0 = Forces premature end errors to be reported with the value 6h

on RXD[3:0] and with RX_ER set to 1. Premature end errors are

caused by the detection of two IDLE symbols in the receive data

stream prior to the T/R symbol pair denoting end of stream delim-

iter.

1 LINK_ERR 0, RW Link Errors:

1 = Forces link errors to be reported with the value 3h on

RXD[3:0] and with RX_ER set to 1.

0 = Data is passed to RXD[3:0] unchanged and with RX_ER set

to 0.

0 PKT_ERR 0, RW Packet Errors:

1 = Forces packet errors (722 s time-out) to be reported with the

value 2h on RXD[3:0] and with RX_ER set to 1.

0 = Data is passed to RXD[3:0] unchanged and with RX_ER set

to 0.

Table 21. Loopback & Bypass Register (LBR) Address 17h

Bit Bit Name Default Description

15 Reserved 0, RO Reserved: Writes ignored, read as 0.

14 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

13 BP_4B5B Strap, RW Bypass 4B5B Encoding and 5B4B Decoding:

Thisbit is setaccordingto the strapconfigurationof theSYMBOL

pin at power-up/reset. After reset this bit may be written to by soft-

ware.

1 = 4B5B encoder and 5B4B decoder functions bypassed

0 = Normal 4B5B and 5B4B operation

Table 20. 100 Mb/s PCS Conﬁguration and Status Register (PCSR) Address 16h (Continued)

Bit Bit Name Default Description

Obsolete

59 www.national.com

8.0 Register Block (Continued)

12 BP_SCR Strap, RW Bypass Scrambler/Descrambler Function:

Thisbit is setaccordingto the strapconfigurationof theSYMBOL

pin or the FXEN pin at power-up/reset. After reset this bit may be

written to by software.

1 = Scrambler and descrambler functions bypassed

0 = Normal scrambler and descrambler operation

11 BP_RX Strap, RW Bypass Receive Function:

Thisbit is setaccordingto the strapconfigurationof theSYMBOL

pin at power-up/reset. After reset this bit may be written to by soft-

ware.

1 = Receive functions (descrambler and symbol decoding func-

tions) bypassed.

0 = Normal operation.

10 BP_TX Strap, RW Bypass Transmit Function:

Thisbit is setaccordingto the strapconfigurationof theSYMBOL

pin at power-up/reset. After reset this bit may be written by soft-

ware.

1 = Transmit functions (symbol encoder and scrambler) by-

passed

0 = Normal operation

9:7 100_DP_CTL Strap, RW 100Mps Data Path Control Bits:

At reset, if FXEN is true then this will default to <011>, else it will

default to <000>. These bits control the 100Mps loopback func-

tion in CorePhy as follows:

<000> Normal Mode

<001> CorePhy Loopback

<010> Reserved

<011> Normal Fiber

<100> Reserved

<101> Reserved

<110> Reserved

<111> Reserved

Note: A write to the Loopback bit (14) of the BMCR (00h) will

override the value set in this register.

6 RESERVED 0, RO Reserved: Writes as 0, read as 0

5 TW_LBEN 0, RW TWISTER Loopback Enable:

1 = TWISTER loopback

0 = Normal mode

Note: A write to the Loopback bit (14) of the BMCR (00h) will

override the value set in this register.

4 10Mb_ENDEC_LB 0, RW 10 Mb/s ENDEC Loopback:

1 = 10Mb/s ENDEC loopback

0 = Normal TREX operation

Note: A write to the Loopback bit (14) of the BMCR (00h) will

override the value set in this register.

3 RESERVED 0, RO Reserved: Writes as 0, read as 0

2 RESERVED 0, RO Reserved: Writes as 0, read as 0

Table 21. Loopback & Bypass Register (LBR) Address 17h (Continued)

Bit Bit Name Default Description

Obsolete

60 www.national.com

8.0 Register Block (Continued)

1 RESERVED 0, RO Reserved: Writes as 0, read as 0

0 RESERVED 0, RO Reserved: Writes as 0, read as 0

Table 22. 10BASE-T Control & Status Register (10BTSCR) Address 18h

Bit Bit Name Default Description

15:14 RESERVED 0, RO Reserved: Writes ignored, read as 0

13 AUI_TPI 0, RO TREX Operating Mode:

This bit shows the current operating mode of TREX as chosen by

the Auto-Switch function.

1 = AUI mode

0 = TPI mode

12 RX_SERIAL Strap, RW 10BASE-T RX Serial Mode:

This bit is set according to the strap configuration of the

SERIAL10 pin at power-up/reset. After reset this bit may be writ-

ten to by software.

1 = 10BASE-T rx Serial mode selected

0 = 10BASE-T rx Nibble mode selected

Serial mode is not supported for 100 Mb/s operation.

11 TX_SERIAL Strap, RW 10BASE-T TX Serial Mode:

This bit is set according to the strap configuration of the

SERIAL_10 pin at power-up/reset. After reset this bit may be writ-

ten to by software.

1 = 10BASE-T tx Serial mode selected

0 = 10BASE-T tx Nibble mode selected

Serial mode is not supported for 100 Mb/s operation.

10 POL_DS 0, RW Polarity Detection & Correction Disable:

1 = Polarity Sense & Correction disabled

0 = Polarity Sense & Correction enabled

9 AUTOSW_EN 0, RW AUI/TPI Autoswitch:

1 = Enable autoswitch

0 = Disable autoswitch function

The use of autoswitch should be strictly limited to applications

that do not support Auto-Negotiation. Do not enable Auto-Nego-

tiation when enabling autoswitch as this may result in improper

operation.

8 LP_DS 0, RW Link Pulse Disable:

1 = Reception of link pulses ignored, good link condition forced

0 = Good link not forced, link pulses observed for good link

7 HB_DS 0, RW Heartbeat Disable:

1 = Heartbeat function disabled

0 = Heartbeat function enabled

Whenthedeviceisconfiguredfor fullduplexoperation,thisbitwill

be ignored (the collision/heartbeat function has no meaning in

Full Duplex mode). HB_DS will read back as 1 if in Full Duplex

mode or Repeater mode.

Table 21. Loopback & Bypass Register (LBR) Address 17h (Continued)

Bit Bit Name Default Description

Obsolete

61 www.national.com

8.0 Register Block (Continued)

6 LS_SEL 0, RW Low Squelch Select:

Selects between standard 10BASE-T receiver squelch threshold

and a reduced squelch threshold that is useful for longer cable

applications.

1 = Low Squelch Threshold selected

0 = Normal 10BASE-T Squelch Threshold selected

5 AUI_SEL 0, RW AUI Select:

1 = Select AUI interface

0 = Select TPI interface

4 JAB_DS 0, RW Jabber Disable:

Enables or disables the Jabber function when the device is in

10BASE-T Full Duplex or 10BASE-T TREX Loopback mode

(TREX_LBEN bit 4 in the LBR, address 17h).

1 = Jabber function disabled

0 = Jabber function enabled

3 THIN_SEL 0, RW Thin Ethernet Select:

1 = Asserts THIN pin (pin 63)

0 = Deasserts THIN pin (pin 63)

This pin may be used as a general purpose select pin.

2 RX_FILT_DS 0, RW TPI Receive Filter Disable:

1 = Disable TPI receive filter

0 = Enable TPI receive filter

1 RESERVED 0, RO Reserved: Writes ignored, read as 0

0 RESERVED 0, RO Reserved: Writes as 0, read as 0

Table 23. PHY Control Register (PHYCTRL) Address 19h

Bit Bit Name Default Description

15 RESERVED 0, RO Reserved: Writes ignored, read as 0

14 RESERVED 0, RO Reserved: Writes ignored, read as 0

13:12 TW_EQSEL[1:0] <00>, RW TWISTER Equalization Select:

Used in combination to select the 4 equalization modes. Modes

3, 2, 1 should be accessible to external device pin for debug pur-

poses.

<11> = Equalization off

<10> = Equalization on

<01> = Adaptive Equalization

<00> = Full Adaptive Equalization

11 TW_BLW_DS 0, RW TWISTER Base Line Wander Disable:

1 = BLW Feedback loop disabled

0 = BLW Feedback loop enabled

10 RESERVED 0, RO Reserved: Writes ignored, read as 0

Table 22. 10BASE-T Control & Status Register (10BTSCR) Address 18h (Continued)

Bit Bit Name Default Description

Obsolete

62 www.national.com

8.0 Register Block (Continued)

9 REPEATER Strap, RW Repeater/Node Mode:

1 = Repeater mode

0 = Node mode

Inrepeatermode the CarrierSense(CRS)outputfromthe device

is asserted due to receive activity only. In Node mode, and not

configuredforfull duplex operation,CRSisasserteddueto either

receive or transmit activity. In 100 Mb/s operation the CIM moni-

tor is disabled. In Repeater mode HB_DS is enabled (bit 7 regis-

ter 10BTSCR(18h))

This bit is set according to the strap configuration of the REPEAT-

ER pin at power-up/reset.

8:7 LED_TXRX_MODE <00>, RW LED_TX/RX Mode Select:

<11> = LED_RX indicates both RX and TX activity and LED_TX

indicates interrupt. Interrupt signal is active high.

<10> = LED_RX indicates both RX and TX activity and LED_TX

indicates Carrier Integrity Monitor status.Interrupt signal is active

high.

<01>=LED_RX indicates RXactivityonlyandLED_TX indicates

Carrier Integrity Monitor status.

<00> = Normal LED_TX and LED_RX operation.

Note: Using LED_TX to indicate Carrier Integrity Monitor status

is useful for network management purposes in 100BASE-TX

mode. This mode only works if the PHY_Address_2 is strapped

low because the PHYTER does not properly implement the Activ-

ity LED function if LED_RX/PHYAD[2] is strapped high.

6 LED_DUP_MODE 0, RW LED_DUP Mode Select:

1 = LED_FDPOL configured to indicate polarity reversal in

10BASE-T mode, and full duplex in 100BASE-TX mode

0= LED_FDPOLconfiguredto indicate fullduplexin alloperating

modes.

5 FX_EN Strap, RW Fiber Mode Enable:

ThisbitissetbytheFX_ENatpower-on/resetor by software after

reset. If this bit is set then the signals FEFI_EN and BP_SCR are

driven internally. When this bit is set, fiber mode enabled, Auto-

Negotiation must be disabled.

1 = Fiber Mode enabled

0 = Fiber Mode disabled

4:0 PHYADDR[4:0] (STRAP), RW PHY Address:

The values of the PHYAD[4:0] pins are latched to this register at

power-up/reset.The first PHYaddressbittransmittedor received

is the MSB of the address (bit 4). A station management entity

connectedto multiplePHYentities must knowtheappropriate ad-

dress of each PHY. A PHY address of <00000> that is latched in

to the part at power up/reset will cause the Isolate bit of the

BMCR (bit 10, register address 00h) to be set.

After power up/reset the only way to enable or disable isolate

mode is to set or clear the Isolate bit (bit 10) of BMCR (address

00). After power up/reset writing <00000> to bits [4:0] of this reg-

ister will not cause the part to enter isolate mode.

Table 23. PHY Control Register (PHYCTRL) Address 19h (Continued)

Bit Bit Name Default Description

Obsolete

63 www.national.com

Absolute Maximum Ratings

Supply Voltage (VCC) -0.5 V to 7.0 V

Input Voltage (DCIN) -0.5 V to VCC + 0.5 V

Output Voltage (DCOUT) -0.5 V to VCC + 0.5 V

Storage Temperature -65oC to 150oC

ECL Signal Output Current -50mA

ESD Protection 2000 V

Recommended Operating Conditions

Min Typ Max Units

Supply voltage (VDD) 4.75 5.0 5.25 V

Ambient Temperature (TA)0 70

X1 Input Frequency Stability

(over temperature) -50 +50 PPM

X1 Input Duty Cycle 35 65 %

Center Frequency (XFC) 25 MHz

9.0 Electrical Specifications

All preliminary electrical speciﬁcations are based on IEEE 802.3u requirements and internal design considerations.

These speciﬁcations will not become ﬁnal until complete veriﬁcation of the DP83843.

Thermal Characteristics*

*Valid for Phyters with data code 9812 or later, for earlier data codes please contact your National Sales Representative for data.

Max Units

Maximum Case Temperature 96 oC

Maximum Die Temperature 104.7 oC

Theta Junction to Case (Tjc) 1.1 oC / W

Theta Junction to Ambient (Tja) degrees Celsius/Watt - No Airflow @ 1.0W 42.7 oC / W

Theta Junction to Ambient (Tja) degrees Celsius/Watt - 225 LFPM Airflow @ 1.0W 35.3 oC / W

Theta Junction to Ambient (Tja) degrees Celsius/Watt - 500 LFPM Airflow @ 1.0W 30.4 oC / W

Theta Junction to Ambient (Tja) degrees Celsius/Watt - 900 LFPM Airflow @ 1.0W 26.9 oC / W

Obsolete

9.0 Electrical Specifications (Continued)

64 www.national.com

9.1 DC Electrical Specification

Symbol Pin Types Parameter Conditions Min Typ Max Units

VIH I

I/O

I/O, Z

Input High Voltage 2.0 V

AN0 and AN1 VCC - 1.0 V

X1 VCC - 1.0 V

VIL I

I/O

I/O, Z

Input Low Voltage 0.8 V

AN0 and AN1 1.0 V

X1 1.0 V

VIM AN0 and AN1 Input Mid Level

Voltage Pin Unconnected (VCC/2)

-0.5 (VCC/2) (VCC/2)

+0.5 V

IIH I

I/O

I/O, Z

Input High Current VIN = VCC 10 µA

X1 X2 = N.C. -100 µA

IIL I

I/O

I/O, Z

Input Low Current VIN = GND 10 µA

X1 X2 = N.C. 100 µA

VOL O, Z

I/O

I/O, Z

Output Low

Voltage IOL = 4 mA 0.4 V

VOH O, Z

I/O

I/O, Z

Output High

Voltage IOL = -4 mA VCC - 0.5 V

VOL LED

SPEED10 Output Low

Voltage IOL = 2.5 mA 0.4 V

VOH LED

SPEED10 Output High

Voltage IOL = -2.5 mA VCC - 0.5 V

IOZ1 I/O, Z

O, Z TRI-STATE

Leakage VOUT = VCC 10 µA

IOZ2 I/O, Z

O, Z TRI-STATE

Leakage VOUT = GND -10 µA

RINdiff TPRD+/− Differential Input

Resistance see Test

Conditions section 56 kΩ

VTPTD_100 TPTD+/− 100M Transmit

Voltage see Test

Conditionssection .95 1 1.05 V

VTPTDsym TPTD+/− 100M Transmit

Voltage Symmetry see Test

Conditions section -2 +2 %

VTPTD_10 TPTD+/− 10M Transmit

Voltage see Test

Conditions section 2.2 2.5 2.8 V

CIN1 I CMOS Input

Capacitance 8pF

CIN2 I PECL Input

Capacitance 10 pF

Obsolete

9.0 Electrical Specifications (Continued)

65 www.national.com

COUT1 O

ZCMOS Output

Capacitance 8pF

COUT2 O

ZPECL Output

Capacitance 10 pF

SDTHon TPRD+/− 100BASE-TX

Signal detect turn-

on thresh

1000 mV diff pk-pk

SDTHoff TPRD+/− 100BASE-TX

Signal detect turn-

off thresh

200 mV diff pk-pk

VTH1 TPRD+/− 10BASE-T Re-

ceive Threshold 300 585 mV

VTH2 TPRD+/− 10BASE-T Re-

ceive Low

Squelch Thresh-

old

150 300 mV

VDIFF FXSD+/−,

FXRD+/− PECL Input Volt-

age Differential see Test

Conditions section 300 mV

VCM FXSD+/−,

FXRD+/− PECL Common

Mode Voltage see Test

Conditions section VCC - 2.0 VCC - 0.5 mV

IINECL FXSD+/−,

FXRD+/− PECL Input

Current VIN = VOLmax or

VOHmax

-300 300 µA

VOHECL FXTD+/− PECLOutputHigh

Voltage VIN = VIHmax VCC - 1.125 VCC - 0.78 V

VOLECL FXTD+/− PECL Output Low

Voltage VIN = VILmax VCC - 1.86 VCC - 1.515 V

VODaui AUITD+/− DifferentialOutput

Voltage see Test

Conditions section ±550 ±1200 mV

VOBaui AUITD+/− Differential Idle

Output Voltage

Imbalance

see Test

Conditions section 40 mV

VDSaui AUIRD+/−,

AUICD+/− Differential

Squelch

Threshold

see Test

Conditions section ±160 ±300 mV

Idd100 Supply 100BASE-TX

(Full Duplex) see Test

Conditions section 135 150 mA

Idd10 Supply 10BASE-TX

(Full Duplex) see Test

Conditions section 100 110 mA

IddFX Supply 100BASE-FX

(Full Duplex) see Test

Conditions section 100 115 mA

IddAN Supply Auto-Negotiation see Test

Conditions section 100 120 mA

IddPD Supply Power Down see Test

Conditions section 25 30 mA

Symbol Pin Types Parameter Conditions Min Typ Max Units

Obsolete

9.0 Electrical Specifications (Continued)

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9.2 CGM Clock Timing

9.3 MII Serial Management AC Timing

Parameter Description Notes Min Typ Max Units

T2.0.1 X1 to TX_CLK Delay -3 +3 ns

T2.0.2 TX_CLK Duty Cycle 35 65 %

Parameter Description Notes Min Typ Max Units

T3.0.1 MDC to MDIO (Output) Delay Time 0 300 ns

T3.0.2 MDIO (Input) to MDC Setup Time 10 ns

T3.0.3 MDIO (Input) to MDC Hold Time 10 ns

T3.0.4 MDC Frequency 2.5 MHz

TX_CLK OUT

X1 IN

T2.0.1 T2.0.2

MDC

MDIO (OUTPUT)

MDIO (INPUT) VALID DATA

T3.0.1

T3.0.2 T3.0.3

T3.0.4

Obsolete

9.0 Electrical Specifications (Continued)

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9.4 100 Mb/s AC Timing

9.4.1 100 Mb/s MII Transmit Timing

9.4.2 100 Mb/s MII Receive Timing

Parameter Description Notes Min Typ Max Units

T4.1.1 TXD[3:0], TX_EN, TX_ER Data Setup to

TX_CLK 100 Mb/s Normal mode 14 ns

TXD[4:0] Data Setup to TX_CLK 100 Mb/s Symbol mode 10 ns

T4.1.2 TXD[3:0], TX_EN, TX_ER Data Hold from

TX_CLK 100 Mb/s Normal mode -1 ns

TXD[4:0] Data Hold from TX_CLK 100 Mb/s Symbol mode -1 ns

Parameter Description Notes Min Typ Max Units

T4.2.1 RX_EN to RX_CLK, RXD[3:0], RX_ER,

RX_DV Active All 100 Mb/s modes 15 ns

T4.2.2 RX_EN to RX_CLK, RXD[3:0], RX_ER,

RX_DV TRI-STATE All 100 Mb/s modes 25 ns

T4.2.3 RX_CLK to RXD[3:0], RX_DV, RX_ER Delay 100 Mb/s Normal mode 10 30 ns

RX_CLK to RXD[4:0], Delay 100 Mb/s Symbol mode 10 30 ns

T4.2.4 RX_CLK Duty Cycle All 100 Mb/s modes 35 65 %

TX_CLK

TXD[3:0]

TX_EN

TX_ER VALID DATA

T4.1.1 T4.1.2

RX_CLK

RXD[3:0]

RX_DV

RX_ER VALID DATA

RX_EN T4.2.1 T4.2.2

T4.2.3

T4.2.4

Obsolete

9.0 Electrical Specifications (Continued)

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9.4.3 100BASE-TX Transmit Packet Latency Timing

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 TPTD±pins. 1 bit time = 10ns in 100 Mb/s mode. For Symbol mode, because TX_EN has no meaning, latency

is measured from the first rising edge of TX_CLK occurring after the assertion of a data nibble on the Transmit MII to the first bit (MSB) of that nibble as

output from the TPTD±pins. 1 bit time = 10 ns in 100 Mb/s mode.

Parameter Description Notes Min Typ Max Units

T4.3.1 TX_CLK to TPTD+/− Latency 100 Mb/s Normal mode 6.0 bits

100 Mb/s Symbol mode 6.0 bits

TX_CLK

TX_EN

TXD

TPTD+/- (J/K) IDLE DATA

T4.3.1

Obsolete

9.0 Electrical Specifications (Continued)

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9.4.4 100BASE-TX Transmit Packet Deassertion Timing

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 TPTD±pins. For Symbol mode, because TX_EN has no meaning, Deassertion is measured from the first rising edge of

TX_CLK occurring after the deassertion of a data nibble on the Transmit MII to the last bit (LSB) of that nibble when it deasserts on the wire. 1 bit time = 10

ns in 100 Mb/s mode.

Parameter Description Notes Min Typ Max Units

T4.4.1 TX_CLK to TPTD+/−

Deassertion 100 Mb/s Normal mode 6.0 bits

100 Mb/s Symbol mode 6.0 bits

TX_CLK

TX_EN

TXD

TPTD+/- (T/R)DATA IDLE

T4.4.1

Obsolete

9.0 Electrical Specifications (Continued)

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9.4.5 100BASE-TX Transmit Timing

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.

Parameter Description Notes Min Typ Max Units

T4.5.1 100 Mb/s TPTD+/− Rise and

Fall Times see Test Conditions section 3 4 5 ns

100 Mb/s Rise/Fall Mismatch 500 ps

T4.5.2 100 Mb/s TPTD+/−

Transmit Jitter 1.4 ns

TPTD+/-

T4.5.1 T4.5.1

T4.5.1

+1 RISE +1 FALL -1 FALL -1 RISE

TPTD+/-

EYE PATTERN

T4.5.2

Obsolete

9.0 Electrical Specifications (Continued)

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9.4.6 100BASE-TX Receive Packet Latency Timing

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: TPRD±voltage amplitude is greater than the Signal Detect Turn-On Threshold Value.

9.4.7 100BASE-TX Receive Packet Deassertion Timing

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.

Parameter Description Notes Min Typ Max Units

T4.6.1 Carrier Sense on Delay 100 Mb/s Normal mode 17.5 bits

T4.6.2 Receive Data Latency 100 Mb/s Normal mode 21 bits

100 Mb/s Symbol mode 12 bits

Parameter Description Notes Min Typ Max Units

T4.7.1 Carrier Sense Off Delay 100 Mb/s Normal mode 21.5 bits

CRS

RXD[3:0]

TPRD+/-

RX_DV

RX_ER/RXD[4]

(J/K)

IDLE DATA

T4.6.1

T4.6.2

CRS

TPRD+/- (T/R) IDLE

DATA

T4.7.1

RXD[3:0]

RX_DV

RX_ER/RXD[4]

Obsolete

9.0 Electrical Specifications (Continued)

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9.4.8 100BASE-FX Transmit Packet Latency Timing

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 FXTD±pins. For Symbol mode, because TX_EN has no meaning, Latency is measured from the first rising

edge of TX_CLK occurring after the assertion of a data nibble on the Transmit MII to the first bit (MSB) of that nibble when it first appears at the FXTD±

outputs.

Parameter Description Notes Min Typ Max Units

T4.8.1 TX_CLK to FXTD+/− Latency 100 Mb/s Normal mode 4.0 bits

100 Mb/s Symbol mode 4.0 bits

TX_CLK

TX_EN

TXD

FXTD+/- (J/K) IDLE DATA

T4.8.1

Obsolete

9.0 Electrical Specifications (Continued)

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9.4.9 100BASE-FX Transmit Packet Deassertion Timing

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 FXTD±pins. For Symbol mode, because TX_EN has no meaning, Deassertion is measured from the first rising edge of

TX_CLK occurring after the deassertion of a data nibble on the Transmit MII to the last bit (LSB) of that nibble when it deasserts as output from the FXTD±

pins. 1 bit time = 10 ns in 100 Mb/s mode.

9.4.10 100BASE-FX Receive Packet Latency Timing

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.

Parameter Description Notes Min Typ Max Units

T4.9.1 TX_CLK to FXTD+/−

Deassertion 100 Mb/s Normal mode 4.0 bits

100 Mb/s Symbol mode 4.0 bits

Parameter Description Notes Min Typ Max Units

T4.10.1 Carrier Sense On Delay 100 Mb/s Normal mode 17.5 bits

T4.10.2 Receive Data Latency 100 Mb/s Normal mode 19 bits

100 Mb/s Symbol mode 19 bits

TX_CLK

TX_EN

TXD

FXTD+/- (T/R)DATA IDLE

T4.9.1

CRS

RXD[3:0]

FXRD+/-

RX_DV

RX_ER/RXD[4]

(J/K)

IDLE DATA

T4.10.2

T4.10.1

Obsolete

9.0 Electrical Specifications (Continued)

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9.4.11 100BASE-FX Receive Packet Deassertion Timing

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.

9.5 10 Mb/s AC Timing

9.5.12 10 Mb/s MII Transmit Timing

Parameter Description Notes Min Typ Max Units

T4.11.1 Carrier Sense Off Delay 100 Mb/s Normal mode 21.5 bits

Parameter Description Notes Min Typ Max Units

T5.12.1 TXD[3:0], TX_EN Data Setup to TX_CLK 10 Mb/s Nibble mode 25 ns

TXD0 Data Setup to TX_CLK 10 Mb/s Serial mode 25 ns

T5.12.2 TXD[3:0], TX_EN Data Hold from TX_CLK 10 Mb/s Nibble mode -1 ns

TXD0 Data Hold from TX_CLK 10 Mb/s Serial mode -1 ns

CRS

FXRD+/- (T/R) IDLE

DATA

T4.11.1

RXD[3:0]

RX_DV

RX_ER/RXD[4]

TX_CLK

TXD[3:0]

TX_EN

TX_ER VALID DATA

T5.12.

1T5.12.

Obsolete

9.0 Electrical Specifications (Continued)

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9.5.13 10 Mb/s MII Receive Timing

9.5.14 10BASE-T Transmit Timing (Start of Packet)

Note: 1 bit time = 100 ns in 10 Mb/s mode for both nibble and serial operation.

Parameter Description Notes Min Typ Max Units

T5.13.1 RX_EN to RX_CLK, RXD[3:0], RX_DV Active All 10 Mb/s modes 10 ns

T5.13.2 RX_EN to RX_CLK, RXD[3:0], RX_DV TRI-

STATE All 10 Mb/s modes 25 ns

T5.13.3 RX_CLK to RXD[3:0], RX_DV, RX_ER Delay 10 Mb/s Nibble mode 190 210 ns

RX_CLK to RXD[3:0], RX_DV, RX_ER Delay 10 Mb/s Serial mode 40 60 ns

T5.13.4 RX_CLK Duty Cycle All 10 Mb/s modes 35 65 %

Parameter Description Notes Min Typ Max Units

T5.14.1 TransmitEnableSetupTimefromthe

Rising Edge of TX_CLK 10 Mb/s Nibble mode 25 ns

10 Mb/s Serial mode 25 ns

T5.14.2 Transmit Data Setup Time from the

Rising Edge of TX_CLK 10 Mb/s Nibble mode 25 ns

10 Mb/s Serial mode 25 ns

T5.14.3 Transmit Data Hold Time from the

Rising Edge of TX_CLK 10 Mb/s Nibble mode -1 ns

10 Mb/s Serial mode -1 ns

T5.14.4 Transmit Output Delay from the

Rising Edge of TX_CLK 10 Mb/s Nibble mode 6.8 bits

10 Mb/s Serial mode 2.5 bits

RX_CLK

RXD[3:0]

RX_DV

RX_ER VALID DATA

RX_EN T5.13.1 T5.13.

T5.13.3

T5.13.4

TX_CLK

TX_EN

TXD

TPTD+/-

T5.14.

T5.14.2 T5.14.

T5.14.4

Obsolete

9.0 Electrical Specifications (Continued)

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9.5.15 10BASE-T Transmit Timing (End of Packet)

Parameter Description Notes Min Typ Max Units

T5.15.1 TransmitEnableHoldTime fromthe

Rising Edge of TX_CLK 10 Mb/s Nibble mode -1 ns

10 Mb/s Serial mode -1 ns

T5.15.2 End of Packet High Time

(with ‘0’ ending bit) 10 Mb/s Nibble mode 250 ns

10 Mb/s Serial mode 250 ns

T5.15.3 End of Packet High Time

(with ‘1’ ending bit) 10 Mb/s Nibble mode 250 ns

10 Mb/s Serial mode 250 ns

TX_CLK

TX_EN

TPTD+/- 00

TPTD+/-

T5.15.2

T5.15.3

T5.15.1

Obsolete

9.0 Electrical Specifications (Continued)

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9.5.16 10BASE-T Receive Timing (Start of Packet)

Note: 10BASE-T receive Data 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 for both nibble and serial operation.

9.5.17 10BASE-T Receive Timing (End of Packet)

Parameter Description Notes Min Typ Max Units

T5.16.1 Carrier Sense Turn On Delay

(TPRD+/− to CRS) 10 Mb/s Nibble mode 1 µs

10 Mb/s Serial mode 1 µs

T5.16.2 Decoder Acquisition Time 10 Mb/s Nibble mode 3.6 µs

10 Mb/s Serial mode 3.2 µs

T5.16.3 Receive Data Latency 10 Mb/s Nibble mode 17.3 bits

10 Mb/s Serial mode 10 bits

T5.16.4 SFD Propagation Delay 10 Mb/s Nibble mode 10 bits

10 Mb/s Serial mode 4.5 bits

Parameter Description Notes Min Typ Max Units

T5.17.1 Carrier Sense Turn Off Delay 10 Mb/s Nibble mode 1.1 us

10 Mb/s Serial mode 450 ns

101

TPRD+/-

CRS

RX_CLK

RXD

1ST SFD BIT DECODED

RX_DV

T5.16.1

T5.16.

T5.16.4

101

TPRD+/-

RX_CLK

CRS

IDLE

T5.17.

Obsolete

9.0 Electrical Specifications (Continued)

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9.5.18 10 Mb/s AUI Timing

Note: The worst case for T5.18.1 is data ending in a ‘0’.

9.5.19 10 Mb/sHeartbeat Timing

Parameter Description Notes Min Typ Max Units

T5.18.1 AUI Transmit Output High Before

Idle 200 ns

T5.18.2 AUI Transmit Output Idle Time 8000 ns

T5.18.3 AUI Receive End of Packet Hold

Time 225 ns

Parameter Description Notes Min Typ Max Units

T5.19.1 CD Heartbeat Delay 10 Mb/s Nibble mode 700 ns

10 Mb/s Serial mode 700 ns

T5.19.2 CD Heartbeat Duration 10 Mb/s Nibble mode 700 ns

10 Mb/s Serial mode 700 ns

AUITD+/-

T5.18.

AUIRD+/-

T5.18.

TXC

TXE

COL

T5.19. T5.19.

Obsolete

9.0 Electrical Specifications (Continued)

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9.5.20 10 Mb/s Jabber Timing

9.5.21 10BASE-T Normal Link Pulse Timing

Note: These specifications represent both transmit and receive timings.

Parameter Description Notes Min Typ Max Units

T5.20.1 Jabber Activation Time 10 Mb/s Nibble mode 26 ms

10 Mb/s Serial mode 26 ms

T5.20.2 Jabber Deactivation Time 10 Mb/s Nibble mode 500 ms

10 Mb/s Serial mode 500 ms

Parameter Description Notes Min Typ Max Units

T5.21.1 Pulse Width 100 ns

T5.21.2 Pulse Period 8 16 24 ms

TXE

TPTD+/-

COL

T5.20.

T5.20.1

T5.21.2

T5.21.1

Obsolete

9.0 Electrical Specifications (Continued)

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9.6 Auto-Negotiation Fast Link Pulse (FLP) Timing

Note: These specifications represent both transmit and receive timings.

9.7 100BASE-X Clock Recovery Module (CRM) Timing

Note: The Ideal window recognition region is ±4 ns.

Parameter Description Notes Min Typ Max Units

T6.21.1 Clock, Data Pulse Width 100 ns

T6.21.2 Clock Pulse to Clock Pulse

Period 111 125 139 µs

T6.21.3 Clock Pulse to Data Pulse

Period Data = 1 55.5 69.5 µs

T6.21.4 Number of Pulses in a Burst 17 33 #

T6.21.5 Burst Width 2ms

T6.21.6 FLP Burst to FLP Burst Period 8 24 ms

Parameter Description Notes Min Typ Max Units

T7.21.1 CRM Window Recognition Region -2.7 2.7 ns

CLOCK

PULSE DATA

PULSE CLOCK

PULSE

FLP BURST FLP BURST

FAST LINK PULSE(S)

T6.21.1 T6.21.

T6.21.

T6.21.4 T6.21.5

T6.21.

FXRD+/-

NOMINAL WINDOW

CENTER

T7.21.1

TPRD+/-

IDEAL WINDOW RECOGNITION

Obsolete

9.0 Electrical Specifications (Continued)

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9.7.22 100BASE-X CRM Acquisition Time

Note: The Clock Generation Module (CGM) must be stable for at least 100 µs before the Clock Recovery Module (CRM) can lock to receive data.

Note: SD+ internal comes from the internal Signal Detect function block when in 100BASE-TX mode.

9.7.23 100BASE-TX Signal Detect Timing

Note: The SD internal signal is available as an external signal in Symbol mode.

Note: The signal amplitude at TPRD +/− is TP-PMD compliant.

Parameter Description Notes Min Typ Max Units

T7.22.1 CRM Acquisition 100 Mb/s 250 µs

Parameter Description Notes Min Typ Max Units

T7.23.1 SD Internal Turn-on Time 1 ms

T7.23.2 SD Internal Turn-off Time 300 µs

FXSD+

FXRD+/- PLL LOCKEDPLL PRIOR TO LOCK

T7.22.1

OR SD+ INTERNAL

T7.23.

SD+ INTERNAL

T7.23.2

TPRD +/-

Obsolete

9.0 Electrical Specifications (Continued)

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9.8 Reset Timing

Note: Software Reset should be initiated no sooner then 500 µs after power-up or the deassertion of hardware reset.

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.

Note: The timing for Hardware Reset Option 2 is equal to parameter T1 plus parameter T2 (501 µs total).

Parameter Description Notes Min Typ Max Units

T8.23.1 Internal Reset Time 500 µs

T8.23.2 Hardware RESET Pulse Width 1 µs

T8.23.3 Post Reset Stabilization time

prior to MDC preamble for reg-

ister accesses

MDIO is pulled high for 32 bit serial man-

agement initialization 500 µs

T8.23.4 Hardware Configuration Latch-

inTimefromtheDeassertionof

Reset (either soft or hard)

Hardware Configuration Pins are de-

scribed in the Pin Description section 800 ns

T8.23.5 Hardware Configuration pins

transition to output drivers It is important to choose pull-up and/or

pull-down resistors for each of the hard-

ware 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

800 ns

VCC

HARDWARE

RESET (OPTION #1)

MDC

32 CLOCKS

LATCH-IN OF HARDWARE

CONFIGURATION PINS

DUAL FUNCTION PINS

BECOME ENABLED AS OUTPUTS

INPUT OUTPUT

HARDWARE

RESET (OPTION #2)

T8.23.5

T8.23.

Obsolete

9.0 Electrical Specifications (Continued)

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9.9 Loopback Timing

Note: Due to the nature of the descrambler function, all 100BASE-X 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-X timing specified is based on device delays after the initial 550µs “dead-time”.

Note: During loopback (all modes) both the TPTD±or FXTD/AUITD±outputs remain inactive by default.

Parameter Description Notes Min Typ Max Units

T9.23.1 TX_EN to RX_DV Loopback 100 Mb/s 240 ns

10 Mb/s Serial mode 650 ns

10 Mb/s Nibble mode 2 µs

TX_CLK

TX_EN

TXD[3:0]

CRS

RX_CLK

RXD[3:0]

RX_DV

T9.23.1

Obsolete

9.0 Electrical Specifications (Continued)

84 www.national.com

9.10 Isolation Timing

Parameter Description Notes Min Typ Max Units

T10.23.1 From software clear of bit 10 in

the BMCR register to the transi-

tion from Isolate to Normal Mode

100 µs

T10.23.2 FromDeassertionofS/WorH/W

ResettotransitionfromIsolateto

Normal mode

500 µs

CLEAR BIT 10 OF BMCR

(RETURN TO NORMAL OPERATION

FROM ISOLATE MODE)

H/W OR S/W RESET

(WITH PHYAD ≠ 00000)

MODE ISOLATE NORMAL

T10.23.2

T10.23.1

Obsolete

85 www.national.com

10.0 Test Conditions

This section contains information relating to the speciﬁc

test environments, including stimulus and loading parame-

ters, for the DP83843. These test conditions are catego-

rized in the following subsections by each type of

pin/interface including:

— FXTD/AUITD+/− Outputs sourcing AUI

— FXTD/AUITD+/− Outputs sourcing 100BASE-FX

— CMOS Outputs i.e. MII and LEDs

— TPTD+/− Outputs sourcing 100BASE-TX

— TPTD+/− Outputs sourcing 10BASE-T

Additionally, testing conditions for Idd measurements are

included.

10.1 FXTD/AUITD+/− Outputs (sourcing AUI lev-

els)

When conﬁgured for AUI operation, these differential out-

puts source Manchester encoded 10 Mb/s data at AUI logic

levels. These outputs are loaded as illustrated in Figure 26.

10.2 FXTD/AUITD+/− Outputs (sourcing PECL)

When conﬁgured for 100BASE-FX operation, these differ-

ential outputs source unscrambled 125 Mb/s data at PECL

logic levels. These outputs are loaded as illustrated in

Figure 27.

10.3 CMOS Outputs (MII and LED)

Each of the MII and LED outputs are loaded with a con-

trolled current source to either ground or VCC for testing

Voh, Vol, and AC parametrics. The associated capacitance

of this load is 50 pF. The diagram in Figure 28 illustrates

the test conﬁguration.

It should be noted that the current source and sink limits

are set to 4.0 mA when testing/loading the MII output pins.

The current source and sink limits are set to 2.5 mA when

testing/loading the LED output pins.

10.4 TPTD+/− Outputs (sourcing 10BASE-T)

When conﬁgured for 10BASE-T operation, these differen-

tial outputs source Manchester encoded binary data at

10BASE-T logic levels. These outputs are loaded as illus-

trated in Figure 29. Note that the transmit amplitude mea-

surements are made across the secondary of the transmit

transformer as speciﬁed by the IEEE 802.3 speciﬁcation.

10.5 TPTD+/− Outputs (sourcing 100BASE-TX)

When conﬁgured for 100BASE-TX operation, these differ-

ential outputs source scrambled 125Mb/s data at MLT-3

logic levels. These outputs are loaded as illustrated in

Figure 29. Note that the transmit amplitude and rise/fall

time measurements are made across the secondary of the

transmit transformer as speciﬁed by the IEEE 802.3u spec-

iﬁcation.

10.6 Idd Measurement Conditions

The DP83843 PHYTER is currently tested for total device

Idd under four operational modes:

— 100BASE-TX Full Duplex (max packet length / min IPG)

— 10BASE-TX Half Duplex (max packet length / min IPG)

— 100BASE-FX Full Duplex (max packet length / min IPG)

Figure 26. AUI Test Load

AUITD AUIRD AUICD

39Ω39Ω

.01µF

78Ω

27µH

200Ω200Ω

TYPICAL AUI

TRANSMIT LOAD

100µH TRANSFORMER

DB-15 CONNECTOR

Obsolete

10.0 Test Conditions (Continued)

86 www.national.com

Figure 27. 100BASE-FX Test Load

Figure 28. CMOS Output Test Load

Figure 29. 10/100 Twisted Pair Load (zero meters)

DP83843

PHYTER

VTT VTT VTT = VCC - 2.2V

50Ω50Ω

AUITD/FXTD+

AUITD/FXTD-

DP83843

PHYTER

GND

CMOS OUTPUT

VCC

50pF

CURRENT SINK

CURRENT SOU

100Ω

10/100

AC COUPLING

TRANSFORMER

DP83843

PHYTER

TPTD-

TPTD+

Obsolete

National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and speciﬁcations.

LIFE SUPPORT POLICY

NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT

DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL

SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or systems

which,(a) are intendedforsurgicalimplantinto the body,

or (b) support or sustain life, and whose failure to per-

form,whenproperlyusedinaccordancewithinstructions

for use provided in the labeling, can be reasonably ex-

pected to result in a significant injury to the user.

2. A critical component is any component of a life support

device or system whose failure to perform can be rea-

sonably expected to cause the failure of the life support

device or system, or to affect its safety or effectiveness.

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www.national.com

DP83843 PHYTER

11.0 Package Dimensions inches (millimeters) unless otherwise noted

Molded Plastic Quad Flat Package

Order Number DP83843BVJE

NC Package Number VJE80A

Obsolete

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