MAXIM DS21448 Technical data

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3.3V E1/T1/J1 Quad Line Interface

GENERAL DESCRIPTION

The DS21448 is a quad-port E1 or T1 line interface unit (LIU) for short-haul and long-haul applications. It incorporates four independent transmitters and four independent receivers in a single 144-pin PBGA or 128-pin LQFP package.

The transmit drivers generate the necessary G.703 E1 waveshapes in 75W or 120W applications and the DSX-1 or CSU line build-outs of 0dB, -7.5dB, -15dB, and -22.5dB for T1 applications.

The DS21448 has a usable receiver sensitivity of 0 to -43dB for E1 applications and 0 to -36dB for T1 that allows it to operate on 0.63mm (22AWG) cables up to 2.5km (E1) and 6000ft (T1) in length. The user has the option to use internal receive termination, software selectable for 75W, 100W, and 120W applications, or external termination.

The on-board crystal-less jitter attenuator can be placed in either the transmit or the receive data path, and requires only a 2.048MHz MCLK for both E1 and T1 applications (with the option of using a 1.544MHz MCLK in T1 applications).

The DS21448 has diagnostic capabilities such as loopbacks and PRBS pattern generation and detection. 16-bit loop-up and loop-down codes can be generated and detected. A single input pin can power down all transmitters to allow the implementation of hitless protection switching (HPS) for 1+1 redundancy without the use of relays.

The device can be controlled through an 8-bit parallel port (muxed or nonmuxed) or a serial port, and it can be used in hardware mode. A standard boundary scan interface supports board-level testing.

APPLICATIONS

Integrated Multiservice Access Platforms T1/E1 Cross-Connects, Multiplexers, and Channel

Banks Central-Office Switches and PBX Interfaces T1/E1 LAN/WAN Routers Wireless Base Stations

DS21448

FEATURES

§ Four Complete E1, T1, or J1 LIUs

§ Supports Long- and Short-Haul Trunks

§ Internal Software-Selectable Receive-Side

Termination for 75W/100W/120W

§ 3.3V Power Supply

§ 32-Bit or 128-Bit Crystal-Less Jitter Attenuator

Requires Only a 2.048MHz Master Clock for E1 and T1, with the Option to Use 1.544MHz for T1

§ Generates the Appropriate Line Build-Outs With

and Without Return Loss for E1, and DSX-1 and CSU Line Build-Outs for T1

§ AMI, HDB3, and B8ZS Encoding/Decoding

§ 16.384MHz, 8.192MHz, 4.096MHz, or 2.048MHz

Clock Output Synthesized to Recovered Clock

§ Programmable Monitor Mode for Receiver

§ Loopbacks and PRBS Pattern Generation/

Detection with Output for Received Errors

§ Generates/Detects In-Band Loop Codes, 1 to 16

Bits, Including CSU Loop Codes

§ 8-Bit Parallel or Serial Interface with Optional

Hardware Mode

§ Muxed and Nonmuxed Parallel Bus Supports

Intel or Motorola

§ Detects/Generates Blue (AIS) Alarms

§ NRZ/Bipolar Interface for Tx/Rx Data I/O

§ Transmit Open-Circuit Detection

§ Receive Carrier Loss (RCL) Indication (G.775)

§ High-Z State for TTIP and TRING

§ 50mA

§ JTAG Boundary Scan Test Port per IEEE 1149.1

§ Meets Latest E1 and T1 Specifications Including

ANSI.403-1999, ANSI T1.408, AT&T TR 62411, ITU G.703, G.704, G.706, G.736, G.775, G.823, I.431, O.151, O.161, ETSI ETS 300 166, JTG.703, JTI.431, TBR12, TBR13, and CTR4

ORDERING INFORMATION

PART TEMP RANGE

DS21448 0°C to +70°C 3.3 144 BGA DS21448N -40°C to +85°C 3.3 144 BGA DS21448L 0°C to +70°C 3.3 128 LQFP DS21448LN -40°C to +85°C 3.3 128 LQFP

Pin Configurations appear in Section 11.

Transmit Current Limiter

RMS

VOLTAGE

(V)

PINPACKAGE

Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata

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REV: 012104

DS21448 3.3V T1/E1/J1 Quad Line Interface

TABLE OF CONTENTS

1. BLOCK DIAGRAMS...................................................................................................................... 5

2. PIN DESCRIPTION ....................................................................................................................... 7

3. DETAILED DESCRIPTION...........................................................................................................13

3.1 DS21448 AND DS21Q348 DIFFERENCES ....................................................................................13

4. PORT OPERATION......................................................................................................................13

4.1 HARDWARE MODE.......................................................................................................................13

4.2 SERIAL PORT OPERATION............................................................................................................15

4.3 PARALLEL PORT OPERATION .......................................................................................................17

4.3.1 Device Power-Up and Reset.................................................................................................................17

4.3.2 Register Map.........................................................................................................................................18

4.3.3 Control Registers ..................................................................................................................................19

5. STATUS REGISTERS..................................................................................................................23

6. DIAGNOSTICS ............................................................................................................................27

6.1 IN-BAND LOOP-CODE GENERATION AND DETECTION.....................................................................27

6.2 LOOPBACKS ................................................................................................................................31

6.2.1 Remote Loopback (RLB) ......................................................................................................................31

6.2.2 Local Loopback (LLB) ...........................................................................................................................31

6.2.3 Analog Loopback (LLB) ........................................................................................................................31

6.2.4 Dual Loopback (DLB)............................................................................................................................31

6.3 PRBS GENERATION AND DETECTION ...........................................................................................31

6.4 ERROR COUNTER........................................................................................................................31

6.5 ERROR COUNTER UPDATE...........................................................................................................32

6.6 ERROR INSERTION.......................................................................................................................32

7. ANALOG INTERFACE.................................................................................................................33

7.1 RECEIVER...................................................................................................................................33

7.2 TRANSMITTER .............................................................................................................................33

7.3 JITTER ATTENUATOR ...................................................................................................................34

7.4 G.703 SYNCHRONIZATION SIGNAL ...............................................................................................34

8. JTAG BOUNDARY SCAN ARCHITECTURE AND TEST ACCESS PORT..................................43

8.1 JTAG TAP CONTROLLER STATE MACHINE ...................................................................................43

8.2 INSTRUCTION REGISTER ..............................................................................................................45

8.3 TEST REGISTERS ........................................................................................................................46

9. OPERATING PARAMETERS.......................................................................................................48

10. AC TIMING PARAMETERS AND DIAGRAMS ............................................................................49

11. PIN CONFIGURATIONS ..............................................................................................................56

11.1 144-PIN BGA ..........................................................................................................................56

11.2 128-PIN LQFP.........................................................................................................................57

12. PACKAGE INFORMATION..........................................................................................................58

13. THERMAL INFORMATION ..........................................................................................................60

14. REVISION HISTORY....................................................................................................................60

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DS21448 3.3V T1/E1/J1 Quad Line Interface

LIST OF FIGURES

Figure 1-1. Block Diagram....................................................................................................................... 5

Figure 1-2. Receive Logic Detail.............................................................................................................. 6

Figure 1-3. Transmit Logic Detail............................................................................................................. 6

Figure 4-1. Serial Port Operation for Read Access (R = 1) Mode 1 ........................................................15

Figure 4-2. Serial Port Operation for Read Access (R = 1) Mode 2 ........................................................16

Figure 4-3. Serial Port Operation for Read Access (R = 1) Mode 3 ........................................................16

Figure 4-4. Serial Port Operation for Read Access (R = 1) Mode 4 ........................................................16

Figure 4-5. Serial Port Operation for Write Access (R = 0) Modes 1 and 2 .............................................17

Figure 4-6. Serial Port Operation for Write Access (R = 0) Modes 3 and 4 .............................................17

Figure 7-1. Basic Interface......................................................................................................................36

Figure 7-2. Protected Interface Using Internal Receive Termination.......................................................37

Figure 7-3. Protected Interface Using External Receive Termination......................................................38

Figure 7-4. Dual Connector-Protected Interface Using Receive Termination ..........................................39

Figure 8-5. E1 Transmit Pulse Template ................................................................................................40

Figure 8-6. T1 Transmit Pulse Template.................................................................................................41

Figure 7-7. Jitter Tolerance.....................................................................................................................42

Figure 7-8. Jitter Attenuation ..................................................................................................................42

Figure 8-1. JTAG Block Diagram............................................................................................................43

Figure 8-2. TAP Controller State Diagram ..............................................................................................44

Figure 10-1. Intel Bus Read Timing (PBTS = 0, BIS0 = 0) ......................................................................49

Figure 10-2. Intel Bus Write Timing (PBTS = 0, BIS0 = 0) ......................................................................50

Figure 10-3. Motorola Bus Timing (PBTS = 1, BIS0 = 0) ........................................................................50

Figure 10-4. Intel Bus Read Timing (PBTS = 0, BIS0 = 1) ......................................................................51

Figure 10-5. Intel Bus Write Timing (PBTS = 0, BIS0 = 1) ......................................................................52

Figure 10-6. Motorola Bus Read Timing (PBTS = 1, BIS0 = 1)...............................................................52

Figure 10-7. Motorola Bus Write Timing (PBTS = 1, BIS0 = 1) ...............................................................52

Figure 10-8. Serial Bus Timing (BIS1 = 1, BIS0 = 0)...............................................................................53

Figure 10-9. Receive-Side Timing ..........................................................................................................54

Figure 10-10. Transmit-Side Timing .......................................................................................................55

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DS21448 3.3V T1/E1/J1 Quad Line Interface

LIST OF TABLES

Table 2-A. Bus Interface Selection .......................................................................................................... 7

Table 2-B. Pin Assignments .................................................................................................................... 7

Table 2-C. Parallel Interface Mode Pin Description ................................................................................. 9

Table 2-D. Serial Interface Mode Pin Description ...................................................................................10

Table 2-E. Hardware Interface Mode Pin Description.............................................................................11

Table 3-A. DS21448 vs. DS21Q348 Pin Differences ..............................................................................13

Table 4-A. Loopback Control in Hardware Mode ....................................................................................14

Table 4-B. Transmit Data Control in Hardware Mode .............................................................................14

Table 4-C. Receive Sensitivity Settings in Hardware Mode ....................................................................14

Table 4-D. Monitor Gain Settings in Hardware Mode..............................................................................14

Table 4-E. Internal Rx Termination Select in Hardware Mode ................................................................14

Table 4-F. MCLK Selection in Hardware Mode.......................................................................................14

Table 4-G. Parallel Port Mode Selection.................................................................................................18

Table 4-H. Register Map ........................................................................................................................18

Table 4-I. Receive Sensitivity Settings....................................................................................................22

Table 4-J. Backplane Clock Select .........................................................................................................22

Table 4-K. Monitor Gain Settings............................................................................................................22

Table 4-L. Internal Rx Termination Select...............................................................................................22

Table 5-A. Received Alarm Criteria ........................................................................................................25

Table 5-B. Receive Level Indication .......................................................................................................27

Table 6-A. Transmit Code Length...........................................................................................................29

Table 6-B. Receive Code Length............................................................................................................29

Table 6-C. Definition of Received Errors.................................................................................................32

Table 6-D. Function of ECRS Bits and RNEG Pin ..................................................................................32

Table 7-A. Line Build-Out Select for E1 in Register CCR4 (ETS = 0)......................................................34

Table 7-B. Line Build-Out Select for T1 in Register CCR4 (ETS = 1)......................................................34

Table 7-C. Line Build-Out Select for E1 in Register CCR4 (ETS = 0) Using Alternate Transformer

Configuration ...................................................................................................................................35

Table 7-D. Transformer Specifications (3.3V Operation) ........................................................................35

Table 8-A. Instruction Codes for IEEE 1149.1 Architecture.....................................................................45

Table 8-B. ID Code Structure .................................................................................................................46

Table 8-C. Device ID Codes...................................................................................................................46

Table 8-D. Boundary Scan Control Bits ..................................................................................................47

Table 10-A. AC Characteristics—Multiplexed Parallel Port (BIS0 = 0)....................................................49

Table 10-B. AC Characteristics—Nonmultiplexed Parallel Port (BIS0 = 1) .............................................51

Table 10-C. AC Characteristics—Serial Port (BIS1 = 1, BIS0 = 0)..........................................................53

Table 10-D. AC Characteristics—Receive Side......................................................................................54

Table 10-E. AC Characteristics—Transmit Side .....................................................................................55

Table 13-A. Thermal Characteristics—BGA ...........................................................................................60

Table 13-B. Theta-JA (qJA) vs. Airflow—BGA..........................................................................................60

Table 13-C. Thermal Characteristics—LQFP..........................................................................................60

Table 13-D. Theta-JA (qJA) vs. Airflow—LQFP........................................................................................60

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1. BLOCK DIAGRAMS

SDI

(R/

)

RD(DS

)

(

A0 TO A4

(

)

RECEIVE PATH)

Figure 1-1. Block Diagram

DS21448 3.3V T1/E1/J1 Quad Line Interface

RRING

RTIP

TRING

TTIP

CHANNEL 4

CHANNEL 3

CHANNEL 2

CHANNEL 1

OPTIONAL

TERMINANATION

POWER

CONNECTIONS

ANALOG LOOPBACK

VSM

FILTER

UNFRAMED

ALL-ONES

INSERTION

LINE DRIVERS

PEAK DETECT

CSU FILERS

VCO/PLL

RECOVERY

CLOCK/DATA

WAVESHAPING

JACLK

TYPICAL OF ALL FOUR CHANNELS

MCLK

MUX

JITTER

ATTENUATOR

DUAL MODE

2.048MHz TO

1.544MHz PLL

16.384MHz OR

8.192MHz OR

4.096MHz OR

2.048MHz

SYNTHESIZER

MUX

See Figure 1-2

REMOTE LOOPBAC

BPCLK

RPOS

RCLK

RNEG

PBEO

REMOTE LOOPBACK

JITTER ATTENUATION

LOCAL LOOPBAC

(CAN BE PLACED IN EITHER TRANSM IT OR

MUX

See Figure 1-3

RCL/LOTC

TPOS TCLK

TNEG

Dallas

RST

TXDIS/TEST

BIS0

MUX (THE SERIAL, PARALLEL, AND HARDWARE INTERFACES

SERIAL

INTERFACE

SHARE DEVICE PINS)

PARALLEL INTERFACE

SCL

SDO

PBTS

ALE

CONTROL AND

(ROUTED TO ALL BLOCKS)

CONTROL AND TEST

PORT (ROUTED TO

ALL BLOCKS)

JTAG PORT

JTMS

JRST

JTDI

JTCL

JTDO

Semiconductor

DS21448

D0 TO D7/AD0

TO AD7

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Figure 1-2. Receive Logic Detail

DS21448 3.3V T1/E1/J1 Quad Line Interface

CLOCK INVERT

FROM REMOTE LOOPBACK

ROUTED TO

LL BLOCKS

4 OR 8 ZERO DETECT

16 ZERO DETECT

RIR1.7 RIR1.6

CCR2.0

B8ZS/HDB3 DECODER

CCR2.3

CCR6.2/ CCR6.0/ CCR6.1

Figure 1-3. Transmit Logic Detail

CCR1.6

RIR1.5

ALL-ONES

DETECTOR

NRZ DATA

BPV/CV/EXZ

LOOP CODE

DETECTOR

SR.6 SR.7SR.4 RIR1.3

CCR3.3

PRBS

DETECTOR

SR.0

CCR1.4

CCR3.4

MUX

16-BIT ERROR

COUNTER (ECR)

MUX

CCR1.6

CCR6.0

RCLK

RPOS

RNEG

PBEO

TO REMOTE

LOOPBAC

CCR3.1

BPV

INSERT

ROUTED TO

LL BLOCKS

GA TE

MUX

CCR1.1

CCR2.2

CCR3.0

PRBS

GENERATOR

MUX

B8ZS/ HDB3

CODER

LOGIC ERROR INSERT

RCLK

MUX

GA TE

CCR1.2

GATE

CCR1.0

TO LOTC OUTPUT PIN

JACLK (FROM MCLK)

LOSS-OF-TRANSMIT

CLOCK DETECT

LOOP CODE

GENERATOR

SR.5

OR GATE

CLOCK INVERT

CCR2.1

TPOS

TNEG

TCLK

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DS21448 3.3V T1/E1/J1 Quad Line Interface

2. PIN DESCRIPTION

The DS21448 can be controlled in parallel port mode, serial port mode, or hardware mode. The bus interface select bits 0 and 1 (BIS0, BIS1) determine the device mode and pin assignments (Table 2-A

Table 2-A. Bus Interface Selection

BIS1 BIS0 BUS INTERFACE TYPE

0 0 Parallel Port Mode (multiplexed) 0 1 Parallel Port Mode (nonmultiplexed) 1 0 Serial Port Mode 1 1 Hardware Mode

Table 2-B. Pin Assignments

BGA LQFP

J3 18 I

D3 57 I D10 84 I K10 114 I

J2 91 I

H1 92 I

K2 95 I ALE (AS) N/A SCLKE

J1 35 I N/A SCLK L2 K3 36 I N/A SDI L1 K1 62 I/O A4 SDO L0 L1 63 I A3 ICES DJA

H11 64 I A2 OCES JAMUX H12 65 I A1 N/A JAS

G12 66 I A0 N/A HBE

J10 75 I/O D7/AD7 N/A CES H10 76 I/O D6/AD6 N/A TPD G11 77 I/O D5/AD5 N/A TX0

J9 78 I/O D4/AD4 N/A TX1

E3 79 I/O D3/AD3 N/A LOOP0

D4 80 I/O D2/AD2 N/A LOOP1

F3 81 I/O D1/AD1 N/A MM0

D5 82 I/O D0/AD0 N/A MM1

— 3 I VSM VSM VSM L5 115–117 — VDD1 VDD1 VDD1 E4 19–21 — VDD2 VDD2 VDD2

D8 49–51 — VDD3 VDD3 VDD3

J8 85–87 — VDD4 VDD4 VDD4

M4 118–120 — VSS1 VSS1 VSS1

F4 22–24 — VSS2 VSS2 VSS2

D9 52–54 — VSS3 VSS3 VSS3 H9 88–90 — VSS4 VSS4 VSS4

K9 97 I/O K5 110 O PBEO1 PBEO1 PBEO1

G3 111 O PBEO2 PBEO2 PBEO2

E10 121 O PBEO3 PBEO3 PBEO3

K8 123 O PBEO4 PBEO4 PBEO4 L6 126 O RCL1/LOTC1 RCL1/LOTC1 RCL1

D7 128 O RCL2/LOTC2 RCL2/LOTC2 RCL2

F9 1 O RCL3/LOTC3 RCL3/LOTC3 RCL3

J7 2 O RCL4/LOTC4 RCL4/LOTC4 RCL4 K7 98 I TXDIS/TEST TXDIS/TEST TXDIS/TEST A1 124 I RTIP1 RTIP1 RTIP1 A4 28 I RTIP2 RTIP2 RTIP2 A7 60 I RTIP3 RTIP3 RTIP3

A10 93 I RTIP4 RTIP4 RTIP4

B2 125 I RRING1 RRING1 RRING1 B5 29 I RRING2 RRING2 RRING2

I/O PARALLEL PORT MODE SERIAL PORT MODE HARDWARE MODE

CS1 CS1 CS2 CS2 CS3 CS3 CS4 CS4

RD (DS)

WR (R/W)

INT INT

N/A ETS N/A NRZE

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EGL1 EGL2 EGL3 EGL4

RT1

DS21448 3.3V T1/E1/J1 Quad Line Interface

BGA LQFP

B8 61 I RRING3 RRING3 RRING3

B11 94 I RRING4 RRING4 RRING4

L9 106 I

J6 109 I MCLK MCLK MCLK

H4 122 O BPCLK1 BPCLK1 BPCLK1 D6 47 O BPCLK2 BPCLK2 BPCLK2

F10 56 O BPCLK3 BPCLK3 BPCLK3

L8 112 O BPCLK4 BPCLK4 BPCLK4 L7 107 I BIS0 BIS0 BIS0

M8 68 I BIS1 BIS1 BIS1

A2 6 O TTIP1 TTIP1 TTIP1 A5 38 O TTIP2 TTIP2 TTIP2 A8 71 O TTIP3 TTIP3 TTIP3

A11 102 O TTIP4 TTIP4 TTIP4

J4 7 — TVSS1 TVSS1 TVSS1

D1 39 — TVSS2 TVSS2 TVSS2

E9 72 — TVSS3 TVSS3 TVSS3

L10 103 — TVSS4 TVSS4 TVSS4

J5 8 — TVDD1 TVDD1 TVDD1

D2 40 — TVDD2 TVDD2 TVDD2 G9 73 — TVDD3 TVDD3 TVDD3 M9 104 — TVDD4 TVDD4 TVDD4

B3 9 O TRING1 TRING1 TRING1 B6 41 O TRING2 TRING2 TRING2 B9 74 O TRING3 TRING3 TRING3

B12 105 O TRING4 TRING4 TRING4

K4 10 O RPOS1 RPOS1 RPOS1 E1 12 O RPOS2 RPOS2 RPOS2

D11 14 O RPOS3 RPOS3 RPOS3 K11 16 O RPOS4 RPOS4 RPOS4

G2 11 O RNEG1 RNEG1 RNEG1

E2 13 O RNEG2 RNEG2 RNEG2

F11 15 O RNEG3 RNEG3 RNEG3

M10 25 O RNEG4 RNEG4 RNEG4

H3 127 O RCLK1 RCLK1 RCLK1

F1 31 O RCLK2 RCLK2 RCLK2

E11 58 O RCLK3 RCLK3 RCLK3

L11 96 O RCLK4 RCLK4 RCLK4

G1 26 I TPOS1 TPOS1 TPOS1

F2 30 I TPOS2 TPOS2 TPOS2

E12 33 I TPOS3 TPOS3 TPOS3 M11 55 I TPOS4 TPOS4 TPOS4

H2 27 I TNEG1 TNEG1 TNEG1

M1 32 I TNEG2 TNEG2 TNEG2 D12 34 I TNEG3 TNEG3 TNEG3 K12 59 I TNEG4 TNEG4 TNEG4

M2 17 I TCLK1 TCLK1 TCLK1

L2 43 I TCLK2 TCLK2 TCLK2 F12 83 I TCLK3 TCLK3 TCLK3 L12 113 I TCLK4 TCLK4 TCLK4

M12 108 I PBTS N/A RT0

L3 42 I JTRST JTRST JTRST

M3 48 I JTMS JTMS JTMS M5 44 I JTCLK JTCLK JTCLK M6 45 I JTDI JTDI JTDI M7 46 O JTDO JTDO JTDO

Note 1: The VSM signal is not available with the BGA package option. Note 2: The LQFP no-connect pin numbers are 4, 5, 37, 67, 69, 70, and 99–101. Note 3: The BGA no-connect pin numbers are A3, A6, A9, A12, B1, B4, B7, B10, C1–C12, E5–E8, F5–F8, G4–G8, G10, H5–H8, J11, J12, K6,

and L4.

I/O PARALLEL PORT MODE SERIAL PORT MODE HARDWARE MODE

HRST HRST HRST

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DS21448 3.3V T1/E1/J1 Quad Line Interface

Table 2-C. Parallel Interface Mode Pin Description

PIN I/O FUNCTION

Read Input (Data Strobe). RD and DS are active-low signals. DS is active low when in

RD (DS)

WR (R/W)

ALE (AS) I

A4–A0 I

D7/AD7–D0/AD0 I/O

INT

TXDIS/TEST I

HRST

MCLK I

BIS0/BIS1 I Bus Interface Select Bit 0 and 1. Used to select bus interface option. See Table 2-A for details.

PBTS I

CS1–CS4

PBEO1–PBEO4 O

RCL1/LOTC1–

RCL4/LOTC4

RTIP1–RTIP4 I

RRING1–RRING4 I

BPCLK1–BPCLK4 O

TTIP1–TTIP4 O

TRING1–TRING4 O

RPOS1–RPOS4 O

RNEG1–RNEG4 O

nonmultiplexed, Motorola mode. See the bus timing diagrams in Section 10

Write Input (Read/Write). WR is an active-low signal. See the bus timing diagrams in Section 10.

Address Latch Enable (Address Strobe). When using multiplexed bus mode (BIS0 = 0), this pin serves to demultiplex the bus on a positive-going edge. In nonmultiplexed bus mode (BIS0 = 1), ALE should be wired low.

Address Bus. In nonmultiplexed bus operation (BIS0 = 1), these pins serve as the address bus. In multiplexed bus operation (BIS0 = 0), these pins are not used and should be wired low.

Data Bus/Address/Data Bus. In nonmultiplexed bus operation (BIS0 = 1), these pins serve as the data bus. In multiplexed bus operation (BIS0 = 0), these pins serve as an 8-bit multiplexed address/data bus.

Interrupt (INT). The interrupt flags the host controller during conditions and change of conditions

defined in the status register. It is an active-low, open-drain output. Tri-State Control, Multifunctional. Set this pin high, with all CS1–CS4 inputs inactive, to tri-state TTIP1–TTIP4 and TRING1–TRING4. Set this pin high with any of the CS1–CS4 inputs active to

tri-state all outputs and I/O pins (including the parallel control port). Set low for normal operation. Hardware Reset. Bringing HRST low resets the DS21448, setting all control bits to the all-zeros

default state. Master Clock. A 2.048MHz (±50ppm) clock source with TTL levels is applied at this pin. This clock is used internally for both clock/data recovery and for jitter attenuation. Use of a T1

1.544MHz clock source is optional (Note 1).

Parallel Bus Type Select. When using the parallel port, set PBTS high to select Motorola bus timing; set low to select Intel bus timing. This pin controls the function of the RD (DS), ALE (AS), and WR (R/W) pins. Chip Select 1. Must be low to read or write to channel 1 of the device. CS1 is an active-low signal. Chip Select 2. Must be low to read or write to channel 2 of the device. CS2 is an active-low signal.

Chip Select 3. Must be low to read or write to channel 3 of the device. CS3 is an active-low signal.

Chip Select 4. Must be low to read or write to channel 4 of the device. CS4 is an active-low signal.

PRBS Bit-Error Output. The receiver constantly searches for a 215 - 1 (E1) or a QRSS (T1) PRBS, depending on the ETS bit setting (CCR1.7). It remains high if it is out of synchronization with the PRBS pattern. It goes low when synchronized to the PRBS pattern. Any errors in the received pattern after synchronization cause a positive-going pulse (with same period as E1 or T1 clock) synchronous with RCLK. PRBS bit errors can also be reported to the ECR1 and ECR2 registers by setting CCR6.2 to logic 1.

Receive Carrier Loss/Loss-of-Transmit Clock. An output that toggles high during a receive carrier

loss (CCR2.7 = 0) or toggles high if the TCLK pin has not been toggled for 5ms ± 2ms (CCR2.7 =

1). CCR2.7 defaults to logic 0 when in hardware mode. Receive Tip and Ring. Analog inputs for clock recovery circuitry. These pins connect through a 1:1 transformer to the line. See Section 7 for details.

Backplane Clock. A 16.384MHz, 8.192MHz, 4.096MHz, or 2.048MHz clock output that is referenced to RCLK selectable through CCR5.7 and CCR5.6.

Transmit Tip and Ring. Analog line-driver outputs. These pins connect through a step-up transformer to the line. See Section 7 for details.

Receive Positive Data. These bits are updated on the rising edge (CCR2.0 = 0) or the falling edge (CCR2.0 = 1) of RCLK with bipolar data out of the line interface. Set NRZE (CCR1.6) to 1 for NRZ applications. In NRZ mode, data is output on RPOS, and a received error (BPV, CV, or EXZ) causes a positive-going pulse synchronous with RCLK at RNEG.

Receive Negative Data. Updated on the rising edge (CCR2.0 = 0) or the falling edge (CCR2.0 =

1) of RCLK with the bipolar data out of the line interface. Set NRZE (CCR1.6) to 1 for NRZ applications. In NRZ mode, data is output on RPOS, and a received error (BPV, CV, or EXZ) causes a positive-going pulse synchronous with RCLK at RNEG.

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DS21448 3.3V T1/E1/J1 Quad Line Interface

PIN I/O FUNCTION

RCLK1–RCLK4 O

TPOS1–TPOS4 I

TNEG1–TNEG4 I

TCLK1–TCLK4 I

JTRST I JTAG Reset

JTMS I JTAG Mode Select

JTCLK I JTAG Clock

JTDI I JTAG Data In

JTDO O JTAG Data Out

VSM I Voltage Supply Mode (LQFP only). Should be wired low for correct operation.

TVDD1–TVDD4 — 3.3V, ±5% Transmitter Positive Supply

VDD1–VDD4 — 3.3V, ±5% Positive Supply

TVSS1–TVSS4 — Transmitter Signal Ground

VSS1–VSS4 — Signal Ground

Receive Clock. Buffered recovered clock from the line. Synchronous to MCLK in absence of signal at RTIP and RRING. Transmit Positive Data. Sampled on the falling edge (CCR2.1 = 0) or the rising edge (CCR2.1 = 1) of TCLK for data to be transmitted out onto the line. Transmit Negative Data. Sampled on the falling edge (CCR2.1 = 0) or the rising edge (CCR2.1 = 1) of TCLK for data to be transmitted out onto the line. Transmit Clock. A 2.048MHz or 1.544MHz primary clock. It is used to clock data through the transmit-side formatter. It can be sourced internally by MCLK or RCLK. See Common Control Register 1 and Figure 1-3

Table 2-D. Serial Interface Mode Pin Description

PIN I/O FUNCTION

Interrupt (INT). Flags host controller during conditions and change of conditions defined in the

INT

TXDIS/TEST I

HRST

MCLK I

BIS0/BIS1 I Bus Interface Select Bit 0 and 1. Used to select bus interface option. See Table 2-A for details.

CS1

CS2

CS3

CS4

ICES I

OCES I

SCLK I Serial Clock. Serial interface clock.

SDI I Serial Data Input. Serial interface data input.

SDO O Serial Data Output. Serial interface data output.

PBEO1–PBEO4 O

RCL1/LOTC1–

RCL4/LOTC4

RTIP1–RTIP4

RRING1–RRING4

I/O

status register. Active-low, open-drain output. Tri-State Control, Multifunctional. Set this pin high with all CS1–CS4 inputs inactive to tri-state TTIP1–TTIP4 and TRING1–TRING4. Set this pin high with any of the CS1–CS4 inputs active to

tri-state all outputs and I/O pins (including the parallel control port). Set low for normal operation. Hardware Reset. Bringing HRST low resets the DS21448, setting all control bits to the all-zeros

Chip Select 1. Must be low to read or write to channel 1 of the device. CS1 is an active-low

signal. Chip Select 2. Must be low to read or write to channel 2 of the device. CS2 is an active-low

signal. Chip Select 3. Must be low to read or write to channel 3 of the device. CS3 is an active-low

signal. Chip Select 4. Must be low to read or write to channel 4 of the device. CS4 is an active-low

signal. Input Clock-Edge Select. Selects whether the serial interface data input (SDI) is sampled on the rising (ICES = 0) or falling edge (ICES = 1) of SCLK. Output Clock-Edge Select. Selects whether the serial interface data output (SDO) changes on the rising (OCES = 1) or falling edge (OCES = 0) of SCLK.

loss (CCR2.7 = 0) or toggles high if the TCLK pin has not been toggled for 5ms ± 2ms (CCR2.7 = 1). CCR2.7 defaults to logic 0 when in hardware mode. Receive Tip and Ring. Analog inputs for clock recovery circuitry. These pins connect through a

1:1 transformer to the line. See Section 7

for details.

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PIN I/O FUNCTION

BPCLK1–BPCLK4 O

TTIP1–TTIP4 O

TRING–TRING4 O

RPOS1–RPOS4 O

RNEG1–RNEG4 O

RCLK1–RCLK4 O

TPOS1–TPOS4 I

TNEG1–TNEG4 I

TCLK1–TCLK4 I

JTRST I JTAG Reset

JTMS I JTAG Mode Select

JTCLK I JTAG Clock

JTDI I JTAG Data In

JTDO O JTAG Data Out

VSM I Voltage Supply Mode (LQFP only). VSM should be wired low for correct operation.

TVDD1–TVDD4 — 3.3V, ±5% Transmitter Positive Supply

VDD1–VDD4 — 3.3V, ±5% Positive Supply

TVSS1–TVSS4 — Transmitter Signal Ground for Transmitter Outputs

VSS1–VSS4 — Signal Ground

Backplane Clock. A 16.384MHz, 8.192MHz, 4.096MHz, or 2.048MHz clock output that is referenced to RCLK selectable through CCR5.7 and CCR5.6. Transmit Tip and Ring. Analog line-driver outputs. These pins connect through a step-up transformer to the line. See Section 7

Receive Positive Data. Updated on the rising edge (CCR2.0 = 0) or the falling edge (CCR2.0 = 1) of RCLK with bipolar data out of the line interface. Set NRZE (CCR1.6) to 1 for NRZ applications. In NRZ mode, data is output on RPOS, and a received error (BPV, CV, or EXZ) causes a positive-going pulse synchronous with RCLK at RNEG. Receive Negative Data. Updated on the rising edge (CCR2.0 = 0) or the falling edge (CCR2.0 =

Receive Clock. Buffered recovered clock from the line. Synchronous to MCLK in absence of signal at RTIP and RRING.

Transmit Positive Data. Sampled on the falling edge (CCR2.1 = 0) or the rising edge (CCR2.1 =

1) of TCLK for data to be transmitted out onto the line. Transmit Negative Data. Sampled on the falling edge (CCR2.1 = 0) or the rising edge (CCR2.1 =

1) of TCLK for data to be transmitted out onto the line. Transmit Clock. A 2.048MHz or 1.544MHz primary clock used to clock data through the transmit side formatter. They can be sourced internally by MCLK or RCLK. See Common Control Register 1 and Figure 1-3.

for details.

Table 2-E. Hardware Interface Mode Pin Description

PIN I/O FUNCTION

E1/T1 Select

ETS I

NRZE I

SCLKE I

DJA I

JAMUX I

JAS I

HBE I

L0/L1/L2 I

0 = E1 1 = T1 NRZ Enable 0 = bipolar data at RPOS/RNEG and TPOS/TNEG 1 = NRZ data at RPOS and TPOS or TNEG; RNEG outputs a positive-going pulse when the device receives a BPV, CV, or EXZ. Receive and Transmit Synchronization Clock Enable. SCLKE combines RSCLKE (CCR5.3) and TSCLKE (CCR5.2). 0 = disable 2.048MHz synchronization transmit and receive mode 1 = enable 2.048MHz synchronization transmit and receive mode Disable Jitter Attenuator 0 = jitter attenuator enabled 1 = jitter attenuator disabled Jitter Attenuator Clock Mux. Controls the source for JACLK. 0 = JACLK sourced from MCLK (2.048MHz or 1.544MHz at MCLK). 1 = JACLK sourced from internal PLL (2.048 MHz at MCLK). Jitter Attenuator Path Select 0 = place the jitter attenuator on the receive side 1 = place the jitter attenuator on the transmit side Receive and Transmit HDB3/B8ZS Enable. HBE combines RHBE (CCR2.3) and THBE (CCR2.2). 0 = enable HDB3 (E1)/B8ZS (T1) 1 = disable HDB3 (E1)/B8ZS (T1) Line Build-Out Select Bits 0,1, and 2. These pins set the transmitter build-out; see (Table 7-A (E1) and Table 7-B

(T1).

DS21448 3.3V T1/E1/J1 Quad Line Interface

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DS21448 3.3V T1/E1/J1 Quad Line Interface

PIN I/O FUNCTION

Receive and Transmit Clock Select. Selects which RCLK edge to update RPOS and RNEG and

CES I

TPD I

TX0/TX1 I

LOOP0/LOOP1 I Loopback Select Bits 0 and 1. These inputs determine the active loopback mode (Table 4-A).

MM0/MM1 I

RT1/RT0 I

TEST I

HRST

MCLK I

BIS0/BIS1 I Bus Interface Select Bit 0 and 1. Used to select bus interface option (Table 2-A).

EGL1–EGL4 I

PBEO1–PBEO4 O

RCL1–RCL4 O Receive Carrier Loss. An output that toggles high during a receive carrier loss.

RTIP1–RTIP4 I RRING1–RRING4 I BPCLK1–BPCLK4 O Backplane Clock. A 16.384MHz clock output that is referenced to RCLK.

TTIP1–TTIP4

TRING1–TRING4

RPOS1–RPOS4 O

RNEG1–RNEG4 O

RCLK1–RCLK4 O

TPOS1–TPOS4 I

TNEG1–TNEG4 I

TCLK1–TCLK4 I

JTRST I JTAG Reset

JTMS I JTAG Mode Select

JTCLK I JTAG Clock

JTDI I JTAG Data In

JTDO O JTAG Data Out

VSM I Voltage Supply Mode (LQFP only). VSM should be wired low for correct operation.

TVDD1–TVDD4 – 3.3V, ±5% Transmitter Positive Supply

VDD1–VDD4 — 3.3V, ±5% Positive Supply

which TCLK edge to sample TPOS and TNEG. CES combines TCES and RCES. 0 = update RPOS/RNEG on rising edge of RCLK; sample TPOS/TNEG on falling edge of TCLK 1 = update RPOS/RNEG on falling edge of RCLK; sample TPOS/TNEG on rising edge of TCLK Transmit Power-Down 0 = normal transmitter operation 1 = powers down the transmitter and tri-states TTIP and TRING pins Transmit Data Source Select Bits 0 and 1. These inputs determine the source of the transmit

- 1 PRBS (ETS = 0) or a

for details.

data (Table 4-B

Monitor Mode Select Bits 0 and 1. These inputs determine if the receive equalizer is in a monitor mode (Table 4-D Receive LIU Termination Select Bits 0 and 1. These inputs determine the receive termination (Table 4-E Tri-State Control. Set high to tri-state all outputs and I/O pins (including the parallel control port). Set low for normal operation. Useful in board-level testing.

Hardware Reset. Bringing HRST low resets the DS21448, setting all control bits to the all-zero

Receive Equalizer Gain-Limit Select. These bits control the sensitivity of the receive equalizers (Table 4-C

PRBS Bit-Error Output. The receiver constantly searches for a 2 QRSS PRBS (ETS = 1). The pattern is chosen automatically by the value of the ETS pin. It remains high if it is out of synchronization with the PRBS pattern. It goes low when synchronized to the PRBS pattern. Any errors in the received pattern after synchronization cause a positivegoing pulse (with same period as E1 or T1 clock) synchronous with RCLK.

Receive Tip and Ring. Analog inputs for clock recovery circuitry. These pins connect through a 1:1 transformer to the line. See Section 7

Transmit Tip and Ring. Analog line-driver outputs. These pins connect through a step-up

transformer to the line. See Section 7 Receive Positive Data. Updated on the rising edge (CES = 0) or the falling edge (CES = 1) of

RCLK with bipolar data out of the line interface. In NRZ mode (NRZE = 1), data is output on RPOS, and a received error (BPV, CV, or EXZ) causes a positive-going pulse synchronous with RCLK at RNEG. Receive Negative Data. Updated on the rising edge (CES = 0) or the falling edge (CES = 1) of RCLK with bipolar data out of the line interface. In NRZ mode (NRZE = 1), data is output on RPOS, and a received error (BPV, CV, or EXZ) causes a positive-going pulse synchronous with RCLK at RNEG.

Receive Clock. Buffered recovered clock from the line. Synchronous to MCLK in absence of signal at RTIP and RRING.

Transmit Positive Data. Sampled on the falling edge (CES = 0) or the rising edge (CES = 1) of TCLK for data to be transmitted out onto the line.

Transmit Negative Data. Sampled on the falling edge (CES = 0) or the rising edge (CES = 1) of TCLK for data to be transmitted out onto the line. Transmit Clock. A 2.048MHz or 1.544MHz primary clock used to clock data through the transmit side formatter. It can be sourced internally by MCLK or RCLK. See Common Control Register 1 and Figure 1-3

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DS21448 3.3V T1/E1/J1 Quad Line Interface

PIN I/O FUNCTION

TVSS1–TVSS4 — Transmitter Signal Ground for Transmitter Outputs

VSS1–VSS4 — Signal Ground

Note 1: G.703 requires an accuracy of ±50ppm for T1 and E1. TR62411 and ANSI specs require ±32ppm accuracy for T1 interfaces.

3. DETAILED DESCRIPTION

The DS21448 contains four independent LIUs that share a common interface for configuration and status. The user can choose between three different means of accessing the device: a parallel microprocessor interface, a serial interface, and a hardwired mode, which configures the device by setting levels on the device’s pins. The DS21448’s four chip selects (

CS1, CS2, CS3, and CS4) determine which LIU is accessed when using the parallel

or serial interface modes. Four sets of identical register maps exist, one for each channel. Using the appropriate chip select accesses a channel’s register map.

The analog AMI/HDB3 waveform off the E1 line or the AMI/B8ZS waveform off the T1 line is transformer-coupled into the RTIP and RRING pins of the DS21448. The user has the option to use internal termination, software selectable for 75W/100W/120W applications, or external termination. The device recovers clock and data from the analog signal and passes it through the jitter attenuation mux, outputting the received line clock at RCLK and bipolar or NRZ data at RPOS and RNEG. The DS21448 contains an active filter that reconstructs the analogreceived signal for the nonlinear losses that occur in transmission. The receive circuitry is also configurable for various monitor applications. The device has a usable receive sensitivity of 0 to -43dB for E1 and 0 to -36dB for T1 that allows the device to operate on 0.63mm (22AWG) cables up to 2.5km (E1) and 6k feet (T1) in length. Data input at TPOS and TNEG is sent through the jitter attenuation mux to the waveshaping circuitry and line driver. The DS21448 drives the E1 or T1 line from the TTIP and TRING pins through a coupling transformer. The line driver can handle both CEPT 30/ISDN-PRI lines for E1 and long-haul (CSU) or short-haul (DSX-1) lines for T1.

3.1 DS21448 and DS21Q348 Differences

The DS21448 BGA is a monolithic quad-port LIU that is a replacement for the DS21Q348. The additional features of JTAG, transmit driver disable, and the serial interface in the DS21448 have changed the function of several pins, as shown in Table 3-A

Table 3-A. DS21448 vs. DS21Q348 Pin Differences

PIN DS21Q348 DS21448

G4 VSM N.C.

J1 VSS SCLK K1 A4 A4/SDO K3 VSS SDI K7 TEST TXDIS/TEST

L3 N.C. JTRST*

M3 N.C. JTMS* M5 N.C. JTCLK M6 N.C. JTDI* M7 N.C. JTDO

*DS21448 pin is internally pulled up.

4. PORT OPERATION

4.1 Hardware Mode

The DS21448 supports a hardware configuration mode that allows the user to configure the device by setting levels on the device’s pins. This mode allows the DS21448 configuration without the use of a microprocessor, simplifying designs. Not all of the device features are supported in the hardware mode.

In hardware mode (BIS0 = 1, BIS1 = 1) several pins have been redefined so they can be used for initializing the DS21448. Refer to Table 2-B

and Table 2-E for pin assignment and definition. Because of limited pin count, several

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DS21448 3.3V T1/E1/J1 Quad Line Interface

functions have been combined and affect all four channels in the device and/or treat the receive and transmit paths as one block. Restrictions when using the hardware mode include the following:

· BPCLK pins only output a 16.384MHz signal.

· The RCL/LOTC pins are designated to RCL.

· The RHBE and THBE control bits are combined and controlled by HBE.

· RSCLKE and TSCLKE bits are combined and controlled by SCLKE.

· TCES and RCES are combined and controlled by CES.

· The transmitter functions are combined and controlled by TX1 and TX0.

· Loopback functions are controlled by LOOP1 and LOOP0.

· JABDS defaults to 128-bit buffer depth.

· All other control bits default to logic 0.

Table 4-A. Loopback Control in Hardware Mode

LOOPBACK SYMBOL LOOP1 LOOP0

Remote Loopback RLB 1 1

Local Loopback LLB 1 0

Analog Loopback ALB 0 1

No Loopback — 0 0

Table 4-B. Transmit Data Control in Hardware Mode

TRANSMIT DATA SYMBOL TX1 TX0

Unframed All Ones TUA1 1 1

Alternating Ones and Zeros TAOZ 1 0

TPOS and TNEG — 0 0

PRBS

TPRBSE

0 1

Table 4-C. Receive Sensitivity Settings in Hardware Mode

EGL ETS RECEIVE SENSITIVITY (dB)

0 0 (E1) -12 (short haul) 1 0 (E1) -43 (long haul) 1 1 (T1) -30 (limited long haul) 0 1 (T1) -36 (long haul)

Table 4-D. Monitor Gain Settings in Hardware Mode

MM1 MM0 INTERNAL LINEAR GAIN BOOST (dB)

0 0 Normal operation (no boost) 0 1 20 1 0 26 1 1 32

Table 4-E. Internal Rx Termination Select in Hardware Mode

RT1 RT0

0 0 Internal receive-side termination disabled 0 1 Internal receive-side 120Ω enabled 1 0 Internal receive-side 100Ω enabled 1 1 Internal receive-side 75Ω enabled

INTERNAL RECEIVE

TERMINATION CONFIGURATION

Table 4-F. MCLK Selection in Hardware Mode

MCLK (MHz) JAMUX ETS

2.048 0 0

2.048 1 1

1.544 0 1

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DS21448 3.3V T1/E1/J1 Quad Line Interface

(

)

4.2 Serial Port Operation

Setting BIS1 = 1 and BIS0 = 0 enables the serial bus interface on the DS21448 (Table 2-A). Serial port read/write timing is unrelated to the system transmit and receive timing, allowing asynchronous reads or writes by the host. See Section 10

Figure 4-2

for the AC timing of the serial port. All serial port accesses are LSB first. See Figure 4-1,

, Figure 4-3, Figure 4-4, Figure 4-5, and Figure 4-6 for additional details.

A serial bus access requires the use of four signals: serial clock (SCLK), one of the four chip selects (

CS), serial

data input (SDI), and serial data output (SDO). The DS21448 uses SCLK to sample data that is present on SDI and output data onto SDO. Input clock-edge select (ICES) allows the user to choose which SCLK edge input data is sampled on. Output clock-edge select (OCES) allows the user to choose which SCLK edge output data changes on. When ICES is low, input data is latched on the rising edge of SCLK, and when ICES is high, input data is latched on the falling edge of SCLK. When OCES is low, data is output on the falling edge of SCLK, and when OCES is high, data is output on the rising edge of SCLK. Data is held until the next falling or rising edge of SCLK. All data transfers are initiated by driving the appropriate port’s must go inactive between data transfers. See the serial bus timing information in Section 10 transfers are terminated if the port’s when all

CS pins are inactive.

CS input transitions high. Port control logic is disabled, and SDO is tri-stated

CS input low and ends with CS going inactive. CS

for details. All data

Reading from or writing to the internal registers requires writing one address/command byte prior to the transferring register data. Two types of serial bus transfers exist, standard and burst. The standard serial bus access always consists of two bytes, an address/command byte that is always supplied by the user on SDI, and a data byte that can either be written to the DS21448 using SDI (write operation) or output by the DS21448 on SDO (read operation). The burst serial bus access consists of a single address/command byte followed either by 22 read or 22 write data bytes.

The first bit written (LSB) of the address/command byte specifies whether the access is to be a read (1) or a write (0). The next 5 bits identify the register address. Valid register addresses are 00h through 15h. Bit 7 is reserved and must be set to 0 for proper operation. Bit 8, the last bit (MSB) of the address/command byte, is the burst modeenable bit. When the burst bit is enabled (set to 0) and a READ operation is performed, the DS21448 automatically outputs the contents of registers 00h through 15h sequentially, starting with register address 00h. When the burst bit is enabled and a WRITE operation is performed, data supplied on SDI is sequentially written into the DS21448’s register space starting at address 00h. Burst operation is stopped once address 15h is read or

CS goes inactive.

For both burst read and burst write transfers, the address/command byte’s register address bits must be set to 0.

The user can broadcast register write accesses to multiple ports simultaneously by enabling the desired channels’ chip selects at the same time. However, only one port can be read at a time. Any attempt to read multiple ports simultaneously results in invalid data being returned on SDO.

Figure 4-1. Serial Port Operation for Read Access (R = 1) Mode 1

ICES = 1 (SAMPLE SDI ON THE FALLING EDGE OF SCLK) OCES = 1 (UPDATE SDO ON RISING EDGE OF SCLK)

SCLK

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

SDI

(LSB)

SDO

A1 A2 A3 A4 A5 0 B

READ ACCESS ENABLED

(MSB)

D1 D2 D3 D4 D5 D6

LSB

(MSB)

15 of 60

DS21448 3.3V T1/E1/J1 Quad Line Interface

(

)

Figure 4-2. Serial Port Operation for Read Access (R = 1) Mode 2

ICES = 1 (SAMPLE SDI ON THE FALLING EDGE OF SCLK) OCES = 0 (UPDATE SDO ON FALLING EDGE OF SCLK)

SCLK

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

SDI

SDO

A1 A2 A3 A4 A5 0 B

1 (LSB)

(MSB)

D1 D2 D3 D4 D5 D6

LSB

Figure 4-3. Serial Port Operation for Read Access (R = 1) Mode 3

ICES = 0 (SAMPLE SDI ON THE RISING EDGE OF SCLK) OCES = 0 (UPDATE SDO ON FALLING EDGE OF SCLK)

SCLK

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

SDI

(LSB)

SDO

A1 A2 A3 A4 A5 0 B

(MSB)

D1 D2 D3 D4 D5 D6

(LSB)

Figure 4-4. Serial Port Operation for Read Access (R = 1) Mode 4

ICES = 0 (SAMPLE SDI ON THE RISING EDGE OF SCLK) OCES = 1 (UPDATE SDO ON RISING EDGE OF SCLK)

SCLK

SDI

SDO

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

A1 A2 A3 A4 A5

1 (LSB) (MSB)

D1 D2 D3 D4 D5 D6 D0 D7

(LSB)

(MSB)

16 of 60

DS21448 3.3V T1/E1/J1 Quad Line Interface

)

Figure 4-5. Serial Port Operation for Write Access (R = 0) Modes 1 and 2

ICES = 1 (SAMPLE SDI ON THE FALLING EDGE OF SCLK)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16SCLK

SDI

(LSB)

WRITE ACCESS ENABLED

SDO

A1 A2 A3 A4 A5 0 B

(MSB)

DO D6

D1 D2 D3 D4 D5 D7

(LSB)

(MSB)

Figure 4-6. Serial Port Operation for Write Access (R = 0) Modes 3 and 4

ICES = 0 (SAMPLE SDI ON THE RISING EDGE OF SCLK

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16SCLK

SDI

(LSB)

A1 A2 A3 A4 A5 0 B

(MSB)

DO D6

D1 D2 D3 D4 D5 D7

(LSB) (MSB)

WRITE ACCESS ENABLED

SDO

4.3 Parallel Port Operation

The option for either multiplexed bus operation (BIS0 = 0) or nonmultiplexed bus operation (BIS0 = 1) is available when using the parallel interface. The DS21448 can operate with either Intel or Motorola bus timing configurations. If the PBTS pin is wired low, Intel timing is selected; if wired high, Motorola timing is selected. All Motorola bus signals are listed in parentheses (). Four sets of identical register maps exist, one for each channel. See Table 4-H for register names and addresses. Use the appropriate chip select ( register map. See the timing diagrams in Section 10

for more details. Hardware and serial port modes are not

CS1, CS2, CS3, or CS4) to access a channel’s

supported when using parallel port operation.

4.3.1 Device Power-Up and Reset

The DS21448 resets itself upon power-up, setting all writeable registers to 00h and clearing the status and information registers. CCR3.7 (TUA1) = 0 results in the LIU transmitting unframed all ones. After the power supplies have settled, initialize all control registers to the desired settings, then toggle the LIRST bit (CCR3.2). The DS21448 can at any time be reset to the default settings by bringing down and powering up again.

HRST low (level triggered) or by powering

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DS21448 3.3V T1/E1/J1 Quad Line Interface

Table 4-G. Parallel Port Mode Selection

PBTS BIS0 PROCESSOR BUS INTERFACE TYPE

0 0 Intel Parallel Port Mode (Multiplexed) 0 1 Intel Parallel Port Mode (Nonmultiplexed) 1 0 Motorola Parallel Port Mode (Multiplexed) 1 1 Motorola Parallel Port Mode (Nonmultiplexed)

4.3.2 Register Map

Table 4-H shows the typical register map for all four ports. Use the appropriate chip select (CS1, CS2, CS3, or CS4)

to access a channel’s register map.

Table 4-H. Register Map

NAME R/W ADDRESS FUNCTION

CCR1 R/W 00h Common Control Register 1 CCR2 R/W 01h Common Control Register 2 CCR3 R/W 02h Common Control Register 3 CCR4 R/W 03h Common Control Register 4 CCR5 R/W 04h Common Control Register 5 CCR6 R/W 05h Common Control Register 6

SR R 06h Status Register

IMR R/W 07h Interrupt Mask Register RIR1 R 08h Receive Information Register 1 RIR2 R 09h Receive Information Register 2 IBCC R/W 0Ah In-Band Code Control Register

TCD1 R/W 0Bh Transmit Code Definition Register 1

TCD2 R/W 0Ch Transmit Code Definition Register 2 RUPCD1 R/W 0Dh Receive-Up Code Definition Register 1 RUPCD2 R/W 0Eh Receive-Up Code Definition Register 2 RDNCD1 R/W 0Fh Receive-Down Code Definition Register 1 RDNCD2 R/W 10h Receive-Down Code Definition Register 2

ECR1 R 11h Error Count Register 1

ECR2 R 12h Error Count Register 2

TEST1 R/W 13h Test 1 TEST2 R/W 14h Test 2 TEST2 R/W 15h Test 3

— — (Note 1) —

Note 1: Register addresses 16h–1Fh do not exist.

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DS21448 3.3V T1/E1/J1 Quad Line Interface

4.3.3 Control Registers

CCR1 (00H): Common Control Register 1

(MSB)

ETS NRZE RCLA ECUE JAMUX TTOJ TTOR LOTCMC

NAME POSITION FUNCTION

ETS CCR1.7

NRZE CCR1.6

RCLA CCR1.5

ECUE CCR1.4

JAMUX CCR1.3

TTOJ CCR1.2

TTOR CCR1.1

LOTCMC CCR1.0

E1/T1 Select 0 = E1 1 = T1 NRZ Enable 0 = bipolar data at RPOS/RNEG and TPOS/TNEG 1 = NRZ data at RPOS and TPOS or TNEG; RNEG outputs a positive-going pulse when the device receives a BPV, CV, or EXZ Receive-Carrier-Loss Alternate Criteria 0 = RCL declared upon 255 (E1) or 192 (T1) consecutive zeros 1 = RCL declared upon 2048 (E1) or 1544 (T1) consecutive zeros Error Counter Update Enable. A 0-to-1 transition forces the next receive clock cycle to load the error counter registers with the latest counts and reset the counters. The user must wait a minimum of two clock cycles (976ns for E1 and 1296ns for T1) before reading the error count registers to allow for a proper update. See Section 6 Jitter Attenuator Clock Mux. Controls the source for JACLK (Figure 1-1 0 = JACLK sourced from MCLK (2.048MHz or 1.544MHz at MCLK) 1 = JACLK sourced from internal PLL (2.048MHz at MCLK) TCLK to JACLK. Internally connects TCLK to JACLK (Figure 1-3 0 = disabled 1 = enabled TCLK to RCLK. Internally connects TCLK to RCLK (Figure 1-3 0 = disabled 1 = enabled Loss-of-Transmit Clock Mux Control. Determines whether the transmit logic should switch to JACLK if the TCLK input should fail to transition (Figure 1-3). 0 = do not switch to JACLK if TCLK stops 1 = switch to JACLK if TCLK stops

for details.

(LSB)

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DS21448 3.3V T1/E1/J1 Quad Line Interface

CCR2 (01H): Common Control Register 2

(MSB)

RLPIN — SCLD CLDS RHBE THBE TCES RCES

NAME POSITION FUNCTION

RLPIN CCR2.7

— CCR2.6 Not Assigned. Should be set to 0 when written to.

SCLD CCR2.5

CLDS CCR2.4

RHBE CCR2.3

THBE CCR2.2

TCES CCR2.1

RCES CCR2.0

RCL/LOTC Pin Function Select. Forced to logic 0 in hardware mode. 0 = toggles high during a receive-carrier loss condition 1 = toggles high if TCLK does not transition for at least 5ms

Short Circuit-Limit Disable (ETS = 0). Controls the 50mA (RMS) current limiter. 0 = enable 50mA current limiter 1 = disable 50mA current limiter Custom Line-Driver Select. Setting this bit to 1 redefines the operation of the transmit line driver. When this bit is set to 1 and CCR4.5 = CCR4.6 = CCR4.7 = 0, the device generates a square wave at the TTIP and TRING outputs instead of a normal waveform. When this bit is set to 1 and CCR4.5 = CCR4.6 = CCR4.7 ¹ 0, the device forces TTIP and TRING outputs to become open-drain drivers instead of their normal push-pull operation. This bit should be set to 0 for normal operation of the device. Contact the factory for more details about how to use this bit. Receive HDB3/B8ZS Enable 0 = enable HDB3 (E1)/B8ZS (T1) 1 = disable HDB3 (E1)/B8ZS (T1) Transmit HDB3/B8ZS Enable 0 = enable HDB3 (E1)/B8ZS (T1) 1 = disable HDB3 (E1)/B8ZS (T1) Transmit Clock-Edge Select. Selects which TCLK edge to sample TPOS and TNEG. 0 = sample TPOS and TNEG on falling edge of TCLK 1 = sample TPOS and TNEG on rising edge of TCLK Receive Clock-Edge Select. Selects which RCLK edge to update RPOS and RNEG. 0 = update RPOS and RNEG on rising edge of RCLK 1 = update RPOS and RNEG on falling edge of RCLK

(LSB)

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DS21448 3.3V T1/E1/J1 Quad Line Interface

CCR3 (02H): Common Control Register 3

(MSB)

TUA1 ATUA1 TAOZ TPRBSE TLCE LIRST IBPV IBE

NAME POSITION FUNCTION

TUA1 CCR3.7

ATUA1 CCR3.6

TAOZ CCR3.5

TPRBSE CCR3.4

TLCE CCR3.3

LIRST CCR3.2

IBPV CCR3.1

IBE CCR3.0

Transmit Unframed All Ones. The polarity of this bit is set such that the device transmits an allones pattern on power-up or device reset. This bit must be set to 1 to allow the device to transmit data. The transmission of this data pattern is always timed off JACLK (Figure 1-1 0 = transmit all ones at TTIP and TRING 1 = transmit data normally Automatic Transmit Unframed All Ones. Automatically transmit an unframed all-ones pattern at TTIP and TRING during an RCL condition. 0 = disabled 1 = enabled Transmit Alternate Ones and Zeros. Transmit a …101010… pattern at TTIP and TRING. The transmission of this data pattern is always timed off TCLK. 0 = disabled 1 = enabled

Transmit PRBS Enable. Transmit a 215 - 1 (E1) or a QRSS (T1) PRBS at TTIP and TRING. 0 = disabled 1 = enabled

Transmit Loop-Code Enable. Enables the transmit side to transmit the loop-up code in the transmit code definition registers (TCD1 and TCD2). See Section 6 for details. 0 = disabled 1 = enabled Line Interface Reset. Setting this bit from 0 to 1 initiates an internal reset that resets the clock recovery state machine and recenters the jitter attenuator. Normally this bit is only toggled on power-up. It must be cleared and set again for a subsequent reset. Insert Bipolar Violation (BPV). A 0-to-1 transition on this bit causes a single bipolar violation to be inserted into the transmit data stream. Once this bit has been toggled from 0 to 1, the device waits for the next occurrence of three consecutive 1s to insert the BPV. This bit must be cleared and set again for a subsequent error to be inserted (Figure 1-3 Insert Bit Error. A 0-to-1 transition on this bit causes a single logic error to be inserted into the transmit data stream. This bit must be cleared and set again for a subsequent error to be inserted (Figure 1-3

(LSB)

CCR4 (03H): Common Control Register 4

(MSB)

L2 L1 L0 EGL JAS JABDS DJA TPD

NAME POSITION FUNCTION

L2 CCR4.7 Line Build-Out Select Bit 2. Sets the transmitter build-out (Table 7-A for E1, Table 7-B for T1). L1 CCR4.6 Line Build Out Select Bit 1. Sets the transmitter build-out (Table 7-A for E1, Table 7-B for T1). L0 CCR4.5 Line Build Out Select Bit 0. Sets the transmitter build-out (Table 7-A for E1, Table 7-B for T1).

EGL CCR4.4 Receive Equalizer Gain Limit. This bit controls the sensitivity of the receive equalizer (Table 4-I).

JAS CCR4.3

JABDS CCR4.2

DJA CCR4.1

TPD CCR4.0

Jitter Attenuator Path Select 0 = place the jitter attenuator on the receive side 1 = place the jitter attenuator on the transmit side Jitter Attenuator Buffer Depth Select 0 = 128 bits 1 = 32 bits (use for delay-sensitive applications) Disable Jitter Attenuator 0 = jitter attenuator enabled 1 = jitter attenuator disabled Transmit Power-Down 0 = normal transmitter operation 1 = powers down the transmitter and tri-states the TTIP and TRING pins

(LSB)

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DS21448 3.3V T1/E1/J1 Quad Line Interface

Table 4-I. Receive Sensitivity Settings

EGL

(CCR4.4)

0 0 (E1) -12 (short haul) 1 0 (E1) -43 (long haul) 1 1 (T1) -30 (limited long haul) 0 1 (T1) -36 (long haul)

CCR5 (04H): Common Control Register 5

(MSB)

BPCS1 BPCS0 MM1 MM0 RSCLKE TSCLKE RT1 RT0

NAME POSITION FUNCTION

BPCS1 CCR5.7 Backplane Clock Frequency Select 1. See Table 4-J for details. BPCS0 CCR5.6 Backplane Clock Frequency Select 0. See Table 4-J for details.

MM1 CCR5.5 Monitor Mode Gain Select 1 (Table 4-K. ) MM0 CCR5.4 Monitor Mode Gain Select 0. See (Table 4-K.

RSCLKE CCR5.3

TSCLKE CCR5.2

RT1 CCR5.1 Receive Termination Select 1. See Table 4-L for details. RT0 CCR5.0 Receive Termination Select 0. See Table 4-L for details.

ETS

(CCR1.7)

RECEIVE SENSITIVITY

(dB)

(LSB)

Receive Synchronization Clock Enable 0 = disable 2.048MHz synchronization receive mode 1 = enable 2.048MHz synchronization receive mode Transmit Synchronization Clock Enable 0 = disable 2.048MHz transmit synchronization clock 1 = enable 2.048MHz transmit synchronization clock

Table 4-J. Backplane Clock Select

BPCS1

(CCR5.7)

0 0 16.384 0 1 8.192 1 0 4.096 1 1 2.048

BPCS0

(CCR5.6)

BPCLK FREQUENCY (MHz)

Table 4-K. Monitor Gain Settings

MM1

(CCR5.5)

0 0 Normal operation (no boost) 0 1 20 1 0 26 1 1 32

MM0

(CCR5.4)

INTERNAL LINEAR GAIN

BOOST (dB)

Table 4-L. Internal Rx Termination Select

RT1

(CCR5.1)

0 0 Internal receive-side termination disabled 0 1 1 0 1 1

RT0

(CCR5.0)

INTERNAL RECEIVE

TERMINATION CONFIGURATION

Internal receive-side 120W enabled Internal receive-side 100W enabled

Internal receive-side 75W enabled

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DS21448 3.3V T1/E1/J1 Quad Line Interface

CCR6 (05H): Common Control Register 6

(MSB)

LLB RLB ARLBE ALB RJAB ECRS2 ECRS1 ECRS0

NAME POSITION FUNCTION

LLB CCR6.7

RLB CCR6.6

ARLBE CCR6.5

ALB CCR6.4

RJAB CCR6.3

ECRS2 CCR6.2 Error Count Register Select 2. See Section 6.4 for details. ECRS1 CCR6.1 Error Count Register Select 1. See Section 6.4 for details. ECRS0 CCR6.0 Error Count Register Select 0. See Section 6.4 for details.

Local Loopback. In local loopback, transmit data is looped back to the receive path, passing through the jitter attenuator if it is enabled. Data in the transmit path acts as normal. See Section 6.2 0 = loopback disabled 1 = loopback enabled Remote Loopback. In remote loopback, data output from the clock/data recovery circuitry is looped back to the transmit path, passing through the jitter attenuator if it is enabled. Data in the receive path acts as normal, while data presented at TPOS and TNEG is ignored. See Section 6.2 0 = loopback disabled 1 = loopback enabled Automatic Remote Loopback Enable and Reset. When this bit is set high, the device automatically goes into remote loopback when it detects loop-up code programmed into the receive loop-up code definition registers (RUPCD1 and RUPCD2) for a minimum of 5 seconds; it also sets the RIR2.1 status bit. Once it is in an RLB state, the bit remains in this state until it has detected the loop code programmed into the receive loop-down code definition registers (RDNCD1 and RDNCD2) for a minimum of 5 seconds, at which point it forces the device out of RLB and clears RIR2.1. Toggling this bit from 1 to 0 resets the automatic RLB circuitry. The action of the automatic remote loopback circuitry is logically ORed with the RLB (CCR6.6) control bit (i.e., either one can cause a RLB to occur). Analog Loopback. In analog loopback, signals at TTIP and TRING are internally connected to RTIP and RRING. The incoming line signals at RTIP and RRING are ignored. The signals at TTIP and TRING are transmitted as normal. See Section 6.2 0 = loopback disabled 1 = loopback enabled RCLK Jitter Attenuator Bypass. This control bit allows the receive-recovered clock and data to bypass the jitter attenuation, while still allowing the BPCLK output to use the jitter attenuator. See Section 7.3 0 = disabled 1 = enabled

for details.

for more details.

for details.

(LSB)

5. STATUS REGISTERS

The three registers that contain information about the device’s real-time status are the status register (SR) and receive information registers 1 and 2 (RIR1/RIR2). When a particular event has occurred (or is occurring), the appropriate bit in one of these registers is set to 1. Some bits in SR, RIR1, and RIR2 are latched bits and some are real-time bits (denoted in the following register descriptions). For latched status bits, when an event or an alarm occurs, the bit is set to 1 and remains set until the user reads that bit. The bit is cleared when it is read, and it is not set until the event has occurred again. Two of the latched status bits (RUA1 and RCL) remain set after reading if the alarm is still present.

The user always precedes a read of any of the three status registers with a write. The byte written to the register informs the DS21448 which bits the user wishes to read and have cleared. The user writes a byte to one of these registers with a 1 in the bit positions to be read and a 0 in the other bit positions. When a 1 is written to a bit location, that location is updated with the latest information. When a 0 is written to a bit position, that bit position is not updated, and the previous value is held. A write to the status and information registers is immediately followed by a read of the same register. The read result should be logically ANDed with the mask byte that was just written, and this value should be written back into the same register to ensure that bit does indeed clear. This second write step is necessary because the alarms and events in the status registers occur asynchronously with respect to their access through the parallel port. This write-read-write scheme allows an external microcontroller or microprocessor to individually poll certain bits without disturbing the other bits in the register. This operation is key in controlling the DS21448 with higher-order software languages.

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DS21448 3.3V T1/E1/J1 Quad Line Interface

The bits in the SR register have the unique ability to initiate a hardware interrupt through the

INT output pin. Each

of the alarms and events in the SR can be either masked or unmasked from the interrupt pin through the interrupt mask register (IMR). The interrupts caused by the RCL, RUA1, and LOTC bits in the SR act differently than the interrupts caused by the other status bits in the SR. The RCL, RUA1, and LOTC bits forces the whenever they change state (i.e., go active or inactive). The

INT pin is allowed to return high (if no other interrupts

INT pin low

are present) when the user reads the alarm bit that caused the interrupt to occur, even if the alarm is still present. The other status bits in the SR can force the

INT pin low when they are set. The INT pin is allowed to return high (if

no other interrupts are present) when the user reads the event bit that caused the interrupt to occur.

The host can quickly determine which of the four LIU channels is generating an interrupt by reading one of the unused addresses in the 16h–1Fh range in any LIU channel. See the following LIU channel interrupt status description for additional information.

LIU Channel Interrupt Status

(MSB)

— — — — LIU4 LIU3 LIU2 LIU1

NAME POSITION FUNCTION

N/A 7 Not Assigned. Could be any value when read. N/A 6 Not Assigned. Could be any value when read. N/A 5 Not Assigned. Could be any value when read. N/A 4 Not Assigned. Could be any value when read.

LIU4 3

LIU3 2

LIU2 1

LIU1 0

LIU4 Status Register. A 1 in this bit position indicates that the status register (SR) in channel 4 is asserting an interrupt. LIU3 Status Register. A 1 in this bit position indicates that the status register (SR) in channel 3 is asserting an interrupt. LIU2 Status Register. A 1 in this bit position indicates that the status register (SR) in channel 2 is asserting an interrupt. LIU1 Status Register. A 1 in this bit position indicates that the status register (SR) in channel 1 is asserting an interrupt.

(LSB)

SR (06H): Status Register

(MSB)

LUP LDN LOTC RUA1 RCL TCLE TOCD PRBSD

NAME POSITION FUNCTION

LUP

(Latched)

LDN

(Latched)

LOTC

(Real Time)

RUA1

(Latched)

RCL

(Latched)

TCLE

(Real Time)

TOCD

(Real Time)

PRBSD

(Real Time)

SR.7

SR.6

SR.5

SR.4

SR.3

SR.2

SR.1

SR.0

Loop-Up Code Detected. This bit is set when the loop-up code defined in registers RUPCD1 and RUPCD2 is being received. See Section 6.1 Loop-Down Code Detected. This bit is set when the loop-down code defined in registers RDNCD1 and RDNCD2 is being received. See Section 6.1

Loss-of-Transmit Clock. This bit is set when the TCLK pin has not transitioned for 5ms (±2ms), forcing the LOTC pin high. Receive Unframed All Ones. This bit is set when an unframed all-ones code is received at RRING and RTIP (Table 5-A Receive Carrier Loss. This bit is set when an RCL condition exists at RRING and RTIP. See (Table 5-A Transmit Current-Limit Exceeded. This bit is set when the 50mA (RMS) current limiter is activated whether or not the current limiter is enabled. Transmit Open-Circuit Detect. This bit is set when the device detects that the TTIP and TRING outputs are open circuited.

PRBS Detect. This bit is set when the receive side detects a 2 pseudorandom bit sequence (PRBS).

) for details.

for details.

- 1 (E1) or a QRSS (T1)

(LSB)

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DS21448 3.3V T1/E1/J1 Quad Line Interface

Table 5-A. Received Alarm Criteria

ALARM E1/T1 SET CRITERIA CLEAR CRITERIA

RUA1 E1 Fewer than two 0s in two frames (512 bits) More than two 0s in two frames (512 bits)

RUA1 T1

RCL

(Note 1)

RCL

(Note 1)

Note 1: RCL is also known as a loss of signal (LOS) or Red Alarm in T1. Note 2: See CCR1.5 for details.

Over a 3ms window, five or fewer 0s are received. 255 (or 2048) consecutive 0s received (G.775) (Note 2)

192 (or 1544) consecutive 0s are received (Note 2)

IMR (07H): Interrupt Mask Register

(MSB)

LUP LDN LOTC RUA1 RCL TCLE TOCD PRBSD

NAME POSITION FUNCTION

LUP IMR.7

LDN IMR.6

LOTC IMR.5

RUA1 IMR.4

RCL IMR.3

TCLE IMR.2

TOCD IMR.1

PRBSD IMR.0

Loop-Up Code Detected 0 = interrupt masked 1 = interrupt enabled Loop-Down Code Detected 0 = interrupt masked 1 = interrupt enabled Loss-of-Transmit Clock 0 = interrupt masked 1 = interrupt enabled Receive Unframed All Ones 0 = interrupt masked 1 = interrupt enabled Receive Carrier Loss 0 = interrupt masked 1 = interrupt enabled Transmit Current-Limiter Exceeded 0 = interrupt masked 1 = interrupt enabled Transmit Open-Circuit Detect 0 = interrupt masked 1 = interrupt enabled PRBS Detection 0 = interrupt masked 1 = interrupt enabled

Over a 3ms window, six or more 0s are received. In 255-bit times, at least 32 1s are received. 14 or more 1s out of 112 possible bit positions are received, starting with the first 1 received.

(LSB)

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DS21448 3.3V T1/E1/J1 Quad Line Interface

RIR1 (08H): Receive Information Register 1

(MSB)

ZD 16ZD HBD RCLC RUA1C JALT — —

NAME POSITION FUNCTION

(Latched)

16ZD

(latched)

HBD

(Latched)

RCLC

(Latched)

RUA1C

(Latched)

JALT

(Latched)

N/A RIR1.1 Not Assigned. Could be any value when read. N/A RIR1.0 Not Assigned. Could be any value when read.

Zero Detect. This bit is set when a string of at least four (ETS = 0) or eight (ETS = 1)

RIR1.7

RIR1.6

RIR1.5

RIR1.4

RIR1.3

RIR1.2

consecutive 0s (regardless of the length of the string) have been received. This bit is cleared when read. 16 Zero Detect. This is set when at least 16 consecutive 0s (regardless of the length of the string) have been received. This bit is cleared when read. HDB3/B8ZS Word Detect. This is set when an HDB3 (ETS = 0) or B8ZS (ETS = 1) codeword is detected independently of the receive HDB3/B8ZS mode (CCR4.6) being enabled. This bit is cleared when read. It is useful for automatically setting the line coding. RCL Clear. Set when the RCL alarm has met the clear criteria defined in Table 5-A is cleared when read. Receive Unframed All-Ones Clear. This bit is set when the unframed all-ones signal is no longer detected. This bit is cleared when read (Table 5-A Jitter Attenuator Limit Trip. This bit is set when the jitter attenuator FIFO reaches within 4 bits of its useful limit. This bit is cleared when read and is useful for debugging jitter attenuation operation.

(LSB)

. This bit

RIR2 (09H): Receive Information Register 2

(MSB)

RL3 RL2 RL1 RL0 — — ARLB SEC

NAME POSITION FUNCTION

RL3

(Real Time)

RL2

(Real Time)

RL1

(Real Time)

RL0

(Real Time)

N/A RIR2.3 Not Assigned. Could be any value when read. N/A RIR2.2 Not Assigned. Could be any value when read.

ARLB

(Real Time)

SEC

(Latched)

RIR2.7 Receive Level Bit 3 (Table 5-B

RIR2.6

RIR2.5 Receive Level Bit 1 (Table 5-B

RIR2.4

RIR2.1

RIR2.0

Receive Level Bit 2

Receive Level Bit 0

Automatic Remote Loopback Detected. This bit is set to 1 when the automatic remote loopback circuitry has detected the presence of a loop-up code for 5 seconds. It remains set until the automatic RLB circuitry has detected the loop-down code for 5 seconds. See Section 11 disabled (CCR6.5 = 0). One-Second Timer. This bit is set to 1 on one-second boundaries as timed by the device, based on the RCLK. It is cleared when read.

for more details. This bit is forced low when the automatic RLB circuitry is

(Table 5-B)

)

(LSB)

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DS21448 3.3V T1/E1/J1 Quad Line Interface

Table 5-B. Receive Level Indication

RL3 RL2 RL1 RL0 RECEIVE LEVEL (dB)

0 0 0 0 Greater than -2.5 0 0 0 1 -2.5 to -5.0 0 0 1 0 -5.0 to -7.5 0 0 1 1 -7.5 to -10.0 0 1 0 0 -10.0 to -12.5 0 1 0 1 -12.5 to -15.0 0 1 1 0 -15.0 to -17.5 0 1 1 1 -17.5 to -20.0 1 0 0 0 -20.0 to -22.5 1 0 0 1 -22.5 to -25.0 1 0 1 0 -25.0 to -27.5 1 0 1 1 -27.5 to -30.0 1 1 0 0 -30.0 to -32.5 1 1 0 1 -32.5 to -35.0 1 1 1 0 -35.0 to -37.5 1 1 1 1 -37.5 to -40.0

6. DIAGNOSTICS

6.1 In-Band Loop-Code Generation and Detection

The DS21448 can generate and detect a repeating bit pattern from 1 to 8 or 16 bits in length. To transmit a pattern, the user loads the pattern into the transmit code definition (TCD1 and TCD2) registers and selects the proper length of the pattern by setting the TC0 and TC1 bits in the in-band code control (IBCC) register. When generating a 1-, 2-, 4-, 8-, or 16-bit pattern, the transmit code registers (TCD1 and TCD2) must be filled with the proper code. Generation of a 1-, 3-, 5-, or 7-bit pattern only requires TCD1 to be filled. Once this is accomplished, the pattern is transmitted, as long as the TLCE control bit (CCR3.3) is enabled. For example, if the user wished to transmit the standard loop-up code for CSUs, which is a repeating pattern of ...10000100001..., then 80h would be loaded into TCD1, and the length would set using TC1 and TC0 in the IBCC register to 5 bits.

The DS21448 can detect two separate repeating patterns to allow for a loop-up code and a loop-down code to be detected. The user programs the codes in the receive-up code definition (RUPCD1 and RUPCD2) registers and the receive-down code definition (RDNCD1 and RDNCD2) registers; the length of each pattern is selected through the IBCC register. The DS21448 detects repeating pattern codes with bit-error rates as high as 1 x 10 detector has a nominal integration period of 48ms, so after approximately 48ms of receiving either code, the proper status bit (LUP at SR.7 and LDN at SR.6) is set to 1. Normally codes are sent for a period of 5 seconds. It is recommended that the software poll the DS21448 every 100ms to 1000ms until 5 seconds has elapsed to ensure the code is continuously present.

-2

. The code

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DS21448 3.3V T1/E1/J1 Quad Line Interface

IBCC (0AH): In-Band Code Control Register

(MSB)

TC1 TC0 RUP2 RUP1 RUP0 RDN2 RDN1 RDN0

NAME POSITION FUNCTION

TC1 IBCC.7 Transmit Code Length Definition Bit 1 (Table 6-A)

TC0 IBCC.6 Transmit Code Length Definition Bit 0. (Table 6-A) RUP2 IBCC.5 Receive Up Code Length Definition Bit 2 (Table 6-B) RUP1 IBCC.4 Receive-Up Code Length Definition Bit 1 (Table 6-B) RUP0 IBCC.3 Receive-Up Code Length Definition Bit 0 (Table 6-B)

RDN2 IBCC.2 Receive-Down Code Length Definition Bit 2 (Table 6-B) RDN1 IBCC.1 Receive-Down Code Length Definition Bit 1 (Table 6-B) RDN0 IBCC.0 Receive-Down Code Length Definition Bit 0 (Table 6-B)

(LSB)

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DS21448 3.3V T1/E1/J1 Quad Line Interface

Table 6-A. Transmit Code Length

TC1 TC0

0 0 5 0 1 6/3 1 0 7 1 1 16/8/4/2/1

LENGTH SELECTED

(BITS)

Table 6-B. Receive Code Length

RUP2/RDN2 RUP1/RDN1 RUP0/RDN0

0 0 0 1 0 0 1 2 0 1 0 3 0 1 1 4 1 0 0 5 1 0 1 6 1 1 0 7 1 1 1 16/8

TCD1 (0BH): Transmit Code Definition Register 1

(MSB)

C7 C6 C5 C4 C3 C2 C1 C0

NAME POSITION FUNCTION

C7 TCD1.7 Transmit Code Definition Bit 7. First bit of the repeating pattern. C6 TCD1.6 Transmit Code Definition Bit 6 C5 TCD1.5 Transmit Code Definition Bit 5 C4 TCD1.4 Transmit Code Definition Bit 4 C3 TCD1.3 Transmit Code Definition Bit 3 C2 TCD1.2 Transmit Code Definition Bit 2. A don’t care if a 5-bit length is selected. C1 TCD1.1 Transmit Code Definition Bit 1. A don’t care if a 5-bit or 6-bit length is selected. C0 TCD1.0 Transmit Code Definition Bit 0. A don’t care if a 5-, 6-, or 7-bit length is selected.

TCD2 (0CH): Transmit Code Definition Register 2

(MSB)

C15 C14 C13 C12 C11 C10 C9 C8

NAME POSITION FUNCTION

C15 TCD2.7 Transmit Code Definition Bit 15 C14 TCD2.6 Transmit Code Definition Bit 14 C13 TCD2.5 Transmit Code Definition Bit 13 C12 TCD2.4 Transmit Code Definition Bit 12 C11 TCD2.3 Transmit Code Definition Bit 11 C10 TCD2.2 Transmit Code Definition Bit 10

C9 TCD2.1 Transmit Code Definition Bit 9

C8 TCD2.0 Transmit Code Definition Bit 8

LENGTH SELECTED

(BITS)

(LSB)

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DS21448 3.3V T1/E1/J1 Quad Line Interface

RUPCD1 (0DH): Receive-Up Code Definition Register 1

(MSB)

C7 C6 C5 C4 C3 C2 C1 C0

NAME POSITION FUNCTION

C7 RUPCD1.7 Receive-Up Code Definition Bit 7. First bit of the repeating pattern. C6 RUPCD1.6 Receive-Up Code Definition Bit 6. A don’t care if a 1-bit length is selected. C5 RUPCD1.5 Receive-Up Code Definition Bit 5. A don’t care if a 1-bit or 2-bit length is selected. C4 RUPCD1.4 Receive-Up Code Definition Bit 4. A don’t care if a 1-bit to 3-bit length is selected. C3 RUPCD1.3 Receive-Up Code Definition Bit 3. A don’t care if a 1-bit to 4-bit length is selected. C2 RUPCD1.2 Receive-Up Code Definition Bit 2. A don’t care if a 1-bit to 5-bit length is selected. C1 RUPCD1.1 Receive-Up Code Definition Bit 1. A don’t care if a 1-bit to 6-bit length is selected. C0 RUPCD1.0 Receive-Up Code Definition Bit 0. A don’t care if a 1-bit to 7-bit length is selected.

(LSB)

RUPCD2 (0EH): Receive-Up Code Definition Register 2

(MSB)

C15 C14 C13 C12 C11 C10 C9 C8

NAME POSITION FUNCTION

C15 RUPCD2.7 Receive-Up Code Definition Bit 15 C14 RUPCD2.6 Receive-Up Code Definition Bit 14 C13 RUPCD2.5 Receive-Up Code Definition Bit 13 C12 RUPCD2.4 Receive-Up Code Definition Bit 12 C11 RUPCD2.3 Receive-Up Code Definition Bit 11 C10 RUPCD2.2 Receive-Up Code Definition Bit 10

C9 RUPCD2.1 Receive-Up Code Definition Bit 9 C8 RUPCD2.0 Receive-Up Code Definition Bit 8

(LSB)

RDNCD1 (0FH): Receive-Down Code Definition Register 1

(MSB)

C7 C6 C5 C4 C3 C2 C1 C0

NAME POSITION FUNCTION

C7 RDNCD1.7 Receive-Down Code Definition Bit 7. First bit of the repeating pattern. C6 RDNCD1.6 Receive-Down Code Definition Bit 6. A don’t care if a 1-bit length is selected. C5 RDNCD1.5 Receive-Down Code Definition Bit 5. A don’t care if a 1-bit or 2-bit length is selected. C4 RDNCD1.4 Receive-Down Code Definition Bit 4. A don’t care if a 1-bit to 3-bit length is selected. C3 RDNCD1.3 Receive-Down Code Definition Bit 3. A don’t care if a 1-bit to 4-bit length is selected. C2 RDNCD1.2 Receive-Down Code Definition Bit 2. A don’t care if a 1-bit to 5-bit length is selected. C1 RDNCD1.1 Receive-Down Code Definition Bit 1. A don’t care if a 1-bit to 6-bit length is selected. C0 RDNCD1.0

Receive-Down Code Definition Bit 0. A don’t care if a 1-bit to 7-bit length is selected.

(LSB)

RDNCD2 (10H): Receive-Down Code Definition Register 2

(MSB)

C15 C14 C13 C12 C11 C10 C9 C8

NAME POSITION FUNCTION

C15 RDNCD2.7 Receive-Down Code Definition Bit 15 C14 RDNCD2.6 Receive-Down Code Definition Bit 14 C13 RDNCD2.5 Receive-Down Code Definition Bit 13 C12 RDNCD2.4 Receive-Down Code Definition Bit 12 C11 RDNCD2.3 Receive-Down Code Definition Bit 11 C10 RDNCD2.2 Receive-Down Code Definition Bit 10

C9 RDNCD2.1 Receive-Down Code Definition Bit 9 C8 RDNCD2.0 Receive-Down Code Definition Bit 8

(LSB)

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DS21448 3.3V T1/E1/J1 Quad Line Interface

6.2 Loopbacks

6.2.1 Remote Loopback (RLB)

When RLB (CCR6.6) is enabled, the DS21448 is placed into remote loopback. In this loopback, data from the clock/data recovery state machine is looped back to the transmit path, passing through the jitter attenuator if it is enabled. The data at the RPOS and RNEG pins is valid, while data presented at TPOS and TNEG is ignored. See

Figure 1-1

If the automatic RLB enable (CCR6.5) is set to 1, the DS21448 automatically goes into remote loopback when it detects the loop-up code programmed in the receive-up code definition registers (RUPCD1 and RUPCD2) for a minimum of 5 seconds. When the DS21448 detects the loop-down code programmed in the receive loop-down code definition registers (RDNCD1 and RDNCD2) for a minimum of 5 seconds, the DS21448 comes out of remote loopback. Setting ARLBE to 0 can also disable the ARLB.

for more details.

6.2.2 Local Loopback (LLB)

When LLB (CCR6.7) is set to 1, the DS21448 is placed into local loopback. In this loopback, data on the transmit side is transmitted as normal. TCLK and TPOS/TNEG pass through the jitter attenuator (if enabled) and are output at RCLK and RPOS/RNEG. Incoming data from the line at RTIP and RRING is ignored. If transmit unframed all ones (CCR3.7) is set to 1 while in LLB, TTIP and TRING transmit all ones while TCLK and TPOS/TNEG are looped back to RCLK and RPOS/RNEG. See Figure 1-1

for more details.

6.2.3 Analog Loopback (LLB)

Setting ALB (CCR6.4) to 1 puts the DS21448 in analog loopback. Signals at TTIP and TRING are internally connected to RTIP and RRING. The incoming signals at RTIP and RRING are ignored. The signals at TTIP and TRING are transmitted as normal. See Figure 1-1

for more details.

6.2.4 Dual Loopback (DLB)

Setting CCR6.7 and CCR6.6 (LLB and RLB, respectively) to 1 puts the DS21448 into dual loopback operation. The TCLK and TPOS/TNEG signals are looped back through the jitter attenuator (if enabled) and output at RCLK and RPOS/RNEG. Clock and data recovered from RTIP and RRING are looped back to the transmit side and output at TTIP and TRING. This mode of operation is not available when implementing hardware operation. See Figure 1-1 more details.

6.3 PRBS Generation and Detection

Setting TPRBSE (CCR3.4) = 1 enables the DS21448 to transmit a 215 - 1 (E1) or a QRSS (T1) PRBS, depending on the ETS bit setting in CCR1.7. The DS21448’s receive side always searches for these PRBS patterns independently of CCR3.4. The PRBS bit-error output (PBEO) remains high until the receiver has synchronized to one of the two patterns (64 bits received without an error), at which time PBEO goes low, and the PRBSD bit in the SR is set. Once synchronized, any bit errors received cause a positive-going pulse at PBEO, synchronous with RCLK. This output can be used with external circuitry track bit-error rates during the PRBS testing. Setting CCR6.2 (ECRS2) = 1 allows the PRBS errors to be accumulated in the 16-bit counter in registers ECR1 and ECR2. The PRBS synchronizer remains in sync until it experiences six bit errors or more within a 64-bit span. Both PRBS patterns comply with the ITU-T O.151 specifications.

6.4 Error Counter

Error count register 1 (ECR1) is the most significant word and ECR2 is the least significant word of a userselectable 16-bit counter that records incoming errors, including BPVs, code violations (CVs), excessive zero violations (EXZs), and/or PRBS errors. See Table 6-C

, Table 6-D, and Figure 1-2 for details.

31 of 60

DS21448 3.3V T1/E1/J1 Quad Line Interface

Table 6-C. Definition of Received Errors

ERROR E1 OR T1 DEFINITION OF RECEIVED ERRORS

BPV E1/T1

CV E1

EXZ E1 When four or more consecutive zeros are detected.

EXZ T1

PRBS E1/T1 A bit error in a received PRBS pattern. See Section 6.3 for details. ITU-T O.151.

Two consecutive marks with the same polarity. Ignores BPVs because of HDB3 and B8ZS zero suppression when CCR2.3 = 0. Typically used with AMI coding (CCR2.3 = 1). ITU-T O.161. When HDB3 is enabled (CCR2.3 = 0) and the receiver detects two consecutive BPVs with the same polarity. ITU-T O.161.

When receiving AMI-coded signals (CCR2.3 = 1), detection of 16 or more 0s or a BPV. ANSI T1.403

1999. When receiving B8ZS-coded signals (CCR2.3 = 0), detection of eight or more 0s or a BPV. ANSI

T1.403 1999.

Table 6-D. Function of ECRS Bits and RNEG Pin

E1 or T1

(CCR1.7)

0 0 0 0 X CVs 0 0 0 1 X BPVs (HDB3 codewords not counted) 0 0 1 0 X CVs + EXZs 0 0 1 1 X BPVs + EXZs 1 0 X 0 0 BPVs (B8ZS codewords not counted) 1 0 X 1 0 BPVs + 8 EXZs 1 0 X 0 1 BPVs 1 0 X 1 1 BPVs + 16 EXZs X 1 X X X PRBS Errors (Note 2)

Note 1: RNEG outputs error data only when in NRZ mode (CCR1.6 = 1). Note 2: PRBS errors are always output at PBEO, independent of ECR control bits and NRZ mode, and are not present at RNEG.

ECRS2

(CCR6.2)

ECRS1

(CCR6.1)

ECRS0

(CCR6.0)

RHBE

(CCR2.3)

FUNCTION OF ECR COUNTERS/RNEG

(Note 1)

6.5 Error Counter Update

A 0-to-1 transition of the ECUE (CCR1.4) control bit updates the ECR registers with the current values and resets the counters. ECUE must be set back to 0 and another 0-to-1 transition must occur for subsequent reads/resets of the ECR registers. Note that the DS21448 can report errors at RNEG when in NRZ mode (CCR1.6 = 1) by outputting a pulse for each error occurrence. The counter saturates at 65,535 and does not roll over.

ECR1 (11H): Upper Error Count Register 1/ECR2 (12H): Lower Error Count Register 2

(MSB)

E15 E14 E13 E12 E11 E10 E9 E8 ECR1

E7 E6 E5 E4 E3 E2 E1 E0 ECR2

NAME POSITION FUNCTION

E15 ECR1.7 MSB of the 16-bit error count.

E0 ECR2.0 LSB of the 16-bit error count.

(LSB)

6.6 Error Insertion

When IBPV (CCR3.1) is transitioned from 0 to 1, the device waits for the next occurrence of three consecutive 1s to insert a BPV. IBPV must be cleared and set again for another BPV error insertion. See Figure 1-3 the insertion of the BPV into the data stream.

When IBE (CCR3.0) is transitioned from 0 to 1, the device inserts a logic error. IBE must be cleared and set again for another logic error insertion. See Figure 1-2

and Figure 1-3 for details about the logic error insertion into the

data steam.

for details on

32 of 60

DS21448 3.3V T1/E1/J1 Quad Line Interface

7. ANALOG INTERFACE

7.1 Receiver

The DS21448 contains a digital clock recovery system. The DS21448 couples to the receive E1 or T1 twisted pair (or coaxial cable in 75W E1 applications) through a 1:1 transformer. See Table 7-C

Figure 7-1

, Figure 7-2, Figure 7-3, and Table 4-L show the receive termination requirements. The DS21448 has the

option of using internal termination resistors.

The DS21448 is designed to be fully software selectable for E1 and T1 without the need to change any external resistors for the receive side. The receive side allows user configuration for 75W, 100W, or 120W receive termination by setting the RT1 (CCR5.1) and RT0 (CCR5.0) bits. When using the internal termination feature, the

resistors should be 60W each. See Figure 7-1 for details. If external termination is required, RT1 and RT0 should

be set to 0, and both R

resistors (Figure 7-1) should be 37.5W, 50W, or 60W each, depending on the line

impedance.

The resultant E1 or T1 clock derived from the 2.048/1.544 PLL (JACLK in Figure 1-1 through another internal PLL and fed to the clock recovery system. The clock recovery system uses the clock from the PLL circuit to form a 16-times oversampler used to recover the clock and data. This oversampling technique offers outstanding performance to meet jitter tolerance specifications, as shown in Figure 7-7

Normally, the clock that is output at the RCLK pin is the recovered clock from the E1 AMI/HDB3 or T1 AMI/B8ZS waveform presented at the RTIP and RRING inputs. When no signal is present at RTIP and RRING, an RCL condition occurs, and the RCLK is derived from the JACLK source. See Figure 1-1 attenuator is placed in the receive path (as is the case in most applications), the jitter attenuator restores the RCLK to an approximate 50% duty cycle. If the jitter attenuator is either placed in the transmit path or is disabled, the RCLK output can exhibit slightly shorter high cycles of the clock. This is because of the highly oversampled digital clock recovery circuitry. See the receive-side AC timing characteristics in Section 10

The receive-side circuitry also contains a clock synthesizer that outputs a user-configurable clock (up to

16.384MHz) synthesized from RCLK at BPCLK (pin 31). See Table 4-J

for details about output clock frequencies at

BPCLK. In hardware mode, BPCLK defaults to a 16.384MHz output.

The DS21448 has a bypass mode for the receive-side clock and data. This allows the BPCLK to be derived from RCLK after the jitter attenuator, while the clock and data presented at RCLK, RPOS, and RNEG go unaltered. This is intended for applications where the receive-side jitter attenuation is done after the LIU. Setting RJAB (CCR6.3) to logic 1 enables the bypass. Ensure the jitter attenuator is in the receive path (CCR4.3 = 0). See Figure 1-1 details.

The DS21448 reports the signal strength at RTIP and RRING in 2.5dB increments through RL3–RL0 located in the receive information register 2. This feature is helpful when troubleshooting line performance problems (Table 5-B

E1 and T1 monitor applications require various flat-gain settings for the receive-side circuitry. The DS21448 can be programmed to support these applications through the monitor mode control bits MM1 and MM0. When the monitor modes are enabled, the receiver tolerates normal line loss up to -6dB (Table 4-K

7.2 Transmitter

The DS21448 uses a set of laser-trimmed delay lines with a precision digital-to-analog converter (DAC) to create the waveforms that are transmitted onto the E1 or T1 line. The waveforms meet the latest ETSI, ITU, ANSI, and AT&T specifications. The user selects which waveform to generate by setting the ETS bit (CCR1.7) for E1 or T1 operation, then programming the L2/L1/L0 bits in common control register 4 for the appropriate application. See

Table 7-A

A 2.048MHz or 1.544MHz TTL clock is required at TCLK for transmitting data at TPOS and TNEG. ITU specification G.703 requires ±50ppm accuracy for T1 and E1. TR62411 and ANSI specs require ±32ppm accuracy for T1 interfaces. The clock can be sourced internally by RCLK or JACLK. See CCR1.2, CCR1.1, CCR1.0, and

Figure 1-3

and Table 7-B for the proper L2/L1/L0 settings.

for details. Because of the transmitter’s design, very little jitter (less than 0.005UI

for transformer details.

) is internally multiplied by 16

for more details. If the jitter

for more details.

for more

broadband from

P-P

33 of 60

DS21448 3.3V T1/E1/J1 Quad Line Interface

10Hz to 100kHz) is added to the jitter present on TCLK. Also, the waveforms created are independent of the duty cycle of TCLK. The transmitter couples to the E1 or T1 transmit-twisted pair (or coaxial cable in some E1 applications) through a 1:2 step-up transformer. For the device to create the proper waveforms, the transformer used must meet the specifications listed in Table 7-C

The DS21448 has an automatic short-circuit limiter that limits the source current to 50mA (RMS) into a 1Ω load. This feature can be disabled by setting the SCLD bit (CCR2.5) = 1. When the current limiter is activated, TCLE (SR.2) is set even if the short-circuit limiter is disabled. The TPD bit (CCR4.0) powers down the transmit-line driver and tri-states the TTIP and TRING pins. The DS21448 can also detect when the TTIP or TRING outputs are open circuited. When an open circuit is detected, TOCD (SR.1) is set.

7.3 Jitter Attenuator

The DS21448 contains an on-board jitter attenuator that can be set to a depth of either 32 or 128 bits through the JABDS bit (CCR4.2). The 128-bit mode is used in applications where large excursions of wander are expected. The 32-bit mode is used in delay-sensitive applications. Figure 7-8

shows the attenuation characteristics. The jitter attenuator can be placed in either the receive path or the transmit path by appropriately setting or clearing the JAS bit (CCR4.3). Also, setting the DJA bit (CCR4.1) can disable the jitter attenuator (in effect, remove it). For the jitter attenuator to operate properly, a 2.048MHz or 1.544MHz clock must be applied at MCLK. ITU specification G.703 requires ±50ppm accuracy for T1 and E1. TR62411 and ANSI specs require ±32ppm accuracy for T1 interfaces. An on-board PLL for the jitter attenuator converts the 2.048MHz clock to a 1.544MHz rate for T1 applications. Setting JAMUX (CCR1.3) to logic 0 bypasses this PLL. On-board circuitry adjusts either the recovered clock from the clock/data recovery block or the clock applied at the TCLK pin to create a smooth jitter-free clock, which is used to clock data out of the jitter attenuator FIFO. It is acceptable to provide a gapped/bursty clock at the TCLK pin if the jitter attenuator is placed on the transmit side. If the incoming jitter exceeds either 120UI bits) or 28UI

(buffer depth is 32 bits), the DS21448 divides the internal nominal 32.768MHz (E1) or 24.704MHz

P-P

(buffer depth is 128

P-P

(T1) clock by either 15 or 17 instead of the normal 16 to keep the buffer from overflowing. When the device divides by either 15 or 17, it also sets the JALT bit in the receive information register 1 (RIR1).

7.4 G.703 Synchronization Signal

The DS21448 can receive a 2.048MHz square-wave synchronization clock, as specified in Section 10 of ITU G.703. To use the DS21448 in this mode, set the receive-synchronization-clock enable (CCR5.3) = 1. The DS21448 can also transmit the 2.048MHz square-wave synchronization clock, as specified in Section 10 of G.703. To transmit the 2.048MHz clock, set the transmit-synchronization-clock enable (CCR5.2) = 1.

Table 7-A. Line Build-Out Select for E1 in Register CCR4 (ETS = 0)

L2 L1 L0 APPLICATION N RETURN LOSS

0 0 0 0 0 1 1 0 0 1 0 1

75W normal

120W normal

75W with high return loss

120W with high return loss

1:2 N.M. 0 1:2 N.M. 0 1:2 21dB 6.2 1:2 21dB 11.6

(W)

Table 7-B. Line Build-Out Select for T1 in Register CCR4 (ETS = 1)

L2 L1 L0 APPLICATION N RETURN LOSS

0 0 0 DSX-1 (0 to 133ft)/0dB CSU 1:2 N.M. 0 0 0 1 DSX-1 (133 to 266f) 1:2 N.M. 0 0 1 0 DSX-1 (266 to 399ft) 1:2 N.M. 0 0 1 1 DSX-1 (399 to 533ft) 1:2 N.M. 0 1 0 0 DSX-1 (533 to 655ft) 1:2 N.M. 0 1 0 1 -7.5dB CSU 1:2 N.M. 0 1 1 0 -15dB CSU 1:2 N.M. 0 1 1 1 -22.5dB CSU 1:2 N.M. 0

Note: See Figure 7-1, Figure 7-2, and Figure 7-3. N.M. = Not meaningful.

(W)

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DS21448 3.3V T1/E1/J1 Quad Line Interface

Table 7-C. Line Build-Out Select for E1 in Register CCR4 (ETS = 0) Using Alternate Transformer Configuration

L2 L1 L0 APPLICATION N RETURN LOSS

0 0 0 0 0 1 1 0 0 1 0 1

Note: See Figure 7-4.

75W normal

120W normal

75W with high return loss

120W with high return loss

0.8:1:1CT N.M. 0

0.8:1:1CT 21dB 11.6

(W)

Table 7-D. Transformer Specifications (3.3V Operation)

SPECIFICATION RECOMMENDED VALUE

Turns Ratio 1:1 (receive) and 1:2 (transmit) ±2% Primary Inductance Leakage Inductance Interwinding Capacitance 40pF (max)

TRANSMIT TRANSFORMER DC RESISTANCE

Primary (Device Side) Secondary

RECEIVE TRANSFORMER DC RESISTANCE

Primary (Device Side) Secondary

600mH (min)

1.0mH (max)

1.0W (max)

1.5W (max)

1.2W (max)

35 of 60

DS21448 3.3V T1/E1/J1 Quad Line Interface

Figure 7-1. Basic Interface

TRANSMIT LINE

2:1

(LARGER WINDING

TOWARD THE NETWORK)

1.0mF

(NONPOLARIZED)

TTIP

TRING

Dallas

Semiconducto

DS21448

0.1

0.01mF 0.01mF

RECEIVE LINE

1:1

RTIP

RRING

0.1mF

MCLK

2.048MHz

(THIS CAN ALSO BE 1.544MHz

FOR T1 ONLY OPERATION)

NOTE 1: ALL RESISTOR VALUES ARE ±1%. NOTE 2: IN E1 APPLICATIONS, THE R

(Table 7-A

NOTE 3: THE RR RESISTORS SHOULD EACH BE SET TO 60W IF THE INTERNAL RECEIVE-SIDE TERMINATION FEATURE IS ENABLED. WHEN THIS

FEATURE IS DISABLED, R

NOTE 4: SEE Table 7-A

). NO RETURN LOSS IS REQUIRED FOR T1 APPLICATIONS.

AND Table 7-B FOR THE APPROPRIATE TRANSMIT TRANSFORMER TURNS RATIO (N).

RESISTORS ARE USED TO INCREASE THE TRANSMITTER RETURN LOSS

= 37.5W FOR 75W OR 60W FOR 120W E1 SYSTEMS, OR 50W FOR 100W T1 LINES.

F0.1mF

68mF

36 of 60

DS21448 3.3V T1/E1/J1 Quad Line Interface

Figure 7-2. Protected Interface Using Internal Receive Termination

1.0mF

(NONPOLARIZED)

0.1mF

TTIP

TRING

Semiconducto

DS21448

RTIP

RRING

Dallas

MCLK

TRANSMIT LINE

RECEIVE LINE

NOTE 1: ALL RESISTOR VALUES ARE ±1%. NOTE 2: S IS A SIDACTOR. NOTE 3: THE FUSES ARE OPTIONAL TO PREVENT AC POWER LINE CROSSES FROM COMPROMISING THE TRANSFORMERS. NOTE 4: THE R

NOTE 5: THE 68mF IS USED TO KEEP THE LOCAL POWER PLANE POTENTIAL WITHIN TOLERANCE DURING A SURGE. NOTE 6: REFER TO APPLICATION NOTE 324 FOR SIDACTOR AND FUSE DETAILS.

FUSE

(LARGER WINDING TOWARD

FUSE

RESISTORS ARE USED TO INCREASE THE TRANSMITTER RETURN LOSS (Table 7-A). NO RETURN LOSS IS REQUIRED

FOR T1 APPLICATIONS.

2:1

THE NETWORK)

1:1

0.1

0.01mF 0.01mF

F0.1mF

2.048MHz

(THIS CAN ALSO BE 1.544MHz

FOR T1 ONLY OPERATION)

68mF

37 of 60

DS21448 3.3V T1/E1/J1 Quad Line Interface

Figure 7-3. Protected Interface Using External Receive Termination

TRANSMIT LINE

FUSE

2:1

(LARGER WINDING TOWARD

THE NETWORK)

RECEIVE LINE

FUSE

1:1

NOTE 1: ALL RESISTOR VALUES ARE ±1%. NOTE 2: S IS A SIDACTOR. NOTE 3: THE FUSES ARE OPTIONAL TO PREVENT AC POWER LINE CROSSES FROM COMPROMISING THE TRANSFORMERS. NOTE 4: R NOTE 5: THE R

NOTE 6: THE 68mF IS USED TO KEEP THE LOCAL POWER PLANE POTENTIAL WITHIN TOLERANCE DURING A SURGE. NOTE 7: REFER TO APPLICATION NOTE 324 FOR SIDACTOR AND FUSE DETAILS.

= 37.5W FOR 75W OR 60W FOR 120W E1 SYSTEMS, OR 50W FOR 100W T1 LINES.

RESISTORS ARE USED TO INCREASE THE TRANSMITTER RETURN LOSS (Table 7-A). NO RETURN LOSS IS REQUIRED FOR

T1 APPLICATIONS.

1.0mF

(NONPOLARIZED)

470

0.1mF

TTIP

TRING

Dallas

Semiconducto

DS21448

RTIP

RRING

MCLK

0.01mF 0.01mF

0.1

F0.1mF

2.048MHz

(THIS CAN ALSO BE 1.544MHz

FOR T1 ONLY OPERATION)

38 of 60

DS21448 3.3V T1/E1/J1 Quad Line Interface

Figure 7-4. Dual Connector-Protected Interface Using Receive Termination

FUSE

0.22mF

0.8:1:1CT

UNBALANCED LINE (75W)

BALANCED LINE (100W/120W)

UNBALANCED LINE (75W)

BALANCED LINE (100W/120W)

FUSE

51.1

FUSE

0.22mF

1.6:1

0.22mF

2:1

0.8:1:1CT

TTIP

1.0mF

TRING

0.1mF

0.01mF 0.01mF

10mF0.1mF

68mF

RTIP

0.8:1

Dallas

Semiconductor

0.22mF

1:1

DS21448

MCLK

2.048MHz (THIS CAN ALSO BE 1.544MHz FOR T1 ONLY OPERATION)

RRING

60 60

0.1mF

NOTE 1: REFER TO APPLICATION NOTE 384 FOR A COMPLETE DISCUSSION OF THIS CIRCUIT. NOTE 2: ALL RESISTOR VALUES ARE ±1%. NOTE 3: THE FUSES ARE OPTIONAL TO PREVENT AC POWER LINE CROSSES FROM COMPROMISING THE TRANSFORMERS. NOTE 4: S IS A SIDACTOR. NOTE 5: THE R

NOTE 6: THE 68mF IS USED TO KEEP THE LOCAL POWER PLANE POTENTIAL WITHIN TOLERANCE DURING A SURGE.

RESISTORS ARE USED TO INCREASE THE TRANSMITTER RETURN LOSS (Table 7-C). NO RETURN LOSS IS REQUIRED

FOR T1 APPLICATIONS.

39 of 60

Figure 7-5. E1 Transmit Pulse Template

1.2

DS21448 3.3V T1/E1/J1 Quad Line Interface

1.1

269ns

1.0

0.9

0.8

in 120Ω SYSTEMS, 1.0 ON

PEAK

)

PEAK

0.7

0.6

194ns

G.703

TEMPLATE

0.5

0.4

219ns

0.3

SCALED AMPLITUDE

THE SCALE = 3.00V

0.2

0.1

-0.1

-0.2

(IN 75W SYSTEMS, 1.0 ON THE SCALE = 2.37V

50 100 150 200 250 -50-100-150 -200 -250

TIME (ns)

40 of 60

Figure 7-6. T1 Transmit Pulse Template

1.2

1.1

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

NORMALIZED AMPLITUDE

-0.1

T1.102/87, T1.403,

-0.2

CB 119 (OCT ‘79), AND

I.431 TEMPLATE

-0.3

DS21448 3.3V T1/E1/J1 Quad Line Interface

MAXIMUM CURVE

UI TimeAmp.

-500

-0.77

-255

-0.39

-175

-0.27

-175

-0.27

-75

-0.12 0

0.00 175

0.27 225

0.35 600

0.93 750

1.16

0.05

0.80

1.15

1.05

-0.07

0.05

MINIMUM CURVE

UI Time Amp.

-500

-0.77

-0.23

-0.15

0.00

0.15

0.23

0.46

0.66

0.93

1.16

-150

-100 0 100 150 150 300 430 600 750

-0.05

0.50

0.95

0.90

0.50

-0.45

-0.20

-0.05

-0.4

-0.5

-500 -300 -100 0 300 500 700 -400 -200 200 400 600 100

TIME (ns)

41 of 60

Figure 7-7. Jitter Tolerance

100

)

P-P

UNIT INTERVALS (UI

0.1

Figure 7-8. Jitter Attenuation

-20

DS21448 3.3V T1/E1/J1 Quad Line Interface

TR 62411 (DEC ‘90)

ITU-T G.823

10 100 1k 10k 100k

FREQUENCY (Hz)

TBR12

PROHIBITED

AREA

CURVE A

DS21448 TOLERANCE

ITU G.7XX

PROHIBITED AREA

T1E1

-40

JITTER ATTENUATION (dB)

-60

10 100 1k 10k

CURVE B

FREQUENCY (Hz)

42 of 60

TR 62411 (DEC 90)

PROHIBITED AREA

100k

DS21448 3.3V T1/E1/J1 Quad Line Interface

8. JTAG BOUNDARY SCAN ARCHITECTURE AND TEST ACCESS PORT

The DS21448 IEEE 1149.1 design supports the standard instruction codes SAMPLE/PRELOAD, BYPASS, and EXTEST. Optional public instructions included are HIGHZ, CLAMP, and IDCODE (Table 8-A contains the following items, which meet the requirements set by the IEEE 1149.1 Standard Test Access Port (TAP) and Boundary Scan Architecture:

Test Access Port TAP Controller Instruction Register

The TAP has the necessary interface pins JTRST, JTCLK, JTMS, JTDI, and JTDO. See the pin descriptions in Section 1

1149.1-1990, IEEE 1149.1a-1993, and IEEE 1149.1b-1994.

for details. Details on Boundary Scan Architecture and the Test Access Port can be found in IEEE

Bypass Register Boundary Scan Register Device Identification Register

Figure 8-1. JTAG Block Diagram

VDD

10kW 10kW 10kW

JTDI JTMS JTCLK

BOUNDRY SCAN

IDENTIFICATION

BYPASS

INSTRUCTION

TEST ACCESS PORT

CONTROLLER

MUX

SELECT

OUTPUT ENABLE

JTRST JTDO

8.1 JTAG TAP Controller State Machine

This section covers the operation of the TAP controller state machine. See Figure 8-2 for details on each of the states described below. The TAP controller is a finite state machine that responds to the logic level at JTMS on the rising edge of JTCLK (Table 8-B

Test-Logic-Reset. Upon power-up, the TAP controller is in test-logic-reset state. The instruction register contains the IDCODE instruction. All system logic of the device operates normally.

Run-Test-Idle. The run-test-idle is used between scan operations or during specific tests. The instruction register and test registers remain idle.

Select-DR-Scan. All test registers retain their previous state. With JTMS LOW, a rising edge of JTCLK moves the controller into the capture-DR state and initiates a scan sequence. JTMS HIGH during a rising edge on JTCLK moves the controller to the select-IR-scan state.

43 of 60

). The DS21448

DS21448 3.3V T1/E1/J1 Quad Line Interface

Figure 8-2. TAP Controller State Diagram

Capture-DR. Data can be parallel-loaded into the test data registers selected by the current instruction. If the

instruction does not call for a parallel load or the selected register does not allow parallel loads, the test register remains at its current value. On the rising edge of JTCLK, the controller goes to the shift-DR state if JTMS is LOW, or it goes to the exit1-DR state if JTMS is HIGH.

Shift-DR. The test data register selected by the current instruction is connected between JTDI and JTDO, and shifts data one stage toward its serial output on each rising edge of JTCLK. If a test register selected by the current instruction is not placed in the serial path, it maintains its previous state.

Exit1-DR. While in this state, a rising edge on JTCLK puts the controller in the update-DR state, which terminates the scanning process, if JTMS is HIGH. A rising edge on JTCLK with JTMS LOW puts the controller in the pauseDR state.

Pause-DR. Shifting of the test registers is halted while in this state. All test registers selected by the current instruction retain their previous state. The controller remains in this state while JTMS is LOW. A rising edge on JTCLK with JTMS HIGH puts the controller in the exit2-DR state.

Exit2-DR. A rising edge on JTCLK with JTMS HIGH while in this state puts the controller in the update-DR state and terminates the scanning process. A rising edge on JTCLK with JTMS LOW enters the shift-DR state.

Update-DR. A falling edge on JTCLK while in the update-DR state latches the data from the shift register path of the test registers into the data output latches. This prevents changes at the parallel output due to changes in the shift register.

Test Logic

Reset

Run Test/ Idle

Select DR-Scan

Select IR-Scan

Capture DR

Shift DR

Exit DR

Pause DR

Exit2 DR

Capture IR

Shift IR

Exit IR

Pause IR

Exit2 IR

Update DR

Update IR

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DS21448 3.3V T1/E1/J1 Quad Line Interface

Select-IR-Scan. All test registers retain their previous state. The instruction register remains unchanged during this state. With JTMS LOW, a rising edge on JTCLK moves the controller into the capture-IR state and initiates a scan sequence for the instruction register. JTMS HIGH during a rising edge on JTCLK puts the controller back into the test-logic-reset state.

Capture-IR. The capture-IR state is used to load the shift register in the instruction register with a fixed value. This value is loaded on the rising edge of JTCLK. If JTMS is HIGH on the rising edge of JTCLK, the controller enters the exit1-IR state. If JTMS is LOW on the rising edge of JTCLK, the controller enters the shift-IR state.

Shift-IR. In this state, the shift register in the instruction register is connected between JTDI and JTDO and shifts data one stage for every rising edge of JTCLK toward the serial output. The parallel register and all test registers remain at their previous states. A rising edge on JTCLK with JTMS HIGH moves the controller to the exit1-IR state. A rising edge on JTCLK with JTMS LOW keeps the controller in the shift-IR state while moving data one stage through the instruction shift register.

Exit1-IR. A rising edge on JTCLK with JTMS LOW puts the controller in the pause-IR state. If JTMS is HIGH on the rising edge of JTCLK, the controller enters the update-IR state and terminates the scanning process.

Pause-IR. Shifting of the instruction shift register is halted temporarily. With JTMS HIGH, a rising edge on JTCLK puts the controller in the exit2-IR state. The controller remains in the pause-IR state if JTMS is LOW during a rising edge on JTCLK. Exit2-IR. A rising edge on JTCLK with JTMS HIGH puts the controller in the update-IR state. The controller loops back to shift-IR if JTMS is LOW during a rising edge of JTCLK in this state.

Update-IR. The instruction code shifted into the instruction shift register is latched into the parallel output on the falling edge of JTCLK as the controller enters this state. Once latched, this instruction becomes the current instruction. A rising edge on JTCLK with JTMS LOW puts the controller in the run-test-idle state. With JTMS HIGH, the controller enters the select-DR-scan state.

8.2 Instruction Register

The instruction register contains a shift register, as well as a latched parallel output, and is 3 bits in length. When the TAP controller enters the shift-IR state, the instruction shift register is connected between JTDI and JTDO. While in the shift-IR state, a rising edge on JTCLK with JTMS LOW shifts the data one stage toward the serial output at JTDO. A rising edge on JTCLK in the exit1-IR state or the exit2-IR state with JTMS HIGH moves the controller to the update-IR state. The falling edge of that same JTCLK latches the data in the instruction shift register to the instruction parallel output. Table 8-A

shows the instructions supported by the DS21448 and its

respective operational binary codes.

Table 8-A. Instruction Codes for IEEE 1149.1 Architecture

INSTRUCTION SELECTED REGISTER INSTRUCTION CODES

SAMPLE/PRELOAD Boundary Scan 010

BYPASS Bypass 111 EXTEST Boundary Scan 000

CLAMP Bypass 011

HIGHZ Bypass 100

IDCODE Device Identification 001

SAMPLE/PRELOAD. This is a mandatory instruction for the IEEE 1149.1 specification that supports two functions. The digital I/Os of the device can be sampled at the boundary scan register without interfering with the normal operation of the device by using the capture-DR state. SAMPLE/PRELOAD also allows the device to shift data into the boundary scan register through JTDI using the shift-DR state.

BYPASS. When the BYPASS instruction is latched into the parallel instruction register, JTDI connects to JTDO through the 1-bit bypass test register. This allows data to pass from JTDI to JTDO without affecting the device’s normal operation.

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DS21448 3.3V T1/E1/J1 Quad Line Interface

EXTEST. This allows testing of all interconnections to the device. When the EXTEST instruction is latched in the instruction register, the following actions occur. Once enabled through the update-IR state, the parallel outputs of all digital output pins are driven. The boundary scan register is connected between JTDI and JTDO. The captureDR samples all digital inputs into the boundary scan register.

CLAMP. All digital outputs of the device are output data from the boundary scan parallel output while connecting the bypass register between JTDI and JTDO. The outputs do not change during the CLAMP instruction.

HIGHZ. All digital outputs of the device are placed in a high-impedance state. The BYPASS register is connected between JTDI and JTDO.

IDCODE. When the IDCODE instruction is latched into the parallel instruction register, the identification test register is selected. The device identification code is loaded into the identification register on the rising edge of JTCLK following entry into the capture-DR state. Shift-DR can be used to shift the identification code out serially through JTDO. During test-logic-reset, the identification code is forced into the instruction register’s parallel output. The ID code always has a 1 in the LSB position. The next 11 bits identify the manufacturer’s JEDEC number and number of continuation bytes followed by 16 bits for the device and 4 bits for the version Table 8-B the device ID code for the SCT devices.

. Table 8-C lists

Table 8-B. ID Code Structure

MSB LSB

Version

(Contact Factory)

4 bits 16 bits 00010100001 1

Device ID JEDEC 1

Table 8-C. Device ID Codes

DEVICE 16-BIT ID

DS21448 0018

8.3 Test Registers

IEEE 1149.1 requires a minimum of two test registers—the bypass register and the boundary scan register. An optional test register, the identification register, has been included with the DS21448 design. It is used with the IDCODE instruction and the test-logic-reset state of the TAP controller.

Bypass Register

The bypass register is a single 1-bit shift register used with the BYPASS, CLAMP, and HIGHZ instructions that provides a short path between JTDI and JTDO.

Identification Register

The identification register contains a 32-bit shift register and a 32-bit latched parallel output. This register is selected during the IDCODE instruction and when the TAP controller is in the test-logic-reset state. See Table 8-B and Table 8-C

Boundary Scan Register

The boundary scan register contains a shift register path and a latched parallel output for all control cells and digital I/O cells, and is n bits in length. See Table 8-D

for more information about bit usage.

for all cell bit locations and definitions.

46 of 60

Table 8-D. Boundary Scan Control Bits

BIT

— A1 124 RTIP1 I

— A2 6 TTIP1 O

— A4 28 RTIP2 I

— A5 38 TTIP2 O

— A7 60 RTIP3 I

— A8 71 TTIP3 O

— A10 93 RTIP4 I

— A11 102 TTIP4 O

— B2 125 RRING1 I

— B3 9 TRING1 O

— B5 29 RRING2 I

— B6 41 TRING2 O

— B8 61 RRING3 I

— B9 74 TRING3 O

— B11 94 RRING4 I

— B12 105 TRING4 O

— D1 39 TVSS2 —

— D2 40 TVDD2 —

64 D3 57

48 D4 80 D2/AD2 I/O

46 D5 82 D0/AD0 I/O

67 D6 47 BPCLK2 O

22 D7 128 RCL/LOTC2 O

— D8 49–51 VDD3 —

— D9 52–54 VSS3 —

44 D10 84

15 D11 14 RPOS3 O

3 D12 34 TNEG3 I

17 E1 12 RPOS2 O

16 E2 13 RNEG2 O

49 E3 79 D3/AD3 I/O

— E4 19–21 VDD2 —

— E9 72 TVSS3 —

27 E10 121 PBEO3 O

63 E11 58 RCLK3 O

4 E12 33 TPOS3 I

6 F1 31 RCLK2 O

7 F2 30 TPOS2 I

47 F3 81 D1/AD1 I/O

— F4 22–24 VSS2 —

21 F9 1 RCL/LOTC3 O

65 F10 56 BPCLK3 O

14 F11 15 RNEG3 O

45 F12 83 TCLK3 I

9 G1 26 TPOS1 I

18 G2 11 RNEG1 O

31 G3 111 PBEO2 O

— G9 73 TVDD3 —

51 G11 77 D5/AD5 I/O

BGA LQFP

NAME I/O

CS2

CS3

DS21448 3.3V T1/E1/J1 Quad Line Interface

PIN BIT

(Note 1)

56 G12 66 A0 I

42 H1 92

8 H2 27 TNEG1 I

23 H3 127 RCLK1 O

26 H4 122 BPCLK1 O

— H9 88–90 VSS4 —

52 H10 76 D6/AD6 I/O

58 H11 64 A2 I

57 H12 65 A1 I

2 J1 35 SCLK I

43 J2 91

11 J3 18

— J4 7 TVSS1 —

— J5 8 TVDD1 —

33 J6 109 MCLK I

20 J7 2 RCL/LOTC4 O

— J8 85–87 VDD4 —

50 J9 78 D4/AD4 I/O

53 J10 75 D7/AD7 I/O

60 K1 62 A4 I

41 K2 95 ALE (AS) I

1 K3 36 SDI I

19 K4 10 RPOS1 O

32 K5 110 PBEO1 O

37 K7 98 TXDIS/TEST I

25 K8 123 PBEO4 O 39

(Note 2)

38 K9 97

28 K10 114

13 K11 16 RPOS4 O

62 K12 59 TNEG4 I

59 L1 63 A3 I

0 L2 43 TCLK2 I

— L3 42 JTRST I

— L5 115–117 VDD1 —

24 L6 126 RCL/LOTC1 O

35 L7 107 BIS0 I

30 L8 112 BPCLK4 O

36 L9 106

— L10 103 TVSS4 —

40 L11 96 RCLK4 O

29 L12 113 TCLK4 I

5 M1 32 TNEG2 I

12 M2 17 TCLK1 I

— M3 48 JTMS I

— M4 118–120 VSS1 —

— M5 44 JTCLK I

BGA LQFP

— BUScntl —

—

NAME I/O

WR (R/W)

RD (DS)

CS1

INTcntl

INT

CS4

HRST

—

I/O

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DS21448 3.3V T1/E1/J1 Quad Line Interface

BIT

— M6 45 JTDI I

— M7 46 JTDO O

55 M8 68 BIS1 I

— M9 104 TVDD4 —

Note 1: 0 = Dn/ADn are inputs; 1 = Dn/ADn are outputs. Note 2: 0 = INT is an input; 1 = INT is an output.

BGA LQFP

NAME I/O

10 M10 25 RNEG4 O

61 — — ADRScntl —

66 M11 55 TPOS4 I

34 M12 108 PBTS I

PIN BIT

BGA LQFP

NAME I/O

9. OPERATING PARAMETERS

ABSOLUTE MAXIMUM RATINGS

Voltage on Any Pin Relative to Ground -1.0V to +6.0V Operating Temperature for DS21448TN -40°C to +85°C Storage Temperature See IPC/JEDEC J-STD-020A Specification

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to the absolute maximum rating conditions for extended periods may affect device.

RECOMMENDED DC OPERATING CONDITIONS

(TA = -40°C to +85°C)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Logic 1 VIH 2.2 5.5 V Logic 0 VIL -0.3 +0.8 V Supply for 3.3V Operation VDD (Note 1) 3.135 3.3 3.465 V

CAPACITANCE

(TA = +25°C)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Input Capacitance CIN 5 pF Output Capacitance C

7 pF

OUT

DC CHARACTERISTICS

(VDD = 3.3V ±5%, TA = -40°C to +85°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Input Leakage IIL (Note 2) -1.0 +1.0 Output Leakage ILO (Note 3) +1.0 Output Current (2.4V) IOH -1.0 mA Output Current (0.4V) IOL +4.0 mA Supply Current at 3.3V IDD (Notes 4, 5) 320 400 mA Power Dissipation at 3.3V PDD (Notes 4, 5) 1.06 1.32 W

Note 1: Applies to VDD. Note 2: 0.0V < V Note 3: Applied to INT when tri-stated. Note 4: TCLK = MCLK = 2.048MHz. Note 5: Power dissipation with all ports active, TTIP and TRING driving a 30W load, for an all-ones data density.

< VDD.

mA mA

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DS21448 3.3V T1/E1/J1 Quad Line Interface

RD W

10. AC TIMING PARAMETERS AND DIAGRAMS

Table 10-A. AC Characteristics—Multiplexed Parallel Port (BIS0 = 0)

(VDD = 3.3V ±5%, TA = -40°C to +85°C.) (Figure 10-1, Figure 10-2, and Figure 10-3)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Cycle Time t Pulse Width, DS Low or RD High Pulse Width, DS High or RD Low Input Rise/Fall Times tR, tF 20 ns R/W Hold Time R/W Setup Time Before DS High

CS Setup Time Before DS, WR, or RD Active CS Hold Time

Read Data Hold Time t Write Data Hold Time t Muxed Address Valid to AS or ALE Fall t Muxed Address Hold Time t Delay Time DS, WR, or RD to AS or ALE Rise Pulse Width AS or ALE High PW Delay Time, AS or ALE to DS, WR, or RD Output Data Delay Time from DS or RD Data Setup Time t

Figure 10-1. Intel Bus Read Timing (PBTS = 0, BIS0 = 0)

ALE

AD0–AD7

ASD

ASL

ASH

200 ns

CYC

100 ns

10 ns

RWH

50 ns

RWS

20 ns

0 ns

10 50 ns

DHR

5 ns

DHW

15 ns

ASL

10 ns

AHL

20 ns

ASD

30 ns

ASH

10 ns

ASED

20 80 ns

DDR

50 ns

DSW

CYC

ASED

AHL

DDR

DHR

49 of 60

Figure 10-2. Intel Bus Write Timing (PBTS = 0, BIS0 = 0)

RD W

W C

AD0–AD7

ALE

ASD

ASL

ASH

AHL

ASED

CYC

Figure 10-3. Motorola Bus Timing (PBTS = 1, BIS0 = 0)

ASH

DS21448 3.3V T1/E1/J1 Quad Line Interface

DHW

DSW

AD0–AD7

(READ)

AD0–AD7 (WRITE)

ASD

ASL

AHL

DHR

DHW

RWH

ASED

CYC

RWS

DDR

DSW

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DS21448 3.3V T1/E1/J1 Quad Line Interface

WR C

Table 10-B. AC Characteristics—Nonmultiplexed Parallel Port (BIS0 = 1)

(VDD = 3.3V ±5%, TA = -40°C to +85°C.) (Figure 10-4, Figure 10-5, Figure 10-6, and Figure 10-7)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Setup Time for A0 to A4, Valid to CS Active Setup Time for CS Active to Either RD,

WR, or DS Active

Delay Time from Either RD or DS Active to Data Valid Hold Time from Either RD, WR, or DS Inactive to

CS Inactive

Hold Time from CS Inactive to Data Bus Tri-State Wait Time from Either WR or DS Active to Latch Data Data Setup Time to Either WR or DS Inactive Data Hold Time from Either WR or DS Inactive Address Hold from Either WR or DS Inactive

t1 0 ns

t2 0 ns

t3 75 ns

t4 0 ns

t5 5.0 20 ns

t6 75 ns

t7 10 ns

t8 10 ns

t9 10 ns

Figure 10-4. Intel Bus Read Timing (PBTS = 0, BIS0 = 1)

A0–A4

D0–D7

0ns (MIN)

t2 t3 t4

ADDRESS VALID

75ns (MAX)

DATA VALID

5ns (MIN) / 20ns (MAX)

0ns (MIN)

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DS21448 3.3V T1/E1/J1 Quad Line Interface

RD CS W

W CS D

W C

Figure 10-5. Intel Bus Write Timing (PBTS = 0, BIS0 = 1)

A0–A4

ADDRESS VALID

D0–D7

t7 t8

10ns (MIN)

0ns (MIN)

t2 t6 t4

75ns (MIN)

Figure 10-6. Motorola Bus Read Timing (PBTS = 1, BIS0 = 1)

A0–A4

ADDRESS VALID

D0–D7

5ns (MIN) / 20ns (MAX)

DATA VALID

0ns (MIN)

t2 t3 t4

75ns (MAX)

Figure 10-7. Motorola Bus Write Timing (PBTS = 1, BIS0 = 1)

10ns (MIN)

0ns (MIN)

A0–A4

ADDRESS VALID

D0–D7

0ns (MIN)

t2 t6 t4

75ns (MIN)

52 of 60

10ns (MIN)

0ns (MIN)

DS21448 3.3V T1/E1/J1 Quad Line Interface

Table 10-C. AC Characteristics—Serial Port (BIS1 = 1, BIS0 = 0)

(VDD = 3.3V ±5%, TA = -40°C to +85°C.) (Figure 10-8)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Setup Time CS to SCLK Setup Time SDI to SCLK t Hold Time SCLK to SDI t SCLK High/Low Time t SCLK Rise/Fall Time t SCLK to CS Inactive

CS Inactive Time

SCLK to SDO Valid t SCLK to SDO Tri-State t

CS Inactive to SDO Tri-State

CSS

50 ns

SSS

50 ns

SSH

200 ns

SLH

50 ns

SRF

LSC

50 ns

SSV

100 ns

SST

CSH

50 ns

250 ns

Figure 10-8. Serial Bus Timing (BIS1 = 1, BIS0 = 0)

CSS

SCLK

(Note 1)

SCLK

(Note 2)

SDI

SSS

LSB MSB

SDO

NOTE 1: OCES =1 AND ICES = 0. NOTE 2: OCES = 0 AND ICES = 1.

SSH

HIGH-Z

SRF

SLH

MSB

LSB

SSV

100 ns

LSC

CSH

SST

HIGH-Z

MSB

53 of 60

Table 10-D. AC Characteristics—Receive Side

(VDD = 3.3V ± 5%, TA =-40°C to +85°C.) (Figure 10-9)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

RCLK Period tCP

(Note 1) 488 (Note 2) 648

RCLK Pulse Width

Delay RCLK to RPOS, RNEG, PBEO, RBPV Valid

Note 1: E1 mode. Note 2: T1 or J1 mode. Note 3: Jitter attenuator enabled in the receive path. Note 4: Jitter attenuator disabled or enabled in the transmit path.

tCH

50.0 ns

(Note 3) 200

(Note 4) 150

Figure 10-9. Receive-Side Timing

RCLK

(Note 1)

RCLK

(Note 2)

RPOS, RNEG

PBEO

RNEG

(Note 3)

NOTE 1: RCES = 1 (CCR2.0) OR CES = 1. NOTE 2: RCES = 0 (CCR2.0) OR CES = 0. NOTE 3:

RNEG IS IN NRZ MODE (CCR1.6 = 1).

BIT

ERROR

BPV/ EXZ/ CV

DS21448 3.3V T1/E1/J1 Quad Line Interface

PRBS DETECTOR OUT OF SYNC

BPV/ EXZ/ CV

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DS21448 3.3V T1/E1/J1 Quad Line Interface

Table 10-E. AC Characteristics—Transmit Side

(VDD = 3.3V ±5%, TA = -40°C to +85°C.) (Figure 10-10)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

TCLK Period tCP

(Note 5) 488 (Note 6) 648

tCH 75

TCLK Pulse Width

TPOS/TNEG Setup to TCLK Falling or Rising TPOS/TNEG Hold from TCLK Falling or Rising

20 ns

TCLK Rise and Fall Times tR, tF 25 ns

Note 5: E1 mode. Note 6: T1 or J1 mode.

Figure 10-10. Transmit-Side Timing

TCLK

(Note 1)

TCLK

(Note 2)

TPOS, TNEG

NOTE 1: TCES = 0 (CCR2.1) OR CES = 0. NOTE 2: TCES = 1 (CCR2.1) OR CES = 1.

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DS21448 3.3V T1/E1/J1 Quad Line Interface

11. PIN CONFIGURATIONS

11.1 144-Pin BGA

1 2 3 4 5 6 7 8 9 10 11 12

RTIP1 TTIP1 N.C. RTIP2 TTIP2 N.C. RTIP3 TTIP3 N.C. RTIP4 TTIP4 N.C.

N.C. RRING1 TRING1 N.C. RRING2 TRING2 N.C. RRING3 TRING3 N.C. RRING4 TRING4

N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C.

TVSS2 TVDD2

RPOS2 RNEG2

RCLK2 TPOS2

TPOS1 RNEG1 PEBO2 N.C. N.C. N.C. N.C. N.C. TVDD3 N.C.

(R/W)

SCLK

A4/

SDO

TNEG1 RCLK1 BPCLK1 N.C. N.C. N.C. N.C. VSS4

(DS)

ALE (AS)

CS2

D3/

AD3

D1/

AD1

CS1

SDI RPOS1 PEBO1 N.C.

D2/

AD2

VDD2 N.C. N.C. N.C. N.C. TVSS3 PEBO3 RCLK3 TPOS3

VSS2 N.C. N.C. N.C. N.C.

TVSS1 TVDD1 MCLK

D0/

AD0

BPCLK2

RCL/

LOTC2

RCL/

LOTC4

TXDIS/

TEST

VDD3 VSS3

LOTC3

VDD4

PEBO4

CS3

RCL/

AD4

BPCLK3 RNEG3 TCLK3

D6/

AD6

D4/

INT CS4

D7/

AD7

RPOS3 TNEG3

D5/

AD5

A2/

OCES

N.C. N.C.

RPOS4 TNEG4

A3/

ICES

TNEG2 TCLK1 JTMS VSS1 JTCLK JTDI JTDO BIS1 TVDD4 RNEG4 TPOS4 PBTS

TCLK2 JTRST N.C. VDD1

RCL/

LOTC1

56 of 60

BIS0 BPCLK4

HRST

TVSS4 RCLK4 TCLK4

11.2 128-Pin LQFP

3 R

HRST

CS4

N.C.

TTIP4

N.C.

DS21448 3.3V T1/E1/J1 Quad Line Interface

)/NRZE

)/ETS

RT1

TXDIS/TEST

RCLK4

LE (AS)/SCLKE

RRING4

VSS4

RTIP4

VSS4

/EGL3

D0/AD0/MM1

VDD4

TCLK3

D4/AD4/TX1

D1/AD1/MM0

D3/AD3/LOOP0

D2/AD2/LOOP1

TRING3

D5/AD5/TX0

D6/AD6/TPD

TVSS3

TVDD3

D7/AD7/CES

N.C.

TTIP3

N.C.

A1/JAS

A0/HBE

N.C.

BIS1

TVSS4

TVDD4

TRING4

BIS0

PBTS/RT0

MCLK PBEO1 PBEO2

BPCLK4

TCLK4

/EGL4

VDD1

VSS1 VSS1 VSS1

PBEO3

BPCLK1

PBEO4

RTIP1

RRING1

RCL1/LOTC1

RCLK1

RCL2/LOTC2

708090 100

110

Dallas Semiconductor

DS21448

120

RCL3/LOTC3

RCL4/LOTC4

N.C.

TTIP1

VSM

10 20 30

TVSS1

TVDD1

TRING1

RPOS1

RNEG1

RPOS2

RNEG2

RPOS3

RNEG3

RPOS4

TCLK1

VDD2

VSS2

S1/

EGL1

VSS2

RNEG4

TPOS1

TNEG1

RTIP2

TPOS2

RRING2

RCLK2

TNEG2

TPOS3

SCLK/L2

TNEG3

SDI/L1

TTIP2

N.C.

2/OCES/JAMU 3/ICES/DJ

4/SD0/L0 RRING3 RTIP3 TNEG4 RCLK3

/EGL2

BPCLK3 TPOS4 VSS3 VSS3 VSS3 VDD3 VDD3 VDD3 JTMS BPCLK2 JTDO JTDI JTCLK TCLK2 JTRST TRING2 TVDD2 TVSS2

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DS21448 3.3V T1/E1/J1 Quad Line Interface

12. PACKAGE INFORMATION

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/DallasPackInfo

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DS21448 3.3V T1/E1/J1 Quad Line Interface

PACKAGE INFORMATION (continued)

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/DallasPackInfo

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DS21448 3.3V T1/E1/J1 Quad Line Interface

13. THERMAL INFORMATION

Table 13-A. Thermal Characteristics—BGA

PARAMETER MIN TYP MAX UNITS

Ambient Temperature (Note 1) -40 +85 °C Junction Temperature +125 °C Theta-JA (qJA) in Still Air (Note 2)

+24

°C/W

Table 13-B. Theta-JA (qJA) vs. Airflow—BGA

FORCED AIR (m/s)

0 24°C/W 1 21°C/W

2.5 19°C/W

THETA-JA (q

)

Table 13-C. Thermal Characteristics—LQFP

PARAMETER MIN TYP MAX UNITS

Ambient Temperature (Note 1) -40 +85 °C Junction Temperature +125 °C Theta-JA (qJA) in Still Air (Note 2) Theta-JC (qJC) in Still Air (Note 3)

+27.8 +0.1

°C/W °C/W

Table 13-D. Theta-JA (qJA) vs. Airflow—LQFP

FORCED AIR (m/s)

THETA-JA (q

0 27.8°C/W 1 23.5°C/W

2.5 21.6°C/W

Note 1: The package is mounted on a four-layer JEDEC-standard test board. Note 2: Theta-JA (q Note 3: While Theta-JC (q

the average temperature on top center of the LQFP package (TC), the proper term is Psi-JT. It is defined by: (Tj - TC) / overall package power.

Note 4: The method of measurement for the thermal parameters is defined in the EIA/JEDEC-standard document EIA-JESD51-2.

) is the junction-to-ambient thermal resistance, when the package is mounted on a four-layer JEDEC-standard test board.

) is commonly used as the thermal parameter that provides a correlation between the junction temperature (Tj) and

)

14. REVISION HISTORY

REVISION DESCRIPTION

042303 New product release.

Table 5-B. Receive Level Indication: Changed “-12.5 to -5.0” to “-12.5 to -15.0”. Adjusted steps after -17.5 dB to be in -2.5dB decrements.

012104

Section 9, Operating Parameters: Updated supply current and power dissipation values in the DC Characteristics table to reflect latest characterization data. Updated Note 5 to show that values are for all ports active.

Maxim/Dallas Semiconductor cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim/Dallas Semiconductor product. No circuit patent licenses are implied. Maxim/Dallas Semiconductor reserves the right to change the circuitry and specifications without notice at any time.

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MAXIM DS21448 Technical data

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