Rainbow Electronics DS2154 User Manual

Download

DS2154

PRELIMINARY

DS2154

Enhanced E1 Single Chip Transceiver

FEATURES

• Complete E1(CEPT) PCM–30/ISDN–PRI transceiver

functionality

• Onboard long and short haul line interface for clock/

data recovery and waveshaping

• 32–bit or 128–bit crystal–less jitter attenuator

• Generates line build outs for both 120Ω and 75Ω lines

• Frames to FAS, CAS, and CRC4 formats

• Dual onboard two–frame elastic store slip buffers that

can connect to asynchronous backplanes up to

8.192 MHz

• 8–bit parallel control port that can be used directly on

either multiplexed or non–multiplexed buses

• Extracts and inserts CAS signaling

• Detects and generates Remote and AIS alarms

• Programmable output clocks for Fractional E1, H0,

and H12 applications

• Fully independent transmit and receive functionality

• Full access to both Si and Sa bits aligned with CRC

multiframe

• Four separate loopbacks for testing functions

PACKAGE OUTLINE

100

ORDERING INFORMATION

DS2154L (0°C to 70°C) DS2154LN (–40°C to +85°C)

• Large counters for bipolar and code violations, CRC4

codeword errors, FAS errors, and E bits

• Pin compatible with DS2152 T1 Enhanced Single–

Chip Transceiver

• 5V supply; low power CMOS

• 100–pin 14mm

DESCRIPTION

The DS2154 Enhanced Single–Chip Transceiver (ESCT) contains all of the necessary functions for connection to E1 lines. The device is an upward compatible version of the DS2153 Single–Chip Transceiver. The onboard clock/data recovery circuitry coverts the AMI/

Copyright 1997 by Dallas Semiconductor Corporation. All Rights Reserved. For important information regarding patents and other intellectual property rights, please refer to Dallas Semiconductor data books.

body LQFP package

HDB3 E1 waveforms to a NRZ serial stream. The DS2154 automatically adjusts to E1 22AWG (0.6 mm) twisted–pair cables from 0 to over 2km in length. The device can generate the necessary G.703 waveshapes for both 75 ohm coax and 120 ohm twisted cables. The

031197 1/69

DS2154

onboard jitter attenuator (selectable to either 32 bits or 128 bits) can be placed in either the transmit or receive

G.704, G.706, G.823, G.932, and I.431 as well as ETS

300 011, 300 233, and 300 166. data paths. The framer locates the frame and multiframe boundaries and monitors the data stream for alarms. It is also used for extracting and inserting signaling data, Si, and Sa bit information. The device contains a set of internal registers which the user can access and control the operation of the unit. Quick access via the parallel control port allows a single controller to handle many E1 lines. The device fully meets

1.0 INTRODUCTION

The DS2154 is a super–set version of the popular

DS2153 E1 Single–Chip Transceiver offering the new

features listed below. All of the original features of the

DS2153 have been retained and software created for

the original devices is transferrable into the DS2154. all of the latest E1 specifications including ITU G.703,

NEW FEATURE

SECTION

Option for non–multiplexed bus operation 1 and 2 Crystal–less jitter attenuation 12 Additional hardware signaling capability including:

Receive signaling reinsertion to a backplane multiframe sync Availability of signaling in a separate PCM data stream Signaling freezing

Interrupt generated on change of signaling data Improved receive sensitivity: 0 dB to –43 dB 12 Per–channel code insertion in both transmit and receive paths 8 Expanded access to Sa and Si bits 11 RCL, RLOS, RRA, and RAIS alarms now interrupt on change of state 4

8.192 MHz clock synthesizer 1 Per–channel loopback 8 Addition of hardware pins to indicate carrier loss and signaling freeze 1 Line interface function can be completely decoupled from the framer/formatter to

allow:

Interface to optical, HDSL, and other NRZ interfaces

“tap” the transmit and receive bipolar data streams for monitoring purposes

Be able corrupt data and insert framing errors, CRC errors, etc. Transmit and receive elastic stores now have independent backplane clocks 1 Ability to monitor one DS0 channel in both the transmit and receive paths 6 Access to the data streams in between the framer/formatter and the elastic stores 1 AIS generation in the line interface that is independent of loopbacks 1 and 3 Transmit current limiter to meet the 50 mA short circuit requirement 12 Option to extend carrier loss criteria to a 1 ms period as per ETS 300 233 3 Automatic RAI generation to ETS 300 011 specifications 3

031197 2/69

DS2154 ENHANCED E1 SINGLE–CHIP TRANSCEIVER Figure 1–1

LOTC

RCL

RCLK

RLOS

8MCLK

RLINK

RLCLK

RCHBLK

RCHCLK

RSIGF

RSIG

RSER

RSYSCLK

RSYNC

RMSYNC

RFSYNC

RDATA

TSYNC

TDATA

TESO

TSSYNC

TSYSCLK

TSER

TSIG

SIGNALING

HARDWARE

STORE

ELASTIC

CLOCK

DATA

SYNC

SA INSERTION

HDB3 ENCODE

LIU AIS

WAVE–

SHAPING

LINE

DRIVERS

RPOSI

RCLKI

RNEGI

RNEGO

RCLKO

RPOSO

8XCLK

XTALD

MCLK

SYNTHESIZER

8.182 MHz CLOCK

16.384 MHz

CLOCK/

CRYSTAL

INTERFACE

POWER

CONNECTIONS

BUFFER

SIGNALING

TIMING

CONTROL

Sa EXTRACTION

PER–CHANNEL CODE INSERT

FRAMER

RECEIVE SIDE

LIUCMUX

MHz

2.048

VCO / PLL

SYNC

SA AND SI EXTRACTION

SIGNALING EXTRACTION

E–BIT COUNTER

FAS ERROR COUNTER

CRC ERROR COUNTER

ALARM DETECTION

SYNCHRONIZER

BPV COUNTER

HDB3 DECODER

32.768 MHz CLOCK/DATA

RECOVERY

PEAK

DETECT

EQUALIZER

SYNC CONTROL

STORE

ELASTIC

CLOCK

DATA

PER–CHANNEL CODE INSERT

SIDE

TRANSMIT

FORMATTER

PER–CHANNEL LOOPBACK

FRAMER LOOPBACK

REMOTE LOOPBACK

JITTER ATTENUA TION

(CAN BE PLACED IN EITHER

TRANSMIT OR RECEIVE PATH)

LOCAL LOOPBACK

FAS WORD INSERTION

SI BIT INSERTION E–BIT INSERTION

SIGNALING INSERTION

CRC4 GENERAITON

AIS GENERAITON

GENERATION

INSERTION

LOTCMUX

TCLK

TCHBLK

TCHCLK

TLINK

STIMING CONTROL

MUX

(ROUTED TO ALL BLOCKS)

PARALLEL AND TEST CONTROL PORT

TLCLK

Sa INSERTION

LIUC

TPOSO TCLKO TNEGO

TNEGI TCLKI TPOSI

INT D0 to D7/

AD0 to AD7

MUX A0 to A6 ALE(AS)/A7 RD WR(R/W) BTS CS TEST

DS2154

(DS)

RVDD

TVDD

DVDD

RVSS

TVSS

DVSS

RRING

RTIP

TRING

TTIP

031197 3/69

DS2154

FUNCTIONAL DESCRIPTION

The analog AMI/HDB3 waveform off of the E1 line is transformer coupled into the RRING and RTIP pins of the DS2154. The device recovers clock and data from the analog signal and passes it through the jitter attenuation mux to the receive side framer where the digital serial stream is analyzed to locate the framing/multiframe pattern. The DS2154 contains an active filter that reconstructs the analog received signal for the non–linear losses that occur in transmission. The device has a usable receive sensitivity of 0 dB to –43 dB which allows the device to operate on cables over 2km in length. The receive side framer locates the FAS frame and CRC and CAS multiframe boundaries as well as detects incoming alarms including, carrier loss, loss of synchronization, AIS, and Remote Alarm. If needed, the receive side elastic store can be enabled in order to absorb the phase and frequency differences between the recovered E1 data stream and an asynchronous backplane clock which is provided at the RSYSCLK input. The clock applied at the RSYSCLK input can be either a

2.048 MHz clock or a 1.544 MHz clock. The RSYSCLK can also be a bursty clock with speeds up to 8.192 MHz.

The transmit side of the DS2154 is totally independent from the receive side in both the clock requirements and characteristics. Data off of a backplane can be passed through a transmit side elastic store if necessary. The

transmit formatter will provide the necessary frame/multiframe data overhead for E1 transmission. Once the data stream has been prepared for transmission, it is sent via the jitter attenuation mux to the waveshaping and line driver functions. The DS2154 will drive the E1 line from the TTIP and TRING pins via a coupling transformer. The line driver can handle both 75Ω and 120Ω lines and it has options for high return loss applications. The line driver contains a current limiter that will restrict the maximum current into a 1Ω load to less than 50 mA (rms).

READER’S NOTE

This data sheet assumes a particular nomenclature of the E1 operating environment. There are 32 eight–bit timeslots in an E1 systems which are number 0 to 31. Timeslot 0 is transmitted first and received first. These 32 timeslots are also referred to as channels with a numbering scheme of 1 to 32. Timeslot 0 is identical to channel 1, timeslot 1 is identical to Channel 2, and so on. Each timeslot (or channel) is made up of eight bits which are numbered 1 to 8. Bit number 1 is the MSB and is transmitted first. Bit number 8 is the LSB and is transmitted last. Throughout this data sheet, the following abbreviations will be used:

FAS Frame Alignment Sig-

CRC4 Cyclical Redundancy

nal

CAS Channel Associated

CCS Common Channel

Signaling MF Multiframe Sa Additional bits Si International bits E–bit CRC4 Error bits

PIN LIST Table 1–1

PIN SYMBOL TYPE DESCRIPTION

1 RCHBLK O Receive Channel Block. 2 NC – No Connect. 3 8MCLK O 8.192 MHz Clock. 4 NC – No Connect. 5 NC – No Connect. 6 RCL O Receive Carrier Loss. 7 NC – No Connect. 8 NC – No Connect.

031197 4/69

Check

Signaling

PIN DESCRIPTIONTYPESYMBOL

9 NC – No Connect. 10 NC – No Connect. 11 BTS I Bus Type Select. 12 LIUC I Line Interface Connect. 13 8XCLK O Eight Times Clock. 14 TEST I Test. 15 NC – No Connect. 16 RTIP I Receive Analog T ip Input. 17 RRING I Receive Analog Ring Input. 18 RVDD – Receive Analog Positive Supply. 19 RVSS – Receive Analog Signal Ground. 20 RVSS – Receive Analog Signal Ground. 21 MCLK I Master Clock Input. 22 XT ALD O Quartz Crystal Driver. 23 NC – No Connect. 24 RVSS – Receive Analog Signal Ground. 25 INT O Interrupt. 26 NC – No Connect. 27 NC – No Connect. 28 NC – No Connect. 29 TTIP O Transmit Analog T ip Output. 30 TVSS – Transmit Analog Signal Ground. 31 TVDD – Transmit Analog Positive Supply. 32 TRING O T ransmit Analog Ring Output. 33 TCHBLK O Transmit Channel Block. 34 TLCLK O Transmit Link Clock. 35 TLINK I Transmit Link Data. 36 NC – No Connect. 37 TSYNC I/O Transmit Sync. 38 TPOSI I Transmit Positive Data Input. 39 TNEGI I Transmit Negative Data Input. 40 TCLKI I Transmit Clock Input. 41 TCLKO O Transmit Clock Output. 42 TNEGO O Transmit Negative Data Output. 43 TPOSO O Transmit Positive Data Output.

DS2154

031197 5/69

DS2154

PIN DESCRIPTIONTYPESYMBOL

44 DVDD – Digital Positive Supply. 45 DVSS – Digital Signal Ground. 46 TCLK I Transmit Clock. 47 TSER I Transmit Serial Data. 48 TSIG I Transmit Signaling Input. 49 TESO O Transmit Elastic Store Output. 50 TDATA I Transmit Data. 51 TSYSCLK I Transmit System Clock. 52 TSSYNC I Transmit System Sync. 53 TCHCLK O Transmit Channel Clock. 54 NC – No Connect. 55 MUX I Bus Operation. 56 D0/AD0 I/O Data Bus Bit 0 / Address/Data Bus Bit 0. 57 D1/AD1 I/O Data Bus Bit 1 / Address/Data Bus Bit 1. 58 D2/AD2 I/O Data Bus Bit 2 / Address/Data Bus Bit 2. 59 D3/AD3 I/O Data Bus Bit 3 / Address/Data Bus Bit 3. 60 DVSS – Digital Signal Ground. 61 DVDD – Digital Positive Supply. 62 D4/AD4 I/O Data Bus Bit 4 / Address/Data Bus Bit 4. 63 D5/AD5 I/O Data Bus Bit 5 / Address/Data Bus Bit 5. 64 D6/AD6 I/O Data Bus Bit 6 / Address/Data Bus Bit 6. 65 D7/AD7 I/O Data Bus Bit 7 / Address/Data Bus Bit 7. 66 A0 I Address Bus Bit 0. 67 A1 I Address Bus Bit 1. 68 A2 I Address Bus Bit 2. 69 A3 I Address Bus Bit 3. 70 A4 I Address Bus Bit 4. 71 A5 I Address Bus Bit 5. 72 A6 I Address Bus Bit 6. 73 A7/ALE I Address Bus Bit 7 / Address Latch Enable. 74 RD (DS) I Read Input (Data Strobe). 75 CS I Chip Select. 76 NC – No Connect. 77 WR (R/W) I Write Input (Read/Write). 78 RLINK O Receive Link Data.

031197 6/69

PIN DESCRIPTIONTYPESYMBOL

79 RLCLK O Receive Link Clock. 80 DVSS – Digital SIgnal Ground. 81 DVDD – Digital Positive Supply. 82 RCLK O Receive Clock. 83 DVDD – Digital Positive Supply. 84 DVSS – Digital Signal Ground. 85 RDATA O Receive Data. 86 RPOSI I Receive Positive Data Input. 87 RNEGI I Receive Negative Data Input. 88 RCLKI I Receive Clock Input. 89 RCLKO O Receive Clock Output. 90 RNEGO O Receive Negative Data Output. 91 RPOSO O Receive Positive Data Output. 92 RCHCLK O Receive Channel Clock. 93 RSIGF O Receive Signaling Freeze Output. 94 RSIG O Receive Signaling Output. 95 RSER O Receive Serial Data. 96 RMSYNC O Receive Multiframe Sync. 97 RFSYNC O Receive Frame Sync. 98 RSYNC I/O Receive Sync. 99 RLOS/LOTC O Receive Loss Of Sync / Loss Of Transmit Clock.

100 RSYSCLK I Receive System Clock.

DS2154

NOTE:

Leave all no connect (NC) pins open circuited.

DS2154 PIN DESCRIPTION Table 1–2 TRANSMIT SIDE DIGITAL PINS

Transmit Clock [TCLK]. A 2.048 MHz primary clock.

Used to clock data through the transmit side formatter. Must be present for the parallel control port to operate properly. If not present, the Loss Of Transmit Clock (LOTC) function can provide a clock.

Transmit Serial Data [TSER]. Transmit NRZ serial data. Sampled on the falling edge of TCLK when the transmit side elastic store is disabled. Sampled on the falling edge of TSYSCLK when the transmit side elastic store is enabled.

Transmit Channel Clock [TCHCLK]. A 256 KHz clock which pulses high during the LSB of each channel. Synchronous with TCLK when the transmit side elastic store is disabled. Synchronous with TSYSCLK when the transmit side elastic store is enabled. Useful for parallel to serial conversion of channel data.

Transmit Channel Block [TCHBLK]. A user programmable output that can be forced high or low during any of the 32 E1 channels. Synchronous with TCLK when the transmit side elastic store is disabled. Synchronous with TSYSCLK when the transmit side elastic store is

031197 7/69

DS2154

enabled. Useful for blocking clocks to a serial UART or LAPD controller in applications where not all E1 channels are used such as Fractional E1, 384K bps (H0), 768K bps, 1920K bps (H12) or ISDN–PRI. Also useful for locating individual channels in drop–and–insert applications, for external per–channel loopback, and for per–channel conditioning. See Section 9 for details.

Transmit System Clock [TSYSCLK]. 1.544 MHz or

2.048 MHz clock. Only used when the transmit side elastic store function is enabled. Should be tied low in applications that do not use the transmit side elastic store. Can be burst at rates up to 8.192 MHz.

Transmit Link Clock [TLCLK]. 4 KHz to 20 KHz demand clock (Sa bits) for the TLINK input. See Section 11 for details.

Transmit Link Data [TLINK]. If enabled, this pin will be sampled on the falling edge of TCLK for data insertion into any combination of the Sa bit positions (Sa4 to Sa8). See Section 11 for details.

Transmit Sync [TSYNC]. A pulse at this pin will establish either frame or multiframe boundaries for the transmit side. This pin can also be programmed to output either a frame or multiframe pulse. Always synchronous with TCLK.

Transmit Frame Sync [TSSYNC]. Only used when the transmit side elastic store is enabled. A pulse at this pin will establish either frame or multiframe boundaries for the transmit side. Should be tied low in applications that do not use the transmit side elastic store. Always synchronous with TSYSCLK.

Transmit Data [TDATA]. Sampled on the falling edge of TCLK with data to be clocked through the transmit side formatter. This pin is normally tied to TESO.

Transmit Positive Data Output [TPOSO]. Updated on the rising edge of TCLKO with the bipolar data out of the transmit side formatter. Can be programmed to source NRZ data via the Output Data Format (TCR1.7) control bit. This pin is normally tied to TPOSI.

Transmit Negative Data Output [TNEGO]. Updated on the rising edge of TCLKO with the bipolar data out of the transmit side formatter . This pin is normally tied to TNEGI.

Transmit Clock Output [TCLKO]. Buf fered clock that is used to clock data through the transmit side formatter (i.e. either TCLK or RCLKO if Loss Of Transmit Clock is enabled and in effect or RCLKI if remote loopback is enabled). This pin is normally tied to TCLKI.

Transmit Positive Data Input [TPOSI]. Sampled on the falling edge of TCLKI for data to be transmitted out onto the E1 line. Can be internally connected to TPOSO by tying the LIUC pin high.

Transmit Negative Data Input [TNEGI]. Sampled on the falling edge of TCLKI for data to be transmitted out onto the E1 line. Can be internally connected to TNEGO by tying the LIUC pin high.

Transmit Clock Input [TCLKI]. Line interface transmit clock. Can be internally connected to TCLKO by tying the LIUC pin high.

Transmit Signaling Input [TSIG]. When enabled, this input will be sample signaling bits for reinsertion into outgoing PCM E1 data stream. Sampled on the falling edge of TCLK when the transmit side elastic store is disabled. Sampled on the falling edge of TSYSCLK when the transmit side elastic store is enabled. See Section 13 for timing examples.

Transmit Elastic Store Data Output [TESO].

Updated on the rising edge of TCLK with data out of the the transmit side elastic store whether the elastic store is enabled or not. This pin is normally tied to TDATA.

031197 8/69

RECEIVE SIDE DIGITAL PINS

Receive Link Data [RLINK]. Updated with the full

recovered E1 data stream on the rising edge of RCLK.

Receive Link Clock [RLCLK]. 4 KHz to 20 KHz clock (Sa bits) for the RLINK output. See Section 11 for details.

Receive Clock [RCLK]. 2.048 MHz clock that is used to clock data through the receive side framer.

DS2154

Receive Channel Clock [RCHCLK]. 256 KHz clock which pulses high during the LSB of each channel. Synchronous with RCLK when the receive side elastic store is disabled. Synchronous with RSYSCLK when the receive side elastic store is enabled. Useful for parallel to serial conversion of channel data.

Receive Channel Block [RCHBLK]. A user programmable output that can be forced high or low during any of the 32 E1 channels. Synchronous with RCLK when the receive side elastic store is disabled. Synchronous with RSYSCLK when the receive side elastic store is enabled. Useful for blocking clocks to a serial UART or LAPD controller in applications where not all E1 channels are used such as Fractional E1, 384K bps service, 768K bps, or ISDN–PRI. Also useful for locating individual channels in drop–and–insert applications, for external per–channel loopback, and for per–channel conditioning. See Section 9 for details.

Receive Serial Data [RSER]. Received NRZ serial data. Updated on rising edges of RCLK when the receive side elastic store is disabled. Updated on the rising edges of RSYSCLK when the receive side elastic store is enabled.

Receive Sync [RSYNC]. An extracted pulse, one RCLK wide, is output at this pin which identifies either frame or CAS/CRC multiframe boundaries. If the receive side elastic store is enabled, then this pin can be enabled to be an input at which a frame or multiframe boundary pulse synchronous with RSYSCLK is applied.

Receive Frame Sync [RFSYNC]. An extracted 8 KHz pulse, one RCLK wide, is output at this pin which identifies frame boundaries.

Receive Multiframe Sync [RMSYNC]. Only used when the receive side elastic store is enabled. An extracted pulse, one RSYSCLK wide, is output at this pin which identifies multiframe boundaries. If the receive side elastic store is disabled, then this output will output multiframe boundaries associated with RCLK.

Receive Data [RDA T A]. Updated on the rising edge of RCLK with the data out of the receive side framer.

Receive System Clock [RSYSCLK]. 1.544 MHz or

2.048 MHz clock. Only used when the elastic store function is enabled. Should be tied low in applications

that do not use the elastic store. Can be burst at rates up to 8.192 MHz.

Receive Signaling Output [RSIG]. Outputs signaling bits in a PCM format. Updated on rising edges of RCLK when the receive side elastic store is disabled. Updated on the rising edges of RSYSCLK when the receive side elastic store is enabled. See Section 13 for timing examples.

Receive Loss of Sync / Loss of Transmit Clock [RLOS/LOTC]. A dual function output that is controlled

by the TCR2.0 control bit. This pin can be programmed to either toggle high when the synchronizer is searching for the frame and multiframe or to toggle high if the TCLK pin has not been toggled for 5 µs.

Receive Carrier Loss [RCL]. Set high when the line interface detects a loss of carrier. [Note: a test mode exists to allow the DS2154 to detect carrier loss at RPOSI and RNEGI in place of detection at RTIP and RRING].

Receive Signaling Freeze [RSIGF]. Set high when the signaling data is frozen via either automatic or manual intervention. Used to alert downstream equipment of the condition.

8 MHz Clock [8MCLK]. 8.192 MHz output clock that is referenced to the clock that is output at the RCLK pin.

Receive Positive Data Output [RPOSO]. Updated on the rising edge of RCLKO with the bipolar data out of the line interface. This pin is normally tied to RPOSI.

Receive Negative Data Output [RNEGO]. Updated on the rising edge of RCLKO with the bipolar data out of the line interface. This pin is normally tied to RNEGI.

Receive Clock Output [RCLKO]. Buffered recovered clock from the E1 line. This pin is normally tied to RCLKI.

Receive Positive Data Input [RPOSI]. Sampled on the falling edge of RCLKI for data to be clocked through the receive side framer. RPOSI and RNEGI can be tied together for a NRZ interface. Can be internally connected to RPOSO by tying the LIUC pin high.

031197 9/69

DS2154

Receive Negative Data Input [RNEGI]. Sampled on the falling edge of RCLKI for data to be clocked through the receive side framer. RPOSI and RNEGI can be tied together for a NRZ interface. Can be internally connected to RNEGO by tying the LIUC pin high.

Receive Clock Input [RCLKI]. Clock used to clock data through the receive side framer. This pin is normally tied to RCLKO. Can be internally connected to RCLKO by tying the LIUC pin high. RCLKI must be present for the parallel control port to operate properly.

PARALLEL CONTROL PORT PINS

Interrupt [INT]. Flags host controller during conditions

and change of conditions defined in the Status Registers 1 and 2. Active low, open drain output.

3–State Control [Test]. Set high to 3–state all output and I/O pins (including the parallel control port). Set low for normal operation. Useful in board level testing.

Bus Operation [MUX]. Set low to select non–multiplexed bus operation. Set high to select multiplexed bus operation.

Data Bus [D0 to D7] or Address/Data Bus [AD0 to AD7]. In non–multiplexed bus operation (MUX=0),

serves as the data bus. In multiplexed bus operation (MUX=1), serves as a 8–bit multiplexed address / data bus.

Address Bus [A0 to A6]. In non–multiplexed bus operation (MUX=0), serves as the address bus. In multiplexed bus operation (MUX=1), these pins are not used and should be tied low.

serves as the upper address bit. In multiplexed bus operation (MUX=1), serves to demultiplex the bus on a positive–going edge.

Write Input [WR] (Read/Write [R/W]). WR is an active low signal.

LINE INTERFACE PINS

Master Clock Input [MCLK]. 2.048 MHz (± 50 ppm)

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 quartz crystal of 2.048 MHz may be applied across MCLK and XTALD instead of the TTL level clock source.

Quartz Crystal Driver [XTALD]. A quartz crystal of

2.048 MHz may be applied across MCLK and XTALD instead of a TTL level clock source at MCLK. Leave open circuited if a TTL clock source is applied at MCLK.

Eight Times Clock [8XCLK]. 16.384 MHz clock that is frequency locked to the 2.048 MHz clock provided from the clock/data recovery block (if the jitter attenuator is enabled on the receive side) or from the TCLKI pin (if the jitter attenuator is enabled on the transmit side). Can be internally disabled via the TEST2 register if not needed.

Line Interface Connect [LIUC]. Tie low to separate the line interface circuitry from the framer/formatter circuitry and activate the TPOSI/TNEGI/TCLKI/RPOSI/RNEGI/ RCLKI pins. Tie high to connect the the line interface circuitry to the framer/formatter circuitry and deactivate the TPOSI/TNEGI/TCLKI/RPOSI/RNEGI/RCLKI pins. When LIUC is tied high, the TPOSI/TNEGI/TCLKI/ RPOSI/RNEGI/RCLKI pins should be tied low.

Bus Type Select [BTS]. Strap high to select Motorola bus timing; strap low to select Intel bus timing. This pin controls the function of the RD\(DS), ALE(AS), and WR\(R/W\) pins. If BTS=1, then these pins assume the function listed in parenthesis ().

Read Input [RD] (Data Strobe [DS]). RD and DS are active low signals.

Chip Select [CS]. Must be low to read or write to the device. CS is an active low signal.

A7 or Address Latch Enable [ALE] (Address Strobe [AS]). In non–multiplexed bus operation (MUX=0),

031197 10/69

Receive Tip and Ring [RTIP and RRING]. Analog inputs for clock recovery circuitry. These pins connect via a 1:1 transformer to either the E1 line. See Section 12 for an example.

Transmit T ip and Ring [TTIP and TRING]. Analog line driver outputs. These pins connect via a 1:1.15 or 1:1.36 step–up transformer to the E1 line. See Section 12 for an example.

SUPPLY PINS

Digital Positive Supply [DVDD]. 5.0 volts ± 5%.

Should be tied to the RVDD and TVDD pins.

DS2154

Receive Analog Positive Supply [RVDD]. 5.0 volts ± 5%. Should be tied to the DVDD and TVDD pins.

Transmit Analog Positive Supply [TVDD]. 5.0 volts ± 5%. Should be tied to the RVDD and DVDD pins.

Receive Analog Signal Ground [RVSS]. 0.0 volts. Should be tied to the DVSS and TVSS pins.

Transmit Analog Ground [TVSS]. 0.0 volts. Should be tied to the RVSS and DVSS pins.

Digital Signal Ground [DVSS]. 0.0 volts. Should be tied to the RVSS and TVSS pins.

DS2154 REGISTER MAP Table 1–3

ADDRESS R/W REGISTER NAME REGISTER ABBREVIATION

00 R BPV or Code Violation Count 1. VCR1 01 R BPV or Code Violation Count 2. VCR2 02 R CRC4 Error Count 1 / FAS Error Count 1. CRCCR1 03 R CRC4 Error Count 2. CRCCR2 04 R E–Bit Count 1 / FAS Error Count 2. EBCR1 05 R E–Bit Count 2. EBCR2 06 R/W Status 1. SR1 07 R/W Status 2. SR2 08 R/W Receive Information. RIR 09 – not present. – 0A – not present. – 0B – not present. – 0C – not present. – 0D – not present. – 0E – not present. – 0F R Device ID Register . IDR 10 R/W Receive Control 1. RCR1

11 R/W Receive Control 2. RCR2 12 R/W Transmit Control 1. TCR1 13 R/W Transmit Control 2. TCR2 14 R/W Common Control 1. CCR1 15 R/W Test 1. TEST1 (set to 00h) 16 R/W Interrupt Mask 1. IMR1 17 R/W Interrupt Mask 2. IMR2 18 R/W Line Interface Control. LICR 19 R/W Test 2. TEST2 (set to 00h)

031197 11/69

DS2154

ADDRESS REGISTER ABBREVIATIONREGISTER NAMER/W

1A R/W Common Control 2. CCR2 1B R/W Common Control 3. CCR3 1C R/W Transmit Sa Bit Control. TSaCR 1D R/W Not present. – 1E R Synchronizer Status. SSR 1F R Receive Non–Align Frame. RNAF 20 R/W T ransmit Align Frame. TAF 21 R/W T ransmit Non–Align Frame. TNAF 22 R/W T ransmit Channel Blocking 1. TCBR1 23 R/W T ransmit Channel Blocking 2. TCBR2 24 R/W T ransmit Channel Blocking 3. TCBR3 25 R/W T ransmit Channel Blocking 4. TCBR4 26 R/W Transmit Idle 1. TIR1 27 R/W Transmit Idle 2. TIR2 28 R/W Transmit Idle 3. TIR3 29 R/W Transmit Idle 4. TIR4 2A R/W Transmit Idle Definition. TIDR 2B R/W Receive Channel Blocking 1. RCBR1 2C R/W Receive Channel Blocking 2. RCBR2 2D R/W Receive Channel Blocking 3. RCBR3 2E R/W Receive Channel Blocking 4. RCBR4 2F R Receive Align Frame. RAF 30 R Receive Signaling 1. RS1 31 R Receive Signaling 2. RS2 32 R Receive Signaling 3. RS3 33 R Receive Signaling 4. RS4 34 R Receive Signaling 5. RS5 35 R Receive Signaling 6. RS6 36 R Receive Signaling 7. RS7 37 R Receive Signaling 8. RS8 38 R Receive Signaling 9. RS9 39 R Receive Signaling 10. RS10 3A R Receive Signaling 11. RS11

031197 12/69

ADDRESS REGISTER ABBREVIATIONREGISTER NAMER/W

3B R Receive Signaling 12. RS12 3C R Receive Signaling 13. RS13 3D R Receive Signaling 14. RS14 3E R Receive Signaling 15. RS15 3F R Receive Signaling 16. RS16 40 R/W T ransmit Signaling 1. TS1 41 R/W T ransmit Signaling 2. TS2 42 R/W T ransmit Signaling 3. TS3 43 R/W T ransmit Signaling 4. TS4 44 R/W T ransmit Signaling 5. TS5 45 R/W T ransmit Signaling 6. TS6 46 R/W T ransmit Signaling 7. TS7 47 R/W T ransmit Signaling 8. TS8 48 R/W T ransmit Signaling 9. TS9 48 R/W T ransmit Signaling 10. TS10 4A R/W Transmit Signaling 11. TS11 4B R/W Transmit Signaling 12. TS12 4C R/W Transmit Signaling 13. TS13 4D R/W Transmit Signaling 14. TS14 4E R/W Transmit Signaling 15. TS15 4F R/W Transmit Signaling 16. TS16 50 R/W Transmit Si Bits Align Frame. TSiAF 51 R/W Transmit Si Bits Non–Align Frame. TSiNAF 52 R/W Transmit Remote Alarm Bits. TRA 53 R/W Transmit Sa4 Bits. TSa4 54 R/W Transmit Sa5 Bits. TSa5 55 R/W Transmit Sa6 Bits. TSa6 56 R/W Transmit Sa7 Bits. TSa7 57 R/W Transmit Sa8 Bits. TSa8 58 R Receive Si Bits Align Frame. RSiAF 59 R Receive Si Bits Non–Align Frame. RSiNAF 5A R Receive Remote Alarm Bits. RRA 5B R Receive Sa4 Bits. RSa4

DS2154

031197 13/69

DS2154

ADDRESS REGISTER ABBREVIATIONREGISTER NAMER/W

5C R Receive Sa5 Bits. RSa5 5D R Receive Sa6 Bits. RSa6 5E R Receive Sa7 Bits. RSa7 5F R Receive Sa8 Bits. RSa8 60 R/W T ransmit Channel 1. TC1 61 R/W T ransmit Channel 2. TC2 62 R/W T ransmit Channel 3. TC3 63 R/W T ransmit Channel 4. TC4 64 R/W T ransmit Channel 5. TC5 65 R/W T ransmit Channel 6. TC6 66 R/W T ransmit Channel 7. TC7 67 R/W T ransmit Channel 8. TC8 68 R/W T ransmit Channel 9. TC9 69 R/W T ransmit Channel 10. TC10 6A R/W Transmit Channel 11. TC11 6B R/W Transmit Channel 12. TC12 6C R/W Transmit Channel 13. TC13 6D R/W Transmit Channel 14. TC14 6E R/W Transmit Channel 15. TC15 6F R/W Transmit Channel 16. TC16 70 R/W T ransmit Channel 17. TC17 71 R/W T ransmit Channel 18. TC18 72 R/W T ransmit Channel 19. TC19 73 R/W T ransmit Channel 20. TC20 74 R/W T ransmit Channel 21. TC21 75 R/W T ransmit Channel 22. TC22 76 R/W T ransmit Channel 23. TC23 77 R/W T ransmit Channel 24. TC24 78 R/W T ransmit Channel 25. TC25 79 R/W T ransmit Channel 26. TC26 7A R/W Transmit Channel 27. TC27 7B R/W Transmit Channel 28. TC28 7C R/W Transmit Channel 29. TC29

031197 14/69

ADDRESS REGISTER ABBREVIATIONREGISTER NAMER/W

7D R/W Transmit Channel 30. TC30 7E R/W Transmit Channel 31. TC31 7F R/W Transmit Channel 32. TC32 80 R/W Receive Channel 1. RC1 81 R/W Receive Channel 2. RC2 82 R/W Receive Channel 3. RC3 83 R/W Receive Channel 4. RC4 84 R/W Receive Channel 5. RC5 85 R/W Receive Channel 6. RC6 86 R/W Receive Channel 7. RC7 87 R/W Receive Channel 8. RC8 88 R/W Receive Channel 9. RC9 89 R/W Receive Channel 10. RC10 8A R/W Receive Channel 11. RC11 8B R/W Receive Channel 12. RC12 8C R/W Receive Channel 13. RC13 8D R/W Receive Channel 14. RC14 8E R/W Receive Channel 15. RC15 8F R/W Receive Channel 16. RC16 90 R/W Receive Channel 17. RC17 91 R/W Receive Channel 18. RC18 92 R/W Receive Channel 19. RC19 93 R/W Receive Channel 20. RC20 94 R/W Receive Channel 21. RC21 95 R/W Receive Channel 22. RC22 96 R/W Receive Channel 23. RC23 97 R/W Receive Channel 24. RC24 98 R/W Receive Channel 25. RC25 99 R/W Receive Channel 26. RC26 9A R/W Receive Channel 27. RC27 9B R/W Receive Channel 28. RC28 9C R/W Receive Channel 29. RC29 9D R/W Receive Channel 30. RC30

DS2154

031197 15/69

DS2154

ADDRESS REGISTER ABBREVIATIONREGISTER NAMER/W

9E R/W Receive Channel 31. RC31 9F R/W Receive Channel 32. RC32 A0 R/W Transmit Channel Control 1. TCC1 A1 R/W Transmit Channel Control 2. TCC2 A2 R/W Transmit Channel Control 3. TCC3 A3 R/W Transmit Channel Control 4. TCC4 A4 R/W Receive Channel Control 1. RCC1 A5 R/W Receive Channel Control 2. RCC2 A6 R/W Receive Channel Control 3. RCC3 A7 R/W Receive Channel Control 4. RCC4 A8 R/W Common Control 4. CCR4 A9 R T ransmit DS0 Monitor. TDS0M AA R/W Common Control 5. CCR5 AB R Receive DS0 Monitor. RDS0M AC R/W Test 3. TEST3 (set to 00h) AD R/W Not Used. (set to 00h) AE R/W Not Used. (set to 00h) AF R/W Not Used. (set to 00h)

NOTES:

1. T est Registers 1, 2, and 3 are used only by the factory; these registers must be cleared (set to all zeros) on power–up initialization to insure proper operation.

2. Register banks Bxh, Cxh, Dxh, Exh, and Fxh are not accessible.

2.0 PARALLEL PORT

The DS2154 is controlled via either a non–multiplexed (MUX=0) or a multiplexed (MUX=1) bus by an external microcontroller or microprocessor. The DS2154 can operate with either Intel or Motorola bus timing configurations. If the BTS pin is tied low, Intel timing will be selected; if tied high, Motorola timing will be selected. All Motorola bus signals are listed in parenthesis (). See the timing diagrams in the A.C. Electrical Characteristics in Section 14 for more details.

3.0 CONTROL, ID AND TEST REGISTERS

The operation of the DS2154 is configured via a set of nine control registers. Typically, the control registers are only accessed when the system is first powered up. Once the DS2154 has been initialized, the control registers will only need to be accessed when there is a change in the system configuration. There are two

Receive Control Register (RCR1 and RCR2), two Transmit Control Registers (TCR1 and TCR2), and five Common Control Registers (CCR1 to CCR5). Each of the nine registers are described in this section.

There is a device IDentification Register (IDR) at address 0FH. The MSB of this read–only register is fixed to a one indicating that the DS2154 is present. The pin–for–pin compatible T1 version of the DS2154 also has an ID register at address 0FH and the user can read the MSB to determine which chip is present since in the DS2154 the MSB will be set to a one and in the DS2152 it will be set to a zero. The lower four bits of the IDR are used to display the die revision of the chip.

The T est Registers at addresses 15, 19, and AC hex are used by the factory in testing the DS2154. On power– up, the T est Registers should be set to 00 hex in order for the DS2154 to operate properly.

031197 16/69

IDR: DEVICE IDENTIFICATION REGISTER (Address= 0F Hex)

(MSB) (LSB)

T1E1 0 0 0 ID3 ID2 ID1 ID0

SYMBOL POSITION NAME AND DESCRIPTION

T1E1 IDR.7 T1 or E1 Chip Determination Bit.

0=T1 chip 1=E1 chip

ID3 IDR.3 Chip Revision Bit 3. MSB of a decimal code that represents the chip revi-

sion. ID2 IDR.1 Chip Revision Bit 2. ID1 IDR.2 Chip Revision Bit 1. ID0 IDR.0 Chip Revision Bit 0. LSB of a decimal code that represents the chip revi-

sion.

RCR1: RECEIVE CONTROL REGISTER 1 (Address=10 Hex)

(MSB) (LSB)

RSMF

SYMBOL POSITION NAME AND DESCRIPTION

RSMF RCR1.7 RSYNC Multiframe Function. Only used if the RSYNC pin is pro-

RSM RCR1.6 RSYNC Mode Select.

RSIO RCR1.5 RSYNC I/O Select. (note: this bit must be set to zero when RCR2.1=0).

– RCR1.4 Not Assigned. Should be set to zero when written. – RCR1.3 Not Assigned. Should be set to zero when written.

FRC RCR1.2 Frame Resync Criteria.

SYNCE RCR1.1 Sync Enable.

RESYNC RCR1.0 Resync. When toggled from low to high, a resync is initiated. Must be

RSM RSIO – – FRC SYNCE RESYNC

grammed in the multiframe mode (RCR1.6=1).

0=RSYNC outputs CAS multiframe boundaries

1=RSYNC outputs CRC4 multiframe boundaries

0=frame mode (see the timing in Section 13)

1=multiframe mode (see the timing in Section 13)

0=RSYNC is an output (depends on RCR1.6)

1=RSYNC is an input (only valid if elastic store enabled)

0=resync if FAS received in error 3 consecutive times

1=resync if FAS or bit 2 of non–F AS is received in error 3 consecutive times

0=auto resync enabled

1=auto resync disabled

cleared and set again for a subsequent resync.

DS2154

031197 17/69

DS2154

SYNC/RESYNC CRITERIA Table 3–1

FRAME OR MULTI-

FRAME LEVEL

FAS FAS present in frame N and

CRC4 Two valid MF alignment words

CAS Valid MF alignment word found

SYNC CRITERIA RESYNC CRITERIA ITU SPEC.

Three consecutive incorrect

N + 2, and FAS not present in

FAS received

frame N + 1

Alternate (RCR1.2=1) the above criteria is met or three consecutive incorrect bit 2 of non–FAS received

915 or more CRC4 code words

found within 8 ms

out of 1000 received in error Two consecutive MF alignment

and previous timeslot 16 con-

words received in error

tains code other than all zeros

4.2 and 4.3.2

RCR2: RECEIVE CONTROL REGISTER 2 (Address=11 Hex)

(MSB) (LSB)

Sa8S Sa7S Sa6S Sa5S Sa4S RBCS RESE –

SYMBOL POSITION NAME AND DESCRIPTION

Sa8S RCR2.7 Sa8 Bit Select. Set to one to have RLCLK pulse at the Sa8 bit position; set

Sa7S RCR2.6 Sa7 Bit Select. Set to one to have RLCLK pulse at the Sa7 bit position; set

Sa6S RCR2.5 Sa6 Bit Select. Set to one to have RLCLK pulse at the Sa6 bit position; set

Sa5S RCR2.4 Sa5 Bit Select. Set to one to have RLCLK pulse at the Sa5 bit position; set

Sa4S RCR2.3 Sa4 Bit Select. Set to one to have RLCLK pulse at the Sa4 bit position; set

RBCS RCR2.2 Receive Side Backplane Clock Select.

RESE RCR2.1 Receive Side Elastic Store Enable.

– RCR2.0 Not Assigned. Should be set to zero when written.

to zero to force RLCLK low during Sa8 bit position. See Section 13 for timing details.

to zero to force RLCLK low during Sa7 bit position. See Section 13 for timing details.

to zero to force RLCLK low during Sa6 bit position. See Section 13 for timing details.

to zero to force RLCLK low during Sa5 bit position. See Section 13 for timing details.

to zero to force RLCLK low during Sa4 bit position. See Section 13 for timing details.

0=if RSYSCLK is 1.544 MHz 1=if RSYSCLK is 2.048 MHz

0=elastic store is bypassed 1=elastic store is enabled

G.706

4.1.1

4.1.2

G.706

G.732

5.2

031197 18/69

TCR1: TRANSMIT CONTROL REGISTER 1 (Address=12 Hex)

(MSB) (LSB)

ODF TFPT T16S TUA1 TSiS TSA1 TSM TSIO

SYMBOL POSITION NAME AND DESCRIPTION

ODF TCR1.7 Output Data Format.

0=bipolar data at TPOSO and TNEGO

1=NRZ data at TPOSO; TNEGO=0

TFPT TCR1.6 Transmit Timeslot 0 Pass Through.

0=FAS bits/Sa bits/Remote Alarm sourced internally from the TAF and

TNAF registers

1=FAS bits/Sa bits/Remote Alarm sourced from TSER

T16S TCR1.5 T ransmit T imeslot 16 Data Select.

0=sample timeslot 16 at TSER pin

1=source timeslot 16 from TS0 to TS15 registers

TUA1 TCR1.4 Transmit Unframed All Ones.

0=transmit data normally

1=transmit an unframed all one’s code at TPOSO and TNEGO

TSiS TCR1.3 Transmit International Bit Select.

0=sample Si bits at TSER pin

1=source Si bits from TAF and TNAF registers (in this mode, TCR1.6 must

be set to 0)

TSA1 TCR1.2 Transmit Signaling All Ones.

0=normal operation

1=force timeslot 16 in every frame to all ones

TSM TCR1.1 TSYNC Mode Select.

0=frame mode (see the timing in Section 13)

1=CAS and CRC4 multiframe mode (see the timing in Section 13)

TSIO TCR1.0 TSYNC I/O Select.

0=TSYNC is an input

1=TSYNC is an output

DS2154

NOTE:

See Figure 13–1 1 for more details about how the Transmit Control Registers affect the operation of the DS2154.

031197 19/69

DS2154

TCR2: TRANSMIT CONTROL REGISTER 2 (Address=13 Hex)

(MSB) (LSB)

Sa8S Sa7S Sa6S Sa5S Sa4S ODM AEBE PF

SYMBOL POSITION NAME AND DESCRIPTION

Sa8S TCR2.7 Sa8 Bit Select. Set to one to source the Sa8 bit from the TLINK pin; set to

Sa7S TCR2.6 Sa7 Bit Select. Set to one to source the Sa7 bit from the TLINK pin; set to

Sa6S TCR2.5 Sa6 Bit Select. Set to one to source the Sa6 bit from the TLINK pin; set to

Sa5S TCR2.4 Sa5 Bit Select. Set to one to source the Sa5 bit from the TLINK pin; set to

Sa4S TCR2.3 Sa4 Bit Select. Set to one to source the Sa4 bit from the TLINK pin; set to

ODM TCR2.2 Output Data Mode.

AEBE TCR2.1 Automatic E–Bit Enable.

PF TCR2.0 Function of RLOS/LOTC Pin.

zero to not source the Sa8 bit. See Section 13 for timing details.

zero to not source the Sa7 bit. See Section 13 for timing details.

zero to not source the Sa6 bit. See Section 13 for timing details.

zero to not source the Sa5 bit. See Section 13 for timing details.

zero to not source the Sa4 bit. See Section 13 for timing details.

0=pulses at TPOSO and TNEGO are one full TCLKO period wide 1=pulses at TPOSO and TNEGO are 1/2 TCLKO period wide

0=E–bits not automatically set in the transmit direction 1=E–bits automatically set in the transmit direction

0=Receive Loss of Sync (RLOS) 1=Loss of Transmit Clock (LOTC)

CCR1: COMMON CONTROL REGISTER 1 (Address=14 Hex)

(MSB) (LSB)

FLB

SYMBOL POSITION NAME AND DESCRIPTION

FLB CCR1.7 Framer Loopback.

THDB3 CCR1.6 Transmit HDB3 Enable.

TG802 CCR1.5 Transmit G.802 Enable. See Section 13 for details.

TCRC4 CCR1.4 Transmit CRC4 Enable.

RSM CCR1.3 Receive Signaling Mode Select.

031197 20/69

THDB3 TG802 TCRC4 RSM RHDB3 RG802 RCRC4

0=loopback disabled 1=loopback enabled

0=HDB3 disabled 1=HDB3 enabled

0=do not force TCHBLK high during bit 1 of timeslot 26 1=force TCHBLK high during bit 1 of timeslot 26

0=CRC4 disabled 1=CRC4 enabled

0=CAS signaling mode 1=CCS signaling mode

DS2154

RHDB3 CCR1.2 Receive HDB3 Enable.

0=HDB3 disabled

1=HDB3 enabled

RG802 CCR1.1 Receive G.802 Enable. See Section 13 for details.

0=do not force RCHBLK high during bit 1 of timeslot 26

1=force RCHBLK high during bit 1 of timeslot 26

RCRC4 CCR1.0 Receive CRC4 Enable.

0=CRC4 disabled

1=CRC4 enabled

FRAMER LOOPBACK

When CCR1.7 is set to a one, the DS2154 will enter a Framer LoopBack (FLB) mode. See Figure 1–1 for more details. This loopback is useful in testing and debugging applications. In FLB, the DS2154 will loop data from the transmit side back to the receive side.

1. Data will be transmitted as normal at TPOSO and TNEGO.

2. Data input via RPOSI and RNEGI will be ignored.

3. The RCLK output will be replaced with the TCLK input.

When FLB is enabled, the following will occur:

CCR2: COMMON CONTROL REGISTER 2 (Address=1A Hex)

(MSB) (LSB)

ECUS VCRFS AAIS ARA RSERC LOTCMC RFF RFE

SYMBOL POSITION NAME AND DESCRIPTION

ECUS CCR2.7 Error Counter Update Select. See Section 5 for details.

VCRFS CCR2.6 VCR Function Select. See Section 5 for details.

AAIS CCR2.5 Automatic AIS Generation.

ARA CCR2.4 Automatic Remote Alarm Generation.

RSERC CCR2.3 RSER Control.

LOTCMC CCR2.2 Loss of Transmit Clock Mux Control. Determines whether the transmit

RFF CCR2.1 Receive Force Freeze. Freezes receive side signaling at RSIG (and

0=update error counters once a second 1=update error counters every 62.5 ms (500 frames)

0=count BiPolar Violations (BPVs) 1=count Code Violations (CVs)

0=disabled 1=enabled

0=allow RSER to output data as received under all conditions 1=force RSER to one under loss of frame alignment conditions

side formatter should switch to the ever present RCLKO if the TCLK should fail to transition (see Figure 1–1). 0=do not switch to RCLKO if TCLK stops 1=switch to RCLKO if TCLK stops

RSER if CCR3.3=1); will override Receive Freeze Enable (RFE). See Section 7–2 for details. 0=do not force a freeze event 1=force a freeze event

031197 21/69

DS2154

RFE CCR2.0 Receive Freeze Enable. See Section 7–2 for details.

0=no freezing of receive signaling data will occur 1=allow freezing of receive signaling data at RSIG (and RSER if CCR3.3=1).

AUTOMATIC ALARM GENERATION

When either CCR2.4 or CCR2.5 is set to one, the DS2154 monitors the receive side to determine if any of the following conditions are present: loss of receive frame synchronization, AIS alarm (all one’s) reception, or loss of receive carrier (or signal). If any one (or more) of the above conditions is present, then the DS2154 will either force an AIS alarm (if CCR2.5=1) or a Remote Alarm (CCR2.4=1) to be transmitted via the TPOSO

and TNEGO pins. It is an illegal state to have both CCR2.4 and CCR2.5 set to one at the same time. If CCR2.4=1, then RAI will be transmitted according to ETS 300 011 specifications and a constant Remote Alarm will be transmitted if the DS2154 cannot find CRC4 multiframe synchronization within 400 ms as per G.706.

CCR3: COMMON CONTROL REGISTER 3 (Address=1B Hex)

(MSB) (LSB)

TESE

SYMBOL POSITION NAME AND DESCRIPTION

TESE CCR3.7 Transmit Side Elastic Store Enable.

TCBFS CCR3.6 Transmit Channel Blocking Registers (TCBR) Function Select.

TIRFS CCR3.5 Transmit Idle Registers (TIR) Function Select. See Section 8 for details.

ESR CCR3.4 Elastic Stores Reset. Setting this bit from a one to a zero will force the

RSRE CCR3.3 Receive Side Signaling Re–Insertion Enable. See Section 7–2 for

TSRE CCR3.2 Transmit Side Signaling Re–Insertion Enable. See Section 7–2 for

TBCS CCR3.1 Transmit Side Backplane Clock Select.

TCBFS TIRFS ESR RSRE TSRE TBCS RCLA

0=elastic store is bypassed 1=elastic store is enabled

0=TCBRs define the operation of the TCHBLK output pin 1=TCBRs define which signaling bits are to be inserted

0=TIRs define in which channels to insert idle code 1=TIRs define in which channels to insert data from RSER (i.e., Per=Channel Loopback function)

elastic stores to a known depth. Should be toggled after RSYSCLK and TSYSCLK have been applied and are stable. Must be set and cleared again for a subsequent reset. Do not leave this bit set high.

details. 0=do not re–insert signaling bits into the data stream presented at the RSER pin 1=re–insert the signaling bits into data stream presented at the RSER pin

details. 0=do not re–insert signaling bits into the data stream presented at the TSER pin 1=re–insert the signaling bits into data stream presented at the TSER pin

0=if TSYSCLK is 1.544 MHz 1=if TSYSCLK is 2.048 MHz

031197 22/69

DS2154

RCLA CCR3.0 Receive Carrier Loss (RCL) Alternate Criteria.

POWER–UP SEQUENCE

On power–up, after the supplies are stable, the DS2154 should be configured for operation by writing to all of the internal registers (this includes the T est Registers) since the contents of the internal registers cannot be predicted on power–up. Next, the LIRST (CCR5.7) bit should be toggled from zero to one to reset the line interface circuitry (it will take the DS2154 about 40 ms to

0=RCL declared upon 255 consecutive zeros (125 us) 1=RCL declared upon 2048 consecutive zeros (1 ms)

recover from the LIRST bit being toggled). Finally, after the RSYSCLK and TSYSCLK inputs are stable, the ESR bit should be toggled from a zero to a one and then back to zero (this step can be skipped if the elastic stores are not being used). Both TCLK and RCLKI must be present for the parallel control port to operate properly.

CCR4: COMMON CONTROL REGISTER 4 (Address=A8 Hex)

(MSB) (LSB)

RLB LLB LIAIS TCM4 TCM3 TCM2 TCM1 TCM0

SYMBOL POSITION NAME AND DESCRIPTION

RLB CCR4.7 Remote Loopback.

LLB CCR4.6 Local Loopback.

LIAIS CCR4.5 Line Interface AIS Generation Enable. See Figure 1–1 for details.

TCM4 CCR4.4 Transmit Channel Monitor Bit 4. MSB of a channel decode that deter-

TCM3 CCR4.3 Transmit Channel Monitor Bit 3. TCM2 CCR4.2 Transmit Channel Monitor Bit 2. TCM1 CCR4.1 Transmit Channel Monitor Bit 1. TCM0 CCR4.0 Transmit Channel Monitor Bit 0. LSB of the channel decode.

0=loopback disabled 1= loopback enabled

0=loopback disabled 1=loopback enabled

0=allow normal data from TPOSI/TNEGI to be transmitted at TTIP and TRING 1=force unframed all ones to be transmitted at TTIP and TRING

mines which transmit channel data will appear in the TDS0M register. See Section 6 for details.

REMOTE LOOPBACK

When CCR4.7 is set to a one, the DS2154 will be forced into Remote LoopBack (RLB). In this loopback, data input via the RPOSI and RNEGI pins will be transmitted back to the TPOSO and TNEGO pins. Data will continue to pass through the receive side framer of the DS2154 as it would normally and the data from the transmit side formatter will be ignored. Please see Figure 1–1 for more details.

LOCAL LOOPBACK

When CCR4.6 is set to a one, the DS2154 will be forced into Local LoopBack (LLB). In this loopback, data will continue to be transmitted as normal through the transmit side of the DS2154. Data being received at RTIP and RRING will be replaced with the data being transmitted. Data in this loopback will pass through the jitter attenuator. Please see Figure 1–1 for more details.

031197 23/69

DS2154

CCR5: COMMON CONTROL REGISTER 5 (Address=AA Hex)

(MSB) (LSB)

LIRST – – RCM4 RCM3 RCM2 RCM1 RCM0

SYMBOL POSITION NAME AND DESCRIPTION

LIRST CCR5.7 Line Interface Reset. Setting this bit from a zero to a one will initiate an

– CCR5.6 Not Assigned. Should be set to zero when written – CCR5.5 Not Assigned. Should be set to zero when written.

RCM4 CCR5.4 Receive Channel Monitor Bit 4. MSB of a channel decode that deter-

RCM3 CCR5.3 Receive Channel Monitor Bit 3. RCM2 CCR5.2 Receive Channel Monitor Bit 2. RCM1 CCR5.1 Receive Channel Monitor Bit 1. RCM0 CCR5.0 Receive Channel Monitor Bit 0. LSB of the channel decode.

4.0 STATUS AND INFORMATION REGISTERS

There is a set of four registers that contain information on the current real time status of the DS2154, Status Register 1 (SR1), Status Register 2 (SR2), Receive Information Register (RIR), and Synchronizer Status Register (SSR). When a particular event has occurred (or is occuring), the appropriate bit in one of these four registers will be set to a one. All of the bits in these registers operate in a latched fashion (except for the SSR). This means that if an event or an alarm occurs and a bit is set to a one in any of the registers, it will remain set until the user reads that bit. The bit will be cleared when it is read and it will not be set again until the event has occurred again (or in the case of the RUA1, RRA, RCL, and RLOS alarms, the bit will remain set if the alarm is still present).

The user will always precede a read of the SR1, SR2, and RIR registers with a write. The byte written to the register will inform the DS2154 which bits the user wishes to read and have cleared. The user will write a byte to one of these three registers, with a one in the bit positions he or she wishes to read and a zero in the bit positions he or she does not wish to obtain the latest information on. When a one is written to a bit location, the read register will be updated with the latest information. When a zero is written to a bit position, the read register will not be updated and the previous value will

internal reset that affects the clock recovery state machine and jitter attenuator. Normally this bit is only toggled on power–up. Must be cleared and set again for a subsequent reset.

mines which receive channel data will appear in the RDS0M register. See Section 6 for details.

be held. A write to the status and information registers will be immediately followed by a read of the same register. The read result should be logically AND’ed with the mask byte that was just written and this value should be written back into the same register to insure that bit does indeed clear. This second write step is necessary because the alarms and events in the status registers occur asynchronously in respect to their access via 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 DS2154 with higher–order software languages.

The SSR register operates differently than the other three. It is a read only register and it reports the status of the synchronizer in real time. This register is not latched and it is not necessary to precede a read of this register with a write.

The SR1 and SR2 registers have the unique ability to initiate a hardware interrupt via the INT

output pin. Each of the alarms and events in the SR1 and SR2 can be either masked or unmasked from the interrupt pins via the Interrupt Mask Register 1 (IMR1) and Interrupt Mask Register 2 (IMR2) respectively.

The interrupts caused by alarms in SR1 (namely RUA1, RRA, RCL, and RLOS) act differently than the interrupts

031197 24/69

DS2154

caused by events in SR1 and SR2 (namely RSA1, RDMA, RSA0, RSLIP, RMF, RAF, TMF, SEC, TAF,

when the user reads the alarm bit that caused the inter-

rupt to occur even if the alarm is still present. LOTC, RCMF , and TSLIP). The alarm caused interrupts will force the INT

pin low whenever the alarm changes state (i.e. the alarm goes active or inactive according to the set/clear criteria in Table 4–1). The INT pin will be allowed to return high (if no other interrupts are present)

The event caused interrupts will force the INT when the event occurs. The INT

pin will be allowed to return high (if no other interrupts are present) when the user reads the event bit that caused the interrupt to occur.

RIR: RECEIVE INFORMATION REGISTER (Address=08 Hex)

(MSB) (LSB)

TESF TESE JALT RESF RESE CRCRC FASRC CASRC

SYMBOL POSITION NAME AND DESCRIPTION

TESF RIR.7 Transmit Side Elastic Store Full. Set when the transmit side elastic store

TESE RIR.6 Transmit Side Elastic Store Empty. Set when the transmit side elastic

JALT RIR.5 Jitter Attenuator Limit Trip. Set when the jitter attenuator FIFO reaches to

RESF RIR.4 Receive Side Elastic Store Full. Set when the receive side elastic store

RESE RIR.3 Receive Side Elastic Store Empty. Set when the receive side elastic

CRCRC RIR.2 CRC Resync Criteria Met. Set when 915/1000 code words are received in

FASRC RIR.1 FAS Resync Criteria Met. Set when 3 consecutive FAS words are

CASRC RIR.0 CAS Resync Criteria Met. Set when 2 consecutive CAS MF alignment

buffer fills and a frame is deleted.

store buffer empties and a frame is repeated.

within 4–bits of its limit; useful for debugging jitter attenuation operation.

buffer fills and a frame is deleted.

store buffer empties and a frame is repeated.

error.

received in error.

words are received in error.

pin low

SSR: SYNCHRONIZER STATUS REGISTER (Address=1E Hex)

(MSB) (LSB)

CSC5 CSC4 CSC3 CSC2 CSC0 FASSA CASSA CRC4SA

SYMBOL POSITION NAME AND DESCRIPTION

CSC5 SSR.7 CRC4 Sync Counter Bit 5. MSB of the 6–bit counter. CSC4 SSR.6 CRC4 Sync Counter Bit 4. CSC3 SSR.5 CRC4 Sync Counter Bit 3. CSC2 SSR.4 CRC4 Sync Counter Bit 2. CSC0 SSR.3 CRC4 Sync Counter Bit 0. LSB of the 6–bit counter. The next to LSB is

not accessible.

031197 25/69

DS2154

FASSA SSR.2 FAS Sync Active. Set while the synchronizer is searching for alignment at

the FAS level.

CASSA SSR.1 CAS MF Sync Active. Set while the synchronizer is searching for the CAS

MF alignment word.

CRC4SA SSR.0 CRC4 MF Sync Active. Set while the synchronizer is searching for the

CRC4 MF alignment word.

CRC4 SYNC COUNTER

The CRC4 Sync Counter increments each time the 8 ms CRC4 multiframe search times out. The counter is cleared when the DS2154 has successfully obtained synchronization at the CRC4 level. The counter can also be cleared by disabling the CRC4 mode

amount of time the DS2154 has been searching for synchronization at the CRC4 level. ITU G.706 suggests that if synchronization at the CRC4 level cannot be obtained within 400 ms, then the search should be abandoned and proper action taken. The CRC4 Sync Counter will rollover.

(CCR1.0=0). This counter is useful for determining the

SR1: STATUS REGISTER 1 (Address=06 Hex)

(MSB) (LSB)

RSA1 RDMA RSA0 RSLIP RUA1 RRA RCL RLOS

SYMBOL POSITION NAME AND DESCRIPTION

RSA1 SR1.7 Receive Signaling All Ones / Signaling Change. Set when the contents

RDMA SR1.6 Receive Distant MF Alarm. Set when bit–6 of timeslot 16 in frame 0 has

RSA0 SR1.5 Receive Signaling All Zeros / Signaling Change. Set when over a full

RSLIP SR1.4 Receive Side Elastic Store Slip. Set when the elastic store has either re-

RUA1 SR1.3 Receive Unframed All Ones. Set when an unframed all ones code is re-

RRA SR1.2 Receive Remote Alarm. Set when a remote alarm is received at RPOSI

RCL SR1.1 Receive Carrier Loss. Set when 255 (or 2048 if CCR3.0=1) consecutive

RLOS SR1.0 Receive Loss of Sync. Set when the device is not synchronized to the

of timeslot 16 contains less than three zeros over 16 consecutive frames. This alarm is not disabled in the CCS signaling mode. Both RSA1 and RSA0 will be set if a change in signaling is detected.

been set for two consecutive multiframes. This alarm is not disabled in the CCS signaling mode.

MF, timeslot 16 contains all zeros. Both RSA1 and RSA0 will be set if a change in signaling is detected.

peated or deleted a frame of data.

ceived at RPOSI and RNEGI.

and RNEGI.

zeros have been detected at RTIP and RRING. [Note: a test mode exists to allow the DS2154 to detect carrier loss at RPOSI and RNEGI in place of detection at RTIP and RRING].

receive E1 stream.

031197 26/69

ALARM CRITERIA Table 4–1

ALARM SET CRITERIA CLEAR CRITERIA

RSA1

(receive signaling all ones)

RSA0

(receive signaling all zeros)

RDMA

(receive distant

over 16 consecutive frames (one full MF) timeslot 16 contains less than three zeros

over 16 consecutive frames (one full MF) timeslot 16 contains all zeros

bit 6 in timeslot 16 of frame 0 set to one for two consecutive MF

over 16 consecutive frames (one full MF) timeslot 16 contains three or more zeros

over 16 consecutive frames (one full MF) timeslot 16 contains at least a single one

bit 6 in timeslot 16 of frame 0 set to zero for a two consecutive MF

multiframe alarm)

RUA1

(receive unframed

less than three zeros in two frames (512–bits)

more than two zeros in two frames (512–bits)

all ones)

RRA

(receive remote

bit 3 of non–align frame set to one for three consecutive occasions

bit 3 of non–align frame set to zero for three consecutive occasions

alarm)

RCL

(receive carrier

255 (or 2048) consecutive zeros received

in 255–bit times, at least 32 ones are received

loss)

SR2: STATUS REGISTER 2 (Address=07 Hex)

(MSB) (LSB)

RMF

RAF TMF SEC TAF LOTC RCMF TSLIP

DS2154

ITU

SPEC.

G.732

4.2

G.732

5.2

O.162

2.1.5

O.162

1.6.1.2

O.162

2.1.4

G.775 / G.962

SYMBOL POSITION NAME AND DESCRIPTION

RMF SR2.7 Receive CAS Multiframe. Set every 2 ms (regardless if CAS signaling is

enabled or not) on receive multiframe boundaries. Used to alert the host that signaling data is available.

RAF SR2.6 Receive Align Frame. Set every 250 µs at the beginning of align frames.

Used to alert the host that Si and Sa bits are available in the RAF and RNAF registers.

TMF SR2.5 Transmit Multiframe. Set every 2 ms (regardless if CRC4 is enabled) on

transmit multiframe boundaries. Used to alert the host that signaling data needs to be updated.

SEC SR2.4 One Second Timer. Set on increments of one second based on RCLK. If

CCR2.7=1, then this bit will be set every 62.5 ms instead of once a second.

TAF SR2.3 T ransmit Align Frame. Set every 250 µs at the beginning of align frames.

Used to alert the host that the TAF and TNAF registers need to be updated.

LOTC SR2.2 Loss of Transmit Clock. Set when the TCLK pin has not transitioned for

one channel time (or 3.9 µs). Will force the LOTC pin high if enabled via TCR2.0.

RCMF SR2.1 Receive CRC4 Multiframe. Set on CRC4 multiframe boundaries; will con-

tinue to be set every 2 ms on an arbitrary boundary if CRC4 is disabled.

TSLIP SR2.0 Transmit Elastic Store Slip. Set when the elastic store has either re-

peated or deleted a frame of data.

031197 27/69

DS2154

IMR1: INTERRUPT MASK REGISTER 1 (Address=16 Hex)

(MSB) (LSB)

RSA1 RDMA RSA0 RSLIP RUA1 RRA RCL RLOS

SYMBOL POSITION NAME AND DESCRIPTION

RSA1 IMR1.7 Receive Signaling All Ones / Signaling Change.

RDMA IMR1.6 Receive Distant MF Alarm.

RSA0 IMR1.5 Receive Signaling All Zeros / Signaling Change.

RSLIP IMR1.4 Receive Elastic Store Slip Occurrence.

RUA1 IMR1.3 Receive Unframed All Ones.

RRA IMR1.2 Receive Remote Alarm.

RCL IMR1.1 Receive Carrier Loss.

RLOS IMR1.0 Receive Loss of Sync.

0=interrupt masked 1=interrupt enabled

IMR2: INTERRUPT MASK REGISTER 2 (Address=17 Hex)

(MSB) (LSB)

RMF RAF TMF SEC TAF LOTC RCMF TSLIP

SYMBOL POSITION NAME AND DESCRIPTION

RMF IMR2.7 Receive CAS Multiframe.

RAF IMR2.6 Receive Align Frame.

TMF IMR2.5 Transmit Multiframe.

031197 28/69

0=interrupt masked 1=interrupt enabled

DS2154

SEC IMR2.4 One Second Timer.

0=interrupt masked 1=interrupt enabled

TAF IMR2.3 Transmit Align Frame.

0=interrupt masked 1=interrupt enabled

LOTC IMR2.2 Loss Of Transmit Clock.

0=interrupt masked 1=interrupt enabled

RCMF IMR2.1 Receive CRC4 Multiframe.

0=interrupt masked 1=interrupt enabled

TSLIP IMR2.0 Transmit Side Elastic Store Slip Occurrence.

0=interrupt masked 1=interrupt enabled

5.0 ERROR COUNT REGISTERS

There are a set of four counters in the DS2154 that record bipolar or code violations, errors in the CRC4 SMF code words, E bits as reported by the far end, and word errors in the FAS. Each of these four counters are automatically updated on either one second boundaries (CCR2.7=0) or every 62.5 ms (CCR2.7=1) as determined by the timer in Status Register 2 (SR2.4). Hence, these registers contain performance data from either the previous second or the previous 62.5 ms. The user can use the interrupt from the timer to determine when to read these registers. The user has a full second (or

62.5 ms) to read the counters before the data is lost.

16–bit counter that records either BiPolar Violations (BPVs) or Code Violations (CVs). If CCR2.6=0, then the VCR counts bipolar violations. Bipolar violations are defined as consecutive marks of the same polarity. In this mode, if the HDB3 mode is set for the receive side via CCR1.2, then HDB3 code words are not counted as BPVs. If CCR2.6=1, then the VCR counts code violations as defined in ITU O.161. Code violations are defined as consecutive bipolar violations of the same polarity. In most applications, the DS2154 should be programmed to count BPVs when receiving AMI code and to count CVs when receiving HDB3 code. This counter increments at all times and is not disabled by loss of sync conditions. The counter saturates at 65,535

5.1 BPV or Code Violation Counter

Violation Count Register 1 (VCR1) is the most significant word and VCR2 is the least significant word of a

and will not rollover. The bit error rate on a E1 line would have to be greater than 10** saturate.

–2

before the VCR would

VCR1: UPPER BIPOLAR VIOLATION COUNT REGISTER 1 (Address=00 Hex) VCR2: LOWER BIPOLAR VIOLATION COUNT REGISTER 2 (Address=01 Hex)

(MSB) (LSB)

V15

V7 V6 V5 V4 V3 V2 V1 V0

SYMBOL POSITION NAME AND DESCRIPTION

V14 V13 V12 V11 V10 V9 V8

V15 VCR1.7 MSB of the 16–bit bipolar or code violation count .

V0 VCR2.0 LSB of the 16–bit bipolar or code violation count.

VCR1 VCR2

031197 29/69

DS2154

5.2 CRC4 Error Counter

CRC4 Count Register 1 (CRCCR1) is the most significant word and CRCCR2 is the least significant word of a 10–bit counter that records word errors in the Cyclic Redundancy Check 4 (CRC4). Since the maximum

CRC4 count in a one second period is 1000, this counter cannot saturate. The counter is disabled during loss of sync at either the FAS or CRC4 level; it will continue to count if loss of multiframe sync occurs at the CAS level.

CRCCR1: CRC4 COUNT REGISTER 1 (Address=02 Hex) CRCCR2: CRC4 COUNT REGISTER 2 (Address=03 Hex)

(MSB) (LSB)

(note 1) (note 1) (note 1) (note 1) (note 1) (note 1) CRC9 CRC8

CRC7 CRC6 CRC5 CRC4 CRC3 CRC2 CRC1 CRC0

SYMBOL POSITION NAME AND DESCRIPTION

CRC9 CRCCR1.1 MSB of the 10–bit CRC4 error count. CRC0 CRCCR2.0 LSB of the 10–bit CRC4 error count.

CRCCR1 CRCCR2

NOTE:

1. The upper six bits of CRCCR1 at address 02 are the most significant bits of the 12–bit FAS error counter.

5.3 E–Bit Counter

E–bit Count Register 1 (EBCR1) is the most significant word and EBCR2 is the least significant word of a 10–bit counter that records Far End Block Errors (FEBE) as reported in the first bit of frames 13 and 15 on E1 lines running with CRC4 multiframe. These count registers

will increment once each time the received E–bit is set to zero. Since the maximum E–bit count in a one second period is 1000, this counter cannot saturate. The counter is disabled during loss of sync at either the FAS or CRC4 level; it will continue to count if loss of multiframe sync occurs at the CAS level.

EBCR1: E–BIT COUNT REGISTER 1 (Address=04 Hex) EBCR2: E–BIT COUNT REGISTER 2 (Address=05 Hex)

(MSB) (LSB)

(note 1) (note 1) (note 1) (note 1) (note 1) (note 1) EB9 EB8

EB7 EB6 EB5 EB4 EB3 EB2 EB1 EB0

SYMBOL POSITION NAME AND DESCRIPTION

EB9 EBCR1.1 MSB of the 10–bit E–Bit count. EB0 EBCR2.0 LSB of the 10–bit E–Bit count.

NOTE:

The upper six bits of EBCR1 at address 04 are the least significant bits of the 12–bit FAS error counter.

031197 30/69

EBCR1 EBCR2

DS2154

5.4 FAS Error Counter

FAS Count Register 1 (F ASCR1) is the most significant word and FASCR2 is the least significant word of a 12–bit counter that records word errors in the Frame Alignment Signal in timeslot 0. This counter is disabled

during loss of frame synchronization conditions, it is not disabled during loss of synchronization at either the CAS or CRC4 multiframe level. Since the maximum FAS word error count in a one second period is 4000, this counter cannot saturate.

FASCR1: FAS BIT COUNT REGISTER 1 (Address=02 Hex) FASCR2: FAS BIT COUNT REGISTER 2 (Address=04 Hex)

(MSB) (LSB)

FAS11

FAS5 FAS4 F AS3 FAS2 FAS1 FAS0 (note 1) (note 1)

SYMBOL POSITION NAME AND DESCRIPTION

FAS10 FAS9 FAS8 FAS7 FAS6 (note 2) (note 2)

FAS11 FASCR1.7 MSB of the 12–bit FAS error count.

FAS0 FASCR2.2 LSB of the 12–bit FAS error count.

FASCR1 FASCR2

NOTES:

1. The lower two bits of FASCR1 at address 02 are the most significant bits of the 10–bit CRC4 error counter.

2. The lower two bits of FASCR2 at address 04 are the most significant bits of the 10–bit E–Bit counter.

6.0 DS0 MONITORING FUNCTION

The DS2154 has the ability to monitor one DS0 64K bps channel in the transmit direction and one DS0 channel in the receive direction at the same time. In the transmit direction the user will determine which channel is to be monitored by properly setting the TCM0 to TCM4 bits in the CCR4 register. In the receive direction, the RCM0 to RCM4 bits in the CCR5 register need to be properly set. The DS0 channel pointed to by the TCM0 to TCM4 bits will appear in the Transmit DS0 Monitor (TDS0M) register and the DS0 channel pointed to by the RCM0 to RCM4 bits will appear in the Receive (RDS0M) register.

The TCM4 to TCM0 and RCM4 to RCM0 bits should be programmed with the decimal decode of the appropriate E1 channel. For example, if DS0 Channel 6 (timeslot 5) in the transmit direction and DS0 Channel 15 (timeslot

14) in the receive direction needed to be monitored, then the following values would be programmed into CCR4 and CCR5:

TCM4=0 RCM4=0 TCM3=0 RCM3=1 TCM2=1 RCM2=1 TCM1=0 RCM1=1 TCM0=1 RCM0=0

CCR4: DS0 MONITORING FUNCTION (Address=A8 Hex) [repeated here from section 3 for convenience]

(MSB) (LSB)

RLB LLB LIAIS TCM4 TCM3 TCM2 TCM1 TCM0

SYMBOL POSITION NAME AND DESCRIPTION

RLB CCR4.7 Remote Loopback. See Section 3 for details.

LLB CCR4.6 Local Loopback. See Section 3 for details.

LIAIS CCR4.5 Line Interface AIS Generation Enable. See Section 3 for details.

TCM4 CCR4.4 Transmit Channel Monitor Bit 4. MSB of a channel decode that deter-

mines which transmit DS0 channel data will appear in the TDS0M register.

031197 31/69

DS2154

mines which transmit DS0 channel data will appear in the TDS0M register.

TDS0M: TRANSMIT DS0 MONITOR REGISTER (Address=A9 Hex)

(MSB) (LSB)

B1 B2 B3 B4 B5 B6 B7 B8

SYMBOL POSITION NAME AND DESCRIPTION

B1 TDS0M.7 Transmit DS0 Channel Bit 8. MSB of the DS0 channel (first bit to be trans-

B2 TDS0M.6 Transmit DS0 Channel Bit 7. B3 TDS0M.5 Transmit DS0 Channel Bit 6. B4 TDS0M.4 Transmit DS0 Channel Bit 5. B5 TDS0M.3 Transmit DS0 Channel Bit 4. B6 TDS0M.2 Transmit DS0 Channel Bit 3. B7 TDS0M.1 Transmit DS0 Channel Bit 2. B8 TDS0M.0 Transmit DS0 Channel Bit 1. LSB of the DS0 channel (last bit to be trans-

mitted).

CCR5: COMMON CONTROL REGISTER 5 (Address=AA Hex) [repeated here from section 3 for convenience]

(MSB) (LSB)

LIRST – – RCM4 RCM3 RCM2 RCM1 RCM0

SYMBOL POSITION NAME AND DESCRIPTION

LIRST CCR5.7 Line Interface Reset. See Section 3 for details.

– CCR5.6 Not Assigned. Should be set to zero when written. – CCR5.5 Not Assigned. Should be set to zero when written.

RCM4 CCR5.4 Receive Channel Monitor Bit 4. MSB of a channel decode that deter-

RCM3 CCR5.3 Receive Channel Monitor Bit 3. RCM2 CCR5.2 Receive Channel Monitor Bit 2. RCM1 CCR5.1 Receive Channel Monitor Bit 1. RCM0 CCR5.0 Receive Channel Monitor Bit 0. LSB of the channel decode that deter-

031197 32/69

mines which receive DS0 channel data will appear in the RDS0M register.

RDS0M: RECEIVE DS0 MONITOR REGISTER (Address=AB Hex)

(MSB) (LSB)

B1 B2 B3 B4 B5 B6 B7 B8

SYMBOL POSITION NAME AND DESCRIPTION

B1 RDS0M.7 Receive DS0 Channel Bit 8. MSB of the DS0 channel (first bit to be

received). B2 RDS0M.6 Receive DS0 Channel Bit 7. B3 RDS0M.5 Receive DS0 Channel Bit 6. B4 RDS0M.4 Receive DS0 Channel Bit 5. B5 RDS0M.3 Receive DS0 Channel Bit 4. B6 RDS0M.2 Receive DS0 Channel Bit 3. B7 RDS0M.1 Receive DS0 Channel Bit 2. B8 RDS0M.0 Receive DS0 Channel Bit 1. LSB of the DS0 channel (last bit to be

received).

7.0 SIGNALING OPERATION

The DS2154 contains provisions for both processor based (i.e., software based) signaling bit access and for hardware based access. Both the processor based access and the hardware based access can be used simultaneously if necessary. The processor based signaling is covered in Section 7.1 and the hardware based signaling is covered in Section 7.2.

7.1 PROCESSOR BASED SIGNALING

The Channel Associated Signaling (CAS) bits embedded in the E1 stream can be extracted from the receive stream and inserted into the transmit stream by

the DS2154. Each of the 30 voice channels has four signaling bits (A/B/C/D) associated with it. The numbers in parenthesis () are the voice channel associated with a particular signaling bit. The voice channel numbers have been assigned as described in the ITU documents. Please note that this is different than the channel numbering scheme (1 to 32) that is used in the rest of the data sheet. For example, voice channel 1 is associated with timeslot 1 (Channel 2) and voice Channel 30 is associated with timeslot 31 (Channel 32). There is a set of 16 registers for the receive side (RS1 to RS16) and 16 registers on the transmit side (TS1 to TS16). The signaling registers are detailed below.

DS2154

031197 33/69

DS2154

RS1 TO RS16: RECEIVE SIGNALING REGISTERS (Address=30 to 3F Hex)

(MSB) (LSB)

A(1) B(1) C(1) D(1) A(16) B(16) C(16) D(16) A(2) B(2) C(2) D(2) A(17) B(17) C(17) D(17) A(3) B(3) C(3) D(3) A(18) B(18) C(18) D(18) A(4) B(4) C(4) D(4) A(19) B(19) C(19) D(19) A(5) B(5) C(5) D(5) A(20) B(20) C(20) D(20) A(6) B(6) C(6) D(6) A(21) B(21) C(21) D(21) A(7) B(7) C(7) D(7) A(22) B(22) C(22) D(22) A(8) B(8) C(8) D(8) A(23) B(23) C(23) D(23)

A(9) B(9) C(9) D(9) A(24) B(24) C(24) D(24) A(10) B(10) C(10) D(10) A(25) B(25) C(25) D(25) A(11) B(11) C(11) D(11) A(26) B(26) C(26) D(26) A(12) B(12) C(12) D(12) A(27) B(27) C(27) D(27) A(13) B(13) C(13) D(13) A(28) B(28) C(28) D(28) A(14) B(14) C(14) D(14) A(29) B(29) C(29) D(29) A(15) B(15) C(15) D(15) A(30) B(30) C(30) D(30)

0 0 0 X Y X X

RS1 (30) RS2 (31) RS3 (32) RS4 (33) RS5 (34) RS6 (35) RS7 (36) RS8 (37) RS9 (38) RS10 (39) RS11 (3A) RS12 (3B)

RS13 (3C) RS14 (3D) RS15 (3E) RS16 (3F)

SYMBOL POSITION NAME AND DESCRIPTION

X RS1.0/1/3 Spare Bits. Y RS1.2 Remote Alarm Bit (integrated and reported in SR1.6).

A(1) RS2.7 Signaling Bit A for Channel 1.

D(30) RS16.0 Signaling Bit D for Channel 30.

Each Receive Signaling Register (RS1 to RS16) reports the incoming signaling from two timeslots. The bits in the Receive Signaling Registers are updated on multiframe boundaries so the user can utilize the Receive Multiframe Interrupt in the Receive Status Register 2 (SR2.7) to know when to retrieve the signaling bits. The user has a full 2 ms to retrieve the signaling bits before the data is lost. The RS registers are updated under all conditions. Their validity should be qualified by checking for synchronization at the CAS level. In CCS signaling mode, RS1 to RS16 can also be used to extract signaling information. Via the SR2.7 bit, the user will be informed when the signaling registers have been loaded

031197 34/69

with data. The user has 2 ms to retrieve the data before it is lost. The signaling data reported in RS1 to RS16 is also available at the RSIG and RSER pins.

A change in the signaling bits from one multiframe to the next will cause the RSA1 (SR1.7) and RSA0 (SR1.5) status bits to be set at the same time. The user can enable the INT

pin to toggle low upon detection of a change in signaling by setting either the IMR1.7 or IMR1.5 bit. Once a signaling change has been detected, the user has at least 1.75 ms to read the data out of the RS1 to RS16 registers before the data will be lost.

TS1 TO TS16: TRANSMIT SIGNALING REGISTERS (Address=40 to 4F Hex)

(MSB) (LSB)

0 0 0 X Y X X

DS2154

TS1 (40) TS2 (41) TS3 (42) TS4 (43) TS5 (44) TS6 (45) TS7 (46) TS8 (47) TS9 (48) TS10 (49) TS11 (4A) TS12 (4B) TS13 (4C)

TS14 (4D) TS15 (4E) TS16 (4F)

SYMBOL POSITION NAME AND DESCRIPTION

X TS1.0/1/3 Spare Bits. Y TS1.2 Remote Alarm Bit.

A(1) TS2.7 Signaling Bit A for Channel 1.

D(30) TS16.0 Signaling Bit D for Channel 30.

Each Transmit Signaling Register (TS1 to TS16) contains the CAS bits for two timeslots that will be inserted into the outgoing stream if enabled to do so via TCR1.5. On multiframe boundaries, the DS2154 will load the values present in the Transmit Signaling Register into an outgoing signaling shift register that is internal to the device. The user can utilize the Transmit Multiframe bit in Status Register 2 (SR2.5) to know when to update the signaling bits. The bit will be set every 2 ms and the user has 2 ms to update the TSR’s before the old data will be retransmitted. ITU specifications recommend that the ABCD signaling not be set to all zeros because they will emulate a CAS multiframe alignment word.

The TS1 register is special because it contains the CAS multiframe alignment word in its upper nibble. The upper nibble must always be set to 0000 or else the terminal at the far end will lose multiframe synchronization.

If the user wishes to transmit a multiframe alarm to the far end, then the TS1.2 bit should be set to a one. If no alarm is to be transmitted, then the TS1.2 bit should be cleared. The three remaining bits in TS1 are the spare bits. If they are not used, they should be set to one. In CCS signaling mode, TS1 to TS16 can also be used to insert signaling information. Via the SR2.5 bit, the user will be informed when the signaling registers need to be loaded with data. The user has 2 ms to load the data before the old data will be retransmitted.

Via the CCR3.6 bit, the user has the option to use the Transmit Channel Blocking Registers (TCBRs) to determine on a channel by channel basis, which signaling bits are to be inserted via the TSRs (the corresponding bit in the TCBRs=1) and which are to be sourced from the TSER or TSIG pin (the corresponding bit in the

031197 35/69

DS2154

TCBRs=0). See the Transmit Data Flow diagram in Section 13 for more details.

7.2 HARDWARE BASED SIGNALING

7.2.1 Receive Side

In the receive side of the hardware based signaling, there are two operating modes for the signaling buffer; signaling extraction and signaling re–insertion. Signaling extraction involves pulling the the signaling bits from the receive data stream and buffering them over a 2 multiframe buffer and outputing them in a serial PCM fashion on a channel–by–channel basis at the RSIG output pin. This mode is always enabled. In this mode, the receive elastic store may be enabled or disabled. If the receive elastic store is enabled, then the backplane clock (RSYSCLK) must be 2.048 MHz. The ABCD signaling bits are output on RSIG in the lower nibble of each channel. See the timing diagrams in Section 13 for an example. The RSIG data is updated once a multiframe (2 ms) unless a freeze is in effect.

The other hardware based signaling operating mode called signaling re–insertion can be invoked by setting the RSRE control bit high (CCR3.3=1). In this mode, the user will provide a multiframe sync at the RSYNC pin and the signaling data will be re–aligned in the PCM data stream provided at the RSER output pin according to this applied multiframe boundary. In this mode, the elastic store must be enabled and the backplane clock (RSYSCLK) must be 2.048 MHz.

The signaling data in the two multiframe buffer will be frozen in a known good state upon either a loss of synchronization (OOF event), carrier loss, or frame slip. T o allow this freeze action to occur, the RFE control bit (CCR2.0) should be set high. The user can force a freeze by setting the RFF control bit (CCR2.1) high. Setting the RFF bit high causes the same freezing action as if a loss of synchronization, carrier loss, or slip has occurred. The RSIGF output pin provides a hard-

ware indication that a freeze is in effect. The RSIGF pin will go high immediately upon detection of any of the events that can cause a freeze to occur. The RSIGF pin will return low 3 ms to 5 ms after the event subsides. The RSIGF pin action cannot be disabled.

The 2 multiframe buffer provides an approximate 1 multiframe delay in the signaling bits provided at the RSIG pin (and at the RSER pin if RSRE=1 via CCR3.3). When freezing is enabled (RFE=1), the signaling data will be held in the last known good state until the corrupting error condition subsides. When the error condition subsides, the signaling data will be held in the old state for an additional 3 ms to 5 ms before being allowed to be updated with new signaling data.

7.2.2 Transmit Side

Via the TSRE control bit (CCR3.2), the DS2154 can be set up to take the signaling data presented at the TSIG pin and re–insert the signaling data into the PCM data stream that is being input at the TSER pin. The signaling re–insertion capabilities of the DS2154 are available whether the transmit side elastic store is enabled or disabled. If the transmit side elastic store is enabled, the backplane clock (TSYSCLK) must be 2.048 MHz.

When signaling re–insertion is enabled on the DS2154 (TSRE=1), then the user must enable the Transmit Channel Blocking Register Function Select (TCBFS) control bit (CCR3.6=1). This is needed so that the CAS multiframe alignment word, multiframe remote alarm, and spare bits can be added to timeslot 16 in frame 0 of the multiframe. The TS1 register should be programmed with the proper information. If CCR3.6=1, then a zero in the TCBRs implies that signaling data is to be sourced from TSER (or TSIG if CCR3.2=1) and a one implies that signaling data for that channel is to be sourced from the Transmit Signaling (TS) registers. See definition below.

031197 36/69

DS2154

TCBR1/TCBR2/TCBR3/TCBR4: DEFINITION WHEN CCR3.6=1

(MSB) (LSB)

CH20 CH24 CH8 CH23 CH7 CH22 CH6 CH21 CH5 CH28 CH12 CH27 CH11 CH26 CH10 CH25 CH9 CH32 CH16 CH31 CH15 CH30 CH14 CH29 CH13

*=CH1 and CH17 should be set to one to allow the internal TS1 register to create the CAS Multiframe Alignment Word and Spare/Remote Alarm bits.

CH4 CH19 CH3 CH18 CH2 CH17* CH1*

TCBR1(22) TCBR2(23) TCBR3(24) TCBR4(25)

The user can also take advantage of this functionality to intermix signaling data from the TSIG pin and from the internal Transmit Signaling Registers (TS1 to TS16). As an example, assume that the user wishes to source all

the signaling data except for voice channels 5 and 10 from the TSIG pin. In this application, the following bits and registers would be programmed as follows:

CONTROL BITS REGISTER VALUES

TSRE=1 (CCR3.2) TS1=0Bh (MF alignment word, remote alarm etc.) TCBFS=1 (CCR3.6) TCBR1=03h (source timeslot 16, frame 1 data) T16S=1 (TCR1.5) TCBR2=01h (source voice Channel 5 signaling data from TS6)

8.0 PER–CHANNEL CODE GENERATION

The DS2154 can replace data on a channel–by–channel basis in both the transmit and receive directions. The transmit direction is from the backplane to the E1 line and is covered in Section 8.1. The receive direction is from the E1 line to the backplane and is covered in Section 8.2.

8.1 TRANSMIT SIDE CODE GENERATION

In the transmit direction there are two methods by which channel data from the backplane can be overwritten with data generated by the DS2154. The first method which is covered in Section 8.1.1 was a feature contained in the original DS2153 while the second method which is covered in Section 8.1.2 is a new feature of the DS2154.

TCBR3=04h (source voice Channel 10 signaling data from TS11) TCBR4=00h

nels should be overwritten with the code placed in the Transmit Idle Definition Register (TIDR). This method allows the same 8–bit code to be placed into any of the 32 E1 channels. If this method is used, then the CCR3.5 control bit must be set to zero.

The Transmit Idle Registers (TIRs) have an alternate function that allow them to define a Per–Channel LoopBack (PCLB). If the CCR3.5 control bit is set to one, then the TIRs will determine which channels (if any) from the backplane should be replaced with the data from the receive side or in other words, off of the E1 line. See Figure 1–1. If this mode is enabled, then transmit and receive clocks and frame syncs must be synchronized. One method to accomplish this would be to tie RCLK to TCLK and RFSYNC to TSYNC. There are no restrictions on which channels can be loopback or on how many channels can be looped back.

8.1.1 Simple Idle Code Insertion and Per–Channel Loopback

The first method involves using the Transmit Idle Registers (TIR1/2/3/4) to determine which of the 32 E1 chan-

031197 37/69

DS2154

TIR1/TIR2/TIR3/TIR4: TRANSMIT IDLE REGISTERS (Address=26 to 29 Hex) [Also used for Per–Channel Loopback]

(MSB) (LSB)

CH8 CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 CH32 CH31 CH30 CH29 CH28 CH27 CH26 CH25

SYMBOL POSITION NAME AND DESCRIPTION

CH32 TIR4.7 Transmit Idle Registers.

CH7 CH6 CH5 CH4 CH3 CH2 CH1

0=do not insert the Idle Code in the TIDR into this channel

CH1 TIR1.0 1=insert the Idle Code in the TIDR into this channel

TIR1 (26) TIR2 (27) TIR3 (28) TIR4 (29)

NOTE:

If CCR3.5=1, then a zero in the TIRs implies that channel data is to be sourced from TSER and a one implies that channel data is to be sourced from the output of the receive side framer (i.e., Per–Channel Loopback; see Figure 1–1).

TIDR: TRANSMIT IDLE DEFINITION REGISTER (Address=2A Hex)

(MSB) (LSB)

TIDR7

SYMBOL POSITION NAME AND DESCRIPTION

TIDR7 TIDR.7 MSB of the Idle Code (this bit is transmitted first) TIDR0 TIDR.0 LSB of the Idle Code (this bit is transmitted last)

TIDR6 TIDR5 TIDR4 TIDR3 TIDR2 TIDR1 TIDR0

8.1.2 Per–Channel Code Insertion

The second method involves using the Transmit Channel Control Registers (TCC1/2/3/4) to determine which of the 32 E1 channels should be overwritten with the

code placed in the Transmit Channel Registers (TC1 to TC32). This method is more flexible than the first in that it allows a different 8–bit code to be placed into each of the 32 E1 channels.

TC1 TO TC32: TRANSMIT CHANNEL REGISTERS (Address=60 to 7F Hex) (for brevity , only channel one is shown; see Table 1–3 for other register address)

(MSB) (LSB)

SYMBOL POSITION NAME AND DESCRIPTION

C7 TC1.7 MSB of the Code (this bit is transmitted first)

C0 TC1.0 LSB of the Code (this bit is transmitted last)

031197 38/69

C6 C5 C4 C3 C2 C0

TC1 (60)

DS2154

TCC1/TCC2/TCC3/TCC4: TRANSMIT CHANNEL CONTROL REGISTER (Address=A0 to A3 Hex)

(MSB) (LSB)

CH8 CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 CH32 CH31 CH30 CH29 CH28 CH27 CH26 CH25

SYMBOL POSITION NAME AND DESCRIPTION

CH32 TCC4.7 Transmit Channel 32 Code Insertion Control Bit

8.2 RECEIVE SIDE CODE GENERATION

On the receive side, the Receive Channel Control Registers (RCC1/2/3/4) are used to determine which of the

CH7 CH6 CH5 CH4 CH3 CH2 CH1

CH1 TCC1.0 Transmit Channel 1 Code Insertion Control Bit

0=do not insert data from the TC1 register into the transmit data stream 1=insert data from the TC1 register into the transmit data stream

0=do not insert data from the TC32 register into the transmit data stream 1=insert data from the TC32 register into the transmit data stream

32 E1 channels off of the E1 line and going to the backplane should be overwritten with the code placed in the Receive Channel Registers (RC1 to RC32).

TCC1 (A0) TCC2 (A1) TCC3 (A2) TCC4 (A3)

RC1 TO RC32: RECEIVE CHANNEL REGISTERS (Address=80 to 9F Hex) (for brevity , only channel one is shown; see Table 1–3 for other register address)

(MSB) (LSB)

C6 C5 C4 C3 C2 C0

RC1 (80)

SYMBOL POSITION NAME AND DESCRIPTION

C7 RC1.7 MSB of the Code (this bit is sent first to the backplane)

C0 RC1.0 LSB of the Code (this bit is sent last to the backplane)

RCC1/RCC2/RCC3/RCC4: RECEIVE CHANNEL CONTROL REGISTER (Address=A4 to A7 Hex)

(MSB) (LSB)

CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 CH32 CH31 CH30 CH29 CH28 CH27 CH26 CH25

SYMBOL POSITION NAME AND DESCRIPTION

CH1 RCC1.0 Receive Channel 1 Code Insertion Control Bit

0=do not insert data from the RC1 register into the receive data stream 1=insert data from the RC1 register into the receive data stream

CH32 RCC4.7 Receive Channel 32 Code Insertion Control Bit

0=do not insert data from the RC32 register into the receive data stream 1=insert data from the RC32 register into the receive data stream

RCC1 (A4) RCC2 (A5) RCC3 (A6) RCC4 (A7)

031197 39/69

DS2154

9.0 CLOCK BLOCKING REGISTERS

The Receive Channel blocking Registers (RCBR1 / RCBR2 / RCBR3 / RCBR4) and the Transmit Channel Blocking Registers (TCBR1 / TCBR2 / TCBR3 / TCBR4) control RCHBLK and TCHBLK pins respectively. (The RCHBLK and TCHBLK pins are user programmable outputs that can be forced either high or low during individual channels). These outputs can be used to block clocks to a USART or LAPD controller in ISDN–PRI applications. When the appropriate bits are set to a one,

the RCHBLK and TCHBLK pin will be held high during the entire corresponding channel time. See the timing in Section 13 for an example. The TCBRs have alternate mode of use. Via the CCR3.6 bit, the user has the option to use the TCBRs to determine on a channel by channel basis, which signaling bits are to be inserted via the TSRs (the corresponding bit in the TCBRs=1) and which are to be sourced from the TSER or TSIG pins (the corresponding bit in the TCBR=0). See Section 7 for more details about this mode of operation.

RCBR1/RCBR2/RCBR3/RCBR4: RECEIVE CHANNEL BLOCKING REGISTERS

(Address=2B to 2E Hex)

(MSB) (LSB)

CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 CH32 CH31 CH30 CH29 CH28 CH27 CH26 CH25

SYMBOL POSITION NAME AND DESCRIPTION

CH32 RCBR4.7 Receive Channel Blocking Registers.

CH1 RCBR1.0 1=force the RCHBLK pin high during this channel time

0=force the RCHBLK pin to remain low during this channel time

RCBR1 (2B) RCBR2 (2C) RCBR3 (2D) RCBR4 (2E)

TCBR1/TCBR2/TCBR3/TCBR4: TRANSMIT CHANNEL BLOCKING REGISTERS

(Address=22 to 25 Hex)

(MSB) (LSB)

CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 CH32 CH31 CH30 CH29 CH28 CH27 CH26 CH25

SYMBOL POSITION NAME AND DESCRIPTION

CH32 TCBR4.7 Transmit Channel Blocking Registers.

0=force the TCHBLK pin to remain low during this channel time

CH1 TCBR1.0 1=force the TCHBLK pin high during this channel time

TCBR1 (22) TCBR2 (23) TCBR3 (24) TCBR4 (25)

NOTE:

If CCR3.6=1, then a zero in the TCBRs implies that signaling data is to be sourced from TSER (or TSIG if CCR3.2=1) and a one implies that signaling data for that channel is to be sourced from the Transmit Signaling (TS) registers. See definition below.

031197 40/69

DS2154

TCBR1/TCBR2/TCBR3/TCBR4: DEFINITION WHEN CCR3.6=1

(MSB) (LSB)

CH20 CH24 CH8 CH23 CH7 CH22 CH6 CH21 CH5 CH28 CH12 CH27 CH11 CH26 CH10 CH25 CH9 CH32 CH16 CH31 CH15 CH30 CH14 CH29 CH13

*=CH1 and CH17 should be set to one to allow the internal TS1 register to create the CAS Multiframe Alignment Word and Spare/Remote Alarm bits.

CH4 CH19 CH3 CH18 CH2 CH17* CH1*

TCBR1(22) TCBR2(23)

TCBR3(24) TCBR4(25)

10.0 ELASTIC STORES OPERATION

The DS2154 contains dual two–frame (512 bits) elastic stores, one for the receive direction, and one for the transmit direction. These elastic stores have two main purposes. First, they can be used to rate convert the E1 data stream to 1.544 Mbps (or a multiple of 1.544 Mbps) which is the T1 rate. Secondly, they can be used to absorb the differences in frequency and phase between the E1 data stream and an asynchronous (i.e., not frequency locked) backplane clock which can be

1.544 MHz or 2.048 MHz. The backplane clock can burst at rates up to 8.192 MHz. Both elastic stores contain full controlled slip capability which is necessary for this second purpose. The elastic stores can be forced to a known depth via the Elastic Store Reset bit (CCR3.4). T oggling the CCR3.4 bit forces the read and write pointers into opposite frames. Both elastic stores within the DS2154 are fully independent and no restrictions apply to the sourcing of the various clocks that are applied to them. The transmit side elastic store can be enabled whether the receive elastic store is enabled or disabled and vice versa. Also, each elastic store can interface to either a 1.544 MHz or 2.048 MHz backplane without regard to the backplane rate the other elastic store is interfacing.

10.1 RECEIVE SIDE

If the receive side elastic store is enabled (RCR2.1=1), then the user must provide either a 1.544 MHz (RCR2.2 =0) or 2.048 MHz (RCR2.2=1) clock at the RSYSCLK pin. The the user has the option of either providing a frame/multiframe sync at the RSYNC pin (RCR1.5=1) or having the RSYNC pin provide a pulse on frame/multiframe boundaries (RCR1.5=0). If the user wishes to obtain pulses at the frame boundary , then RCR1.6 must be set to zero and if the user wishes to have pulses occur at the multiframe boundary, then RCR1.6 must be set to one. The DS2154 will always indicate frame

boundaries via the RFSYNC output whether the elastic store is enabled or not. If the elastic store is enabled, then either CAS (RCR1.7=0) or CRC4 (RCR1.7=1) multiframe boundaries will be indicated via the RMSYNC output. If the user selects to apply a 1.544 MHz clock to the RSYSCLK pin, then every fourth channel of the received E1 data will be deleted and a F–bit position (which will be forced to one) will be inserted. Hence Channels 1, 5, 9, 13, 17, 21, 25, and 29 (timeslots 0, 4, 8, 12, 16, 20, 24, and 28) will be deleted from the received E1 data stream. Also, in 1.544 MHz applications, the RCHBLK output will not be active in Channels 25 through 32 (or in other words, RCBR4 is not active). See Section 13 for timing details. If the 512–bit elastic buffer either fills or empties, a controlled slip will occur . If the buffer empties, then a full frame of data (256–bits) will be repeated at RSER and the SR1.4 and RIR.3 bits will be set to a one. If the buffer fills, then a full frame of data will be deleted and the SR1.4 and RIR.4 bits will be set to a one.

10.2 TRANSMIT SIDE

The operation of the transmit elastic store is very similar to the receive side. The transmit side elastic store is enabled via CCR3.7. A 1.544 MHz (CCR3.1=0) or

2.048 MHz (CCR3.1=1) clock can be applied to the TSYSCLK input. The TSYSCLK can be a bursty clock with rates up to 8.192 MHz. If the user selects to apply a

1.544 MHz clock to the TSYSCLK pin, then the data sampled at TSER will be ignored every fourth channel. Hence Channels 1, 5, 9, 13, 17, 21, 25, and 29 (timeslots 0, 4, 8, 12, 16, 20, 24, and 28) will be ignored. The user must supply a 8 KHz frame sync pulse to the TSSYNC input. See Section 13 for timing details. Controlled slips in the transmit elastic store are reported in the SR2.0 bit and the direction of the slip is reported in the RIR.6 and RIR.7 bits.

031197 41/69

DS2154

11.0 ADDITIONAL (Sa) AND INTERNATIONAL (Si) BIT OPERATION

The DS2154 provides for access to both the Sa and the Si bits via three different methods. The first is via a hardware scheme using the RLINK/RLCLK and TLINK/ TLCLK pins. The first method is discussed in Section 11.1. The second involves using the internal RAF/RNAF and TAF/TNAF registers and is discussed in Section 11.2 The third method which is covered in Section 11.3 involves an expanded version of the second method and is one of the features added to the DS2154 from the original DS2153 definition.

11.1 HARDWARE SCHEME

On the receive side, all of the received data is reported at the RLINK pin. Via RCR2, the user can control the RLCLK pin to pulse during any combination of Sa bits. This allows the user to create a clock that can be used to capture the needed Sa bits. If RSYNC is programmed to output a frame boundary, it will identify the Si bits. See Section 13 for detailed timing.

On the transmit side, the individual Sa bits can be either sourced from the internal TNAF register (see Section 11.2 for details) or from the external TLINK pin. Via TCR2, the DS2154 can be programmed to source any combination of the additional bits from the TLINK pin. If the user wishes to pass the Sa bits through the DS2154 without them being altered, then the device should be set up to source all five Sa bits via the TLINK pin and the TLINK pin should be tied to the TSER pin. Si

bits can be inserted through the TSER pin via the clearing of the TCR1.3 bit. Please see the timing diagrams and the transmit data flow diagram in Section 13 for examples.

11.2 INTERNAL REGISTER SCHEME BASED ON DOUBLE–FRAME

On the receive side, the RAF and RNAF registers will always report the data as it received in the Additional and International bit locations. The RAF and RNAF registers are updated with the setting of the Receive Align Frame bit in Status Register 2 (SR2.6). The host can use the SR2.6 bit to know when to read the RAF and RNAF registers. It has 250 us to retrieve the data before it is lost.

On the transmit side, data is sampled from the TAF and TNAF registers with the setting of the Transmit Align Frame bit in Status Register 2 (SR2.3). The host can use the SR2.3 bit to know when to update the T AF and TNAF registers. It has 250 us to update the data or else the old data will be retransmitted. Data in the Si bit position will be overwritten if either the DS2154 is programmed: (1) to source the Si bits from the TSER pin, (2) in the CRC4 mode, or (3) have automatic E–bit insertion enabled. Data in the Sa bit position will be overwritten if any of the TCR2.3 to TCR2.7 bits are set to one (please see Section 11.1 for details). Please see the register descriptions for TCR1 and TCR2 and the Transmit Data Flow diagram in Section 13 for more details.

RAF: RECEIVE ALIGN FRAME REGISTER (Address=2F Hex)

(MSB) (LSB)

SYMBOL POSITION NAME AND DESCRIPTION

Si RAF.7 International Bit.

0 RAF.6 Frame Alignment Signal Bit. 0 RAF.5 Frame Alignment Signal Bit. 1 RAF.4 Frame Alignment Signal Bit. 1 RAF.3 Frame Alignment Signal Bit. 0 RAF.2 Frame Alignment Signal Bit. 1 RAF.1 Frame Alignment Signal Bit. 1 RAF.0 Frame Alignment Signal Bit.

031197 42/69

0 0 1 1 0 1 1

RNAF: RECEIVE NON–ALIGN FRAME REGISTER (Address=1F Hex)

(MSB) (LSB)

Si 1 A Sa4 Sa5 Sa6 Sa7 Sa8

SYMBOL POSITION NAME AND DESCRIPTION

Si RNAF.7 International Bit.

1 RNAF.6 Frame Non–Alignment Signal Bit.

A RNAF.5 Remote Alarm. Sa4 RNAF .4 Additional Bit 4. Sa5 RNAF .3 Additional Bit 5. Sa6 RNAF .2 Additional Bit 6. Sa7 RNAF .1 Additional Bit 7. Sa8 RNAF .0 Additional Bit 8.

TAF: TRANSMIT ALIGN FRAME REGISTER (Address=20 Hex)

(MSB) (LSB)

Si 0 0 1 1 0 1 1

[Must be programmed with the seven bit FAS word; the DS2154 does not automatically set these bits]

DS2154

SYMBOL POSITION NAME AND DESCRIPTION

Si TAF.7 International Bit.

0 TAF.6 Frame Alignment Signal Bit. 0 TAF.5 Frame Alignment Signal Bit. 1 TAF.4 Frame Alignment Signal Bit. 1 TAF.3 Frame Alignment Signal Bit. 0 TAF.2 Frame Alignment Signal Bit. 1 TAF.1 Frame Alignment Signal Bit. 1 TAF.0 Frame Alignment Signal Bit.

TNAF: TRANSMIT NON–ALIGN FRAME REGISTER (Address=21 Hex)

(MSB) (LSB)

Si 1 A Sa4 Sa5 Sa6 Sa7 Sa8

[Bit 2 must be programmed to one; the DS2154 does not automatically set this bit]

SYMBOL POSITION NAME AND DESCRIPTION

Si TNAF.7 International Bit.

1 TNAF.6 Frame Non–Alignment Signal Bit.

031197 43/69

DS2154

A TNAF.5 Remote Alarm (used to transmit the alarm). Sa4 TNAF.4 Additional Bit 4. Sa5 TNAF.3 Additional Bit 5. Sa6 TNAF.2 Additional Bit 6. Sa7 TNAF.1 Additional Bit 7. Sa8 TNAF.0 Additional Bit 8.

11.3 INTERNAL REGISTER SCHEME BASED ON CRC4 MULTIFRAME

On the receive side, there is a set of eight registers (RSiAF , RSiNAF , RRA, RSa4 to RSa8) that report the Si and Sa bits as they are received. These registers are updated with the setting of the Receive CRC4 Multiframe bit in Status Register 2 (SR2.1). The host can use the SR2.1 bit to know when to read these registers. The user has 2 ms to retrieve the data before it is lost. The MSB of each register is the first received. Please see the register descriptions below and the Transmit Data Flow diagram in Section 13 for more details.

On the transmit side, there is also a set of eight registers (TSiAF , TSiNAF , TRA, TSa4 to TSa8) that via the Transmit Sa Bit Control Register (TSaCR), can be programmed to insert both Si and Sa data. Data is sampled from these registers with the setting of the Transmit Multiframe bit in Status Register 2 (SR2.5). The host can use the SR2.5 bit to know when to update these registers. It has 2 ms to update the data or else the old data will be retransmitted. The MSB of each register is the first bit transmitted. Please see the register descriptions below and the Transmit Data Flow diagram in Section 13 for more details.

031197 44/69

DS2154

NAME

ADDRESS

(HEX)

FUNCTION

RSiAF 58 The eight Si bits in the align frame

RSiNAF 59 The eight Si bits in the non–align frame

RRA 5A The eight reportings of the receive remote alarm (RA) RSa4 5B The eight Sa4 reported in each CRC4 multiframe RSa5 5C The eight Sa5 reported in each CRC4 multiframe RSa6 5D The eight Sa6 reported in each CRC4 multiframe RSa7 5E The eight Sa7 reported in each CRC4 multiframe RSa8 5F The eight Sa8 reported in each CRC4 multiframe

TSiAF 50 The eight Si bits to be inserted into the align fram

TSiNAF 51 The eight Si bits to be inserted into the non–align frame

TRA 52 The eight settings of remote alarm (RA) TSa4 53 The eight Sa4 settings in each CRC4 multiframe TSa5 54 The eight Sa5 settings in each CRC4 multiframe TSa6 55 The eight Sa6 settings in each CRC4 multiframe TSa7 56 The eight Sa7 settings in each CRC4 multiframe TSa8 57 The eight Sa8 settings in each CRC4 multiframe

TSaCR: TRANSMIT Sa BIT CONTROL REGISTER (Address=1C Hex)

(MSB) (LSB)

SiAF

SYMBOL POSITION NAME AND DESCRIPTION

SiAF TSaCR.7 International Bit in Align Frame Insertion Control Bit.

SiNAF TSaCR.6 International Bit in Non–Align Frame Insertion Control Bit.

RA TSaCR.5 Remote Alarm Insertion Control Bit.

Sa4 TSaCR.4 Additional Bit 4 Insertion Control Bit.

Sa5 TSaCR.3 Additional Bit 5 Insertion Control Bit.

SiNAF RA Sa4 Sa5 Sa6 Sa7 Sa8

0=do not insert data from the TSiAF register into the transmit data stream 1=insert data from the TSiAF register into the transmit data stream

0=do not insert data from the TSiNAF register into the transmit data stream 1=insert data from the TSiNAF register into the transmit data stream

0=do not insert data from the TRA register into the transmit data stream 1=insert data from the TRA register into the transmit data stream

0=do not insert data from the TSa4 register into the transmit data stream 1=insert data from the TSa4 register into the transmit data stream

0=do not insert data from the TSa5 register into the transmit data stream 1=insert data from the TSa5 register into the transmit data stream

031197 45/69

DS2154

Sa6 TSaCR.2 Additional Bit 6 Insertion Control Bit.

Sa7 TSaCR.1 Additional Bit 7 Insertion Control Bit.

Sa8 TSaCR.0 Additional Bit 8 Insertion Control Bit.

0=do not insert data from the TSa6 register into the transmit data stream 1=insert data from the TSa6 register into the transmit data stream

0=do not insert data from the TSa7 register into the transmit data stream 1=insert data from the TSa7 register into the transmit data stream

0=do not insert data from the TSa8 register into the transmit data stream 1=insert data from the TSa8 register into the transmit data stream

12.0 LINE INTERFACE FUNCTIONS

The line interface function in the DS2154 contains three sections; (1) the receiver which handles clock and data recovery, (2) the transmitter which waveshapes and

drives the E1 line, and (3) the jitter attenuator. Each of the these three sections is controlled by the Line Interface Control Register (LICR) which is described below.

LICR: LINE INTERFACE CONTROL REGISTER (Address=18 Hex)

(MSB) (LSB)

L2 L1 L0 EGL JAS JABDS DJA TPD

SYMBOL POSITION NAME AND DESCRIPTION

L2 LICR.7 Line Build Out Bit 2. Transmit waveshape setting; see Table 12–2.

L1 LICR.6 Line Build Out Bit 1. Transmit waveshape setting; see Table 12–2.

L0 LICR.5 Line Build Out Bit 0. Transmit waveshape setting; see Table 12–2.

EGL LICR.4 Receive Equalizer Gain Limit.

JAS LICR.3 Jitter Attenuator Select.

JABDS LICR.2 Jitter Attenuator Buffer Depth Select

DJA LICR.1 Disable Jitter Attenuator.

TPD LICR.0 Transmit Power Down.

12.1 RECEIVE CLOCK AND DATA RECOVERY

The DS2154 contains a digital clock recovery system. See the DS2154 Block Diagram in Section 1 and Figure 12–1 for more details. The DS2154 couples to the receive E1 shielded twisted pair or COAX via a 1:1 transformer. See Table 12–3 for transformer details. The 2.048 MHz clock attached at the MCLK pin is internally multiplied by 16 via an internal PLL and fed to the

0=–12 dB 1=–43 dB

0=place the jitter attenuator on the receive side 1=place the jitter attenuator on the transmit side

0=128–bits 1=32–bits (use for delay sensitive applications)

0=jitter attenuator enabled 1=jitter attenuator disabled

0=normal transmitter operation 1=powers down the transmitter and 3–states the TTIP and TRING pins

clock recovery system. The clock recovery system uses the clock from the PLL circuit to form a 16 times oversampler which is used to recover the clock and data. This oversampling technique offers outstanding jitter tolerance (see Figure 12–2).

Normally, the clock that is output at the RCLKO pin is the recovered clock from the E1 AMI/HDB3 waveform presented at the RTIP and RRING inputs. When no AMI sig-

LICR

031197 46/69

DS2154

nal is present at RTIP and RRING, a Receive Carrier Loss (RCL) condition will occur and the RCLKO will be sourced from the clock applied at the MCLK pin. If the jitter attenuator is either placed in the transmit path or is disabled, the RCLKO output can exhibit slightly shorter high cycles of the clock. This is due to the highly oversampled digital clock recovery circuitry. If the jitter attenuator is placed in the receive path (as is the case in most applications), the jitter attenuator restores the RCLK to being close to 50% duty cycle. Please see the Receive AC Timing Characteristics in Section 14 for more details.

12.2 TRANSMIT WAVESHAPING AND LINE DRIVING

The DS2154 uses a set of laser–trimmed delay lines along with a precision Digital–to–Analog Converter (DAC) to create the waveforms that are transmitted onto the E1 line. The waveforms created by the DS2154 meet the ITU G.703 specifications. See Figure 12–3. The user will select which waveform is to be generated by properly programming the L2/L1/L0 bits in the Line Interface Control Register (LICR). The DS2154 can set set up in a number of various configurations depending on the application. See Table 12–2 and Figure 12–1.

LINE BUILD OUT SELECT IN LICR Table 12–2

LLL

210

000 75 ohm normal (See Note 1) 1:1.15 step–up NM 0 ohms 001 120 ohm normal 1:1.15 step–up NM 0 ohms 010 75 ohm w/ protection resistors 1:1.15 step–up NM 8.2 ohms

011 120 ohm w/ protection resistors 1:1.15 step–up NM 8.2 ohms

100 75 ohm w/ high return loss 1:1.15 step–up 21dB 27 ohms

110 75 ohm w/ high return loss 1:1.36 step–up 21dB 18 ohms

100 120 ohm w/ high return loss 1:1.36 step–up 21dB 27 ohms

APPLICATION TRANSFORMER

RETURN

LOSS

RT (SEE

FIGURE 12–1)

NOTE:

1. This LBO is not recommended for use in the A2 revision of the DS2154. Due to the nature of the design of the transmitter in the

DS2154, very little jitter (less then 0.005 UIpp broadband from 10 Hz to 100 KHz) is added to the jitter present on TCLK. Also, the waveforms that they create are independent of the duty cycle of TCLK. The transmitter in the DS2154 couples to the E1 transmit shielded twisted pair or COAX via a 1:1.15 or 1:1.36 step up

transformer as shown in Figure 12–1. In order for the devices to create the proper waveforms, this transformer used must meet the specifications listed in T able 12–3 The line driver in the DS2154 contains a current limiter that will prevent more than 50 mA (rms) from being sourced in a 1 ohm load.

TRANSFORMER SPECIFICATIONS Table 12–3

SPECIFICATION RECOMMENDED VALUE

Turns Ratio 1:1 (receive) and 1:1.15 or 1:1.36 (transmit) ± 5% Primary Inductance 600 uH minimum Leakage Inductance 1.0 uH maximum Intertwining Capacitance 40 pF maximum DC Resistance 1.2 ohms maximum

031197 47/69

DS2154

12.3 JITTER ATTENUATOR

The DS2154 contains an onboard jitter attenuator that can be set to a depth of either 32 or 128 bits via the JABDS bit in the Line Interface Control Register (LICR). 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. The characteristics of the attenuation are shown in Figure 12–4. The jitter attenuator can be placed in either the receive path or the transmit path by appropriately setting or clearing the JAS bit in the LICR. Also, the jitter attenuator can be disabled (in effect, removed) by setting the DJA bit in the LICR. In order for the jitter attenuator to operate properly, a 2.048 MHz clock (±50 ppm) must be applied at the MCLK pin or a crystal with similar characteristics must be applied across the MCLK and XTALD pins. If a crystal is applied across the MCLK and XTALD pins, then the maximum effective series resistance should be 40

ohms and capacitors should be placed from each leg of the crystal to ground as shown in Figure 12–1. Onboard circuitry adjusts either the recovered clock from the clock/data recovery block or the clock applied at the TCLKI 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 TCLKI pin if the jitter attenuator is placed on the transmit side. If the incoming jitter exceeds either 120 UIpp (buffer depth is 128 bits) or 28 UIpp (buffer depth is 32 bits), then the DS2154 will divide the internal nominal 32.768 MHz 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 Jitter Attenuator Limit Trip (JAL T) bit in the Receive Information Register (RIR.5).

DS2154 EXTERNAL ANALOG CONNECTIONS Figure 12–1

0.47 uF (non–

polarized)

E1 TRANSMIT

LINE

1.15:1 or 1.36:1

(larger winding toward

the network)

TTIP

TRING

DS2154

DVDD

DVSS

RVDD

RVSS

TVDD TVSS

61 60

0. 01u F 18 19

31 30

0. 1uF

+5V

E1 RECEIVE

LINE

1:1

RTIP

RRING

Rr Rr

0.1 uF

XTALD

MCLK

XTALD

MCLK

2. 048MHz

C1/C2

–or–

2.048 MHz

NOTES:

1. All resistor values are ±1%.

2. The Rt resistors are used to increase the transmitter return loss or to protect the device from over–voltage.

3. The Rr resistors are used to terminate the receive E1 line.

4. For 75 ohm termination, Rr=37.5 ohms/for 120 ohm termination Rr=60 ohm.

5. See the separate Application Note for details on how to construct a protected interface.

6. Either a crystal can be applied across the MCLK and XTALD pins or a TTL level clock can be applied to just MCLK.

7. C1 and C2 should be 5 pF lower than two times the nominal loading capacitance of the crystal to adjust for the input capacitance of the DS2154.

031197 48/69

DS2154 JITTER TOLERANCE Figure 12–2

DS2154

1.5

DS2154 TOLERANCE

UNIT INTERVALS (UIpp)

100

0.1

MINIMUM TOLERANCE

LEVEL AS PER

ITU G.823

10 100 1K 10K 100K

FREQUENCY (Hz)

DS2154 TRANSMIT WAVEFORM TEMPLATE Figure 12–3

1. 2

1. 1

1. 0

0. 9

0. 8

0. 7

0. 6

0. 5

0. 4

0. 3

0. 2

SCALED AMPLITUDE

0. 1 0

(in 75 ohm systems, 1.0 on the scale = 2.37Vpeak

–0. 1

in 120 ohm systems, 1.0 on the scale = 3.00Vpeak)

–0. 2

194 ns

219 ns

2.4K

0.2

18K

269 ns

G.703

Template

TIME (ns)

50 100 150 200 250–50–100–150–200–250

031197 49/69

DS2154

DS2154 JITTER ATTENUATION Figure 12–4

0 dB

–20 dB

DS2154 JITTER

ATTENUATION

–40 dB

JITTER ATTEN UATION (dB)

–60 dB

1 10 100 1K 10K

CURVE

FREQUENCY (Hz)

ITU G.7XX

PROHIBITED AREA

ETS 300 011 AND TBR12 PROHIBITED AREA

100K

031197 50/69

13.0 TIMING DIAGRAMS/SYNC FLOWCHART/TRANSMIT DATA FLOW DIAGRAM RECEIVE SIDE TIMING Figure 13–1

15 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15FRAME# 1612345614

RSYNC1/ RFSYNC

RSYNC

RLCLK

RLINK

NOTES:

1. RSYNC in the frame mode (RCR1.6=0).

2. RSYNC in the multiframe mode (RCR1.6=1).

3. RLCLK is programmed to pulse high during the Sa4 bit position.

4. RLINK will always output all five Sa bits as well as the rest of the receive data stream.

5. This diagram assumes the CAS MF begins with the FAS word.

RECEIVE SIDE BOUNDARY TIMING (WITH ELASTIC STORE DISABLED) Figure 13–2

DS2154

RCLK

RSER/ RDATA

RSYNC/ RFSYNC

RSIG

RCHCLK

RCHBLK

RLINK

RLCLK

CHANNEL 32

MSB

CHANNEL 32 CHANNEL 2

BCD

LSB

CHANNEL 1

A MSBSa4 Sa5 Sa6 Sa7 Sa8

CHANNEL 1

NOTE 4

NOTES:

1. RCHBLK is programmed to block Channel 2.

2. RLCLK is programmed to pulse high during the Sa4 bits position.

3. Shown is a non–align frame boundary.

4. RSIG normally contains the CAS multiframe alignment nibble (0000) in Channel 1.

CHANNEL 2

MSBSa4 Sa5 Sa6 Sa7 Sa8

031197 51/69

DS2154

RECEIVE SIDE 1.544 MHz BOUNDARY TIMING (WITH ELASTIC STORE ENABLED) Figure 13–3

RSYSCLK

RSER

RSYNC2/ RMSYNC

RSYNC

RCHCLK

RCHBLK

LSB MSB LSB MSBF

CHANNEL 24/32 CHANNEL 1/2CHANNEL 23/31

NOTES:

1. Data from the E1 Channels 1, 5, 9, 13, 17, 21, 25, and 29 is dropped (Channel 2 from the E1 link is mapped to Channel 1 of the T1 link, etc.) and the F–bit position is added (forced to one).

2. RSYNC is in the output mode (RCR1.5=0).

3. RSYNC is in the input mode (RCR1.5=1).

4. RCHBLK is programmed to block Channel 24.

RECEIVE SIDE 2.048 MHz BOUNDARY TIMING (WITH ELASTIC STORE ENABLED) Figure 13–4

RSYSCLK

CHANNEL 32 CHANNEL 1CHANNEL 31

RSER

RSYNC RMSYNC

RSYNC

RSIG

RCHCLK

RCHBLK

CHANNEL 31 CHANNEL 1

A BCD

LSB MSB LSB MSB

CHANNEL 32

ABCD

NOTE 4

NOTES:

1. RSYNC is in the output mode (RCR1.5=0).

2. RSYNC is in the input mode (RCR1.5=1).

3. RCHBLK is programmed to block Channel 1.

4. RSIG normally contains the CAS multiframe alignment nibble (0000) in Channel 1.

031197 52/69

TRANSMIT SIDE TIMING Figure 13–5

DS2154

FRAME#

TSYNC1/ TFSYNC

TSYNC

TLCLK

TLINK

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

16 1 2 3 4 5 614

NOTES:

1. TSYNC in the frame mode (TCR1.1=0).

2. TSYNC in the multiframe mode (TCR1.1=1).

3. TLINK is programmed to source only the Sa4 bit.

4. This diagram assumes both the CAS MF and the CRC4 begin with the align frame.

TRANSMIT SIDE BOUNDARY TIMING Figure 13–6

TCLK

TSER

TSYNC TFSYNC

TSYNC

TSIG

CHANNEL 32 B

LSB Si 1 A Sa4 Sa5 Sa6 Sa7 Sa8 MSB MSBLSB

CHANNEL 1

CD ABCD

CHANNEL 2CHANNEL 1

CHANNEL 2

TCHCLK

TCHBLK

TLCLK

TLINK

Don’t Care

NOTES:

1. TSYNC is in the input mode (TCR1.0=0).

2. TSYNC is in the output mode (TCR1.0=1).

3. TCHBLK is programmed to block Channel 2.

4. TLINK is programmed to source the Sa4 bits.

5. The signaling data at TSIG during Channel 1 is normally overwritten in the transmit formatter with the CAS multiframe alignment nibble (0000).

6. Shown is a non–align frame boundary.

031197 53/69

DS2154

TRANSMIT SIDE 1.544 MHz BOUNDARY TIMING (WITH ELASTIC STORE ENABLED) Figure 13–7

TSYSCLK

TSER

TSSYNC

TCHCLK TCHBLK

LSB MSB MSBLSB

CHANNEL 24

F–BIT

NOTES:

1. TCHBLK is programmed to block Channel 23.

2. The F–bit position is ignored by the DS2154.

TRANSMIT SIDE 2.048 MHz (WITH ELASTIC STORE ENABLED) Figure 13–8

CHANNEL 1CHANNEL 23

TSYSCLK

TSER

TSSYNC

TSIG

TCHCLK TCHBLK

CHANNEL 31

BCD

LSB MSB LSB

NOTE:

1. TCHBLK is programmed to block Channel 31.

CHANNEL 32

ABCD

CHANNEL 1CHANNEL 31

MSB

CHANNEL 1

031197 54/69

DS2154

G.802 TIMING Figure 13–9

TIMESLOT# 30 31 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 0 1 2 3 4

RSYNC/ TSYNC

RCHCLK/ TCHCLK

RCHBLK/

TCHBLK

DETAIL

RCLK/RSYSCLK

TCLK/TSYSCLK

TIMESLOT 25 TIMESLOT 26

RSER/TSER

RCHCLK/TCHCLK

RCHBLK/TCHCLK

LSB MSB

NOTE:

1. RCHBLK or TCHBLK is programmed to pulse high during timeslots 1 to 15, 17 to 25, and during bit 1 of timeslot 26.

031197 55/69

DS2154

DS2154 SYNCHRONIZATION FLOWCHART Figure 13–10

POWER UP

RLOS=1

FAS SEARCH

FASSA=1

RLOS=1

RESYNC IF

RCR1.1=0

INCREMENT CRC4

SYNC COUNTER;

CRC4SA=0

SET FASRC

(RIR.1)

CRC4 RESYNC

CRITERIA MET

(RIR.2)

8 MS TIME OUT

FAS RESYNC

CRITERIA MET

CHECK FOR >=915

OUT OF 1000 CRC

CRC WORD ERROS

CRC4 MULTIFRAME

SEARCH (IF ENABLED

VIA CCR 1.0)

CRC4SA=1

CRC4 SYNC CRITERIA

MET; CRC4SA=0;

RESET CRC4 SYNC

COUNTER

CHECK FOR FAS

FRAMING ERROR

(DEPENDS ON

RCR1.2)

IF CRC4 IS ON

(CCR1.0=1)

FAS SYNC

CRITERIA MET

FASSA=0

SYNC DECLARED

RLOS=0

CAS MULTIFRAME

SEARCH (IF ENABLED

VIA CCR1.3)

CASSA=1

CAS SYNC

CRITERIA MET

CASSA=0

031197 56/69

IF CAS IS ON

(CCR1.3=0)

CAS RESYNC

CRITERIA MET;

SET CASRC

(RIR.0)

CHECK FOR CAS

MF WORD ERROR

DS2154 TRANSMIT DATA FLOW Figure 13–1 1

TSER

TDATA

TC1 TO TC32

TLINK

RSER

(note 1)

DS2154

TAF

TNAF

TIMESLOT 0

PASS–THROUGH

(TCR1.6)

TCBR1/2/3/4

CCR3.6

Si BIT INSERTION

CONTROL

(TCR1.3)

CRC4 MULTIFRAME ALIGNMENT WORD

GENERATION(CCR1.4)

E–BIT GENERATION

TCR1.5

KEY

= REGISTER = DEVICE PIN

= SELECTOR

PER–CHANNEL CODE

GENERATION

(TCC1/2/3/4)

RECEIVE SIDE

CRC4 ERROR

DETECTOR

(TCR2.1)

Sa BIT INSERTION CONTROL (TCR2.3

THRU TCR2.7)

AUTO REMOTE

ALARM GENERATION

(CCR2.4)

Sa BIT INSERTION

CONTROL REGISTER

TSa4 to TSa8

(TSaCR)

IDLE CODE/CHANNEL INSERTION CONTROL

VIA TIR1/2/3/4

SIGNALING BIT

INSERTION CONTROL

CRC4 ENABLE

DS0 MONITOR

TSiAF

TSiNAF

TRA

TS1 TO TS16

(CCR.4)

TRANSMIT UNFRAMED ALL ONES (TCR1.4) OR

AUTO AIS (CCR2.5)

TRANSMIT SIGNALLING

TPOS,

TNEG

CODE WORD

GENERATION

TIDR

TIR FUNCTION SELECT

(CCR3.5)

AIS

GENERATION

ALL ONES

(TCR1.2)

AIS

GENERATION 1

NOTES:

1. TCLK should be tied to RCLK and TSYNC should be tied to RFSYNC for data to be properly sourced from RSER.

2. Auto Remote Alarm if enabled will only overwrite bit 3 of timeslot 0 in the Non Align Frames if the alarm needs to be sent.

031197 57/69

DS2154

ABSOLUTE MAXIMUM RATINGS*

Voltage on Any Pin Relative to Ground –1.0V to +7.0V Operating Temperature for DS2154L 0°C to 70°C Operating Temperature for DS2154LN –40°C to +85°C Storage Temperature –55°C to +125°C Soldering Temperature 260°C for 10 seconds

* This is a stress rating only and functional operation of the device at these or any other conditions above those

indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability.

RECOMMENDED DC OPERATING CONDITIONS (0°C to 70°C for DS2154L;

–40°C to +

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

Logic 1 V Logic 0 V Supply V

2.0 VDD + 0.3 V

–0.3 +0.8 V

4.75 5.25 V 1

85°C for DS2154LN)

CAPACITANCE (tA=25°C)

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

Input Capacitance C Output Capacitance C

OUT

5 pF 7 pF

DC CHARACTERISTICS (0°C to 70°C; VDD=5V ± 5% for DS2154L;

–40°C to +

85°C; V

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

Supply Current @ 5V I Input Leakage I Output Leakage I Output Current (2.4V) I Output Current (0.4V) I

–1.0 +1.0 µA 3

–1.0 mA

+4.0 mA

75 mA 2

=5V ± 5% for DS2154LN)

1.0 µA 4

NOTES:

1. Applies to RVDD, TVDD, and DVDD.

2. TCLK=RCLK=TSYSCLK=RSYSCLK=2.048 MHz; outputs open circuited.

3. 0.0V < V

4. Applied to INT

031197 58/69

< VDD.

when 3–stated.

AC CHARACTERISTICS – MULTIPLEXED PARALLEL PORT (MUX=1) (0°C to 70°C; V

–40°C to +

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

Cycle Time t Pulse Width, DS low or RD high PW Pulse Width, DS high or RD low PW Input Rise/Fall times tR, t R/W Hold Time t R/W Set Up time before DS high t CS Set Up time before DS, WR or

active

RD CS Hold time t Read Data Hold time t Write Data Hold time t Muxed Address valid to AS or

ALE fall Muxed Address Hold time t Delay time DS, WR or RD to AS

or ALE rise Pulse Width AS or ALE high PW Delay time, AS or ALE to DS, WR

or RD Output Data Delay time from DS

or RD Data Set Up time t

See Figures 14–1 to 14–3 for details.

CYC

RWH RWS

CH DHR DHW

ASL

AHL

ASD

ASED

DDR

DSW

ASH

200 ns 100 ns 100 ns

10 ns 50 ns 20 ns

0 ns

10 50 ns

0 ns

15 ns

10 ns 20 ns

30 ns 10 ns

20 80 ns

50 ns

85°C; V

=5V ± 5% for DS2154L;

=5V ± 5% for DS2154LN)

20 ns

DS2154

031197 59/69

DS2154

AC CHARACTERISTICS – RECEIVE SIDE (0°C to 70°C; VDD=5V ± 5% for DS2154L;

–40°C to +

85°C; V

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

RCLKO Period t RCLKO Pulse Width t

RCLKO Pulse Width t

RCLKI Period t RCLKI Pulse Width t

RSYSCLK Period t

RSYSCLK Pulse Width t

RSYNC Set Up to RSYSCLK Falling

RSYNC Pulse Width t RPOSI/RNEGI Set Up to RCLKI

Falling RPOSI/RNEGI Hold From RCLKI

Falling RSYSCLK/RCLKI Rise and Fall

Times Delay RCLKO to RPOSO,

RNEGO Valid Delay RCLK to RSER, RDATA,

RSIG, RLINK Valid Delay RCLK to RCHCLK,

RSYNC, RCHBLK, RFSYNC,

CP CH

t t

tR, t

LP LH

LL LH

CL SP

200 200

150 150

75 75

122 122

50 50

20 tSH–5 ns

50 ns 20 ns

20 ns

488 ns 244

244 244

244 488 ns

648 488

RLCLK Delay RSYSCLK to RSER,

RSIG Valid Delay RSYSCLK to RCHCLK,

RCHBLK, RMSYNC, RSYNC

See Figures 14–4 to 14–6 for details.

=5V ± 5% for DS2154LN)

ns ns

25 ns

50 ns

1 1

2 2

3 4

NOTES:

1. Jitter attenuator enabled in the receive path.

2. Jitter attenuator disabled or enabled in the transmit path.

3. RSYSCLK=1.544 MHz.

4. RSYSCLK=2.048 MHz.

031197 60/69

14.0 A. C. AND D. C. CHARACTERISTICS

INTEL BUS READ AC TIMING (BTS=0/MUX=1) Figure 14–1

CYC

ALE

ASD

ASH

ASD

ASED

ASL

AD0-AD7

AHL

INTEL BUS WRITE AC TIMING (BTS=0/MUX=1) Figure 14–2

CYC

ALE

ASD

ASH

DDR

DS2154

DHR

AD0-AD7

ASD

ASED

ASL

AHL

DHW

DSW

031197 61/69

DS2154

MOTOROLA BUS AC TIMING (BTS=1/MUX=1) Figure 14–3

ASH

ASD

R/W

AD0-AD7 (READ)

ASL

AHL

t AD0-AD7 (WRITE)

ASL

AHL

RECEIVE SIDE AC TIMING Figure 14–4

RCLK

RSER/RDAT A/RSIG

RCHCLK

RCHBLK

RFSYNC/RMSYNC

RSYNC

RLCLK

RLINK

Sa4 TO Sa8

BIT POSITION

ASED

RWS

CHANNEL 1

MSB OF

CYC

DDR

DSW

RWH

DHR

DHW

NOTES:

1. RSYNC is in the output mode (RCR1.5=0).

2. RLCLK will only pulse high during Sa bit locations as defined in RCR2; no relationship between RLCLK and RSYNC or RFSYNC is implied.

031197 62/69

DS2154

AC CHARACTERISTICS – TRANSMIT SIDE (0°C to 70°C; VDD=5V ± 5% for DS2154L;

–40°C to +

85°C; V

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

TCLK Period t TCLK Pulse Width t

TCLKI Period t TCLKI Pulse Width t

TSYSCLK Period t

TSYSCLK Pulse Width t

TSYNC or TSSYNC Set Up to TCLK or TSYSCLK falling

TSYNC or TSSYNC Pulse Width t TSER, TSIG, TDATA, TLINK,

TPOSI, TNEGI Set Up to

CP CH

SP SH

t t

75 75

122 122

50 50

20 tCH–5 or

50 ns 20 ns

488 ns

648 448

TCLK, TSYSCLK, TCLKI Falling TSER, TSIG, TDATA, TLINK,

TPOSI, TNEGI Hold from

20 ns

TCLK, TSYSCLK, TCLKI Falling TCLK, TCLKI, or TSYSCLK Rise

and Fall Times Delay TCLKO to TPOSO,

TNEGO Valid Delay TCLK to TESO Valid t Delay TCLK to TCHBLK,

TCHBLK, TSYNC, TLCLK Delay TSYSCLK to TCHCLK,

TCHBLK

tR, t

See Figures 14–7 to 14–9 for details.

=5V ± 5% for DS2154LN)

ns ns

–5

25 ns

50 ns

50 ns 50 ns

75 ns

1 2

NOTES:

1. TSYSCLK=1.544 MHz.

2. TSYSCLK=2.048 MHz.

031197 63/69

DS2154

RECEIVE SYSTEM SIDE AC TIMING Figure 14–5

RSYSCLK

RSER/RSIG

RCHCLK

RCHBLK

RMSYNC

RSYNC

MSB

OF CHANNEL 1

NOTES:

1. RSYNC is in the output mode (RCR1.5=0).

2. RSYNC is in the input mode (RCR1.5=1).

RECEIVE LINE INTERFACE AC TIMING Figure 14–6

RCLKO

RPOSO, RNEGO

RPOSI, RNEGI

031197 64/69

RCLKI

TRANSMIT SIDE AC TIMING Figure 14–7

TCLK

TESO

TSER/TSIG/

TDATA

TCHCLK

TCHBLK

TSYNC

TLCLK

TLINK

DS2154

NOTES:

1. TSYNC is in the output mode (TCR1.0=1).

2. TSYNC is in the input mode (TCR1.0=0).

3. TSER is sampled on the falling edge of TCLK when the transmit side elastic store is disabled.

4. TCHCLK and TCHBLK are synchronous with TCLK when the transmit side elastic store is disabled.

5. TLINK is only sampled during Sa–bit locations as defined in TCR2; no relationship between TLCLK/TLINK and TSYNC is implied.

031197 65/69

DS2154

TRANSMIT SYSTEM SIDE AC TIMING Figure 14–8

TSYSCLK

TSER

TCHCLK

TCHBLK

TSSYNC

NOTES:

1. TSER is only sampled on the falling edge of TSYSCLK when the transmit side elastic store is enabled.

2. TCHCLK and TCHBLK are synchronous with TSYSCLK when the transmit side elastic store is enabled.

TRANSMIT LINE INTERFACE SIDE AC TIMING Figure 14–9

TCLKO

TPOSO, TNEGO

TCLKI

TPOSI, TNEGI

031197 66/69

AC CHARACTERISTICS – NON–MULTIPLEXED PARALLEL PORT (MUX=0 ) (0°C to 70°C; V

–40°C to +

PARAMETER SYMBOL MIN TYP MAX UNITS NOTES

Set Up Time for A0 to A7 Valid to

Active

CS Set Up Time for CS Active to

either RD

, WR, or DS Active

Delay Time from either RD or DS Active to Data Valid

Hold Time from either RD, WR, or

Inactive to CS Inactive

DS Hold Time from CS Inactive to

Data Bus 3–state Wait Time from either WR or DS

Active to Latch Data Data Set Up Time to either WR or

Inactive

DS Data Hold Time from either WR or

Inactive

DS Address Hold from either

or DS inactive

See Figures 14–10 to 14–13 for details.

t1 0 ns

t2 0 ns

t3 75 ns

t4 0 ns

t5 5 20 ns

t6 75 ns

t7 10 ns

t8 10 ns

10 ns

85°C; V

=5V ± 5% for DS2154T;

=5V ± 5% for DS2154TN)

INTEL BUS READ AC TIMING (BTS=0/MUX=0) Figure 14–10

DS2154

A0 TO A7

D0 TO D7

0 ns min.

ADDRESS VALID

0 ns min.

75 ns max.

DATA VALID

5 ns min. / 20 ns max.

0 ns min.

031197 67/69

DS2154

INTEL BUS WRITE AC TIMING (BTS=0/MUX=0) Figure 14–1 1

t9 10 ns min.

A0 TO A7

ADDRESS VALID

D0 TO D7

0 ns min.

0 ns min. 0 ns min.

75 ns min.

MOTOROLA BUS READ AC TIMING (BTS=1/MUX=0) Figure 14–12

A0 TO A7

D0 TO D7

R/W

ADDRESS VALID

DATA VALID

5 ns min. /20 ns max.

0 ns min.

0 ns min. 0 ns min.

75 ns max.

10 ns

min.

10 ns

min.

MOTOROLA BUS WRITE AC TIMING (BTS=1/MUX=0) Figure 14–13

A0 TO A7

D0 TO D7

R/W

031197 68/69

ADDRESS VALID

0 ns min.

0 ns min. 0 ns min.

75 ns min.

t7t

10 ns

min.

10 ns

min.

10 ns min.

DS2154 100–PIN LQFP

DS2154

PKG 100–PIN

DIM MIN MAX

A – 1.60 A1 0.05 – A2 1.35 1.45

B 0.17 0.27

C 0.09 0.20

D 15.80 16.20 D1 14.00 BSC

E 15.80 16.20 E1 14.00 BSC

e 0.50 BSC L 0.45 0.75

031197 69/69

Rainbow Electronics DS2154 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual