DS21448+ - Hytronics - Datasheet.Live

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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

75Ω or 120Ω applications and the DSX-1 or CSU line

build-outs of 0dB, -7.5dB, -15dB, and -22.5dB for T1

applications.

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

ORDERING INFORMATION

PART* TEMP RANGE PIN-PACKAGE

DS21448 0°C to +70°C 144 TE-PBGA

DS21448+ 0°C to +70°C 144 TE-PBGA

DS21448N -40°C to +85°C 144 TE-PBGA

DS21448N+ -40°C to +85°C 144 TE-PBGA

DS21448L 0°C to +70°C 128 LQFP

DS21448L+ 0°C to +70°C 128 LQFP

DS21448LN -40°C to +85°C 128 LQFP

DS21448LN+ -40°C to +85°C 128 LQFP

+ Denotes lead-free/RoHS-compliant package.

*All devices rated at 3.3V.

Pin Configurations appear in Section 11.

FEATURES

 Four Complete E1, T1, or J1 LIUs

 Supports Long- and Short-Haul Trunks

 Internal Software-Selectable Receive-Side

Termination for 75Ω/100Ω/120Ω

 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

 50mARMS Transmit Current Limiter

 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

DS21448

3.3V E1/T1/J1 Quad Line Interface

www.maxim-ic.com

DS21448 3.3V T1/E1/J1 Quad Line Interface

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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 .......................................................................................................................14

4.1 HARDWARE MODE.........................................................................................................................14

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

4.3 PARALLEL PORT OPERATION .........................................................................................................18

4.3.1 Device Power-Up and Reset................................................................................................................ 18

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

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

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

6. DIAGNOSTICS .............................................................................................................................. 28

6.1 IN-BAND LOOP-CODE GENERATION AND DETECTION ......................................................................28

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

12.1 144-BALL TE-PBGA (56-G6020-001) ....................................................................................... 58

12.2 128-PIN LQFP (56-G4011-001) ................................................................................................ 59

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

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

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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 .........................................................16

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 .........................................................17

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 7-5. E1 Transmit Pulse Template..................................................................................................40

Figure 7-6. 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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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 ........................................................................................15

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 (θJA) vs. Airflow—BGA...........................................................................................60

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

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

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1. BLOCK DIAGRAMS

Figure 1-1. Block Diagram

VDD

VSS

POWER

CONNECTIONS

VCO/PLL

MCLK

2.048MHz TO

1.544MHz PLL

JITTER

ATTENUATOR

MUX

VSM

TRING

TTIP

FILTER

RRING

RTIP

UNFRAMED

ALL-ONES

INSERTION

BIS0

CONTROL AND TEST

PORT (ROUTED TO

ALL BLOCKS)

MUX (THE SERIAL, PARALLEL, AND HARDWARE INTERFACES

SHARE DEVICE PINS)

RST

TXDIS/TEST

16.384MHz OR

8.192MHz OR

4.096MHz OR

2.048MHz

SYNTHESIZER

BPCLK

RPOS

RCLK

RNEG

TPOS

TCLK

TNEG

JACLK

MUX

See Figure 1-2

See Figure 1-3

PBEO

MUX RCL/LOTC

TYPICAL OF ALL FOUR CHANNELS

CHANNEL 1

CHANNEL 2

CHANNEL 3

CHANNEL 4

JRST

JTMS

JTDI

JTDO

JTAG PORT

JTCL

CONTROL AND

(ROUTED TO

ALL BLOCKS)

PARALLEL INTERFACE

SDO

SCL

SERIAL

INTERFACE

SDI

PBTS

(R/

)

(

)

ALE (AS)

A0 TO A4

D0 TO D7/AD0

TO AD7

OPTIONAL

TERMINANATION

ANALOG LOOPBACK

LINE DRIVERS

CSU FILERS

WAVESHAPING

PEAK DETECT

CLOCK/DATA

RECOVERY

REMOTE LOOPBACK

(

DUAL MODE

)

LOCAL LOOPBAC

JITTER ATTENUATION

(CAN BE PLACED IN EITHER TRANSMIT OR

RECEIVE PATH)

REMOTE LOOPBAC

Dallas

Semiconductor

DS21448

DS21448 3.3V T1/E1/J1 Quad Line Interface

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Figure 1-2. Receive Logic Detail

Figure 1-3. Transmit Logic Detail

RPOS

RNEG

FROM

REMOTE

LOOPBACK

CLOCK

INVERT RCLK

CCR2.0

CCR1.6

ROUTED TO

LL BLOCKS

MUX

4 OR 8 ZERO DETECT

16 ZERO DETECT

RIR1.7 RIR1.6

B8ZS/HDB3

DECODER

ALL-ONES

DETECTOR

LOOP CODE

DETECTOR

PRBS

DETECTOR

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

CCR2.3

RIR1.5

16-BIT ERROR

COUNTER (ECR)

MUX CCR6.0

SR.0

CCR6.2/

CCR6.0/

CCR6.1

NRZ DATA

BPV/CV/EXZ

PBEO

CCR1.4

BPV

INSERT

MUX

B8ZS/

HDB3

CODER

LOGIC

ERROR

INSERT

MUX

GATE

GA TE

CCR3.1

CCR1.6

CCR2.2

CCR3.0

CCR3.4

CCR3.3

TPOS

TNEG

TO REMOTE

LOOPBACK

PRBS

GENERATOR

LOOP CODE

GENERATOR

CLOCK

INVERT

LOSS-OF-TRANSMIT

CLOCK DETECT

TCLK

CCR2.1

RCLK

JACLK

(FROM MCLK)

CCR1.0

CCR1.1

CCR1.2

MUX

GA TE

TO LOTC OUTPUT PIN

GATE

ROUTED TO

LL BLOCKS

SR.5

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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 I/O PARALLEL PORT MODE SERIAL PORT MODE HARDWARE MODE

J3 18 I CS1 CS1

EGL1

D3 57 I CS2 CS2

EGL2

D10 84 I CS3 CS3

EGL3

K10 114 I CS4 CS4

EGL4

J2 91 I RD (DS) N/A ETS

H1 92 I WR (R/W) N/A NRZE

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 INT INT

RT1

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

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BGA LQFP I/O PARALLEL PORT MODE SERIAL PORT MODE HARDWARE MODE

B8 61 I RRING3 RRING3 RRING3

B11 94 I RRING4 RRING4 RRING4

L9 106 I HRST HRST HRST

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.

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Table 2-C. Parallel Interface Mode Pin Description

PIN I/O FUNCTION

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

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

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

ALE (AS) I

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.

A4–A0 I

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.

D7/AD7–D0/AD0 I/O

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.

INT O 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.

TXDIS/TEST I

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.

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

default state.

MCLK I

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).

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

PBTS I

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.

CS1–CS4 I

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

signal.

PBEO1–PBEO4 O

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.

RCL1/LOTC1–

RCL4/LOTC4 O

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 5µs ± 2µs (CCR2.7 =

1). CCR2.7 defaults to logic 0 when in hardware mode.

RTIP1–RTIP4 I

RRING1–RRING4 I

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.

BPCLK1–BPCLK4 O 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.

TTIP1–TTIP4 O

TRING1–TRING4 O

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

transformer to the line. See Section 7 for details.

RPOS1–RPOS4 O

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.

RNEG1–RNEG4 O

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.

DS21448 3.3V T1/E1/J1 Quad Line Interface

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PIN I/O FUNCTION

RCLK1–RCLK4 O

Receive Clock. Buffered recovered clock from the line. Synchronous to MCLK in absence of

signal at RTIP and RRING.

TPOS1–TPOS4 I

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.

TNEG1–TNEG4 I

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.

TCLK1–TCLK4 I

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

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

Table 2-D. Serial Interface Mode Pin Description

PIN I/O FUNCTION

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

status register. Active-low, open-drain output.

TXDIS/TEST I

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.

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

default state.

MCLK I

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. A T1 1.544MHz

clock source is optional (Note 1).

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

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

signal.

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

signal.

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

signal.

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

signal.

ICES I

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.

OCES I

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.

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

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.

RCL1/LOTC1–

RCL4/LOTC4 O

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 5µs ± 2µs

(CCR2.7 = 1). CCR2.7 defaults to logic 0 when in hardware mode.

RTIP1–RTIP4

RRING1–RRING4 I 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 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.

TTIP1–TTIP4 O

TRING–TRING4 O

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

transformer to the line. See Section 7 for details.

RPOS1–RPOS4 O

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.

RNEG1–RNEG4 O

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.

RCLK1–RCLK4 O

Receive Clock. Buffered recovered clock from the line. Synchronous to MCLK in absence of

signal at RTIP and RRING.

TPOS1–TPOS4 I

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.

TNEG1–TNEG4 I

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.

TCLK1–TCLK4 I

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.

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

Table 2-E. Hardware Interface Mode Pin Description

PIN I/O FUNCTION

ETS I

E1/T1 Select

0 = E1

1 = T1

NRZE I

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.

SCLKE I

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

DJA I

Disable Jitter Attenuator

0 = jitter attenuator enabled

1 = jitter attenuator disabled

JAMUX I

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).

JAS I

Jitter Attenuator Path Select

0 = place the jitter attenuator on the receive side

1 = place the jitter attenuator on the transmit side

HBE I

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)

L0/L1/L2 I

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).

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PIN I/O FUNCTION

CES I

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

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

TPD I

Transmit Power-Down

0 = normal transmitter operation

1 = powers down the transmitter and tri-states TTIP and TRING pins

TX0/TX1 I

Transmit Data Source Select Bits 0 and 1. These inputs determine the source of the transmit

data (Table 4-B).

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

MM0/MM1 I

Monitor Mode Select Bits 0 and 1. These inputs determine if the receive equalizer is in a monitor

mode (Table 4-D).

RT1/RT0 I

Receive LIU Termination Select Bits 0 and 1. These inputs determine the receive termination

(Table 4-E).

TEST I

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.

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

default state.

MCLK I

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. A T1 1.544MHz

clock source is optional (Note 1). See Table 4-F for details.

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

EGL1–EGL4 I

Receive Equalizer Gain-Limit Select. These bits control the sensitivity of the receive equalizers

(Table 4-C).

PBEO1–PBEO4 O

PRBS Bit-Error Output. The receiver constantly searches for a 215 - 1 PRBS (ETS = 0) or a

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 positive-

going pulse (with same period as E1 or T1 clock) synchronous with RCLK.

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

RTIP1–RTIP4 I

RRING1–RRING4 I

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.

BPCLK1–BPCLK4 O Backplane Clock. A 16.384MHz clock output that is referenced to RCLK.

TTIP1–TTIP4

TRING1–TRING4 O Transmit Tip and Ring. Analog line-driver outputs. These pins connect through a step-up

transformer to the line. See Section 7 for details.

RPOS1–RPOS4 O

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.

RNEG1–RNEG4 O

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.

RCLK1–RCLK4 O

Receive Clock. Buffered recovered clock from the line. Synchronous to MCLK in absence of

signal at RTIP and RRING.

TPOS1–TPOS4 I

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.

TNEG1–TNEG4 I

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.

TCLK1–TCLK4 I

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.

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

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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 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 75Ω, 100Ω, and 120Ω 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.

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 75Ω/100Ω/120Ω 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 analog-

received 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.

DS21448 3.3V T1/E1/J1 Quad Line Interface

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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

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

PRBS TPRBSE 0 1

TPOS and TNEG — 0 0

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 INTERNAL RECEIVE

TERMINATION CONFIGURATION

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

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Table 4-F. MCLK Selection in Hardware Mode

MCLK (MHz) JAMUX ETS

2.048 0 0

2.048 1 1

1.544 0 1

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

Figure 4-2, 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 CS input low and ends with CS going inactive. CS

must go inactive between data transfers. See the serial bus timing information in Section 10 for details. All data

transfers are terminated if the port’s CS input transitions high. Port control logic is disabled, and SDO is tri-stated

when all CS pins are inactive.

Reading from or writing to the internal registers requires writing one address/command byte prior to the transferring

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 mode-

enable 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

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.

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

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

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

1 2 3 4 5 6 78910 11 12 13 14 15 16

5 0 B

D1 D2 D3 D4 D5 D6

SCLK

SDI

SDO

(LSB) (MSB)

(

LSB

)

(MSB)

READ ACCESS ENABLED

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

OCES = 1 (UPDATE SDO ON RISING EDGE OF SCLK)

1 2 3 4 5 6 78910 11 12 13 14 15 16

5 0 B

D1 D2 D3 D4 D5 D6

SCLK

SDI

SDO

(LSB) (MSB)

(

LSB

)

(MSB)

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

OCES = 0 (UPDATE SDO ON FALLING EDGE OF SCLK)

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

OCES = 0 (UPDATE SDO ON FALLING EDGE OF SCLK)

1 2 3 4 5 6 78910 11 12 13 14 15 16

5 0 B

D1 D2 D3 D4 D5 D6

SCLK

SDI

SDO

(LSB) (MSB)

(LSB)

(MSB)

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

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

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)

OCES = 1 (UPDATE SDO ON RISING EDGE OF SCLK)

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

5 0 B

SCLK

SDI

SDO

(LSB) (MSB)

D1 D2 D3 D4 D5 D6 D0 D7

1 2 3 4 5 6 78910 11 12 13 14 15 16SCLK

5 0 B

(MSB)

SDI

SDO

D1 D2 D3 D4 D5 D7

(LSB) (MSB)

DO D6

(LSB)

WRITE ACCESS ENABLED

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

5 0 B

(MSB)

SDI

SDO

D1 D2 D3 D4 D5 D7

(LSB) (MSB)

DO D6

(LSB)

WRITE ACCESS ENABLED

ICES = 0

(

SAMPLE SDI ON THE RISING EDGE OF SCLK

)

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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 (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 HRST low (level triggered) or by powering

down and powering up again.

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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4.3.3 Control Registers

CCR1 (00H): Common Control Register 1

(MSB)

(LSB)

ETS NRZE RCLA ECUE JAMUX TTOJ TTOR LOTCMC

NAME POSITION FUNCTION

ETS CCR1.7

E1/T1 Select

0 = E1

1 = T1

NRZE CCR1.6

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

RCLA CCR1.5

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

ECUE CCR1.4

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 for details.

JAMUX CCR1.3

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)

TTOJ CCR1.2

TCLK to JACLK. Internally connects TCLK to JACLK (Figure 1-3).

0 = disabled

1 = enabled

TTOR CCR1.1

TCLK to RCLK. Internally connects TCLK to RCLK (Figure 1-3).

0 = disabled

1 = enabled

LOTCMC CCR1.0

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

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CCR2 (01H): Common Control Register 2

(MSB)

(LSB)

RLPIN — SCLD CLDS RHBE THBE TCES RCES

NAME POSITION FUNCTION

RLPIN CCR2.7

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 5µs

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

SCLD CCR2.5

Short Circuit-Limit Disable (ETS = 0). Controls the 50mA (RMS) current limiter.

0 = enable 50mA current limiter

1 = disable 50mA current limiter

CLDS CCR2.4

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 ≠ 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.

RHBE CCR2.3

Receive HDB3/B8ZS Enable

0 = enable HDB3 (E1)/B8ZS (T1)

1 = disable HDB3 (E1)/B8ZS (T1)

THBE CCR2.2

Transmit HDB3/B8ZS Enable

0 = enable HDB3 (E1)/B8ZS (T1)

1 = disable HDB3 (E1)/B8ZS (T1)

TCES CCR2.1

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

RCES CCR2.0

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

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CCR3 (02H): Common Control Register 3

(MSB)

(LSB)

TUA1 ATUA1 TAOZ TPRBSE TLCE LIRST IBPV IBE

NAME POSITION FUNCTION

TUA1 CCR3.7

Transmit Unframed All Ones. The polarity of this bit is set such that the device transmits an all-

ones 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

ATUA1 CCR3.6

Automatic Transmit Unframed All Ones. Automatically transmit an unframed all-ones pattern at

TTIP and TRING during an RCL condition.

0 = disabled

1 = enabled

TAOZ CCR3.5

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

TPRBSE CCR3.4

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

0 = disabled

1 = enabled

TLCE CCR3.3

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

LIRST CCR3.2

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.

IBPV CCR3.1

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).

IBE CCR3.0

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).

CCR4 (03H): Common Control Register 4

(MSB)

(LSB)

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

Jitter Attenuator Path Select

0 = place the jitter attenuator on the receive side

1 = place the jitter attenuator on the transmit side

JABDS CCR4.2

Jitter Attenuator Buffer Depth Select

0 = 128 bits

1 = 32 bits (use for delay-sensitive applications)

DJA CCR4.1

Disable Jitter Attenuator

0 = jitter attenuator enabled

1 = jitter attenuator disabled

TPD CCR4.0

Transmit Power-Down

0 = normal transmitter operation

1 = powers down the transmitter and tri-states the TTIP and TRING pins

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Table 4-I. Receive Sensitivity Settings

EGL

(CCR4.4)

ETS

(CCR1.7)

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)

CCR5 (04H): Common Control Register 5

(MSB)

(LSB)

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

Receive Synchronization Clock Enable

0 = disable 2.048MHz synchronization receive mode

1 = enable 2.048MHz synchronization receive mode

TSCLKE CCR5.2

Transmit Synchronization Clock Enable

0 = disable 2.048MHz transmit synchronization clock

1 = enable 2.048MHz transmit synchronization clock

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.

Table 4-J. Backplane Clock Select

BPCS1

(CCR5.7)

BPCS0

(CCR5.6) BPCLK FREQUENCY (MHz)

0 0 16.384

0 1 8.192

1 0 4.096

1 1 2.048

Table 4-K. Monitor Gain Settings

MM1

(CCR5.5)

MM0

(CCR5.4)

INTERNAL LINEAR GAIN

BOOST (dB)

0 0 Normal operation (no boost)

0 1 20

1 0 26

1 1 32

Table 4-L. Internal Rx Termination Select

RT1

(CCR5.1)

RT0

(CCR5.0)

INTERNAL RECEIVE

TERMINATION CONFIGURATION

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

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CCR6 (05H): Common Control Register 6

(MSB)

(LSB)

LLB RLB ARLBE ALB RJAB ECRS2 ECRS1 ECRS0

NAME POSITION FUNCTION

LLB CCR6.7

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 for details.

0 = loopback disabled

1 = loopback enabled

RLB CCR6.6

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 for details.

0 = loopback disabled

1 = loopback enabled

ARLBE CCR6.5

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).

ALB CCR6.4

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 for more details.

0 = loopback disabled

1 = loopback enabled

RJAB CCR6.3

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 for details.

0 = disabled

1 = enabled

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.

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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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 INT pin low

whenever they change state (i.e., go active or inactive). The INT pin is allowed to return high (if no other interrupts

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)

(LSB)

— — — — 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

LIU4 Status Register. A 1 in this bit position indicates that the status register (SR) in channel 4 is

asserting an interrupt.

LIU3 2

LIU3 Status Register. A 1 in this bit position indicates that the status register (SR) in channel 3 is

asserting an interrupt.

LIU2 1

LIU2 Status Register. A 1 in this bit position indicates that the status register (SR) in channel 2 is

asserting an interrupt.

LIU1 0

LIU1 Status Register. A 1 in this bit position indicates that the status register (SR) in channel 1 is

asserting an interrupt.

SR (06H): Status Register

(MSB)

(LSB)

LUP LDN LOTC RUA1 RCL TCLE TOCD PRBSD

NAME POSITION FUNCTION

LUP

(Latched) SR.7 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 for details.

LDN

(Latched) SR.6 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 for details.

LOTC

(Real Time) SR.5 Loss-of-Transmit Clock. This bit is set when the TCLK pin has not transitioned for 5µs (±2µs),

forcing the LOTC pin high.

RUA1

(Latched) SR.4 Receive Unframed All Ones. This bit is set when an unframed all-ones code is received at RRING

and RTIP (Table 5-A).

RCL

(Latched) SR.3 Receive Carrier Loss. This bit is set when an RCL condition exists at RRING and RTIP. See

(Table 5-A) for details.

TCLE

(Real Time) SR.2 Transmit Current-Limit Exceeded. This bit is set when the 50mA (RMS) current limiter is activated

whether or not the current limiter is enabled.

TOCD

(Real Time) SR.1 Transmit Open-Circuit Detect. This bit is set when the device detects that the TTIP and TRING

outputs are open circuited.

PRBSD

(Real Time) SR.0 PRBS Detect. This bit is set when the receive side detects a 215 - 1 (E1) or a QRSS (T1)

pseudorandom bit sequence (PRBS).

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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

Over a 3ms window, five or fewer 0s are

received.

Over a 3ms window, six or more 0s are

received.

RCL

(Note 1) E1 255 (or 2048) consecutive 0s received

(G.775) (Note 2)

In 255-bit times, at least 32 1s are

received.

RCL

(Note 1) T1 192 (or 1544) consecutive 0s are received

(Note 2)

14 or more 1s out of 112 possible bit

positions are received, starting with the

first 1 received.

Note 1: RCL is also known as a loss of signal (LOS) or Red Alarm in T1.

Note 2: See CCR1.5 for details.

IMR (07H): Interrupt Mask Register

(MSB)

(LSB)

LUP LDN LOTC RUA1 RCL TCLE TOCD PRBSD

NAME POSITION FUNCTION

LUP IMR.7

Loop-Up Code Detected

0 = interrupt masked

1 = interrupt enabled

LDN IMR.6

Loop-Down Code Detected

0 = interrupt masked

1 = interrupt enabled

LOTC IMR.5

Loss-of-Transmit Clock

0 = interrupt masked

1 = interrupt enabled

RUA1 IMR.4

Receive Unframed All Ones

0 = interrupt masked

1 = interrupt enabled

RCL IMR.3

Receive Carrier Loss

0 = interrupt masked

1 = interrupt enabled

TCLE IMR.2

Transmit Current-Limiter Exceeded

0 = interrupt masked

1 = interrupt enabled

TOCD IMR.1

Transmit Open-Circuit Detect

0 = interrupt masked

1 = interrupt enabled

PRBSD IMR.0

PRBS Detection

0 = interrupt masked

1 = interrupt enabled

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RIR1 (08H): Receive Information Register 1

(MSB)

(LSB)

ZD 16ZD HBD RCLC RUA1C JALT — —

NAME POSITION FUNCTION

(Latched) RIR1.7

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

consecutive 0s (regardless of the length of the string) have been received. This bit is cleared

when read.

16ZD

(latched) RIR1.6 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.

HBD

(Latched) RIR1.5

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.

RCLC

(Latched) RIR1.4 RCL Clear. Set when the RCL alarm has met the clear criteria defined in Table 5-A. This bit

is cleared when read.

RUA1C

(Latched) RIR1.3 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).

JALT

(Latched) RIR1.2

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.

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

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

RIR2 (09H): Receive Information Register 2

(MSB)

(LSB)

RL3 RL2 RL1 RL0 — — ARLB SEC

NAME POSITION FUNCTION

RL3

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

RL2

(Real Time) RIR2.6 Receive Level Bit 2 (Table 5-B)

RL1

(Real Time) RIR2.5 Receive Level Bit 1 (Table 5-B)

RL0

(Real Time) RIR2.4 Receive Level Bit 0 (Table 5-B)

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) RIR2.1

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

disabled (CCR6.5 = 0).

SEC

(Latched) RIR2.0 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.

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Table 5-B. Receive Level Indication

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

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

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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 10-2. The code

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.

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

(MSB)

(LSB)

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)

D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0D0

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Table 6-A. Transmit Code Length

TC1 TC0

LENGTH SELECTED

(BITS)

0 0 5

0 1 6/3

1 0 7

1 1 16/8/4/2/1

Table 6-B. Receive Code Length

RUP2/RDN2 RUP1/RDN1 RUP0/RDN0 LENGTH SELECTED

(BITS)

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)

(LSB)

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)

(LSB)

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

DS21448 3.3V T1/E1/J1 Quad Line Interface

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

(MSB)

(LSB)

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.

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

(MSB)

(LSB)

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

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

(MSB)

(LSB)

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.

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

(MSB)

(LSB)

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

DS21448 3.3V T1/E1/J1 Quad Line Interface

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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 for more details.

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.

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 user-

selectable 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.

DS21448 3.3V T1/E1/J1 Quad Line Interface

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Table 6-C. Definition of Received Errors

ERROR E1 OR T1 DEFINITION OF RECEIVED ERRORS

BPV E1/T1

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.

CV E1

When HDB3 is enabled (CCR2.3 = 0) and the receiver detects two consecutive BPVs with the same

polarity. ITU-T O.161.

EXZ E1 When four or more consecutive zeros are detected.

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

1999.

EXZ T1

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

T1.403 1999.

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

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

E1 or T1

(CCR1.7)

ECRS2

(CCR6.2)

ECRS1

(CCR6.1)

ECRS0

(CCR6.0)

RHBE

(CCR2.3)

FUNCTION OF ECR COUNTERS/RNEG

(Note 1)

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.

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)

(LSB)

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.

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 for details on

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.

DS21448 3.3V T1/E1/J1 Quad Line Interface

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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 75Ω E1 applications) through a 1:1 transformer. See Table 7-C for transformer details.

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 75Ω, 100Ω, or 120Ω receive

termination by setting the RT1 (CCR5.1) and RT0 (CCR5.0) bits. When using the internal termination feature, the

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

be set to 0, and both Rr resistors (Figure 7-1) should be 37.5Ω, 50Ω, or 60Ω 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) is internally multiplied by 16

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 for more details. If the jitter

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 for more details.

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 for more

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

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 for details. Because of the transmitter’s design, very little jitter (less than 0.005UIP-P broadband from

DS21448 3.3V T1/E1/J1 Quad Line Interface

34 of 60

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 120UIP-P (buffer depth is 128

bits) or 28UIP-P (buffer depth is 32 bits), the DS21448 divides the internal nominal 32.768MHz (E1) or 24.704MHz

(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 Rt (Ω)

0 0 0 75Ω normal 1:2 N.M. 0

0 0 1 120Ω normal 1:2 N.M. 0

1 0 0 75Ω with high return loss 1:2 21dB 6.2

1 0 1 120Ω with high return loss 1:2 21dB 11.6

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

L2 L1 L0 APPLICATION N RETURN LOSS Rt (Ω)

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.

DS21448 3.3V T1/E1/J1 Quad Line Interface

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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 Rt (Ω)

0 0 0 75Ω normal 0.8:1:1CT N.M. 0

0 0 1 120Ω normal 0.8:1:1CT N.M. 0

1 0 0 75Ω with high return loss 0.8:1:1CT 21dB 11.6

1 0 1 120Ω with high return loss 0.8:1:1CT 21dB 11.6

Note: See Figure 7-4.

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

SPECIFICATION RECOMMENDED VALUE

Turns Ratio 1:1 (receive) and 1:2 (transmit) ±2%

Primary Inductance 600µH (min)

Leakage Inductance 1.0µH (max)

Interwinding Capacitance 40pF (max)

TRANSMIT TRANSFORMER DC RESISTANCE

Primary (Device Side)

Secondary

1.0Ω (max)

1.5Ω (max)

RECEIVE TRANSFORMER DC RESISTANCE

Primary (Device Side)

Secondary

1.2Ω (max)

DS21448 3.3V T1/E1/J1 Quad Line Interface

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Figure 7-1. Basic Interface

NOTE 1: ALL RESISTOR VALUES ARE ±1%.

NOTE 2: IN E1 APPLICATIONS, THE RT RESISTORS ARE USED TO INCREASE THE TRANSMITTER RETURN LOSS

(Table 7-A). NO RETURN LOSS IS REQUIRED FOR T1 APPLICATIONS.

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

FEATURE IS DISABLED, RR = 37.5Ω FOR 75Ω OR 60Ω FOR 120Ω E1 SYSTEMS, OR 50Ω FOR 100Ω T1 LINES.

NOTE 4: SEE Table 7-A AND Table 7-B FOR THE APPROPRIATE TRANSMIT TRANSFORMER TURNS RATIO (N).

VDD

VSS

TTIP

TRING

RTIP

RRING

VDD

VSS

0.01µF 0.01

0.1µF

F0.1µF

0.1

1.0

(NONPOLARIZED)

2:1

(LARGER WINDING

TOWARD THE NETWORK)

1:1

TRANSMIT LINE

RECEIVE LINE

MCLK 2.048MHz

(THIS CAN ALSO BE 1.544MHz

FOR T1 ONLY OPERATION)

Dallas

Semiconducto

DS21448

DS21448 3.3V T1/E1/J1 Quad Line Interface

37 of 60

Figure 7-2. Protected Interface Using Internal Receive Termination

VDD

VSS

TTIP

TRING

RTIP

RRING

Dallas

Semiconducto

DS21448

VDD

VSS

0.01µF 0.01µF

0.1µF

F0.1µF

0.1

S S

1.0

(NONPOLARIZED)

FUSE

2:1

(LARGER WINDING TOWARD

THE NETWORK)

1:1

TRANSMIT

LINE

RECEIVE

LINE

MCLK 2.048MHz

(THIS CAN ALSO BE 1.544MHz

FOR T1 ONLY OPERATION)

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

FOR T1 APPLICATIONS.

NOTE 5: THE 68µF IS USED TO KEEP THE LOCAL POWER PLANE POTENTIAL WITHIN TOLERANCE DURING A SURGE.

NOTE 6: REFER TO

PPLICATION NOTE 324 FOR SIDACTOR AND FUSE DETAILS.

DS21448 3.3V T1/E1/J1 Quad Line Interface

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Figure 7-3. Protected Interface Using External Receive Termination

VDD

VSS

TTIP

TRING

RTIP

RRING

Dallas

Semiconducto

DS21448

VDD

VSS

0.01µF 0.01µF

0.1µF

F0.1µF

S S

1.0

(NONPOLARIZED)

FUSE

2:1

(LARGER WINDING TOWARD

THE NETWORK)

TRANSMIT

LINE

MCLK 2.048MHz

(THIS CAN ALSO BE 1.544MHz

FOR T1 ONLY OPERATION)

0.1

FUSE

FUSE 1:1

RECEIVE

LINE

470

r Rr

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: Rr = 37.5Ω FOR 75Ω OR 60Ω FOR 120Ω E1 SYSTEMS, OR 50Ω FOR 100Ω T1 LINES.

NOTE 5: THE RT RESISTORS ARE USED TO INCREASE THE TRANSMITTER RETURN LOSS (Table 7-A). NO RETURN LOSS IS REQUIRED FOR

T1 APPLICATIONS.

NOTE 6: THE 68µF 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.

DS21448 3.3V T1/E1/J1 Quad Line Interface

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

VDD

VSS

TTIP

TRING

RTIP

RRING

Dallas

Semiconductor

DS21448

VDD

VSS

0.01µF 0.01

0.1µF

10µF0.1µF

1.0

MCLK 2.048MHz (THIS CAN ALSO

BE 1.544MHz FOR T1 ONLY

OPERATION)

0.1

60 60

FUSE

BALANCED LINE

(100Ω/120Ω)

UNBALANCED

LINE (75Ω)

FUSE 0.22µF

0.22

FUSE

FUSE 0.22µF

0.22

0.8:1:1CT

51.1

BALANCED LINE

(100Ω/120Ω)

UNBALANCED

LINE (75Ω)

1:1

0.8:1

1.6:1

2:1

0.8:1:1CT

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

FOR T1 APPLICATIONS.

NOTE 6: THE 68

F IS USED TO KEEP THE LOCAL POWER PLANE POTENTIAL WITHIN TOLERANCE DURING A SURGE.

DS21448 3.3V T1/E1/J1 Quad Line Interface

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Figure 7-5. E1 Transmit Pulse Template

-0.1

-0.2

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

TIME (ns)

SCALED AMPLITUDE

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

269ns

194ns

219ns

(IN 75Ω SYSTEMS, 1.0 ON THE SCALE = 2.37VPEAK in 120Ω SYSTEMS, 1.0 ON

THE SCALE = 3.00VPEAK)

G.703

TEMPLATE

DS21448 3.3V T1/E1/J1 Quad Line Interface

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Figure 7-6. T1 Transmit Pulse Template

-0.1

-0.2

-0.3

-0.4

-0.5

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

-500 -300 -100 0300 500 700 -400 -200 200 400 600100

TIME (ns)

NORMALIZED AMPLITUDE

T1.102/87, T1.403,

CB 119 (OCT ‘79), AND

I.431 TEMPLATE

-0.77

-0.39

-0.27

-0.12

0.00

0.27

0.35

0.93

1.16

-500

-255

-175

-75

175

225

600

750

0.05

0.80

1.15

1.05

-0.07

0.05

-0.77

-0.23

-0.15

0.00

0.15

0.23

0.46

0.66

0.93

1.16

-500

-150

-100

100

150

300

430

600

750

-0.05

0.50

0.95

0.90

0.50

-0.45

-0.20

-0.05

UI Time

mp.

MAXIMUM CURVE

UI Time

mp.

MINIMUM CURVE

DS21448 3.3V T1/E1/J1 Quad Line Interface

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Figure 7-7. Jitter Tolerance

Figure 7-8. Jitter Attenuation

FREQUENCY (Hz)

UNIT INTERVALS (UIP-P)

100

0.1

10 100 1k 10k 100k

DS21448 TOLERANCE

TR 62411 (DEC ‘90)

ITU-T G.823

FREQUENCY (Hz)

-20

-40

-60

1 10 100 1k 10k

JITTER ATTENUATION (dB)

100k

TR 62411 (DEC 90)

PROHIBITED AREA

ITU G.7XX

PROHIBITED AREA

TBR12

PROHIBITED

REA

T1E1

CURVE B

CURVE A

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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). The DS21448

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

Bypass Register

Boundary Scan Register

Device Identification Register

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

Section 1 for details. Details on Boundary Scan Architecture and the Test Access Port can be found in IEEE

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

Figure 8-1. JTAG Block Diagram

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.

JTDI JTMS JTCLK

JTRST JTDO

TEST ACCESS PORT

CONTROLLER

VDD VDD VDD

BOUNDRY SCAN

BYPASS

INSTRUCTION

IDENTIFICATION

MUX

SELECT

OUTPUT ENABLE

10kΩ 10kΩ 10k

Ω

DS21448 3.3V T1/E1/J1 Quad Line Interface

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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 pause-

DR 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.

Select

DR-Scan

Capture DR

Shift DR

Exit DR

Pause DR

Exit2 DR

Update DR

Select

IR-Scan

Capture IR

Shift IR

Exit IR

Pause IR

Exit2 IR

Update IR

Test Logic

Reset

Run Test/

Idle

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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

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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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 capture-

DR 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

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. Table 8-C lists

the device ID code for the SCT devices.

Table 8-B. ID Code Structure

MSB LSB

Version

(Contact Factory) Device ID JEDEC 1

4 bits 16 bits 00010100001 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 for more information about bit usage.

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 all cell bit locations and definitions.

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Table 8-D. Boundary Scan Control Bits

BIT BGA LQFP NAME I/O

— 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 CS2 I

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 CS3 I

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

PIN BIT

BGA LQFP

NAME I/O

(Note 1) — BUScntl —

56 G12 66 A0 I

42 H1 92

WR (R/W) I

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

RD (DS) I

11 J3 18 CS1 I

— 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

(Note 2) —

INTcntl —

38 K9 97 INT I/O

28 K10 114 CS4 I

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

HRST I

— 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

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BIT BGA LQFP NAME I/O

— M6 45 JTDI I

— M7 46 JTDO O

55 M8 68 BIS1 I

— M9 104 TVDD4 —

PIN BIT

BGA LQFP

NAME I/O

10 M10 25 RNEG4 O

61 — — ADRScntl —

66 M11 55 TPOS4 I

34 M12 108 PBTS I

Note 1: 0 = Dn/ADn are inputs; 1 = Dn/ADn are outputs.

Note 2: 0 = INT is an input; 1 = INT is an output.

9. OPERATING PARAMETERS

ABSOLUTE MAXIMUM RATINGS

Voltage Range on Any Pin Relative to Ground -1.0V to +6.0V

Operating Temperature Range for DS21448TN -40°C to +85°C

Storage Temperature Range -55°C to +125°C

Soldering Temperature See IPC/JEDEC J-STD-020 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 reliability.

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 COUT 7 pF

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

µA

Output Leakage ILO (Note 3) +1.0 µA

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 < VIN < VDD.

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 30Ω load, for an all-ones data density.

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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 tCYC 200 ns

Pulse Width, DS Low or RD High PWEL 100 ns

Pulse Width, DS High or RD Low PWEH 100 ns

Input Rise/Fall Times tR, tF 20 ns

R/W Hold Time tRWH 10 ns

R/W Setup Time Before DS High tRWS 50 ns

CS Setup Time Before DS, WR, or RD Active tCS 20 ns

CS Hold Time tCH 0 ns

Read Data Hold Time tDHR 10 50 ns

Write Data Hold Time tDHW 5 ns

Muxed Address Valid to AS or ALE Fall tASL 15 ns

Muxed Address Hold Time tAHL 10 ns

Delay Time DS, WR, or RD to AS or ALE Rise tASD 20 ns

Pulse Width AS or ALE High PWASH 30 ns

Delay Time, AS or ALE to DS, WR, or RD tASED 10 ns

Output Data Delay Time from DS or RD tDDR 20 80 ns

Data Setup Time tDSW 50 ns

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

ASH

tCYC

ASD

ASD PW

AHL

ASL

ASED

AD0–AD7

DHR

tDDR

ALE

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

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

ASH

tCYC

ASD

ASD PW

AHL DSW

DHW

ASL

ASED

AD0–AD7

ALE

HL tCS

DSW

DHW

tCH

DDR DHR

RWH

SED PWEH

tRWS

EL tCYC

D0–AD7

(WRITE)

D0–AD7

(READ)

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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 t1 0 ns

Setup Time for CS Active to Either RD,

WR, or DS Active t2 0 ns

Delay Time from Either RD or DS Active

to Data Valid t3 75 ns

Hold Time from Either RD, WR, or DS

Inactive to CS Inactive t4 0 ns

Hold Time from CS Inactive to Data Bus

Tri-State t5 5.0 20 ns

Wait Time from Either WR or DS Active to

Latch Data t6 75 ns

Data Setup Time to Either WR or DS

Inactive t7 10 ns

Data Hold Time from Either WR or DS

Inactive t8 10 ns

Address Hold from Either WR or DS

Inactive t9 10 ns

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

ADDRESS VALID

DATA VALID

A0–A4

D0–D7

0ns (MIN)

75ns (MAX)

0ns (MIN)

5ns (MIN) / 20ns (MAX)

t2 t3 t4

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

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

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

ADDRESS VALID

A0–A4

D0–D7

0ns (MIN)

75ns (MIN)

0ns (MIN)

10ns

(MIN)

10ns

(MIN)

t2 t6 t4

t7 t8

ADDRESS VALID

DATA VALID

A0–A4

D0–D7

0ns (MIN)

75ns (MAX)

0ns (MIN)

5ns (MIN) / 20ns (MAX)

t2 t3 t4

ADDRESS VALID

A0–A4

D0–D7

0ns (MIN)

75ns (MIN)

0ns (MIN)

10ns

(MIN)

10ns

(MIN)

t2 t6 t4

t7 t8

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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 tCSS 50 ns

Setup Time SDI to SCLK tSSS 50 ns

Hold Time SCLK to SDI tSSH 50 ns

SCLK High/Low Time tSLH 200 ns

SCLK Rise/Fall Time tSRF 50 ns

SCLK to CS Inactive tLSC 50 ns

CS Inactive Time tCM 250 ns

SCLK to SDO Valid tSSV 50 ns

SCLK to SDO Tri-State tSST 100 ns

CS Inactive to SDO Tri-State tCSH 100 ns

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

SCLK

(Note 1)

SCLK

(Note 2)

SDI

HIGH-Z

SDO

CSS

SSS t

SSH

tSRF tSLH tLSC

tSSV tSST

CSH

HIGH-Z

LSB

LSB MSB

MSB

NOTE 1: OCES =1 AND ICES = 0.

NOTE 2: OCES = 0 AND ICES = 1.

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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

(Note 1) 488

RCLK Period tCP (Note 2) 648 ns

tCH

RCLK Pulse Width tCL (Note 3) 200

tCH

RCLK Pulse Width tCL (Note 4) 150

Delay RCLK to RPOS, RNEG,

PBEO, RBPV Valid tDD 50.0 ns

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.

Figure 10-9. Receive-Side Timing

RPOS, RNEG

RCLK

(Note 2)

tCP

RCLK

(Note 1)

PBEO

BIT

ERROR

BPV/

EXZ/

PRBS DETECTOR OUT OF SYNC

RNEG

(Note 3)

BPV/

EXZ/

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).

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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

(Note 5) 488

TCLK Period tCP (Note 6) 648 ns

tCH 75

TCLK Pulse Width tCL 75 ns

TPOS/TNEG Setup to TCLK

Falling or Rising tSU 20 ns

TPOS/TNEG Hold from TCLK

Falling or Rising tHD 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

t F

TPOS, TNEG

tCH

tHD

tSU

TCLK

(Note 1)

TCLK

(Note 2)

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

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

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11. PIN CONFIGURATIONS

11.1 144-Pin TE-PBGA

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

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

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

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

D TVSS2 TVDD2 CS2 D2/

AD2

D0/

AD0 BPCLK2 RCL/

LOTC2 VDD3 VSS3 CS3 RPOS3 TNEG3

E RPOS2 RNEG2 D3/

AD3 VDD2 N.C. N.C. N.C. N.C. TVSS3 PEBO3 RCLK3 TPOS3

F RCLK2 TPOS2 D1/

AD1 VSS2 N.C. N.C. N.C. N.C. RCL/

LOTC3 BPCLK3 RNEG3 TCLK3

G TPOS1 RNEG1 PEBO2 N.C. N.C. N.C. N.C. N.C. TVDD3 N.C. D5/

AD5 A0

H WR

(R/W) TNEG1 RCLK1 BPCLK1 N.C. N.C. N.C. N.C. VSS4 D6/

AD6

A2/

OCES A1

J SCLK RD

(DS) CS1 TVSS1 TVDD1 MCLK RCL/

LOTC4 VDD4 D4/

AD4

D7/

AD7 N.C. N.C.

K A4/

SDO

ALE

(AS) SDI RPOS1 PEBO1 N.C. TXDIS/

TEST PEBO4 INT CS4 RPOS4 TNEG4

L A3/

ICES TCLK2 JTRST N.C. VDD1 RCL/

LOTC1 BIS0 BPCLK4 HRST TVSS4 RCLK4 TCLK4

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

DS21448 3.3V T1/E1/J1 Quad Line Interface

57 of 60

11.2 128-Pin LQFP

RCL3/LOTC3

RCL4/LOTC4

VSM

N.C.

TTIP1

TVSS1

TVDD1

TRING1

RPOS1

RNEG1

RPOS2

RNEG2

RPOS3

RNEG3

RPOS4

TCLK1

S1/

EGL1

VDD2

10 20 30

VDD2

VSS2

RNEG4

VSS2

TPOS1

TNEG1

RTIP2

TPOS2

RRING2

RCLK2

TNEG2

TPOS3

SCLK/L2

TNEG3

SDI/L1

TTIP2

N.C.

TVSS2

TVDD2

TRING2

JTRST

TCLK2

708090 100

110

120

JTCLK

JTDI

JTDO

BPCLK2

JTMS

VDD3

VSS3

TPOS4

BPCLK3

S2/EGL2

RCLK3

TNEG4

RTIP3

RRING3

4/SD0/L0

3/ICES/DJA

2/OCES/JAMUX

1/JAS

0/HBE

N.C.

BIS1

N.C.

TTIP3

TVSS3

TVDD3

TRING3

D7/AD7/CES

D6/AD6/TPD

D5/AD5/TX0

D4/AD4/TX1

D3/AD3/LOOP0

D2/AD2/LOOP1

D1/AD1/MM0

D0/AD0/MM1

TCLK3

/EGL3

VDD4

VSS4

(

)/ETS

(R/

)/NRZE

RTIP4

RRING4

ALE (AS)/SCLKE

RCLK4

NT/

RT1

TXDIS/TEST

N.C.

TTIP4

TVSS4

TVDD4

TRING4

RST

BIS0

PBTS/RT0

MCLK

PBEO1

PBEO2

BPCLK4

TCLK4

/EGL4

VDD1

VSS1

PBEO3

BPCLK1

PBEO4

RTIP1

RRING1

RCL1/LOTC1

RCLK1

RCL2/LOTC2

Dallas Semiconductor

DS21448

DS21448 3.3V T1/E1/J1 Quad Line Interface

58 of 60

12. PACKAGE INFORMATION

(The package drawing(s) in this data sheet may not reflect the most current specifications. The package number provided for

each package is a link to the latest package outline information.)

12.1 144-Ball TE-PBGA (56-G6020-001)

DS21448 3.3V T1/E1/J1 Quad Line Interface

59 of 60

12.2 128-Pin LQFP (56-G4011-001)

DS21448 3.3V T1/E1/J1 Quad Line Interface

60 of 60

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.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

The Maxim logo is a registered trademark of Maxim Integrated Products, Inc. The Dallas logo is a registered trademark of Dallas Semiconductor.

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 (θJA) in Still Air (Note 2) +24

°C/W

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

FORCED AIR (m/s) THETA-JA (θJA)

0 24°C/W

1 21°C/W

2.5 19°C/W

Table 13-C. Thermal Characteristics—LQFP

PARAMETER MIN TYP MAX UNITS

Ambient Temperature (Note 1) -40 +85 °C

Junction Temperature +125 °C

Theta-JA (θJA) in Still Air (Note 2) +27.8 °C/W

Theta-JC (θJC) in Still Air (Note 3) +0.1

°C/W

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

FORCED AIR (m/s) THETA-JA (θJA)

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

Note 3: While Theta-JC (θJC) is commonly used as the thermal parameter that provides a correlation between the junction temperature (Tj) and

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.

14. REVISION HISTORY

REVISION DESCRIPTION

042303 New product release.

012104

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.

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.

113004 In the Absolute Maximum Ratings section, added range for storage temperature and changed

soldering temperature from IPC JEDEC J-STD-020A to J-STD-020.

011206 Added lead-free packages to Ordering Information table.

ENGLISH • ???? • ??? • ???

WHAT'S NEW

PRODUCTS

SOLUTIONS

DESIGN

APPNOTES

SUPPORT

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MEMBERS

DS21448

Part Number Table

Notes:

See the DS21448 QuickView Data Sheet for further information on this product family or download the

DS21448 full data sheet (PDF, 836kB).

Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.2.

Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually

within one business day.

Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: See

full data sheet or Part Naming Conventions.

* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the

product uses.

Part Number

Free

Sample

Buy

Direct

Package:

TYPE PINS SIZE

DRAWING CODE/VAR *

Temp

RoHS/Lead-Free?

Materials Analysis

DS21448L+W

LQFP;128 pin;787

Dwg: 21-0086D (PDF)

Use pkgcode/variation: C128L+3*

0C to +70C

RoHS/Lead-Free: Yes

Materials Analysis

DS21448L

LQFP;128 pin;787

Dwg: 21-0086D (PDF)

Use pkgcode/variation: C128L-3*

0C to +70C

RoHS/Lead-Free: No

Materials Analysis

DS21448L+

LQFP;128 pin;787

Dwg: 21-0086D (PDF)

Use pkgcode/variation: C128L+3*

0C to +70C

RoHS/Lead-Free: Yes

Materials Analysis

DS21448LN

LQFP;128 pin;787

Dwg: 21-0086D (PDF)

Use pkgcode/variation: C128L-3*

-40C to +85C

RoHS/Lead-Free: No

Materials Analysis

DS21448LN+

LQFP;128 pin;787

Dwg: 21-0086D (PDF)

Use pkgcode/variation: C128L+3*

-40C to +85C

RoHS/Lead-Free: Yes

Materials Analysis

DS21448

TEBGAQ;144 pin;669

Dwg: 56-G6020-001A (PDF)

Use pkgcode/variation: V144T-1*

0C to +70C

RoHS/Lead-Free: No

DS21448A1

TEBGAQ;144 pin;669

Dwg: 56-G6020-001A (PDF)

Use pkgcode/variation: V144T-1*

0C to +70C

RoHS/Lead-Free: No

Didn't Find What You Need?

DS21448N

TEBGAQ;144 pin;669

Dwg: 56-G6020-001A (PDF)

Use pkgcode/variation: V144T-1*

-40C to +85C

RoHS/Lead-Free: No

Didn't Find What You Need?

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