1 of 94 092299
FEATURES
§ Complete DS1/ISDN-PRI transceiver
functionality
§ Line interface can handle both long and short haul
trunks
§ 32-bit or 128-bit crystal-less jitter attenuator
§ Generates DSX-1 and CSU line build outs
§ Frames to D4, ESF, and SLC-96R 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
(Intel or Motorola)
§ Extracts and inserts robbed-bit signaling
§ Detects and generates yellow (RAI) and blue
(AIS) alarms
§ Programmable output clocks for Fractional T1
§ Fully independent transmit and receive
functionality
§ Integral HDLC controller with 16-byte buffers for
the FDL
§ Generates and detects in-band loop codes from 1
to 8 bits in length including CSU loop codes
§ Contains ANSI 1's density monitor and enforcer
§ Large path and line error counters including BPV,
CV, CRC6, and framing bit errors
§ Pin compatible with DS2154 E1 Enhanced Single-
Chip Transceiver
§ 5V supply; low power CMOS
§ 100-pin 14mm2 body LQFP package
PIN ASSIGNMENT
ORDERING INFORMATION
DS2152L (0°C to 70°C)
DS2152LN (-40°C to +85°C)
DESCRIPTION
The DS2152 T1 Enhanced Single-Chip Transceiver contains all of the necessary functions for connection
to T1 lines, whether they be DS-1 long haul or DSX-1 short haul. The clock recovery circuitry
automatically adjusts to T1 lines from 0 feet to over 6000 feet in length. The device can generate both
DSX-1 line build outs as well as CSU line build outs of -7.5 dB, -15 dB, and -22.5 dB. The onboard jitter
attenuator (selectable to either 32 bits or 128 bits) can be placed in either the transmit or receive 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 robbed-bit signaling data and FDL data. 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 T1 lines. The device fully meets all of the
latest T1 specifications including ANSI T1.403-1995, ANSI T1.231-1993, AT&T TR 62411 (12-90),
AT&T TR54016, and ITU G.703, G.704, G.706, G.823, and I.431.
DS2152
Enhanced T1 Single-Chip Transceiver
www.dalsemi.com
1
100
DS2152
2 of 93
TABLE OF CONTENTS
1.0 INTRODUCTION..................................................................................... 4
Block Diagram............................................................................................................................... 6
Pin List........................................................................................................................................... 7
Pin Description .............................................................................................................................. 9
Register Map.................................................................................................................................. 13
2.0 PARALLEL PORT................................................................................... 17
3.0 CONTROL, ID, AND TEST REGISTERS................................................ 18
Payload Loopback ......................................................................................................................... 23
Framer Loopback........................................................................................................................... 23
Pulse Density Enforcer.................................................................................................................. 25
Local Loopback............................................................................................................................. 27
Power-up Sequence ....................................................................................................................... 29
Remote Loopback.......................................................................................................................... 29
4.0 STATUS AND INFORMATION REGISTERS.......................................... 30
5.0 ERROR COUNT REGISTERS ................................................................ 38
Line Code Violation Count Register ............................................................................................. 39
Path Code Violation Count Register.............................................................................................. 39
Multiframes Out of SYNC Count Register ................................................................................... 40
6.0 DSO MONITORING FUNCTION ............................................................. 41
7.0 SIGNALING OPERATION....................................................................... 44
Processor Based Signaling.......................................................................................................... 44
Hardware Based Signaling.......................................................................................................... 46
8.0 PER-CHANNEL CODE (IDLE) GENERATION AND LOOPBACK.......... 47
Transmit Side Code Generation..................................................................................................... 47
Receive Side Code Generation...................................................................................................... 49
9.0 CLOCK BLOCKING REGISTERS .......................................................... 51
10.0 ELASTIC STORES OPERATION............................................................ 52
11.0 FDL/FS EXTRACTION AND INSERTION................................................ 53
HDLC and BOC Controller for the FDL....................................................................................... 53
Legacy FDL Support ..................................................................................................................... 63
D4/SLC-96 Operation.................................................................................................................... 64
12.0 PROGRAMMABLE IN-BAND CODE GENERATION AND DETECTION 65
13.0 TRANSMIT TRANSPARENCY................................................................ 68
DS2152
3 of 93
14.0 LINE INTERFACE FUNCTION................................................................ 69
15.0 TIMING DIAGRAMS................................................................................ 74
Transmit Data Flow Diagram........................................................................................................ 80
16.0 CHARACTERISTICS .............................................................................. 81
Absolute Maximum Rating............................................................................................................ 81
DC Parameters............................................................................................................................... 81
AC Parameters............................................................................................................................... 82
Timing............................................................................................................................................ 85
Package Description ...................................................................................................................... 93
DS2152
4 of 93
1.0 INTRODUCTION
The DS2152 is a superset version of the popular DS2151 T1 Single-Chip Transceiver offering the new
features listed below. All of the original features of the DS2151 have been retained and software created
for the original devices is transferable into the DS2152.
New Features
§ option for non-multiplexed bus operation
§ crystal-less jitter attenuation
§ 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
§ per-channel code insertion in both transmit and receive paths
§ full HDLC controller for the FDL with 16-byte buffers in both transmit and receive paths
§ RCL, RLOS, RRA, and RAIS alarms now interrupt on change of state
§ 8.192 MHz clock synthesizer
§ per-channel loopback
§ addition of hardware pins to indicate carrier loss & signaling freeze
§ line interface function can be completely decoupled from the framer/formatter to allow:
– interface to optical, HDSL, and other NRZ interfaces
– ability to “tap” the transmit and receive bipolar data streams for monitoring purposes
– ability to corrupt data and insert framing errors, CRC errors, etc.
§ transmit and receive elastic stores now have independent backplane clocks
§ ability to monitor one DS0 channel in both the transmit and receive paths
§ access to the data streams in between the framer/formatter and the elastic stores
§ AIS generation in the line interface that is independent of loopbacks
§ ability to calculate and check CRC6 according to the Japanese standard
§ ability to pass the F-bit position through the elastic stores in the 2.048 MHz backplane mode
§ programmable in-band loop code generator and detector
Functional Description
The analog AMI/B8ZS waveform off the T1 line is transformer-coupled into the RRING and RTIP pins
of the DS2152. 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/multi-frame pattern. The DS2152 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 -36 dB, which allows the device to operate on cables up to 6000 feet in length. The receive side
framer locates D4 (SLC-96) or ESF multiframe boundaries as well as detects incoming alarms, including
carrier loss, loss of synchronization, blue (AIS) and yellow alarms. If needed, the receive side elastic store
can be enabled in order to absorb the phase and frequency differences between the recovered T1 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 be a bursty clock with speeds up to 8.192 MHz.
The transmit side of the DS2152 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
T1 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 DS2152 will drive the T1 line from the
DS2152
5 of 93
TTIP and TRING pins via a coupling transformer. The line driver can handle both long (CSU) and short
haul (DSX-1) lines.
Reader’s Note
This data sheet assumes a particular nomenclature of the T1 operating environment. In each 125 us frame,
there are 24 8-bit channels plus a framing bit. It is assumed that the framing bit is sent first followed by
channel 1. Each channel is made up of 8 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:
D4 Superframe (12 frames per multiframe) Multiframe Structure
SLC-96 Subscriber Loop Carrier - 96 Channels (SLC-96 is an AT&T registered trademark)
ESF Extended Superframe (24 frames per multiframe) Multiframe Structure
B8ZS Bipolar with 8 0 Subsitution
CRC Cyclical Redundancy Check
Ft Terminal Framing Pattern in D4
Fs Signaling Framing Pattern in D4
FPS Framing Pattern in ESF
MF Multiframe
BOC Bit Oriented Code
HDLC High Level Data Link Control
FDL Facility Data Link
DS2152
6 of 93
DS2152 ENHANCED T1 SINGLE-CHIP TRANSCEIVER Figure 1-1
DS2152
7 of 93
PIN LIST Table 1-1
PIN SYMBOL TYPE DESCRIPTION
1RCHBLK OReceive Channel Block
2NC -No Connect
38MCLK O8.192 MHz Clock
4NC -No Connect
5NC -No Connect
6RCL OReceive Carrier Loss
7NC -No Connect
8NC -No Connect
9NC -No Connect
10 NC -No Connect
11 BTS IBus Type Select
12 LIUC ILine Interface Connect
13 8XCLK OEight Times Clock
14 TEST ITest
15 NC -No Connect
16 RTIP IReceive Analog Tip Input
17 RRING IReceive Analog Ring Input
18 RVDD -Receive Analog Positive Supply
19 RVSS -Receive Analog Signal Ground
20 RVSS -Receive Analog Signal Ground
21 MCLK IMaster Clock Input
22 XTALD OQuartz Crystal Driver
23 NC -No Connect
24 RVSS -Receive Analog Signal Ground
25 INT OInterrupt
26 NC -No Connect
27 NC -No Connect
28 NC -No Connect
29 TTIP OTransmit Analog Tip Output
30 TVSS -Transmit Analog Signal Ground
31 TVDD -Transmit Analog Positive Supply
32 TRING OTransmit Analog Ring Output
33 TCHBLK OTransmit Channel Block
34 TLCLK OTransmit Link Clock
35 TLINK ITransmit Link Data
36 NC -No Connect
37 TSYNC I/O Transmit Sync
38 TPOSI ITransmit Positive Data Input
39 TNEGI ITransmit Negative Data Input
40 TCLKI ITransmit Clock Input
41 TCLKO OTransmit Clock Output
42 TNEGO OTransmit Negative Data Output
43 TPOSO OTransmit Positive Data Output
44 DVDD -Digital Positive Supply
45 DVSS -Digital Signal Ground
46 TCLK ITransmit Clock
DS2152
8 of 93
PIN SYMBOL TYPE DESCRIPTION
47 TSER ITransmit Serial Data
48 TSIG ITransmit Signaling Input
49 TESO OTransmit Elastic Store Output
50 TDATA ITransmit Data
51 TSYSCLK ITransmit System Clock
52 TSSYNC ITransmit System Sync
53 TCHCLK OTransmit Channel Clock
54 NC -No Connect
55 MUX IBus 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 IAddress Bus Bit 0
67 A1 IAddress Bus Bit 1
68 A2 IAddress Bus Bit 2
69 A3 IAddress Bus Bit 3
70 A4 IAddress Bus Bit 4
71 A5 IAddress Bus Bit 5
72 A6 IAddress Bus Bit 6
73 A7/ALE IAddress Bus Bit 7 / Address Latch Enable
74
RD
(DS)IRead Input (Data Strobe)
75 CS IChip Select
76 NC -No Connect
77 WR (R/W)IWrite Input (Read/Write)
78 RLINK OReceive Link Data
79 RKCLK OReceive Link Clock
80 DVSS -Digital Signal Ground
81 DVDD -Digital Positive Supply
82 RCLK OReceive Clock
83 DVDD -Digital Positive Supply
84 DVSS -Digital Signal Ground
85 RDATA OReceive Data
86 RPOSI IReceive Positive Data Input
87 RNEGI IReceive Negative Data Input
88 RCLKI IReceive Clock Input
89 RCLKO OReceive Clock Output
90 RNEGO OReceive Negative Data Output
91 RPOSO OReceive Positive Data Output
92 RCHCLK OReceive Channel Clock
93 RSIGF OReceive Signaling Freeze Output
DS2152
9 of 93
PIN SYMBOL TYPE DESCRIPTION
94 RSIG OReceive Signaling Output
95 RSER OReceive Serial Data
96 RMSYNC OReceive Multiframe Sync
97 RFSYNC OReceive Frame Sync
98 RSYNC I/O Receive Sync
99 RLOS/LOTC OReceive Loss Of Sync / Loss of Transmit Clock
100 RSYSCLK IReceive System Clock
NOTE:
Leave all no connect (NC) pins open circuited.
DS2152 PIN DESCRIPTION Table 1-2
TRANSMIT SIDE DIGITAL PINS
Transmit Clock [TCLK]. A 1.544 MHz primary clock. Used to clock data through the transmit side
formatter.
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 192 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 24 T1 channels. Synchronous with TCLK when the transmit side elastic store is
disabled. Synchronous with TSYSCLK when the transmit side elastic store is enabled. Useful for
blocking clocks to a serial UART or LAPD controller in applications where not all T1 channels are used
such as Fractional T1, 384 kbps (H0), 768 kbps 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 or 2 kHz (ZBTSI) demand clock for the TLINK input. See
Section 11 for details. Transmit Link Data [TLINK].
Transmit Link Data [TLINK]. If enabled via TCR1.2, this pin will be sampled on the falling edge of
TCLK for data insertion into either the FDL stream (ESF) or the Fs-bit position (D4) or the Z-bit position
(ZBTSI). See Section 11 for details.
Transmit Sync [TSYNC]. A pulse at this pin will establish either frame or multiframe boundaries for the
transmit side. Via TCR2.2, the DS2152 can be programmed to output either a frame or multiframe pulse
DS2152
10 of 93
at this pin. If this pin is set to output pulses at frame boundaries, it can also be set via TCR2.4 to output
double-wide pulses at signaling frames. See Section 15 for details.
Transmit System 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.
Transmit Signaling Input [TSIG]. When enabled, this input will sample signaling bits for insertion into
outgoing PCM T1 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.
Transmit Elastic Store Data Output [TESO]. Updated on the rising edge of TCLK with data out of the
transmit side elastic store whether the elastic store is enabled or not. This pin is normally tied to TDATA.
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
(CCR1.6) 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]. Buffered clock that is used to clock data through the transmit side
formatter (i.e., either TCLK or RCLKI). 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 T1 line. Can be internally connected to TPOSO by tying the LIUC pin high.
TPOSI and TNEGI can be tied together in NRZ applications.
Transmit Negative Data Input [TNEGI]. Sampled on the falling edge of TCLKI for data to be
transmitted out onto the T1 line. Can be internally connected to TNEGO by tying the LIUC pin high.
TPOSI and TNEGI can be tied together in NRZ applications.
Transmit Clock Input [TCLKI]. Line interface transmit clock. Can be internally connected to TCLKO
by tying the LIUC pin high.
RECEIVE SIDE DIGITAL PINS
Receive Link Data [RLINK]. Updated with either FDL data (ESF) or Fs bits (D4) or Z bits (ZBTSI) one
RCLK before the start of a frame. See Section 15 for details.
Receive Link Clock [RLCLK]. A 4 kHz or 2 kHz (ZBTSI) clock for the RLINK output.
Receive Clock [RCLK]. 1.544 MHz clock that is used to clock data through the receive side framer.
Receive Channel Clock [RCHCLK]. A 192 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.
DS2152
11 of 93
Receive Channel Block [RCHBLK]. A user-programmable output that can be forced high or low during
any of the 24 T1 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 T1 channels are used, such as Fractional
T1, 384 kbps service, 768 kbps, 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 (RCR2.4=0) or multiframe (RCR2.4=1) boundaries. If set to output frame boundaries then via
RCR2.5, RSYNC can also be set to output double-wide pulses on signaling frames. If the receive side
elastic store is enabled via CCR1.2, then this pin can be enabled to be an input via RCR2.3 at which a
frame or multiframe boundary pulse is applied. See Section 15 for details.
Receive Frame Sync [RFSYNC]. An extracted 8 kHz pulse 1 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, 1 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 [RDATA]. 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.
Receive Loss of Sync / Loss of Transmit Clock [RLOS/LOTC]. A dual function output that is
controlled by the CCR3.5 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.
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]. A 8.192 MHz output clock that is referenced to the clock that is output at the
RCLK pin and is used to clock data through the receive side framer.
DS2152
12 of 93
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 T1 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.
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.
PARALLEL CONTROL PORT PINS
Interrupt [INT]. Flags host controller during conditions and change of conditions defined in the Status
Registers 1 and 2 and the FDL Status Register. 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 an 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.
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 when MUX=1. DS is active
high when MUX = 0. See bus timing diagrams.
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), serves as the upper address bit. In multiplexed bus operation (MUX = 1), serves to demultiplex the bus
on a positive-going edge.
DS2152
13 of 93
Write Input [WR ] (Read/Write [R/W]). WR is an active low signal.
LINE INTERFACE PINS
Master Clock Input [MCLK]. A 1.544 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 1.544 MHz may be applied across MCLK and XTALD instead of the TTL level clock source.
Quartz Crystal Driver [XTALD]. A quartz crystal of 1.544 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]. A 12.352 MHz clock that is frequency locked to the 1.544 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 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.
Receive Tip and Ring [RTIP & RRING]. Analog inputs for clock recovery circuitry. These pins
connect via a 1:1 transformer to the T1 line. See Section 14 for details.
Transmit Tip and Ring [TTIP & TRING]. Analog line driver outputs. These pins connect via a 1:1.15
or 1:1.36 step-up transformer to the T1 line. See Section 14 for details.
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.
Digital Signal Ground [DVSS]. Should be tied to the RVSS and TVSS 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.
SUPPLY PINS
Digital Positive Supply [DVDD]. 5.0 volts ± 5%. Should be tied to the RVDD and TVDD pins.
DS2152 REGISTER MAP Table 1-3
ADDRESS R/W REGISTER NAME REGISTER ABBREVIATION
00 R/W FDL Control FDLC
01 R/W FDL Status FDLS
02 R/W FDL Interrupt Mask FIMR
03 R/W Receive Performance Report Message RPRM
04 R/W Receive Bit Oriented Code RBOC
DS2152
14 of 93
ADDRESS R/W REGISTER NAME REGISTER ABBREVIATION
05 RReceive FDL FIFO RFFR
06 R/W Transmit Performance Report Message TPRM
07 R/W Transmit Bit Oriented Code TBOC
08 WTransmit FDL FIFO TFFR
09 R/W Test 2 TEST2 (set to 00h)
0A R/W Common Control 7 CCR7
0B -not present -
0C -not present -
0D -not present -
0E -not present -
0F RDeceive ID IDR
10 R/W Receive Information 3 RIR3
11 R/W Common Control 4 CCR4
12 R/W In-Band Code Control IBCC
13 R/W Transmit Code Definition TCD
14 R/W Receive Up Code Definition RUPCD
15 R/W Receive Down Code Definition RDNCD
16 R/W Transmit Channel Control 1 TCC1
17 R/W Transmit Channel Control 2 TCC2
18 R/W Transmit Channel Control 3 TCC3
19 R/W Common Control 5 CCR5
1A RTransmit DS0 Monitor TDS0M
1B R/W Receive Channel Control 1 RCC1
1C R/W Receive Channel Control 2 RCC2
1D R/W Receive Channel Control 3 RCC3
1E R/W Common Control 6 CCR6
1F RReceive DS0 Monitor RDS0M
20 R/W Status 1 SR1
21 R/W Status 2 SR2
22 R/W Receive Information 1 RIR1
23 RLine Code Violation Count 1 LCVCR1
24 RLine Code Violation Count 2 LCVCR2
25 RPath Code Violation Count 1 PCVCR1
26 RPath Code Violation Count 2 PCVCR2
27 RMultiframe Out of Sync Count 2 MOSCR2
28 RReceive FDL Register RFDL
29 R/W Receive FDL Match 1 RMTCH1
2A R/W Receive FDL Match 2 RMTCH2
2B R/W Receive Control 1 RCR1
2C R/W Receive Control 2 RCR2
2D R/W Receive Mark 1 RMR1
2E R/W Receive Mark 2 RMR2
2F R/W Receive Mark 3 RMR3
30 R/W Common Control 3 CCR3
31 R/W Receive Information 2 RIR2
32 R/W Transmit Channel Blocking 1 TCBR1
33 R/W Transmit Channel Blocking 2 TCBR2
DS2152
15 of 93
ADDRESS R/W REGISTER NAME REGISTER ABBREVIATION
34 R/W Transmit Channel Blocking 3 TCBR3
35 R/W Transmit Control 1 TCR1
36 R/W Transmit Control 2 TCR2
37 R/W Common Control 1 CCR1
38 R/W Common Control 2 CCR2
39 R/W Transmit Transparency 1 TTR1
3A R/W Transmit Transparency 2 TTR2
3B R/W Transmit Transparency 3 TTR3
3C R/W Transmit Idle 1 TIR1
3D R/W Transmit Idle 2 TIR2
3E R/W Transmit Idle 3 TIR3
3F R/W Transmit Idle Definition TIDR
40 R/W Transmit Channel 9 TC9
41 R/W Transmit Channel 10 TC10
42 R/W Transmit Channel 11 TC11
43 R/W Transmit Channel 12 TC12
44 R/W Transmit Channel 13 TC13
45 R/W Transmit Channel 14 TC14
46 R/W Transmit Channel 15 TC15
47 R/W Transmit Channel 16 TC16
48 R/W Transmit Channel 17 TC17
49 R/W Transmit Channel 18 TC18
4A R/W Transmit Channel 19 TC19
4B R/W Transmit Channel 20 TC20
4C R/W Transmit Channel 21 TC21
4D R/W Transmit Channel 22 TC22
4E R/W Transmit Channel 23 TC23
4F R/W Transmit Channel 24 TC24
50 R/W Transmit Channel 1 TC1
51 R/W Transmit Channel 2 TC2
52 R/W Transmit Channel 3 TC3
53 R/W Transmit Channel 4 TC4
54 R/W Transmit Channel 5 TC5
55 R/W Transmit Channel 6 TC6
56 R/W Transmit Channel 7 TC7
57 R/W Transmit Channel 8 TC8
58 R/W Receive Channel 1 RC17
59 R/W Receive Channel 18 RC18
5A R/W Receive Channel 19 RC19
5B R/W Receive Channel 20 RC20
5C R/W Receive Channel 21 RC21
5D R/W Receive Channel 22 RC22
5E R/W Receive Channel 23 RC23
5F R/W Receive Channel 24 RC24
60 RReceive Signaling 1 RS1
61 RReceive Signaling 2 RS2
62 RReceive Signaling 3 RS3
DS2152
16 of 93
ADDRESS R/W REGISTER NAME REGISTER ABBREVIATION
63 RReceive Signaling 4 RS4
64 RReceive Signaling 5 RS5
65 RReceive Signaling 6 RS6
66 RReceive Signaling 7 RS7
67 RReceive Signaling 8 RS8
68 RReceive Signaling 9 RS9
69 RReceive Signaling 10 RS10
6A RReceive Signaling 11 RS11
6B RReceive Signaling 12 RS12
6C R/W Receive Channel Blocking 1 RCBR1
6D R/W Receive Channel Blocking 2 RCBR2
6E R/W Receive Channel Blocking 3 RCBR3
6F R/W Interrupt Mask 2 IMR2
70 R/W Transmit Signaling 1 TS1
71 R/W Transmit Signaling 2 TS2
72 R/W Transmit Signaling 3 TS3
73 R/W Transmit Signaling 4 TS4
74 R/W Transmit Signaling 5 TS5
75 R/W Transmit Signaling 6 TS6
76 R/W Transmit Signaling 7 TS7
77 R/W Transmit Signaling 8 TS8
78 R/W Transmit Signaling 9 TS9
79 R/W Transmit Signaling 10 TS10
7A R/W Transmit Signaling 11 TS11
7B R/W Transmit Signaling 12 TS12
7C R/W Line Interface Control LICR
7D R/W Test 1 TEST1 (set to 00h)
7E R/W Transmit FDL Register TFDL
7F R/W Interrupt Mask Register 1 IMR1
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
DS2152
17 of 93
NOTES:
1. Test Registers 1 and 2 are used only by the factory; these registers must be cleared (set to all 0s) on
power-up initialization to insure proper operation.
2. Register banks 9xh, Axh, Bxh, Cxh, Dxh, Exh, and Fxh are not accessible.
2.0 PARALLEL PORT
The DS2152 is controlled via either a non-multiplexed (MUX = 0) or a multiplexed (MUX = 1) bus by an
external microcontroller or microprocessor. The DS2152 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 16 for more details.
3.0 CONTROL, ID AND TEST REGISTERS
The operation of the DS2152 is configured via a set of eleven control registers. Typically, the control
registers are only accessed when the system is first powered up. Once the DS2152 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 seven Common Control Registers (CCR1 to CCR7). Each of the eleven 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 0 indicating that the DS2152 is present. The E1 pin-for-pin compatible version of the DS2152
is the DS2154, which also has an ID register at address 0Fh. The user can read the MSB to determine
which chip is present since in the DS2152 the MSB will be set to a 0 and in the DS2154 it will be set to a
1. The lower 4 bits of the IDR are used to display the die revision of the chip.
IDR: DEVICE IDENTIFICATION REGISTER (Address=0F Hex)
(MSB) (LSB)
T1E1 000ID3 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 revision.
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 revision.
The two Test Registers at addresses 09 and 7D hex are used by the factory in testing the DS2152. On
power-up, the Test Registers should be set to 00 hex in order for the DS2152 to operate properly.
DS2152
18 of 93
RCR1: RECEIVE CONTROL REGISTER 1 (Address=2B Hex)
(MSB) (LSB)
LCVCRF ARC OOF1 OOF2 SYNCC SYNCT SYNCE RESYNC
SYMBOL POSITION NAME AND DESCRIPTION
LCVCRF RCR1.7 Line Code Violation Count Register Function Select.
0 = do not count excessive 0s
1 = count excessive 0s
ARC RCR1.6 Auto Resync Criteria.
0 = Resync on OOF or RCL event
1 = Resync on OOF only
OOF1 RCR1.5 Out Of Frame Select 1.
0 = 2/4 frame bits in error
1 = 2/5 frame bits in error
OOF2 RCR1.4 Out Of Frame Select 2.
0 = follow RCR1.5
1 = 2/6 frame bits in error
SYNCC RCR1.3 Sync Criteria.
In D4 Framing Mode
0 = search for Ft pattern, then search for Fs pattern
1 = cross couple Ft and Fs pattern
In ESF Framing Mode
0 = search for FPS pattern only
1 = search for FPS and verify with CRC6
SYNCT RCR1.2 Sync Time.
0 = qualify 10 bits
1 = qualify 24 bits
SYNCE RCR1.1 Sync Enable.
0 = auto resync enabled
1 = auto resync disabled
RESYNC RCR1.0
Resync.
When toggled from low to high, a resynchronization of
the receive side framer is initiated. Must be cleared and set again
for a subsequent resync.
DS2152
19 of 93
RCR2: RECEIVE CONTROL REGISTER 2 (Address=2C Hex)
(MSB) (LSB)
RCS RZBTSI RSDW RSM RSIO RD4YM FSBE MOSCRF
SYMBOL POSITION NAME AND DESCRIPTION
RCS RCR2.7 Receive Code Select. See Section 8 for more details.
0 = idle code (7F Hex)
1 = digital milliwatt code (1E/0B/0B/1E/9E/8B/8B/9E Hex)
RZBTSI RCR2.6 Receive Side ZBTSI Enable.
0 = ZBTSI disabled
1 = ZBTSI enabled
RSDW RCR2.5
RSYNC Double-Wide.
(note: this bit must be set to 0 when
RCR2.4 = 1 or when RCR2.3 = 1)
0 = do not pulse double-wide in signaling frames
1 = do pulse double-wide in signaling frames
RSM RCR2.4
RSYNC Mode Select.
(A Don’t Care if RSYNC is programmed
as an input)
0 = frame mode (see the timing in Section 15)
1 = multiframe mode (see the timing in Section 15)
RSIO RCR2.3
RSYNC I/O Select.
(note: this bit must be set to 0 when
CCR1.2 = 0)
0 = RSYNC is an output
1 = RSYNC is an input (only valid if elastic store enabled)
RD4YM RCR2.2 Receive Side D4 Yellow Alarm Select.
0 = 0s in bit 2 of all channels
1 = a 1 in the S-bit position of frame 12
FSBE RCR2.1 PCVCR Fs-Bit Error Report Enable.
0 = do not report bit errors in Fs-bit position; only Ft bit position
1 = report bit errors in Fs-bit position as well as Ft bit position
MOSCRF RCR2.0 Multiframe Out of Sync Count Register Function Select.
0 = count errors in the framing bit position
1 = count the number of multiframes out of sync
DS2152
20 of 93
TCR1: TRANSMIT CONTROL REGISTER 1 (Address=35 Hex)
(MSB) (LSB)
LOTCMC TFPT TCPT TSSE GB7S TFDLS TBL TYEL
SYMBOL POSITION NAME AND DESCRIPTION
LOTCMC TCR1.7
Loss Of Transmit Clock Mux Control.
Determines whether
the transmit side formatter should switch to the ever present
RCLKO if the TCLK input should fail to transition (see Figure
1-1 for details).
0 = do not switch to RCLKO if TCLK stops
1 = switch to RCLKO if TCLK stops
TFPT TCR1.6 Transmit F-Bit Pass Through. (see note below)
0 = F bits sourced internally
1 = F bits sampled at TSER
TCPT TCR1.5 Transmit CRC Pass Through. (see note below)
0 = source CRC6 bits internally
1 = CRC6 bits sampled at TSER during F-bit time
TSSE TCR1.4 Software Signaling Insertion Enable. (see note below)
0 = no signaling is inserted in any channel - from the TS1-TS12
registers
1 = signaling is inserted in all channels - from the TS1-TS12
registers (the TTR registers can be used to block insertion on a
channel by channel basis)
GB7S TCR1.3 Global Bit 7 Stuffing. (see note below)
0 = allow the TTR registers to determine which channels
containing all 0s are to be Bit 7 stuffed
1 = force Bit 7 stuffing in all 0-byte channels regardless of how
the TTR registers are programmed
TFDLS TCR1.2 TFDL Register Select. (see note below)
0 = source FDL or Fs bits from the internal TFDL register
(legacy FDL support mode)
1 = source FDL or Fs bits from the internal HDLC/BOC
controller or the TLINK pin
TBL TCR1.1 Transmit Blue Alarm. (see note below)
0 = transmit data normally
1 = transmit an unframed all 1s code at TPOSO and TNEGO
TYEL TCR1.0 Transmit Yellow Alarm. (see note below)
0 = do not transmit yellow alarm
1 = transmit yellow alarm
NOTE:
For a description of how the bits in TCR1 affect the transmit side formatter, see Figure 15-11.
DS2152
21 of 93
TCR2: TRANSMIT CONTROL REGISTER 2 (Address=36 Hex)
(MSB) (LSB)
TEST1 TEST0 TZBTSI TSDW TSM TSIO TD4YM TB7ZS
SYMBOL POSITION NAME AND DESCRIPTION
TEST1 TCR2.7 Test Mode Bit 1 for Output Pins. See Table 3-1.
TEST0 TCR2.6 Test Mode Bit 0 for Output Pins. See Table 3-1.
TZBTSI TCR2.5 Transmit Side ZBTSI Enable.
0 = ZBTSI disabled
1 = ZBTSI enabled
TSDW TCR2.4
TSYNC Double-Wide.
(note: this bit must be set to 0 when
TCR2.3=1 or when TCR2.2=0)
0 = do not pulse double-wide in signaling frames
1 = do pulse double-wide in signaling frames
TSM TCR2.3 TSYNC Mode Select.
0 = frame mode (see the timing in Section 15)
1 = multiframe mode (see the timing in Section 15)
TSIO TCR2.2 TSYNC I/O Select.
0 = TSYNC is an input
1 = TSYNC is an output
TD4YM TCR2.1 Transmit Side D4 Yellow Alarm Select.
0 = 0s in bit 2 of all channels
1 = a 1 in the S-bit position of frame 12
TB7ZS TCR2.0 Transmit Side Bit 7 0 Suppression Enable.
0 = no stuffing occurs
1 = Bit 7 force to a 1 in channels with all 0s
OUTPUT PIN TEST MODES Table 3-1
TEST 1 TEST 0 EFFECT ON OUTPUT PINS
0 0 operate normally
0 1 force all output pins 3-state (including all I/O pins and parallel port pins)
1 0 force all output pins low (including all I/O pins except parallel port pins)
1 1 force all output pins high (including all I/O pins except parallel port pins)
DS2152
22 of 93
CCR1: COMMON CONTROL REGISTER 1 (Address=37 Hex)
(MSB) (LSB)
TESE ODF RSAO TSCLKM RSCLKM RESE PLB FLB
SYMBOL POSITION NAME AND DESCRIPTION
TESE CCR1.7 Transmit Elastic Store Enable.
0 = elastic store is bypassed
1 = elastic store is enabled
ODF CCR1.6 Output Data Format.
0 = bipolar data at TPOSO and TNEGO
1 = NRZ data at TPOSO; TNEGO = 0
RSAO CCR1.5
Receive Signaling All 1s.
This bit should not be enabled if
hardware signaling is being utilized. See Section 7 for more
details.
0 = allow robbed signaling bits to appear at RSER
1 = force all robbed signaling bits at RSER to 1
TSCLKM CCR1.4 TSYSCLK Mode Select.
0 = if TSYSCLK is 1.544 MHz
1 = if TSYSCLK is 2.048 MHz
RSCLKM CCR1.3 RSYSCLK Mode Select.
0 = if RSYSCLK is 1.544 MHz
1 = if RSYSCLK is 2.048 MHz
RESE CCR1.2 Receive Elastic Store Enable.
0 = elastic store is bypassed
1 = elastic store is enabled
PLB CCR1.1 Payload Loopback.
0 = loopback disabled
1 = loopback enabled
FLB CCR1.0 Framer Loopback.
0 = loopback disabled
1 = loopback enabled
DS2152
23 of 93
Payload Loopback
When CCR1.1 is set to a 1, the DS2152 will be forced into Payload LoopBack (PLB). Normally, this
loopback is only enabled when ESF framing is being performed but can be enabled also in D4 framing
applications. In a PLB situation, the DS2152 will loop the 192 bits of payload data (with BPVs corrected)
from the receive section back to the transmit section. The FPS framing pattern, CRC6 calculation, and the
FDL bits are not looped back, they are reinserted by the DS2152. When PLB is enabled, the following
will occur:
1. data will be transmitted from the TPOSO and TNEGO pins synchronous with RCLK instead of
TCLK
2. all of the receive side signals will continue to operate normally
3. the TCHCLK and TCHBLK signals are forced low
4. data at the TSER, TDATA, and TSIG pins is ignored
5. the TLCLK signal will become synchronous with RCLK instead of TCLK.
Framer Loopback
When CCR1.0 is set to a 1, the DS2152 will enter a Framer LoopBack (FLB) mode. This loopback is
useful in testing and debugging applications. In FLB, the DS2152 will loop data from the transmit side
back to the receive side. When FLB is enabled, the following will occur:
1. an unframed all 1s code will be transmitted at TPOSO and TNEGO
2. data at RPOSI and RNEGI will be ignored
3. all receive side signals will take on timing synchronous with TCLK instead of RCLKI.
Please note that it is not acceptable to have RCLK tied to TCLK during this loopback because this will
cause an unstable condition.
DS2152
24 of 93
CCR2: COMMON CONTROL REGISTER 2 (Address=38 Hex)
(MSB) (LSB)
TFM TB8ZS TSLC96 TFDL RFM RB8ZS RSLC96 RFDL
SYMBOL POSITION NAME AND DESCRIPTION
TFM CCR2.7 Transmit Frame Mode Select.
0 = D4 framing mode
1 = ESF framing mode
TB8ZS CCR2.6 Transmit B8ZS Enable.
0 = B8ZS disabled
1 = B8ZS enabled
TSLC96 CCR2.5
Transmit SLC-96 / Fs-Bit Loading Enable.
Only set this bit to
a 1 in D4 framing applications. Must be set to 1 to source the Fs
pattern. See Section 11 for details.
0 = SLC-96/Fs-bit loading disabled
1 = SLC-96/Fs-bit loading enabled
TFDL CCR2.4
Transmit FDL 0 Stuffer Enable.
Set this bit to 0 if using the
internal HDLC/BOC controller instead of the legacy support for
the FDL. See Section 11 for details.
0 = 0 stuffer disabled
1 = 0 stuffer enabled
RFM CCR2.3 Receive Frame Mode Select.
0 = D4 framing mode
1 = ESF framing mode
RB8ZS CCR2.2 Receive B8ZS Enable.
0 = B8ZS disabled
1 = B8ZS enabled
RSLC96 CCR2.1
Receive SLC-96 Enable.
Only set this bit to a 1 in D4/SLC-96
framing applications. See Section 11 for details.
0 = SLC-96 disabled
1 = SLC-96 enabled
RFDL CCR2.0
Receive FDL 0 Destuffer Enable.
Set this bit to 0 if using the
internal HDLC/BOC controller instead of the legacy support for
the FDL. See Section 11 for details.
0 = 0 destuffer disabled
1 = 0 destuffer enabled
DS2152
25 of 93
CCR3: COMMON CONTROL REGISTER 3 (Address=30 Hex)
(MSB) (LSB)
ESMDM ESR RLOSF RSMS PDE ECUS TLOOP -
SYMBOL POSITION NAME AND DESCRIPTION
ESMDM CCR3.7
Elastic Store Minimum Delay Mode.
See Section 10.3 for
details.
0 = elastic stores operate at full two-frame depth
1 = elastic stores operate at 32-bit depth
ESR CCR3.6 Elastic Store Reset. Setting this bit from a 0 to a 1 will force the
elastic stores to a known depth. Should be toggled after
RSYSCLK and TSYSCLK have been applied and are stable.
Must be cleared and set again for a subsequent reset.
RLOSF CCR3.5 Function of the RLOS/LOTC Output.
0 = Receive Loss of Sync (RLOS)
1 = Loss of Transmit Clock (LOTC)
RSMS CCR3.4
RSYNC Multiframe Skip Control.
Useful in framing format
conversions from D4 to ESF. This function is not available when
the receive side elastic store is enabled.
0 = RSYNC will output a pulse at every multiframe
1 = RSYNC will output a pulse at every other multiframe
note: for this bit to have any affect, the RSYNC must be set to
output multiframe pulses (RCR2.4=1 and RCR2.3=0).
PDE CCR3.3 Pulse Density Enforcer Enable.
0 = disable transmit pulse density enforcer
1 = enable transmit pulse density enforcer
ECUS CCR3.2 Error Counter Update Select. See Section 5 for details.
0 = update error counters once a second
1 = update error counters every 42 ms (333 frames)
TLOOP CCR3.1 Transmit Loop Code Enable. See Section 12 for details.
0 = transmit data normally
1 = replace normal transmitted data with repeating code as
defined in TCD register
-CCR3.0 Not Assigned. Must be set to 0 when written.
Pulse Density Enforcer
The SCT always examines both the transmit and receive data streams for violations of the following rules
which are required by ANSI T1.403:
- no more than 15 consecutive 0s
- at least N 1s in each and every time window of 8 x (N +1) bits where N = 1 through 23
Violations for the transmit and receive data streams are reported in the RIR2.0 and RIR2.1 bits
respectively. When the CCR3.3 is set to 1, the DS2152 will force the transmitted stream to meet this
requirement no matter the content of the transmitted stream. When running B8ZS, the CCR3.3 bit should
be set to 0 since B8ZS encoded data streams cannot violate the pulse density requirements.
DS2152
26 of 93
CCR4: COMMON CONTROL REGISTER 4 (Address=11 Hex)
(MSB) (LSB)
RSRE RPCSI RFSA1 RFE RFF THSE TPCSI TIRFS
SYMBOL POSITION NAME AND DESCRIPTION
RSRE CCR4.7
Receive Side Signaling Reinsertion Enable.
See Section 7.2 for
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
RPCSI CCR4.6
Receive Per-Channel Signaling Insert.
See Section 7.2 for more
details.
0 = do not use RCHBLK to determine which channels should have
signaling re-inserted
1 = use RCHBLK to determine which channels should have
signaling re-inserted
RFSA1 CCR4.5 Receive Force Signaling All 1s. See Section 7.2 for more details.
0 = do not force extracted robbed-bit signaling bit positions to a 1
1 = force extracted robbed-bit signaling bit positions to a 1
RFE CCR4.4 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
CCR4.7 = 1).
RFF CCR4.3
Receive Force Freeze.
Freezes receive side signaling at RSIG (and
RSER if CCR4.7=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
THSE CCR4.2
Transmit Hardware Signaling Insertion Enable.
See Section 7.2
for details.
0 = do not insert signaling from the TSIG pin into the data stream
presented at the TSER pin
1 = insert the signaling from the TSIG pin into data stream presented
at the TSER pin
TPCSI CCR4.1
Transmit Per-Channel Signaling Insert.
See Section 7.2 for
details.
0 = do not use TCHBLK to determine which channels should have
signaling inserted from TSIG
1 = use TCHBLK to determine which channels should have
signaling inserted from TSIG
TIRFS CCR4.0
Transmit Idle Registers (TIR) Function Select.
See Section 8 for
timing details.
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)
DS2152
27 of 93
CCR5: COMMON CONTROL REGISTER 5 (Address=19 Hex)
(MSB) (LSB)
TJC LLB LIAIS TCM4 TCM3 TCM2 TCM1 TCM0
SYMBOL POSITION NAME AND DESCRIPTION
TJC CCR5.7 Transmit Japanese CRC6 Enable.
0 = use ANSI/AT&T/ITU CRC6 calculation (normal operation)
1 = use Japanese standard JT-G704 CRC6 calculation
LLB CCR5.6 Local Loopback.
0 = loopback disabled
1 = loopback enabled
LIAIS CCR5.5
Line Interface AIS Generation Enable.
See Figure 1-1 for
details.
0 = allow normal data from TPOSI/TNEGI to be transmitted at
TTIP and TRING
1 = force unframed all 1s to be transmitted at TTIP and TRING
TCM4 CCR5.4
Transmit Channel Monitor Bit 4.
MSB of a channel decode
that determines which transmit channel data will appear in the
TDS0M register. See Section 6 for details.
TCM3 CCR5.3 Transmit Channel Monitor Bit 3.
TCM2 CCR5.2 Transmit Channel Monitor Bit 2.
TCM1 CCR5.1 Transmit Channel Monitor Bit 1.
TCM0 CCR5.0 Transmit Channel Monitor Bit 0. LSB of the channel decode.
Local Loopback
When CCR5.6 is set to a 1, the DS2152 will be forced into Local LoopBack (LLB). In this loopback, data
will continue to be transmitted as normal through the transmit side of the DS2152 (unless LIAIS = 1).
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. Please note that it
is not acceptable to have RCLKO tied to TCLKI during this loopback because this will cause an unstable
condition. Also it is recommended that the jitter attenuator be placed on the transmit side during this
loopback.
DS2152
28 of 93
CCR6: COMMON CONTROL REGISTER 6 (Address=1E Hex)
(MSB) (LSB)
RJC - - RCM4 RCM3 RCM2 RCM1 RCM0
SYMBOL POSITION NAME AND DESCRIPTION
RJC CCR6.7 Receive Japanese CRC6 Enable.
0 = use ANSI/AT&T/ITU CRC6 calculation (normal operation)
1 = use Japanese standard JT-G704 CRC6 calculation
-CCR6.6 Not Assigned. Should be set to 0 when written.
-CCR6.5 Not Assigned. Should be set to 0 when written.
RCM4 CCR6.4
Receive Channel Monitor Bit 4.
MSB of a channel decode that
determines which receive channel data will appear in the
RDS0M register. See Section 6 for details.
RCM3 CCR6.3 Receive Channel Monitor Bit 3.
RCM2 CCR6.2 Receive Channel Monitor Bit 2.
RCM1 CCR6.1 Receive Channel Monitor Bit 1.
RCM0 CCR6.0 Receive Channel Monitor Bit 0. LSB of the channel decode.
DS2152
29 of 93
CCR7: COMMON CONTROL REGISTER 7 (Address=0A Hex)
(MSB) (LSB)
LIRST RLB - - - - - -
SYMBOL POSITION NAME AND DESCRIPTION
LIRST CCR7.7
Line Interface reset.
Setting this bit from a 0 to a 1 will initiate
an 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.
RLB CCR7.6 Remote Loopback.
0 = loopback disabled
1 = loopback enabled
-CCR7.5 Not Assigned. Should be set to 0 when written to.
-CCR7.4 Not Assigned. Should be set to 0 when written to.
-CCR7.3 Not Assigned. Should be set to 0 when written to.
-CCR7.2 Not Assigned. Should be set to 0 when written to.
-CCR7.1 Not Assigned. Should be set to 0 when written to.
-CCR7.0 Not Assigned. Should be set to 0 when written to.
Power-Up Sequence
On power-up, after the supplies are stable, the DS2152 should be configured for operation by writing to
all of the internal registers (this includes setting the Test Registers to 00Hex) since the contents of the
internal registers cannot be predicted on power-up. Finally, after the TSYSCLK and RSYSCLK inputs
are stable, the ESR bit should be toggled from a 0 to a 1 (this step can be skipped if the elastic stores are
disabled).
Remote Loopback
When CCR7.6 is set to a 1, the DS2152 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 DS2152 as it would normally and the data
from the transmit side formatter will be ignored. Please see Figure 1-1 for more details.
DS2152
30 of 93
4.0 STATUS AND INFORMATION REGISTERS
There is a set of nine registers that contain information on the current real time status of the DS2152,
Status Register 1 (SR1), Status Register 2 (SR2), Receive Information Registers 1 to 3
(RIR1/RIR2/RIR3) and a set of four registers for the onboard HDLC and BOC controller for the FDL.
The specific details on the four registers pertaining to the FDL are covered in Section 11.1, but they
operate the same as the other status registers in the DS2152 and this operation is described below.
When a particular event has occurred (or is occurring), the appropriate bit in one of these nine registers
will be set to a 1. All of the bits in SR1, SR2, RIR1, RIR2, and RIR3 registers operate in a latched
fashion. This means that if an event or an alarm occurs and a bit is set to a 1 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 RBL, RYEL, LRCL, and RLOS alarms, the bit
will remain set if the alarm is still present). There are bits in the four FDL status registers that are not
latched and these bits are listed in Section 11.1.
The user will always proceed a read of any of the nine registers with a write. The byte written to the
register will inform the DS2152 which bits the user wishes to read and have cleared. The user will write a
byte to one of these registers, with a 1 in the bit positions he or she wishes to read and a 0 in the bit
positions he or she does not wish to obtain the latest information on. When a 1 is written to a bit location,
the read register will be updated with the latest information. When a 0 is written to a bit position, the read
register will not be updated and the previous value will 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 DS2152 with
higher-order software languages.
The SR1, SR2, and FDLS registers have the unique ability to initiate a hardware interrupt via the INT
output pin. Each of the alarms and events in the SR1, SR2, and FDLS can be either masked or unmasked
from the interrupt pin via the Interrupt Mask Register 1 (IMR1), Interrupt Mask Register 2 (IMR2), and
FDL Interrupt Mask Register (FIMR) respectively. The FIMR register is covered in Section 11.1.
The interrupts caused by alarms in SR1 (namely RYEL, LRCL, RBL, and RLOS) act differently than the
interrupts caused by events in SR1 and SR2 (namely LUP, LDN, LOTC, RSLIP, RMF, TMF, SEC,
RFDL, TFDL, RMTCH, RAF, and RSC) and FIMR. 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 4-2). The INT pin will be allowed to return high (if no other interrupts are present) when
the user reads the alarm bit that caused the interrupt to occur even if the alarm is still present.
The event caused interrupts will force the INT pin low 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.
DS2152
31 of 93
RIR1: RECEIVE INFORMATION REGISTER 1 (Address=22 Hex)
(MSB) (LSB)
COFA 8ZD 16ZD RESF RESE SEFE B8ZS FBE
SYMBOL POSITION NAME AND DESCRIPTION
COFA RIR1.7
Change of Frame Alignment.
Set when the last resync resulted
in a change of frame or multiframe alignment.
8ZD RIR1.6 Eight-0 Detect. Set when a string of at least eight consecutive 0s
(regardless of the length of the string) have been received at
RPOSI and RNEGI.
16ZD RIR1.5
Sixteen-0 Detect.
Set when a string of at least 16 consecutive 0s
(regardless of the length of the string) have been received at
RPOSI and RNEGI.
RESF RIR1.4
Receive Elastic Store Full.
Set when the receive elastic store
buffer fills and a frame is deleted.
RESE RIR1.3
Receive Elastic Store Empty.
Set when the receive elastic store
buffer empties and a frame is repeated.
SEFE RIR1.2
Severely Errored Framing Event.
Set when 2 out of 6 framing
bits (Ft or FPS) are received in error.
B8ZS RIR1.1
B8ZS Code Word Detect.
Set when a B8ZS code word is
detected at RPOS and RNEG independent of whether the B8ZS
mode is selected or not via CCR2.6. Useful for automatically
setting the line coding.
FBE RIR1.0
Frame Bit Error.
Set when a Ft (D4) or FPS (ESF) framing bit
is received in error.
DS2152
32 of 93
RIR2: RECEIVE INFORMATION REGISTER 2 (Address=31 Hex)
(MSB) (LSB)
RLOSC LRCLC TESF TESE TSLIP RBLC RPDV TPDV
SYMBOL POSITION NAME AND DESCRIPTION
RLOSC RIR2.7
Receive Loss of Sync Clear.
Set when the framer achieves
synchronization; will remain set until read.
LRCLC RIR2.6
Line Interface Receive Carrier Loss Clear.
Set when the
carrier signal is restored; will remain set until read. See Table 4-2.
TESF RIR2.5
Transmit Elastic Store Full.
Set when the transmit elastic store
buffer fills and a frame is deleted.
TESE RIR2.4
Transmit Elastic Store Empty.
Set when the transmit elastic
store buffer empties and a frame is repeated.
TSLIP RIR2.3
Transmit Elastic Store Slip Occurrence.
Set when the transmit
elastic store has either repeated or deleted a frame.
RBLC RIR2.2 Receive Blue Alarm Clear. Set when the Blue Alarm (AIS) is no
longer detected; will remain set until read. See Table 4-2.
RPDV RIR2.1
Receive Pulse Density Violation.
Set when the receive data
stream does not meet the ANSI T1.403 requirements for pulse
density.
TPDV RIR2.0
Transmit Pulse Density Violation.
Set when the transmit data
stream does not meet the ANSI T1.403 requirements for pulse
density.
DS2152
33 of 93
RIR3: RECEIVE INFORMATION REGISTER 3 (Address=10 Hex)
(MSB) (LSB)
RL1 RL0 JALT LORC FRCL - - -
SYMBOL POSITION NAME AND DESCRIPTION
RL1 RIR3.7 Receive Level Bit 1. See Table 4-1.
RL0 RIR3.6 Receive Level Bit 0. See Table 4-1.
JALT RIR3.5
Jitter Attenuator Limit Trip.
Set when the jitter attenuator
FIFO reaches to within 4 bits of its limit; useful for debugging
jitter attenuation operation.
LORC RIR3.4
Loss of Receive Clock.
Set when the RCLKI pin has not
transitioned for at least 2 us (3 us ± 1 us).
FRCL RIR3.3
Framer Receive Carrier Loss.
Set when 192 consecutive 0s
have been received at the RPOSI and RNEGI pins; allowed to be
cleared when 14 or more 1s out of 112 possible bit positions are
received.
-RIR3.2 Not Assigned. Could be any value when read.
-RIR3.1 Not Assigned. Could be any value when read.
-RIR3.0 Not Assigned. Could be any value when read.
DS2152 RECEIVE T1 LEVEL INDICATION Table 4-1
RL1 RL0 TYPICAL LEVEL RECEIVED
0 0 +2 dB to -7.5 db
0 1 -7.5 dB to -15 db
1 0 -15 dB to -22.5 db
1 1 less than -22.5 db
DS2152
34 of 93
SR1: STATUS REGISTER 1 (Address=20 Hex)
(MSB) (LSB)
LUP LDN LOTC RSLIP RBL RYEL LRCL RLOS
SYMBOL POSITION NAME AND DESCRIPTION
LUP SR1.7
Loop Up Code Detected.
Set when the loop up code as defined
in the RUPCD register is being received. See Section 12 for
details.
LDN SR1.6
Loop Down Code Detected.
Set when the loop down code as
defined in the RDNCD register is being received. See Section 12
for details.
LOTC SR1.5
Loss of Transmit Clock.
Set when the TCLK pin has not
transitioned for one channel time (or 5.2 us). Will force the
RLOS/LOTC pin high if enabled via CCR1.6. Also will force
transmit side formatter to switch to RCLKO if so enabled via
TCR1.7.
RSLIP SR1.4
Receive Elastic Store Slip Occurrence.
Set when the receive
elastic store has either repeated or deleted a frame.
RBL SR1.3
Receive Blue Alarm.
Set when an unframed all 1s code is
received at RPOSI and RNEGI.
RYEL SR1.2
Receive Yellow Alarm.
Set when a yellow alarm is received at
RPOSI and RNEGI.
LRCL SR1.1
Line Interface Receive Carrier Loss.
Set when 192
consecutive 0s have been detected at RTIP and RRING. See
Table 4-2.
RLOS SR1.0
Receive Loss of Sync.
Set when the device is not synchronized
to the receive T1 stream.
DS2152
35 of 93
ALARM CRITERIA Table 4-2
ALARM SET CRITERIA CLEAR CRITERIA
Blue Alarm (AIS)
(see note 1 below) when over a 3ms window, five
or less 0s are received when over a 3 ms window, six or
more 0s are received
Yellow Alarm (RAI)
1. D4 bit 2 mode(RCR2.2=0)
2. D4 12th F-bit mode
(RCR2.2=1; this mode is
also referred to as the
"Japanese Yellow Alarm"
3. ESF mode
when bit 2 of 256 consecutive
channels is set to 0 for at least
254 occurrences
when the 12th framing bit is set
to 1 for two consecutive
occurrences
when 16 consecutive patterns of
00FF appear in the FDL
when bit 2 of 256 consecutive
channels is set to 0 for less than
254 occurrences
when the 12th framing bit is set to
0 for two consecutive occurrences
when 14 or less patterns of 00FF
hex out of 16 possible appear in
the FDL
Red Alarm (LRCL)
(this alarm is also referred to as
Loss Of Signal)
when 192 consecutive 0s are
received when 14 or more 1s out of 112
possible bit positions are received
starting with the first one received
NOTES:
1. The definition of Blue Alarm (or Alarm Indication Signal) is an unframed all 1s signal. Blue alarm
detectors should be able to operate properly in the presence of a 10-3 error rate and they should not
falsely trigger on a framed all 1s signal. The blue alarm criteria in the DS2152 have been set to
achieve this performance. It is recommended that the RBL bit be qualified with the RLOS bit.
2. ANSI specifications use a different nomenclature than the DS2152 does; the following terms are
equivalent: RBL = AIS
LRCL = LOS
RLOS = LOF
RYEL = RAI
DS2152
36 of 93
SR2: STATUS REGISTER 2 (Address=21 Hex)
(MSB) (LSB)
RMF TMF SEC RFDL TFDL RMTCH RAF RSC
SYMBOL POSITION NAME AND DESCRIPTION
RMF SR2.7 Receive Multiframe. Set on receive multiframe boundaries.
TMF SR2.6 Transmit Multiframe. Set on transmit multiframe boundaries.
SEC SR2.5
1-Second Timer.
Set on increments of 1 second based on
RCLK; will be set in increments of 999 ms, 999 ms, and 1002
ms every 3 seconds.
RFDL SR2.4
Receive FDL Buffer Full.
Set when the receive FDL buffer
(RFDL) fills to capacity (8 bits).
TFDL SR2.3
Transmit FDL Buffer Empty.
Set when the transmit FDL
buffer (TFDL) empties.
RMTCH SR2.2
Receive FDL Match Occurrence.
Set when the RFDL matches
either RFDLM1 or RFDLM2.
RAF SR2.1 Receive FDL Abort. Set when eight consecutive 1s are received
in the FDL.
RSC SR2.0
Receive Signaling Change.
Set when the DS2152 detects a
change of state in any of the robbed-bit signaling bits.
DS2152
37 of 93
IMR1: INTERRUPT MASK REGISTER 1 (Address=7F Hex)
(MSB) (LSB)
LUP LDN LOTC SLIP RBL RYEL LRCL RLOS
SYMBOL POSITION NAME AND DESCRIPTION
LUP IMR1.7 Loop Up Code Detected.
0 = interrupt masked
1 = interrupt enabled
LDN IMR1.6 Loop Down Code Detected.
0 = interrupt masked
1 = interrupt enabled
LOTC IMR1.5 Loss of Transmit Clock.
0 = interrupt masked
1 = interrupt enabled
SLIP IMR1.4 Elastic Store Slip Occurrence.
0 = interrupt masked
1 = interrupt enabled
RBL IMR1.3 Receive Blue Alarm.
0 = interrupt masked
1 = interrupt enabled
RYEL IMR1.2 Receive Yellow Alarm.
0 = interrupt masked
1 = interrupt enabled
LRCL IMR1.1 Line Interface Receive Carrier Loss.
0 = interrupt masked
1 = interrupt enabled
RLOS IMR1.0 Receive Loss of Sync.
0 = interrupt masked
1 = interrupt enabled
DS2152
38 of 93
IMR2: INTERRUPT MASK REGISTER 2 (Address=6F Hex)
(MSB) (LSB)
RMF TMF SEC RFDL TFDL RMTCH RAF RSC
SYMBOL POSITION NAME AND DESCRIPTION
RMF IMR2.7 Receive Multiframe.
0 = interrupt masked
1 = interrupt enabled
TMF IMR2.6 Transmit Multiframe.
0 = interrupt masked
1 = interrupt enabled
SEC IMR2.5 1-Second Timer.
0 = interrupt masked
1 = interrupt enabled
RFDL IMR2.4 Receive FDL Buffer Full.
0 = interrupt masked
1 = interrupt enabled
TFDL IMR2.3 Transmit FDL Buffer Empty.
0 = interrupt masked
1 = interrupt enabled
RMTCH IMR2.2 Receive FDL Match Occurrence.
0 = interrupt masked
1 = interrupt enabled
RAF IMR2.1 Receive FDL Abort.
0 = interrupt masked
1 = interrupt enabled
RSC IMR2.0 Receive Signaling Change.
0 = interrupt masked
1 = interrupt enabled
5.0 ERROR COUNT REGISTERS
There are a set of three counters in the DS2152 that record bipolar violations, excessive 0s, errors in the
CRC6 code words, framing bit errors, and number of multiframes that the device is out of receive
synchronization. Each of these three counters are automatically updated on either 1-second boundaries
(CCR3.2=0) or every 42 ms (CCR3.2=1) as determined by the timer in Status Register 2 (SR2.5). Hence,
these registers contain performance data from either the previous second or the previous 42 ms. The user
can use the interrupt from the 1-second timer to determine when to read these registers. The user has a
full second (or 42 ms) to read the counters before the data is lost. All three counters will saturate at their
respective maximum counts and they will not rollover (note: only the Line Code Violation Count Register
has the potential to overflow but the bit error would have to exceed 10-2 before this would occur).
DS2152
39 of 93
5.1 Line Code Violation Count Register (LCVCR)
Line Code Violation Count Register 1 High (LCVCR1) is the most significant word and LCVCR2 is the
least significant word of a 16-bit counter that records code violations (CVs). CVs are defined as Bipolar
Violations (BPVs) or excessive 0s. See Table 5.1 for details of exactly what the LCVCRs count. If the
B8ZS mode is set for the receive side via CCR2.2, then B8ZS code words are not counted. This counter is
always enabled; it is not disabled during receive loss of synchronization (RLOS=1) conditions.
LCVCR1: LINE CODE VIOLATION COUNT REGISTER 1 (Address=23 Hex)
LCVCR2: LINE CODE VIOLATION COUNT REGISTER 2 (Address=24 Hex)
(MSB) (LSB)
LCV15 LCV14 LCV13 LCV12 LCV11 LCV10 LCV9 LCV8 LCVCR1
LCV7 LCV6 LCV5 LCV4 LCV3 LCV2 LCV1 LCV0 LCVCR2
SYMBOL POSITION NAME AND DESCRIPTION
LCV15 LCVCR1.7 MSB of the 16-bit code violation count
LCV0 LCVCR2.0 LSB of the 16-bit code violation count
LINE CODE VIOLATION COUNTING ARRANGEMENTS Table 5-1
COUNT EXCESSIVE 0S?
(RCR1.7) B8ZS ENABLED?
(CCR2.2) WHAT IS COUNTED
IN THE LCVCRs
no no BPVs
yes no BPVs + 16 consecutive 0s
no yes BPVs (B8ZS code words not counted)
yes yes BPVs + 8 consecutive 0s
5.2 Path Code Violation Count Register (PCVCR)
When the receive side of the DS2152 is set to operate in the ESF framing mode (CCR2.3=1), PCVCR
will automatically be set as a 12-bit counter that will record errors in the CRC6 code words. When set to
operate in the D4 framing mode (CCR2.3=0), PCVCR will automatically count errors in the Ft framing
bit position. Via the RCR2.1 bit, the DS2152 can be programmed to also report errors in the Fs framing
bit position. The PCVCR will be disabled during receive loss of synchronization (RLOS=1) conditions.
See Table 5-2 for a detailed description of exactly what errors the PCVCR counts.
PCVCR1: PATH VIOLATION COUNT REGISTER 1 (Address=25 Hex)
PCVCR2: PATH VIOLATION COUNT REGISTER 2 (Address=26 Hex)
(MSB) (LSB)
(note 1) (note 1) (note 1) (note 1) CRC/FB11 CRC/FB10 CRC/FB9 CRC/FB8 PCVCR1
CRC/FB7 CRC/FB6 CRC/FB5 CRC/FB4 CRC/FB3 CRC/FB2 CRC/FB1 CRC/FB0 PCVCR2
SYMBOL POSITION NAME AND DESCRIPTION
CRC/FB11 PCVCR1.3 MSB of the 12-Bit CRC6 Error or Frame Bit Error Count
(note #2)
CRC/FB0 PCVCR2.0 LSB of the 12-Bit CRC6 Error or Frame Bit Error Count
(note #2)
DS2152
40 of 93
NOTES:
1. The upper nibble of the counter at address 25 is used by the Multiframes Out of Sync Count Register.
2. PCVCR counts either errors in CRC code words (in the ESF framing mode; CCR2.3=1) or errors in
the framing bit position (in the D4 framing mode; CCR2.3=0).
PATH CODE VIOLATION COUNTING ARRANGEMENTS Table 5-2
FRAMING MODE
(CCR2.3) COUNT Fs ERRORS?
(RCR2.1) WHAT IS COUNTED
IN THE PCVCRs
D4 no errors in the Ft pattern
D4 yes errors in both the Ft & Fs patterns
ESF don't care errors in the CRC6 code words
5.3 MULTIFRAMES OUT OF SYNC COUNT REGISTER (MOSCR)
Normally the MOSCR is used to count the number of multiframes that the receive synchronizer is out of
sync (RCR2.0=1). This number is useful in ESF applications needing to measure the parameters Loss Of
Frame Count (LOFC) and ESF Error Events as described in AT&T publication TR54016. When the
MOSCR is operated in this mode, it is not disabled during receive loss of synchronization (RLOS=1)
conditions. The MOSCR has alternate operating mode whereby it will count either errors in the Ft
framing pattern (in the D4 mode) or errors in the FPS framing pattern (in the ESF mode). When the
MOSCR is operated in this mode, it is disabled during receive loss of synchronization (RLOS=1)
conditions. See Table 5-3 for a detailed description of what the MOSCR is capable of counting.
MOSCR1:
MULTIFRAMES OUT OF SYNC COUNT REGISTER 1 (Address=25 Hex)
MOSCR2:
MULTIFRAMES OUT OF SYNC COUNT REGISTER 2 (Address=27 Hex)
(MSB) (LSB)
MOS/FB11 MOS/FB10 MOS/FB9 MOS/FB8 (note 1) (note 1) (note 1) (note 1) MOSCR1
MOS/FB7 MOS/FB6 MOS/FB5 MOS/FB4 MOS/FB3 MOS/FB2 MOS/FB1 MOS/FB0 MOSCR2
SYMBOL POSITION NAME AND DESCRIPTION
MOS/FB11 MOSCR1.7 MSB of the 12-Bit Multiframes Out of Sync or F-Bit Error
Count (note #2)
MOS/FB0 MOSCR2.0 LSB of the 12-Bit Multiframes Out of Sync or F-Bit Error
Count (note #2)
NOTES:
1. The lower nibble of the counter at address 25 is used by the Path Code Violation Count Register.
2. MOSCR counts either errors in framing bit position (RCR2.0=0) or the number of multiframes out of
sync (RCR2.0=1).
DS2152
41 of 93
MULTIFRAMES OUT OF SYNC COUNTING ARRANGEMENTS Table 5-3
FRAMING MODE
(CCR2.3) COUNT MOS OR F-BIT
ERRORS (RCR2.0) WHAT IS COUNTED
IN THE MOSCRs
D4 MOS number of multiframes out of sync
D4 F-Bit errors in the Ft pattern
ESF MOS number of multiframes out of sync
ESF F-Bit errors in the FPS pattern
6.0 DS0 MONITORING FUNCTION
The DS2152 has the ability to monitor one DS0 64kbps 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 CCR5 register. In the
receive direction, the RCM0 to RCM4 bits in the CCR6 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 DS0
(RDS0M) register.
The TCM4 to TCM0 and RCM4 to RCM0 bits should be programmed with the decimal decode of the
appropriate T1 channel. For example, if DS0 channel 6 in the transmit direction and DS0 channel 15 in
the receive direction needed to be monitored, then the following values would be programmed into CCR5
and CCR6: TCM4 = 0 RCM4 = 0
TCM3 = 0 RCM3 = 1
TCM2 = 1 RCM2 = 1
TCM1 = 0 RCM1 = 1
TCM0 = 1 RCM0 = 0
DS2152
42 of 93
CCR5: COMMON CONTROL REGISTER 5 (Address=19 Hex)
[repeated here from section 3 for convenience]
(MSB) (LSB)
TJC LLB LIAIS TCM4 TCM3 TCM2 TCM1 TCM0
SYMBOL POSITION NAME AND DESCRIPTION
TJC CCR5.7 Transmit Japanese CRC Enable. See Section 3 for details.
LLB CCR5.6 Local Loopback. See Section 3 for details.
LIAIS CCR5.5
Line Interface AIS Generation Enable.
See Section 3 for
details.
TCM4 CCR5.4
Transmit Channel Monitor Bit 4.
MSB of a channel decode
that determines which transmit DS0 channel data will appear in
the TDS0M register.
TCM3 CCR5.3 Transmit Channel Monitor Bit 3.
TCM2 CCR5.2 Transmit Channel Monitor Bit 2.
TCM1 CCR5.1 Transmit Channel Monitor Bit 1.
TCM0 CCR5.0
Transmit Channel Monitor Bit 0.
LSB of the channel decode
that determines which transmit DS0 channel data will appear in
the TDS0M register.
DS2152
43 of 93
TDS0M: TRANSMIT DS0 MONITOR REGISTER (Address=1A Hex)
(MSB) (LSB)
B1 B2 B3 B4 B5 B6 B7 B8
SYMBOL POSITION NAME AND DESCRIPTION
B1 TDS0M.7
Transmit DS0 Channel Bit 1.
MSB of the DS0 channel (first
bit to be transmitted).
B2 TDS0M.6 Transmit DS0 Channel Bit 2.
B3 TDS0M.5 Transmit DS0 Channel Bit 3.
B4 TDS0M.4 Transmit DS0 Channel Bit 4.
B5 TDS0M.3 Transmit DS0 Channel Bit 5.
B6 TDS0M.2 Transmit DS0 Channel Bit 6.
B7 TDS0M.1 Transmit DS0 Channel Bit 7.
B8 TDS0M.0
Transmit DS0 Channel Bit 8.
LSB of the DS0 channel (last bit
to be transmitted).
CCR6: COMMON CONTROL REGISTER 6 (Address=1E Hex)
[repeated here from section 3 for convenience]
(MSB) (LSB)
RJC - - RCM4 RCM3 RCM2 RCM1 RCM0
SYMBOL POSITION NAME AND DESCRIPTION
RJC CCR6.7 Receive Japanese CRC Enable. See Section 3 for details.
-CCR6.6 Not Assigned. Should be set to 0 when written.
-CCR6.5 Not Assigned. Should be set to 0 when written.
RCM4 CCR6.4
Receive Channel Monitor Bit 4.
MSB of a channel decode that
determines which receive DS0 channel data will appear in the
RDS0M register.
RCM3 CCR6.3 Receive Channel Monitor Bit 3.
RCM2 CCR6.2 Receive Channel Monitor Bit 2.
RCM1 CCR6.1 Receive Channel Monitor Bit 1.
RCM0 CCR6.0
Receive Channel Monitor Bit 0.
LSB of the channel decode
that determines which receive DS0 channel data will appear in
the RDS0M register.
DS2152
44 of 93
DS2152
45 of 93
RDS0M: RECEIVE DS0 MONITOR REGISTER (Address=1F Hex)
(MSB) (LSB)
B1 B2 B3 B4 B5 B6 B7 B8
SYMBOL POSITION NAME AND DESCRIPTION
B1 RDS0M.7
Receive DS0 Channel Bit 1.
MSB of the DS0 channel (first bit
to be received).
B2 RDS0M.6 Receive DS0 Channel Bit 2.
B3 RDS0M.5 Receive DS0 Channel Bit 3.
B4 RDS0M.4 Receive DS0 Channel Bit 4.
B5 RDS0M.3 Receive DS0 Channel Bit 5.
B6 RDS0M.2 Receive DS0 Channel Bit 6.
B7 RDS0M.1 Receive DS0 Channel Bit 7.
B8 RDS0M.0 Receive DS0 Channel Bit 8. LSB of the DS0 channel (last bit to
be received).
7.0 SIGNALING OPERATION
The DS2152 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 robbed-bit signaling bits embedded in the T1 stream can be extracted from the receive stream and
inserted into the transmit stream by the DS2152. There is a set of 12 registers for the receive side (RS1 to
RS12) and 12 registers on the transmit side (TS1 to TS12). The signaling registers are detailed below.
The CCR1.5 bit is used to control the robbed signaling bits as they appear at RSER. If CCR1.5 is set to 0,
then the robbed signaling bits will appear at the RSER pin in their proper position as they are received. If
CCR1.5 is set to a 1, then the robbed signaling bit positions will be forced to a 1 at RSER. If hardware
based signaling is being used, then CCR1.5 must be set to 0.
DS2152
46 of 93
RS1 TO RS12: RECEIVE SIGNALING REGISTERS (Address=60 to 6B Hex)
(MSB) (LSB)
A(8) A(7) A(6) A(5) A(4) A(3) A(2) A(1) RS1 (60)
A(16) A(15) A(14) A(13) A(12) A(11) A(10) A(9) RS2 (61)
A(24) A(23) A(22) A(21) A(20) A(19) A(18) A(17) RS3 (62)
B(8) B(7) B(6) B(5) B(4) B(3) B(2) B(1) RS4 (63)
B(16) B(15) B(14) B(13) B(12) B(11) B(10) B(9) RS5 (64)
B(24) B(23) B(22) B(21) B(20) B(19) B(18) B(17) RS6 (65)
A/C(8) A/C(7) A/C(6) A/C(5) A/C(4) A/C(3) A/C(2) A/C(1) RS7 (66)
A/C(16) A/C(15) A/C(14) A/C(13) A/C(12) A/C(11) A/C(10) A/C(9) RS8 (67)
A/C(24) A/C(23) A/C(22) A/C(21) A/C(20) A/C(19) A/C(18) A/C(17) RS9 (68)
B/D(8) B/D(7) B/D(6) B/D(5) B/D(4) B/D(3) B/D(2) B/D(1) RS10 (69)
B/D(16) B/D(15) B/D(14) B/D(13) B/D(12) B/D(11) B/D(10) B/D(9) RS11 (6A)
B/D(24) B/D(23) B/D(22) B/D(21) B/D(20) B/D(19) B/D(18) B/D(17) RS12 (6B)
SYMBOL POSITION NAME AND DESCRIPTION
D(24) RS12.7 Signaling Bit D in Channel 24
A(1) RS1.0 Signaling Bit A in Channel 1
Each Receive Signaling Register (RS1 to RS12) reports the incoming robbed-bit signaling from eight
DS0 channels. In the ESF framing mode, there can be up to 4 signaling bits per channel (A, B, C, and D).
In the D4 framing mode, there are only 2 signaling bits per channel (A and B). In the D4 framing mode,
the DS2152 will replace the C and D signaling bit positions with the A and B signaling bits from the
previous multiframe. Hence, whether the DS2152 is operated in either framing mode, the user needs only
to retrieve the signaling bits every 3 ms. 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 Receive Signaling Registers are
frozen and not updated during a loss of sync condition (SR1.0=1). They will contain the most recent
signaling information before the “OOF” occurred. The signaling data reported in RS1 to RS12 is also
available at the RSIG and RSER pins.
A change in the signaling bits from one multiframe to the next will cause the RSC status bit (SR2.0) to be
set. The user can enable the INT pin to toggle low upon detection of a change in signaling by setting the
IMR2.0 bit. Once a signaling change has been detected, the user has at least 2.75 ms to read the data out
of the RS1 to RS12 registers before the data will be lost.
DS2152
47 of 93
TS1 TO TS12: TRANSMIT SIGNALING REGISTERS (Address=70 to 7B Hex)
(MSB) (LSB)
A(8) A(7) A(6) A(5) A(4) A(3) A(2) A(1) TS1 (70)
A(16) A(15) A(14) A(13) A(12) A(11) A(10) A(9) TS2 (71)
A(24) A(23) A(22) A(21) A(20) A(19) A(18) A(17) TS3 (72)
B(8) B(7) B(6) B(5) B(4) B(3) B(2) B(1) TS4 (73)
B(16) B(15) B(14) B(13) B(12) B(11) B(10) B(9) TS5 (74)
B(24) B(23) B(22) B(21) B(20) B(19) B(18) B(17) TS6 (75)
A/C(8) A/C(7) A/C(6) A/C(5) A/C(4) A/C(3) A/C(2) A/C(1) TS7 (76)
A/C(16) A/C(15) A/C(14) A/C(13) A/C(12) A/C(11) A/C(10) A/C(9) TS8 (77)
A/C(24) A/C(23) A/C(22) A/C(21) A/C(20) A/C(19) A/C(18) A/C(17) TS9 (78)
B/D(8) B/D(7) B/D(6) B/D(5) B/D(4) B/D(3) B/D(2) B/D(1) TS10 (79)
B/D(16) B/D(15) B/D(14) B/D(13) B/D(12) B/D(11) B/D(10) B/D(9) TS11 (7A)
B/D(24) B/D(23) B/D(22) B/D(21) B/D(20) B/D(19) B/D(18) B/D(17) TS12 (7B)
SYMBOL POSITION NAME AND DESCRIPTION
D(24) TS12.7 Signaling Bit A in Channel 24
A(1) TS1.0 Signaling Bit D in Channel 1
Each Transmit Signaling Register (TS1 to TS12) contains the robbed-bit signaling for eight DS0 channels
that will be inserted into the outgoing stream if enabled to do so via TCR1.4. In the ESF framing mode,
there can be up to 4 signaling bits per channel (A, B, C, and D). On multiframe boundaries, the DS2152
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 Interrupt in Status Register 2
(SR2.6) to know when to update the signaling bits. In the ESF framing mode, the interrupt will come
every 3 ms and the user has a full 3ms to update the TSRs. In the D4 framing mode, there are only 2
signaling bits per channel (A and B). However, in the D4 framing mode the DS2152 uses the C and D bit
positions as the A and B bit positions for the next multiframe. The DS2152 will load the values in the
TSRs into the outgoing shift register every other D4 multiframe.
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 reinsertion. Signaling extraction involves pulling the signaling
bits from the receive data stream and buffering them over a four multiframe buffer and outputting them in
a serial PCM fashion on a channel-by-channel basis at the RSIG output. 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) can be either 1.544 MHz or 2.048 MHz. In the ESF framing mode, the
ABCD signaling bits are output on RSIG in the lower nibble of each channel. The RSIG data is updated
once a multiframe (3 ms) unless a freeze is in effect. In the D4 framing mode, the AB signaling bits are
output twice on RSIG in the lower nibble of each channel. Hence, bits 5 and 6 contain the same data as
bits 7 and 8 respectively in each channel. The RSIG data is updated once a multiframe (1.5 ms) unless a
freeze is in effect. See the timing diagrams in Section 15 for some examples.
The other hardware based signaling operating mode called signaling reinsertion can be invoked by setting
the RSRE control bit high (CCR4.7=1). In this mode, the user will provide a multiframe sync at the
DS2152
48 of 93
RSYNC pin and the signaling data will be re-aligned at the RSER output according to this applied
multiframe boundary. In this mode, the elastic store must be enabled however the backplane clock can be
either 1.544 MHz or 2.048 MHz.
If the signaling reinsertion mode is enabled, the user can control which channels have signaling
reinsertion performed on a channel-by-channel basis by setting the RPCSI control bit high (CCR4.6) and
then programming the RCHBLK output pin to go high in the channels in which the signaling reinsertion
should not occur. If the RPCSI bit is set low, then signaling reinsertion will occur in all channels when
the signaling reinsertion mode is enabled (RSRE=1). How to control the operation of the RCHBLK
output pin is covered in Section 9.
In signaling reinsertion mode, the user has the option to replace all of the extracted robbed-bit signaling
bit positions with 1s. This option is enabled via the RFSA1 control bit (CCR4.5) and it can be invoked on
a per-channel basis by setting the RPCSI control bit (CCR4.6) high and then programming RCHBLK
appropriately just like the per-channel signaling reinsertion operates.
The signaling data in the four-multiframe buffer will be frozen in a known good state upon either a loss of
synchronization (OOF event), carrier loss, or frame slip. This action meets the requirements of BellCore
TR-TSY-000170 for signaling freezing. To allow this freeze action to occur, the RFE control bit
(CCR4.4) should be set high. The user can force a freeze by setting the RFF control bit (CCR4.3) high.
The RSIGF output pin provides a hardware indication that a freeze is in effect. The four-multiframe
buffer provides a three-multiframe delay in the signaling bits provided at the RSIG pin (and at the RSER
pin if RSRE=1). 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 at least an additional 9 ms (or 4.5 ms in D4 framing mode) before
being allowed to be updated with new signaling data.
7.2.2 Transmit Side
Via the THSE control bit (CCR4.2), the DS2152 can be set up to take the signaling data presented at the
TSIG pin and insert the signaling data into the PCM data stream that is being input at the TSER pin. The
user has the ability to control which channels are to have signaling data from the TSIG pin inserted into
them on a channel-by-channel basis by setting the TPCSI control bit (CCR4.1) high. When TPCSI is
enabled, channels in which the TCHBLK output has been programmed to be set high in, will not have
signaling data from the TSIG pin inserted into them. The hardware signaling insertion capabilities of the
DS2152 are available whether the transmit side elastic store is enabled or disabled. If the elastic store is
enabled, the backplane clock (TSYSCLK) can be either 1.544 MHz or 2.048 MHz.
8.0 PER-CHANNEL CODE (IDLE) GENERATION AND LOOPBACK
The DS2152 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 T1 line and is covered in Section 8.1. The receive
direction is from the T1 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 DS2152. The first method which is covered in Section 8.1.1 was a
feature contained in the original DS2151 while the second method, which is covered in Section 8.1.2, is a
new feature of the DS2152.
DS2152
49 of 93
8.1.1 Simple Idle Code Insertion and Per-Channel Loopback
The first method involves using the Transmit Idle Registers (TIR1/2/3) to determine which of the 24 T1
channels 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 24 T1 channels. If this method is
used, then the CCR4.0 control bit must be set to 0.
Each of the bit positions in the Transmit Idle Registers (TIR1/TIR2/TIR3) represents a DS0 channel in
the outgoing frame. When these bits are set to a 1, the corresponding channel will transmit the Idle Code
contained in the Transmit Idle Definition Register (TIDR). Robbed-bit signaling and Bit 7 stuffing will
occur over the programmed Idle Code unless the DS0 channel is made transparent by the Transmit
Transparency Registers.
The Transmit Idle Registers (TIRs) have an alternate function that allows them to define a Per-Channel
Loop-Back (PCLB). If the TIRFS control bit (CCR4.0) is set to 1, 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 T1 line. 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.
TIR1/TIR2/TIR3: TRANSMIT IDLE REGISTERS (Address=3C to 3E Hex)
[Also used for Per-Channel Loopback]
(MSB) (LSB)
CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 TIR1 (3C)
CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 TIR2 (3D)
CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 TIR3 (3E)
SYMBOL POSITION NAME AND DESCRIPTION
CH24 TIR3.7 Transmit Idle Registers.
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
NOTE:
If CCR4.0=1, then a 0 in the TIRs implies that channel data is to be sourced from TSER and a 1 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=3F Hex)
(MSB) (LSB)
TIDR7 TIDR6 TIDR5 TIDR4 TIDR3 TIDR2 TIDR1 TIDR0
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)
DS2152
50 of 93
8.1.2 Per-Channel Code Insertion
The second method involves using the Transmit Channel Control Registers (TCC1/2/3) to determine
which of the 24 T1 channels should be overwritten with the code placed in the Transmit Channel
Registers (TC1 to TC24). This method is more flexible than the first in that it allows a different 8-bit code
to be placed into each of the 24 T1 channels.
TC1 TO TC24:
TRANSMIT CHANNEL REGISTERS (Address=40 to 4F and 50 to 57 Hex)
(for brevity, only channel 1 is shown; see Table 1-3 for other register address)
(MSB) (LSB)
C7 C6 C5 C4 C3 C2 C1 C0 TC1 (50)
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)
TCC1/TCC2/TCC3:
TRANSMIT CHANNEL CONTROL REGISTER (Address=16 to 18 Hex)
(MSB) (LSB)
CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 TCC1 (16)
CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 TCC2 (17)
CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 TCC3 (18)
SYMBOL POSITION NAME AND DESCRIPTION
CH24 TCC3.7 Transmit Channel 24 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
CH1 TCC1.0 Transmit Channel 1 Code Insertion Control Bit
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
8.2 RECEIVE SIDE CODE GENERATION
In the receive direction there are also two methods by which channel data to the backplane can be
overwritten with data generated by the DS2152. The first method which is covered in Section 8.2.1 was a
feature contained in the original DS2151 while the second method which is covered in Section 8.2.2 is a
new feature of the DS2152.
8.2.1 Simple Code Insertion
The first method on the receive side involves using the Receive Mark Registers (RMR1/2/3) to determine
which of the 24 T1 channels should be overwritten with either a 7Fh idle code or with a digital milliwatt
DS2152
51 of 93
pattern. The RCR2.7 bit will determine which code is used. The digital milliwatt code is an 8-byte
repeating pattern that represents a 1 kHz sine wave (1E/0B/0B/1E/9E/8B/8B/9E). Each bit in the RMRs
represents a particular channel. If a bit is set to a 1, then the receive data in that channel will be replaced
with one of the two codes. If a bit is set to 0, no replacement occurs.
RMR1/RMR2/RMR3: RECEIVE MARK REGISTERS (Address=2D to 2F Hex)
(MSB) (LSB)
CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 RMR1(2D)
CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 RMR2(2E)
CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 RMR3(2F)
SYMBOL POSITION NAME AND DESCRIPTION
CH24 RMR3.7 Receive MARK Registers.
0=do not affect the receive data associated with this channel
CH1 RMR1.0 1=replace the receive data associated with this channel with
either the idle code or the digital milliwatt code (depends on the
RCR2.7 bit)
8.2.2 Per-Channel Code Insertion
The second method involves using the Receive Channel Control Registers (RCC1/2/3) to determine
which of the 24 T1 channels off of the T1 line and going to the backplane should be overwritten with the
code placed in the Receive Channel Registers (RC1 to RC24). This method is more flexible than the first
in that it allows a different 8-bit code to be placed into each of the 24 T1 channels.
RC1 TO RC24:
RECEIVE CHANNEL REGISTERS (Address=58 to 5F and 80 to 8F Hex)
(for brevity, only channel 1 is shown; see Table 1-3 for other register address)
(MSB) (LSB)
C7 C6 C5 C4 C3 C2 C1 C0 RC1 (58)
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)
DS2152
52 of 93
RCC1/RCC2/RCC3:
RECEIVE CHANNEL CONTROL REGISTER (Address=1B to 1D Hex)
(MSB) (LSB)
CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 RCC1 (1B)
CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 RCC2 (1C)
CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 RCC3 (1D)
SYMBOL POSITION NAME AND DESCRIPTION
CH24 RCC3.7 Receive Channel 24 Code Insertion Control Bit
0=do not insert data from the RC24 register into the receive data
stream
1=insert data from the RC24 register into the receive data stream
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
9.0 CLOCK BLOCKING REGISTERS
The Receive Channel Blocking Registers (RCBR1/RCBR2/RCBR3) and the Transmit Channel Blocking
Registers (TCBR1/TCBR2/TCBR3) control the RCHBLK and TCHBLK pins respectively. The
RCHBLK and TCHCLK 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
Fractional T1 or ISDN-PRI applications. When the appropriate bits are set to a 1, the RCHBLK and
TCHCLK pins will be held high during the entire corresponding channel time. See the timing in Section
15 for an example.
RCBR1/RCBR2/RCBR3:
RECEIVE CHANNEL BLOCKING REGISTERS (Address=6C to 6E Hex)
(MSB) (LSB)
CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 RCBR1 (6C)
CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 RCBR2 (6D)
CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 RCBR3 (6E)
SYMBOL POSITION NAME AND DESCRIPTION
CH24 RCBR3.7 Receive Channel Blocking Registers.
0=force the RCHBLK pin to remain low during this channel
time
CH1 RCBR1.0 1=force the RCHBLK pin high during this channel time
DS2152
53 of 93
TCBR1/TCBR2/TCBR3:
TRANSMIT CHANNEL BLOCKING REGISTERS (Address=32 to 34 Hex)
(MSB) (LSB)
CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 TCBR1 (32)
CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 TCBR1 (33)
CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 TCBR1 (34)
SYMBOL POSITION NAME AND DESCRIPTION
CH24 TCBR3.7 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
10.0 ELASTIC STORES OPERATION
The DS2152 contains dual two-frame (386 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 T1 data stream to 2.048 Mbps (or a multiple of 2.048 Mbps), which is the E1 rate. Secondly, they can
be used to absorb the differences in frequency and phase between the T1 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 fully controlled slip
capability, which is necessary for this second purpose. The receive side elastic store can be enabled via
CCR1.2 and the transmit side elastic store is enabled via CCR1.7. The elastic stores can be forced to a
known depth via the Elastic Store Reset bit (CCR3.6). Toggling the CCR3.6 bit forces the read and write
pointers into opposite frames. Both elastic stores within the DS2152 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 (CCR1.2=1), then the user must provide either a 1.544 MHz
(CCR1.3=0) or 2.048 MHz (CCR1.3=1) clock at the RSYSCLK pin. The user has the option of either
providing a frame/multiframe sync at the RSYNC pin (RCR2.3=1) or having the RSYNC pin provide a
pulse on frame boundaries (RCR2.3=0). If the user wishes to obtain pulses at the frame boundary, then
RCR2.4 must be set to 0; if the user wishes to have pulses occur at the multiframe boundary, then
RCR2.4 must be set to 1. The DS2152 will always indicate frame boundaries via the RFSYNC output
whether the elastic store is enabled or not. If the elastic store is enabled, then multiframe boundaries will
be indicated via the RMSYNC output. If the user selects to apply a 2.048 MHz clock to the RSYSCLK
pin, then the data output at RSER will be forced to all 1s every fourth channel and the F-bit will be placed
in the MSB bit position of channel 1. Hence channels 1, 5, 9, 13, 17, 21, 25, and 29 (timeslots 0, 4, 8, 12,
16, 20, 24, and 28) will be forced to a 1. Also, in 2.048 MHz applications, the RCHBLK output will be
forced high during the same channels as the RSER pin. See Section 15 for more details. This is useful in
T1 to CEPT (E1) conversion applications. If the 386-bit elastic buffer either fills or empties, a controlled
slip will occur. If the buffer empties, then a full frame of data (193 bits) will be repeated at RSER and the
SR1.4 and RIR1.3 bits will be set to a 1 except the MSB of channel 1. See Figure 15-5. If the buffer fills,
then a full frame of data will be deleted and the SR1.4 and RIR1.4 bits will be set to a 1.
DS2152
54 of 93
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 CCR1.7. A 1.544 MHz (CCR1.4=0) or 2.048 MHz (CCR1.4=1) clock can be applied
to the TSYSCLK input. If the user selects to apply a 2.048 MHz clock to the TSYSCLK pin, then the data
input 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 F-bit may be sampled at the MSB of
channel 1. See Figure 15-10. The user must supply an 8 kHz frame sync pulse to the TSSYNC input.
Also, in 2.048 MHz applications the TCHBLK output will be forced high during the channels ignored by
the DS2152. See Section 15 for more details. Controlled slips in the transmit elastic store are reported in
the RIR2.3 bit, and the direction of the slip is reported in the RIR2.5 and RIR2.4 bits.
10.3 MINIMUM DELAY SYNCHRONOUS RSYSCLK/TSYSCLK MODE
In applications where the DS2152 is connected to backplanes that are frequency-locked to the recovered
T1 clock (i.e., the RCLK output), the full two-frame depth of the onboard elastic stores is really not
needed. In fact, in some delay-sensitive applications the normal two-frame depth may be excessive. If the
CCR3.7 bit is set to 1, then the receive elastic store (and also the transmit elastic store if it is enabled) will
be forced to a maximum depth of 32 bits instead of the normal 386 bits. In this mode, RSYSCLK and
TSYSCLK must be tied together and they must be frequency-locked to RCLK. All of the slip contention
logic in the DS2152 is disabled (since slips cannot occur). Also, since the buffer depth is no longer two
frames deep, the DS2152 must be set up to source a frame pulse at the RSYNC pin and this output must
be tied to the TSSYNC input. On power-up after the RSYSCLK and TSYSCLK signals have locked to
the RCLK signal, the elastic store reset bit (CCR3.6) should be toggled from a 0 to a 1 to insure proper
operation.
11.0 FDL/Fs EXTRACTION AND INSERTION
The DS2152 has the ability to extract/insert data from/into the Facility Data Link (FDL) in the ESF
framing mode and from/into Fs-bit position in the D4 framing mode. Since SLC-96 utilizes the Fs-bit
position, this capability can also be used in SLC-96 applications. The DS2152 contains a complete
HDLC and BOC controller for the FDL and this operation is covered in Section 11.1. To allow for
backward compatibility between the DS2152 and earlier devices, the DS2152 maintains some legacy
functionality for the FDL and this is covered in Section 11.2. Section 11.3 covers D4 and SLC-96
operation. Please contact the factory for a copy of C language source code for implementing the FDL on
the DS2152.
11.1 HDLC AND BOC CONTROLLER FOR THE FDL
11.1.1 General Overview
The DS2152 contains a complete HDLC controller with 16-byte buffers in both the transmit and receive
directions as well as separate dedicated hardware for Bit Oriented Codes (BOC). The HDLC controller
performs all the necessary overhead for generating and receiving Performance Report Messages (PRM)
as described in ANSI T1.403 and the messages as described in AT&T TR54016. The HDLC controller
automatically generates and detects flags, generates and checks the CRC check sum, generates and
detects abort sequences, stuffs and destuffs 0s (for transparency), and byte-aligns to the FDL data stream.
The 16-byte buffers in the HDLC controller are large enough to allow a full PRM to be received or
transmitted without host intervention. The BOC controller will automatically detect incoming BOC
sequences and alert the host. When the BOC ceases, the DS2152 will also alert the host. The user can set
the device up to send any of the possible 6-bit BOC codes.
DS2152
55 of 93
There are nine registers that the host will use to operate and control the operation of the HDLC and BOC
controllers. A brief description of the registers is shown in Table 11-1.
HDLC/BOC CONTROLLER REGISTER LIST Table 11-1
NAME FUNCTION
FDL Control Register (FDLC)
FDL Status Register (FDLS)
FDL Interrupt Mask Register (FIMR)
general control over the HDLC and BOC controllers key
status information for both transmit and receive directions
allows/stops status bits to/from causing an interrupt
Receive PRM Register (RPRM)
Receive BOC Register (RBOC)
Receive FDL FIFO Register (RFFR)
status information on receive HDLC controller status
information on receive BOC controller access to 16-byte
HDLC FIFO in receive direction
Transmit PRM Register (TPRM)
Transmit BOC Register (TBOC)
Transmit FDL FIFO Register (TFFR)
status information on transmit HDLC controller
enables/disables transmission of BOC codes access to 16-byte
HDLC FIFO in transmit direction
11.1.2 Status Register for the FDL
Four of the HDLC/BOC controller registers (FDLS, RPRM, RBOC, and TPRM) provide status
information. When a particular event has occurred (or is occurring), the appropriate bit in one of these
four registers will be set to a 1. Some of the bits in these four FDL status registers are latched and some
are real-time bits that are not latched. Section 11.1.4 contains register descriptions that list which bits are
latched and which are not. With the latched bits, when an event occurs and a bit is set to a 1, 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. The real-time bits report the current instantaneous conditions that are
occurring, and the history of these bits is not latched.
Like the other status registers in the DS2152, the user will always proceed a read of any of the four
registers with a write. The byte written to the register will inform the DS2152 which of the latched bits
the user wishes to read and have cleared (the real-time bits are not affected by writing to the status
register). The user will write a byte to one of these registers, with a 1 in the bit positions he or she wishes
to read and a 0 in the bit positions he or she does not wish to obtain the latest information on. When a 1 is
written to a bit location, the read register will be updated with current value and it will be cleared. When a
0 is written to a bit position, the read register will not be updated and the previous value will 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 (for polled driven access) or write-read (for interrupt-
driven access) 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 DS2152 with
higher-order software languages.
Like the SR1 and SR2 status registers, the FDLS register has the unique ability to initiate a hardware
interrupt via the INT output pin. Each of the events in the FDLS can be either masked or unmasked from
the interrupt pin via the FDL Interrupt Mask Register (FIMR). Interrupts will force the INT pin low 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.
DS2152
56 of 93
11.1.3 Basic Operation Details
To allow the DS2152 to properly source/receive data from/to the HDLC and BOC controller the legacy
FDL circuitry (which is described in Section 11.2) should be disabled and the following bits should be
programmed as shown:
TCR1.2 = 1 (source FDL data from the HDLC and BOC controller)
TBOC.6 = 1 (enable HDLC and BOC controller)
CCR2.5 = 0 (disable SLC-96 and D4 Fs-bit insertion)
CCR2.4 = 0 (disable legacy FDL 0 stuffer)
CCR2.1 = 0 (disable SLC-96 reception)
CCR2.0 = 0 (disable legacy FDL 0 stuffer)
IMR2.4 = 0 (disable legacy receive FDL buffer full interrupt)
IMR2.3 = 0 (disable legacy transmit FDL buffer empty interrupt)
IMR2.2 = 0 (disable legacy FDL match interrupt)
IMR2.1 = 0 (disable legacy FDL abort interrupt)
As a basic guideline for interpreting and sending both HDLC messages and BOC messages, the following
sequences can be applied:
Receive a HDLC Message or a BOC
1. enable RBOC and RPS interrupts
2. wait for interrupt to occur
3. if RBOC=1, then follow steps 5 and 6
4. if RPS=1, then follow steps 7 thru 12
5. if LBD=1, a BOC is present, then read the code from the RBOC register and take action as needed
6. if BD=0, a BOC has ceased, take action as needed and then return to step 1
7. disable RPS interrupt and enable either RPE, RNE, or RHALF interrupt
8. read RPRM to obtain REMPTY status
a. if REMPTY=0, then record OBYTE, CBYTE, and POK bits and then read the FIFO
a1. if CBYTE=0 then skip to step 9
a2. if CBYTE=1 then skip to step 11
b. if REMPTY=1, then skip to step 10
9. repeat step 8
10. wait for interrupt, skip to step 8
11. if POK=0, then discard whole packet, if POK=1, accept the packet
12. disable RPE, RNE, or RHALF interrupt, enable RPS interrupt and return to step 1
Transmit a HDLC Message
1. make sure HDLC controller is finished sending any previous messages and is currently sending flags
by checking that the FIFO is empty by reading the TEMPTY status bit in the TPRM register
2. enable either the THALF or TNF interrupt
3. read TPRM to obtain TFULL status
a. if TFULL=0, then write a byte into the FIFO and skip to next step (special case occurs when the
last byte is to be written, in this case set TEOM=1 before writing the byte and then skip to step 6)
b. if TFULL=1, then skip to step 5
DS2152
57 of 93
4. repeat step 3
5. wait for interrupt, skip to step 3
6. disable THALF or TNF interrupt and enable TMEND interrupt
7. wait for an interrupt, then read TUDR status bit to make sure packet was transmitted correctly.
Transmit a BOC
1. write 6-bit code into TBOC
2. set SBOC bit in TBOC=1
11.1.4 HDLC/BOC Register Description
FDLC: FDL CONTROL REGISTER (Address=00 Hex)
(MSB) (LSB)
RBR RHR TFS THR TABT TEOM TZSD TCRCF
SYMBOL POSITION NAME AND DESCRIPTION
RBR FDLC.7
Receive BOC Reset.
A 0 to 1 transition will reset the BOC
circuitry. Must be cleared and set again for a subsequent reset.
RHR FDLC.6
Receive HDLC Reset.
A 0 to 1 transition will reset the HDLC
controller. Must be cleared and set again for a subsequent reset.
TFS FDLC.5 Transmit Flag/Idle Select.
0 = 7Eh
1 = FFh
THR FDLC.4
Transmit HDLC Reset.
A 0 to 1 transition will reset both the
HDLC controller and the transmit BOC circuitry. Must be
cleared and set again for a subsequent reset.
TABT FDLC.3
Transmit Abort.
A 0 to 1 transition will cause the FIFO
contents to be dumped and one FEh abort to be sent followed by
7Eh or FFh flags/idle until a new packet is initiated by writing
new data into the FIFO. Must be cleared and set again for a
subsequent abort to be sent.
TEOM FDLC.2
Transmit End of Message.
Should be set to a 1 just before the
last data byte of a HDLC packet is written into the transmit
FIFO at TFFR. This bit will be cleared by the HDLC controller
when the last byte has been transmitted.
TZSD FDLC.1 Transmit 0 Stuffer Defeat. Overrides internal enable.
0 = enable the 0 stuffer (normal operation)
1 = disable the 0 stuffer
TCRCD FDLC.0 Transmit CRC Defeat.
0 = enable CRC generation (normal operation)
1 = disable CRC generation
DS2152
58 of 93
FDLS: FDL STATUS REGISTER (Address=01 Hex)
(MSB) (LSB)
RBOC RPE RPS RHALF RNE THALF TNF TMEND
SYMBOL POSITION NAME AND DESCRIPTION
RBOC FDLS.7
Receive BOC Detector Change of State.
Set whenever the
BOC detector sees a change of state from a BOC Detected to a
No Valid Code seen or vice versa. The setting of this bit prompt
the user to read the RBOC register for details.
RPE FDLS.6
Receive Packet End.
Set when the HDLC controller detects
either the finish of a valid message (i.e., CRC check complete)
or when the controller has experienced a message fault such as a
CRC checking error, or an overrun condition, or an abort has
been seen. The setting of this bit prompts the user to read the
RPRM register for details.
RPS FDLS.5
Receive Packet Start.
Set when the HDLC controller detects an
opening byte. The setting of this bit prompts the user to read the
RPRM register for details.
RHALF FDLS.4
Receive FIFO Half Full.
Set when the receive 16-byte FIFO
fills beyond the halfway point. The setting of this bit prompts the
user to read the RPRM register for details.
RNE FDLS.3
Receive FIFO Not Empty.
Set when the receive 16-byte FIFO
has at least 1 byte available for a read. The setting of this bit
prompts the user to read the RPRM register for details.
THALF FDLS.2
Transmit FIFO Half Empty.
Set when the transmit 16-byte
FIFO empties beyond the halfway point. The setting of this bit
prompts the user to read the TPRM register for details.
TNF FDLS.1
Transmit FIFO Not Full.
Set when the transmit 16-byte FIFO
has at least 1 byte available. The setting of this bit prompts the
user to read the TPRM register for details.
TMEND FDLS.0
Transmit Message End.
Set when the transmit HDLC
controller has finished sending a message. The setting of this bit
prompts the user to read the TPRM register for details.
NOTE:
The RBOC, RPE, RPS, and TMEND bits are latched and will be cleared when read.
DS2152
59 of 93
FIMR: FDL INTERRUPT MASK REGISTER (Address=02 Hex)
(MSB) (LSB)
RBOC RPE RPS RHALF RNE THALF TNF TMEND
SYMBOL POSITION NAME AND DESCRIPTION
RBOC FIMR.7 Receive BOC Detector Change of State.
0 = interrupt masked
1 = interrupt enabled
RPE FIMR.6 Receive Packet End.
0 = interrupt masked
1 = interrupt enabled
RPS FIMR.5 Receive Packet Start.
0 = interrupt masked
1 = interrupt enabled
RHALF FIMR.4 Receive FIFO Half Full.
0 = interrupt masked
1 = interrupt enabled
RNE FIMR.3 Receive FIFO Not Empty.
0 = interrupt masked
1 = interrupt enabled
THALF FIMR.2 Transmit FIFO Half Empty.
0 = interrupt masked
1 = interrupt enabled
TNF FIMR.1 Transmit FIFO Not Full.
0 = interrupt masked
1 = interrupt enabled
TMEND FIMR.0 Transmit Message End.
0 = interrupt masked
1 = interrupt enabled
DS2152
60 of 93
RPRM: RECEIVE RPM REGISTER (Address=03 Hex)
(MSB) (LSB)
RABT RCRCE ROVR RVM REMPTY POK CBYTE OBYTE
SYMBOL POSITION NAME AND DESCRIPTION
RABT RPRM.7
Abort Sequence Detected.
Set whenever the HDLC controller
sees 7 or more 1s in a row.
RCRCE RPRM.6 CRC Error. Set when the CRC checksum is in error.
ROVR RPRM.5
Overrun.
Set when the HDLC controller has attempted to write
a byte into an already full receive FIFO.
RVM RPRM.4
Valid Message.
Set when the HDLC controller has detected and
checked a complete HDLC packet.
REMPTY RPRM.3
Empty.
A real-time bit that is set high when the receive FIFO is
empty.
POK RPRM.2
Packet OK.
Set when the byte available for reading in the
receive FIFO at RFDL is the last byte of a valid message (and
hence no abort was seen, no overrun occurred, and the CRC was
correct).
CBYTE RPRM.1
Closing Byte.
Set when the byte available for reading in the
receive FIFO at RFDL is the last byte of a message (whether the
message was valid or not).
OBYTE RPRM.0
Opening Byte.
Set when the byte available for reading in the
receive FIFO at RFDL is the first byte of a message.
NOTE:
The RABT, RCRCE, ROVR, and RVM bits are latched and will be cleared when read.
DS2152
61 of 93
RBOC: RECEIVE BOC REGISTER (Address=04 Hex)
(MSB) (LSB)
LBD BD BOC5 BOC4 BOC3 BOC2 BOC1 BOC0
SYMBOL POSITION NAME AND DESCRIPTION
LBD RBOC.7
Latched BOC Detected.
A latched version of the BD status bit
(RBOC.6). Will be cleared when read.
BD RBOC.6
BOC Detected.
A real-time bit that is set high when the BOC
detector is presently seeing a valid sequence and set low when
no BOC is currently being detected.
BOC5 RBOC.5 BOC Bit 5. Last bit received of the 6-bit codeword.
BOC4 RBOC.4 BOC Bit 4.
BOC3 RBOC.3 BOC Bit 3.
BOC2 RBOC.2 BOC Bit 2.
BOC1 RBOC.1 BOC Bit 1.
BOC0 RBOC.0 BOC Bit 0. First bit received of the 6-bit codeword.
NOTE:
1. The LBD bit is latched and will be cleared when read.
2. The RBOC0 to RBOC5 bits display the last valid BOC code verified; these bits will be set to all 1s on
reset.
DS2152
62 of 93
RFFR: RECEIVE FDL FIFO REGISTER (Address=05 Hex)
(MSB) (LSB)
FDL7 FDL6 FDL5 FDL4 FDL3 FDL2 FDL1 FDL0
SYMBOL POSITION NAME AND DESCRIPTION
FDL7 RFFR.7 FDL Data Bit 7. MSB of a HDLC packet data byte.
FDL6 RFFR.6 FDL Data Bit 6.
FDL5 RFFR.5 FDL Data Bit 5.
FDL4 RFFR.4 FDL Data Bit 4.
FDL3 RFFR.3 FDL Data Bit 3.
FDL2 RFFR.2 FDL Data Bit 2.
FDL1 RFFR.1 FDL Data Bit 1.
FDL0 RFFR.0 FDL Data Bit 0. LSB of a HDLC packet data byte.
TPRM: TRANSMIT PRM REGISTER (Address=06 Hex)
(MSB) (LSB)
-----TEMPTY TFULL UDR
SYMBOL POSITION NAME AND DESCRIPTION
-TPRM.7 Not Assigned. Could be any value when read.
-TPRM.6 Not Assigned. Could be any value when read.
-TPRM.5 Not Assigned. Could be any value when read.
-TPRM.4 Not Assigned. Could be any value when read.
-TPRM.3 Not Assigned. Could be any value when read.
TEMPTY TPRM.2
Transmit FIFO Empty.
A real-time bit that is set high when
the FIFO is empty.
TFULL TPRM.1
Transmit FIFO Full.
A real-time bit that is set high when the
FIFO is full.
UDR TPRM.0
Underrun.
Set when the transmit FIFO unwantedly empties out
and an abort is automatically sent.
NOTE:
The UDR bit is latched and will be cleared when read.
DS2152
63 of 93
TBOC: TRANSMIT BOC REGISTER (Address=07 Hex)
(MSB) (LSB)
SBOC HBEN BOC5 BOC4 BOC3 BOC2 BOC1 BOC0
SYMBOL POSITION NAME AND DESCRIPTION
SBOC TBOC.7 Send BOC. Rising edge triggered. Must be transitioned from a 0
to a 1 transmit the BOC code placed in the BOC0 to BOC5 bits
instead of data from the HDLC controller.
HBEN TBOC.6 Transmit HDLC & BOC Controller Enable.
0 = source FDL data from the TLINK pin
1 = source FDL data from the onboard HDLC and BOC
controller
BOC5 TBOC.5 BOC Bit 5. Last bit transmitted of the 6-bit codeword.
BOC4 TBOC.4 BOC Bit 4.
BOC3 TBOC.3 BOC Bit 3.
BOC2 TBOC.2 BOC Bit 2.
BOC1 TBOC.1 BOC Bit 1.
BOC0 TBOC.0 BOC Bit 0. First bit transmitted of the 6-bit codeword.
TFFR: TRANSMIT FDL FIFO REGISTER (Address=08 Hex)
(MSB) (LSB)
FDL7 FDL6 FDL5 FDL4 FDL3 FDL2 FDL1 FDL0
SYMBOL POSITION NAME AND DESCRIPTION
FDL7 TFFR.7 FDL Data Bit 7. MSB of a HDLC packet data byte.
FDL6 TFFR.6 FDL Data Bit 6.
FDL5 TFFR.5 FDL Data Bit 5.
FDL4 TFFR.4 FDL Data Bit 4.
FDL3 TFFR.3 FDL Data Bit 3.
FDL2 TFFR.2 FDL Data Bit 2.
FDL1 TFFR.1 FDL Data Bit 1.
FDL0 TFFR.0 FDL Data Bit 0. LSB of a HDLC packet data byte.
DS2152
64 of 93
11.2 LEGACY FDL SUPPORT
11.2.1 Overview
In order to provide backward compatibility to the older DS2151 device, the DS2152 maintains the
circuitry that existed in the previous generation of T1 Single-Chip Transceivers. Section 11.2 covers the
circuitry and operation of this legacy functionality. In new applications, it is recommended that the
HDLC controller and BOC controller described in Section 11.1 be used. On the receive side, it is possible
to have both the new HDLC/BOC controller and the legacy hardware working at the same time.
However, this is not possible on the transmit side since their can be only one source the of the FDL data
internal to the device.
11.2.2 Receive Section
In the receive section, the recovered FDL bits or Fs bits are shifted bit-by-bit into the Receive FDL
register (RFDL). Since the RFDL is 8 bits in length, it will fill up every 2 ms (8 times 250 us). The
DS2152 will signal an external microcontroller that the buffer has filled via the SR2.4 bit. If enabled via
IMR2.4, the INT pin will toggle low indicating that the buffer has filled and needs to be read. The user
has 2 ms to read this data before it is lost. If the byte in the RFDL matches either of the bytes
programmed into the RFDLM1 or RFDLM2 registers, then the SR2.2 bit will be set to a 1 and the INT
pin will toggled low if enabled via IMR2.2. This feature allows an external microcontroller to ignore the
FDL or Fs pattern until an important event occurs.
The DS2152 also contains a 0 destuffer which is controlled via the CCR2.0 bit. In both ANSI T1.403 and
TR54016, communications on the FDL follows a subset of a LAPD protocol. The LAPD protocol states
that no more than five 1s should be transmitted in a row so that the data does not resemble an opening or
closing flag (01111110) or an abort signal (11111111). If enabled via CCR2.0, the DS2152 will
automatically look for five 1s in a row, followed by a 0. If it finds such a pattern, it will automatically
remove the 0. If the 0 destuffer sees six or more 1s in a row followed by a 0, the 0 is not removed. The
CCR2.0 bit should always be set to a 1 when the DS2152 is extracting the FDL. More on how to use the
DS2152 in FDL applications in this legacy support mode is covered in a separate Application Note.
RFDL: RECEIVE FDL REGISTER (Address=28 Hex)
(MSB) (LSB)
RFDL7 RFDL6 RFDL5 RFDL4 RFDL3 RFDL2 RFDL1 RFDL0
SYMBOL POSITION NAME AND DESCRIPTION
RFDL7 RFDL.7 MSB of the Received FDL Code
RFDL0 RFDL.0 LSB of the Received FDL Code
The Receive FDL Register (RFDL) reports the incoming Facility Data Link (FDL) or the incoming Fs
bits. The LSB is received first.
DS2152
65 of 93
RFDLM1: RECEIVE FDL MATCH REGISTER 1 (Address=29 Hex)
RFDLM2: RECEIVE FDL MATCH REGISTER 2 (Address=2A Hex)
(MSB) (LSB)
RFDL7 RFDL6 RFDL5 RFDL4 RFDL3 RFDL2 RFDL1 RFDL0
SYMBOL POSITION NAME AND DESCRIPTION
RFDL7 RFDL.7 MSB of the FDL Match Code
RFDL0 RFDL.0 LSB of the FDL Match Code
When the byte in the Receive FDL Register matches either of the two Receive FDL Match Registers
(RFDLM1/RFDLM2), RSR2.2 will be set to a 1 and the INT will go active if enabled via IMR2.2.
11.2.3 Transmit Section
The transmit section will shift out into the T1 data stream either the FDL (in the ESF framing mode) or
the Fs bits (in the D4 framing mode) contained in the Transmit FDL register (TFDL). When a new value
is written to the TFDL, it will be multiplexed serially (LSB first) into the proper position in the outgoing
T1 data stream. After the full 8 bits have been shifted out, the DS2152 will signal the host microcontroller
that the buffer is empty and that more data is needed by setting the SR2.3 bit to a 1. The INT will also
toggle low if enabled via IMR2.3. The user has 2 ms to update the TFDL with a new value. If the TFDL
is not updated, the old value in the TFDL will be transmitted once again.
The DS2152 also contains a 0 stuffer which is controlled via the CCR2.4 bit. In both ANSI T1.403 and
TR54016, communications on the FDL follows a subset of a LAPD protocol. The LAPD protocol states
that no more than five 1s should be transmitted in a row so that the data does not resemble an opening or
closing flag (01111110) or an abort signal (11111111). If enabled via CCR2.4, the DS2152 will
automatically look for five 1s in a row. If it finds such a pattern, it will automatically insert a 0 after the
five 1s. The CCR2.0 bit should always be set to a 1 when the DS2152 is inserting the FDL. More on how
to use the DS2152 in FDL applications is covered in a separate Application Note.
TFDL: TRANSMIT FDL REGISTER (Address=7E Hex)
[also used to insert Fs framing pattern in D4 framing mode; see Section 11.3]
(MSB) (LSB)
TFDL7 TFDL6 TFDL5 TFDL4 TFDL3 TFDL2 TFDL1 TFDL0
SYMBOL POSITION NAME AND DESCRIPTION
TFDL7 TFDL.7 MSB of the FDL code to be transmitted
TFDL0 TFDL.0 LSB of the FDL code to be transmitted
The Transmit FDL Register (TFDL) contains the Facility Data Link (FDL) information that is to be
inserted on a byte basis into the outgoing T1 data stream. The LSB is transmitted first.
11.3 D4/SLC-96 OPERATION
In the D4 framing mode, the DS2152 uses the TFDL register to insert the Fs framing pattern. To allow
the device to properly insert the Fs framing pattern, the TFDL register at address 7Eh must be
programmed to 1Ch and the following bits must be programmed as shown:
DS2152
66 of 93
TCR1.2=0 (source Fs data from the TFDL register)
CCR2.5=1 (allow the TFDL register to load on multiframe boundaries)
Since the SLC-96 message fields share the Fs-bit position, the user can access these message fields via
the TFDL and RFDL registers. Please see the separate Application Note for a detailed description of how
to implement an SLC-96 function.
12.0 PROGRAMMABLE IN-BAND CODE GENERATION AND DETECTION
The DS2152 has the ability to generate and detect a repeating bit pattern that is from 1 to 8 bits in length.
To transmit a pattern, the user will load the pattern to be sent into the Transmit Code Definition (TCD)
register and select the proper length of the pattern by setting the TC0 and TC1 bits in the In-Band Code
Control (IBCC) register. Once this is accomplished, the pattern will be transmitted as long as the TLOOP
control bit (CCR3.1) is enabled. Normally (unless the transmit formatter is programmed to not insert the
F-bit position) the DS2152 will overwrite the repeating pattern once every 193 bits to allow the F-bit
position to be sent. See Figure 15-11 for more details. As an example, if the user wished to transmit the
standard “loop up” code for Channel Service Units which is a repeating pattern of ...10000100001... then
80h would be loaded into TDR and the length would set to 5 bits.
The DS2152 can detect two separate repeating patterns to allow for both a “loop up” code and a “loop
down” code to be detected. The user will program the codes to be detected in the Receive Up Code
Definition (RUPCD) register and the Receive Down Code Definition (RDNCD) register and the length of
each pattern will be selected via the IBCC register. The DS2152 will detect repeating pattern codes in
both framed and unframed circumstances with bit error rates as high as 10**-2. The code detector has a
nominal integration period of 48 ms. Hence, after about 48 ms of receiving either code, the proper status
bit (LUP at SR1.7 and LDN at SR1.6) will be set to a 1. Normally codes are sent for a period of 5
seconds. It is recommend that the software poll the DS2152 every 100 ms to 1000 ms until 5 seconds has
elapsed to insure that the code is continuously present.
IBCC: IN-BAND CODE CONTROL REGISTER (Address=12 Hex)
(MSB) (LSB)
TC1 TC0 RUP2 RUP1 RUP0 RDN2 RDN1 RDN0
SYMBOL POSITION NAME AND DESCRIPTION
TC1 IBCC.7 Transmit Code Length Definition Bit 1. See Table 12-1
TC0 IBCC.6 Transmit Code Length Definition Bit 0. See Table 12-1
RUP2 IBCC.5 Receive Up Code Length Definition Bit 2. See Table 12-2
RUP1 IBCC.4 Receive Up Code Length Definition Bit 1. See Table 12-2
RUP0 IBCC.3 Receive Up Code Length Definition Bit 0. See Table 12-2
RDN2 IBCC.2 Receive Down Code Length Definition Bit 2. See Table 12-2
RDN1 IBCC.1 Receive Down Code Length Definition Bit 1. See Table 12-2
RDN0 IBCC.0 Receive Down Code Length Definition Bit 0. See Table 12-2
DS2152
67 of 93
TRANSMIT CODE LENGTH Table 12-1
TC1 TC0 LENGTH SELECTED
0 0 5 bits
0 1 6 bits / 3 bits
1 0 7 bits
1 1 8 bits / 4 bits / 2 bits / 1 bits
RECEIVE CODE LENGTH Table 12-2
RUP2/
RDN2 RUP1/
RDN1 RUP0/
RDN0 LENGTH
SELECTED
0 0 0 1 bits
0 0 1 2 bits
0 1 0 3 bits
0 1 1 4 bits
1 0 0 5 bits
1 0 1 6 bits
1 1 0 7 bits
1 1 1 8 bits
TCD: TRANSMIT CODE DEFINITION REGISTER (Address=13 Hex)
(MSB) (LSB)
C7 C6 C5 C4 C3 C2 C1 C0
SYMBOL POSITION NAME AND DESCRIPTION
C7 TCD.7
Transmit Code Definition Bit 7.
First bit of the repeating
pattern.
C6 TCD.6 Transmit Code Definition Bit 6.
C5 TCD.5 Transmit Code Definition Bit 5.
C4 TCD.4 Transmit Code Definition Bit 4.
C3 TCD.3 Transmit Code Definition Bit 3.
C2 TCD.2
Transmit Code Definition Bit 2.
A Don’t Care if a 5-bit length
is selected.
C1 TCD.1
Transmit Code Definition Bit 1.
A Don’t Care if a 5 or 6-bit
length is selected.
C0 TCD.0
Transmit Code Definition Bit 0.
A Don’t Care if a 5, 6 or 7-bit
length is selected.
DS2152
68 of 93
RUPCD: RECEIVE UP CODE DEFINITION REGISTER (Address=14 Hex)
(MSB) (LSB)
C7 C6 C5 C4 C3 C2 C1 C0
SYMBOL POSITION NAME AND DESCRIPTION
C7 RUPCD.7
Receive Up Code Definition Bit 7.
First bit of the repeating
pattern.
C6 RUPCD.6
Receive Up Code Definition Bit 6.
A Don’t Care if a 1-bit
length is selected.
C5 RUPCD.5
Receive Up Code Definition Bit 5.
A Don’t Care if a 1 or 2-bit
length is selected.
C4 RUPCD.4
Receive Up Code Definition Bit 4.
A Don’t Care if a 1 to 3-bit
length is selected.
C3 RUPCD.3
Receive Up Code Definition Bit 3.
A Don’t Care if a 1 to 4-bit
length is selected.
C2 RUPCD.2
Receive Up Code Definition Bit 2.
A Don’t Care if a 1 to 5-bit
length is selected.
C1 RUPCD.1
Receive Up Code Definition Bit 1.
A Don’t Care if a 1 to 6-bit
length is selected.
C0 RUPCD.0
Receive Up Code Definition Bit 0.
A Don’t Care if a 1 to 7-bit
length is selected.
DS2152
69 of 93
RDNCD: RECEIVE DOWN CODE DEFINITION REGISTER (Address=15 Hex)
(MSB) (LSB)
C7 C6 C5 C4 C3 C2 C1 C0
SYMBOL POSITION NAME AND DESCRIPTION
C7 RDNCD.7
Receive Down Code Definition Bit 7.
First bit of the repeating
pattern.
C6 RDNCD.6
Receive Down Code Definition Bit 6.
A Don’t Care if a 1-bit
length is selected.
C5 RDNCD.5 Receive Down Code Definition Bit 5. A Don’t Care if a 1 or 2-
bit length is selected.
C4 RDNCD.4 Receive Down Code Definition Bit 4. A Don’t Care if a 1 to 3-
bit length is selected.
C3 RDNCD.3 Receive Down Code Definition Bit 3. A Don’t Care if a 1 to 4-
bit length is selected.
C2 RDNCD.2 Receive Down Code Definition Bit 2. A Don’t Care if a 1 to 5-
bit length is selected.
C1 RDNCD.1 Receive Down Code Definition Bit 1. A Don’t Care if a 1 to 6-
bit length is selected.
C0 RDNCD.0 Receive Down Code Definition Bit 0. A Don’t Care if a 1 to 7-
bit length is selected.
13.0 TRANSMIT TRANSPARENCY
Each of the 24 T1 channels in the transmit direction of the DS2152 can be either forced to be transparent
or, in other words, can be forced to stop Bit 7 Stuffing and/or Robbed Signaling from overwriting the data
in the channels. Transparency can be invoked on a channel by channel basis by properly setting the
TTR1, TTR2, and TTR3 registers.
TTR1/TTR2/TTR3:
TRANSMIT TRANSPARENCY REGISTER (Address=39 to 3B Hex)
(MSB) (LSB)
CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 TTR1 (39)
CH16 CH15 CH14 CH13 CH12 CH11 CH10 CH9 TTR2 (3A)
CH24 CH23 CH22 CH21 CH20 CH19 CH18 CH17 TTR3 (3B)
SYMBOL POSITION NAME AND DESCRIPTION
CH24 TTR3.7 Transmit Transparency Registers.
0=this DS0 channel is not transparent
CH1 TTR1.0 1=this DS0 channel is transparent
DS2152
70 of 93
Each of the bit positions in the Transmit Transparency Registers (TTR1/TTR2/TTR3) represent a DS0
channel in the outgoing frame. When these bits are set to a 1, the corresponding channel is transparent (or
clear). If a DS0 is programmed to be clear, no robbed-bit signaling will be inserted nor will the channel
have Bit 7 stuffing performed. However, in the D4 framing mode, bit 2 will be overwritten by a 0 when a
Yellow Alarm is transmitted. Also, the user has the option to prevent the TTR registers from determining
which channels are to have Bit 7 stuffing performed. If the TCR2.0 and TCR1.3 bits are set to 1, then all
24 T1 channels will have Bit 7 stuffing performed on them regardless of how the TTR registers are
programmed. In this manner, the TTR registers are only affecting which channels are to have robbed-bit
signaling inserted into them. Please see Figure 15-11 for more details.
14.0 LINE INTERFACE FUNCTION
The line interface function in the DS2152 contains three sections; (1) the receiver which handles clock
and data recovery, (2) the transmitter which waveshapes and drives the T1 line, and (3) the jitter
attenuator. Each of these three sections is controlled by the Line Interface Control Register (LICR), which
is described below.
LICR: LINE INTERFACE CONTROL REGISTER (Address=7C Hex)
(MSB) (LSB)
L2 L1 L0 EGL JAS JABDS DJA TPD LICR
SYMBOL POSITION NAME AND DESCRIPTION
L2 LICR.7
Line Build Out Select Bit 2.
Sets the transmitter build out; see
the Table 14-2
L1 LICR.6
Line Build Out Select Bit 1.
Sets the transmitter build out; see
the Table 14-2
L0 LICR.5
Line Build Out Select Bit 0.
Sets the transmitter build out; see
the Table 14-2
EGL LICR.4 Receive Equalizer Gain Limit.
0 = -36 dB
1 = -30 dB
JAS LICR.3 Jitter Attenuator Select.
0 = place the jitter attenuator on the receive side
1 = place the jitter attenuator on the transmit side
JABDS LICR.2 Jitter Attenuator Buffer Depth Select
0 = 128 bits
1 = 32 bits (use for delay sensitive applications)
DJA LICR.1 Disable Jitter Attenuator.
0 = jitter attenuator enabled
1 = jitter attenuator disabled
TPD LICR.0 Transmit Power Down.
0 = normal transmitter operation
1 = powers down the transmitter and 3-states the TTIP and
TRING pins
DS2152
71 of 93
14.1 RECEIVE CLOCK AND DATA RECOVERY
The DS2152 contains a digital clock recovery system. See the DS2152 Block Diagram in Section 1 and
Figure 14-1 for more details. The DS2152 couples to the receive T1 twisted pair via a 1:1 transformer.
See Table 14-3 for transformer details. The 1.544 MHz clock attached at the MCLK pin is internally
multiplied by 16 via an internal PLL and fed to the clock recovery system. The clock recovery system
uses the clock from the PLL circuit to form a 16 times oversampler which is used to recover the clock and
data. This oversampling technique offers outstanding jitter tolerance (see Figure 14-2).
Normally, the clock that is output at the RCLKO pin is the recovered clock from the T1 AMI/B8ZS
waveform presented at the RTIP and RRING inputs. When no AMI signal is present at RTIP and RRING,
a Receive Carrier Loss (LRCL) 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 over-
sampled 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 16 for more details.
14.2 TRANSMIT WAVESHAPING AND LINE DRIVING
The DS2152 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 T1 line. The waveforms created by the
DS2152 meet the latest ANSI, AT&T, and ITU specifications. See Figure 14-3. 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 DS2152 can set up in a number of various configurations depending on the
application. See Table 14-2 and Figure 14-1.
LINE BUILD OUT SELECT IN LICR Table 14-2
L2 L1 L0 LINE BUILD OUT APPLICATION
0 0 0 0 to 133 feet / 0dB DSX-1 / CSU
0 0 1 133 to 266 feet DSX-1
0 1 0 266 to 399 feet DSX-1
0 1 1 399 to 533 feet DSX-1
1 0 0 533 to 655 feet DSX-1
1 0 1 -7.5 dB CSU
1 1 0 -15 dB CSU
1 1 1 -22.5 dB CSU
Due to the nature of the design of the transmitter in the DS2152, very little jitter (less then 0.005 UIpp
broadband from 10 Hz to 100 kHz) is added to the jitter present on TCLKI. Also, the waveforms that they
create are independent of the duty cycle of TCLK. The transmitter in the DS2152 couples to the T1
transmit twisted pair via a 1:1.15 or 1:1.36 step up transformer as shown in Figure 14-1. In order for the
devices to create the proper waveforms, this transformer used must meet the specifications listed in Table
14-3.
DS2152
72 of 93
TRANSFORMER SPECIFICATIONS Table 14-3
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
14.3 JITTER ATTENUATOR
The DS2152 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 14-4. 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 1.544 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 capacitors should be placed from each leg of
the crystal to the local ground plane as shown in Figure 14-1. 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 DS2152 will divide the internal nominal 24.704 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 (JALT) bit in the Receive Information Register (RIR3.5).
DS2152
73 of 93
DS2152 EXTERNAL ANALOG CONNECTIONS Figure 14-1
NOTES:
1. Resistor values are ± 1%.
2. The Rt resistors are used to protect the device from over-voltage.
3. See the Separate Application Note for details on how to construct a protected interface.
4. Either a crystal can be applied across the MCLK and XTALD pins or a TTL level clock can be
applied to just MCLK.
5. C1 and C2 should be 5 pF lower than 2 times the nominal loading capacitance of the crystal to adjust
for the input capacitance of the DS2152.
DS2152
74 of 93
DS2152 JITTER TOLERANCE Figure 14-2
DS2152 TRANSMIT WAVEFORM TEMPLATE Figure 14-3
DS2152
75 of 93
DS2152 JITTER ATTENUATION Figure 14-4
15.0 TIMING DIAGRAMS
RECEIVE SIDE D4 TIMING Figure 15-1
NOTES:
1. RSYNC in the frame mode (RCR2.4=0) and double-wide frame sync is not enabled (RCR2.5=0).
2. RSYNC in the frame mode (RCR2.4=0) and double-wide frame sync is enabled (RCR2.5=1).
3. RSYNC in the multiframe mode (RCR2.4=1).
4. RLINK data (Fs bits) is updated 1 bit prior to even frames and held for two frames.
5. RLINK and RLCLK are not synchronous with RSYNC when the receive side elastic store is enabled.
DS2152
76 of 93
RECEIVE SIDE BOUNDARY TIMING
(WITH ELASTIC STORE DISABLED) Figure 15-2
NOTES:
1. RSYNC in the frame mode (RCR2.4=0) and double-wide frame sync is not enabled (RCR2.5=0).
2. RSYNC in the frame mode (RCR2.4=0) and double-wide frame sync is enabled (RCR2.5=1).
3. RSYNC in the multiframe mode (RCR2.4=1).
4. ZBTSI mode disabled (RCR2.6=0).
5. RLINK data (FDL bits) is updated 1 bit-time before odd frames and held for two frames.
6. ZBTSI mode is enabled (RCR2.6=1).
7. RLINK data (Z bits) is updated 1 bit-time before odd frames and held for four frames.
8. RLINK and RLCLK are not synchronous with RSYNC when the receive side elastic store is enabled.
RECEIVE SIDE BOUNDARY TIMING
(WITH ELASTIC STORE DISABLED) Figure 15-3
NOTES:
1. RCHBLK is programmed to block channel 24.
2. Shown is RLINK/RLCLK in the ESF framing mode.
DS2152
77 of 93
RECEIVE SIDE 1.544 MHz BOUNDARY TIMING
(WITH ELASTIC STORE ENABLED) Figure 15-4
NOTES:
1. RSYNC is in the output mode (RCR2.3=0).
2. RSYNC is in the input mode (RCR2.3=1).
3. RCHBLK is programmed to block channel 24.
RECEIVE SIDE 2.048 MHz BOUNDARY TIMING
(WITH ELASTIC STORE ENABLED) Figure 15-5
NOTES:
1. RSER data in channels 1, 5, 9, 13, 17, 21, 25, and 29 are forced to 1.
2. RSYNC is in the output mode (RCR2.3=0).
3. RSYNC is in the input mode (RCR2.3=1).
4. RCHBLK is forced to 1 in the same channels as RSER (see Note 1).
5. The F-bit position is passed through the receive side elastic store.
6. RCHCLK does not transition high in the channels in which the RSER data is forced to 1 (see note 1).
DS2152
78 of 93
TRANSMIT SIDE D4 TIMING Figure 15-6
NOTES:
1. TSYNC in the frame mode (TCR2.3=0) and double-wide frame sync is not enabled (TCR2.4=0).
2. TSYNC in the frame mode (TCR2.3=0) and double-wide frame sync is enabled (TCR2.4=1).
3. TSYNC in the multiframe mode (TCR2.3=1).
4. TLINK data (Fs bits) is sampled during the F-bit position of even frames for insertion into the
outgoing T1 stream when enabled via TCR1.2.
5. TLINK and TLCLK are not synchronous with TSSYNC.
TRANSMIT SIDE TIMING Figure 15-7
NOTES:
1. TSYNC in the frame mode (TCR2.3=0) and double-wide frame sync is not enabled (TCR2.4=0).
2. TSYNC in the frame mode (TCR2.3=0) and double-wide frame sync is enabled (TCR2.4=1).
3. TSYNC in the multiframe mode (TCR2.3=1).
4. ZBTSI mode disabled (TCR2.5=0).
5. TLINK data (FDL bits) is sampled during the F-bit time of odd frame and inserted into the outgoing
T1 stream if enabled via TCR1.2.
6. ZBTSI mode is enabled (TCR2.5=1).
7. TLINK data (Z bits) is sampled during the F-bit time of frames 1, 5, 9, 13, 17, and 21 and inserted
into the outgoing stream if enabled via TCR1.2.
8. TLINK and TLCLK are not synchronous with TSSYNC.
DS2152
79 of 93
TRANSMIT SIDE BOUNDARY TIMING Figure 15-8
NOTES:
1. TSYNC is in the output mode (TCR2.2=1).
2. TSYNC is in the input mode (TCR2.2=0).
3. TCHBLK is programmed to block channel 2.
4. Shown is TLINK/TLCLK in the ESF framing mode.
TRANSMIT SIDE 1.544 MHz BOUNDARY TIMING
(WITH ELASTIC STORE ENABLED) Figure 15-9
NOTES:
1. TCHBLK is programmed to block channel 24 (if the TPCSI bit is set, then the signaling data at TSIG
will be ignored during channel 24).
DS2152
80 of 93
TRANSMIT SIDE 2.048 MHz BOUNDARY TIMING
(WITH ELASTIC STORE ENABLED) Figure 15-10
NOTES:
1. TSER data in channels 1, 5, 9, 13, 17, 21, 25, and 29 is ignored.
2. TCHBLK is programmed to block channel 31 (if the TPCSI bit is set, then the signaling data at TSIG
will be ignored).
3. TCHBLK is forced to 1 in the same channels where TSER is ignored (see Note 1).
4. The F-bit position for the T1 frame is sampled and passed through the transmit side elastic store
(normally the transmit side formatter overwrites the F-bit position unless the formatter is programmed
to pass-through the F-bit position).
5. TCHCLK does not transition high in the channel in which the data at TSER is ignored (see note 1).
DS2152
81 of 93
DS2152 TRANSMIT DATA FLOW Figure 15-11
NOTE:
1. TCLK should be tied to RCLK and TSYNC should be tied to RFSYNC for data to be properly
sourced from RSER.
DS2152
82 of 93
ABSOLUTE MAXIMUM RATINGS*
Voltage on Any Pin Relative to Ground -1.0V to +7.0V
Operating Temperature for DS2152L 0°C to 70°C
Operating Temperature for DS2152LN -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 (0°C to 70°C for DS2152L;
OPERATING CONDITIONS -40°C to +85°C for DS2152LN)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Logic 1 VIH 2.0 V
DD
+0.3 V
Logic 0 VIL -0.3 +0.8 V
Supply VDD 4.75 5.25 V1
CAPACITANCE (tA=25°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Input Capacitance CIN 5pF
Output Capacitance COUT 7pF
DC CHARACTERISTICS (0°C to 70°C; VDD=5V ± 5% for DS2152L;
-40°C to +85°C; VDD=5V ± 5% for DS2152LN)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Supply Current @ 5V IDD 75 mA 2
Input Leakage IIL -1.0 +1.0 µA3
Output Leakage ILO 1.0 µA4
Output Current (2.4V) IOH -1.0 mA
Output Current (0.4V) IOL +4.0 mA
NOTES:
1. Applies to RVDD, TVDD, and DVDD.
2. TCLK=RCLK=TSYSCLK=RSYSCLK=1.544 MHz; outputs open circuited.
3. 0.0V < VIN < VDD.
4. Applied to INT when 3-stated.
DS2152
83 of 93
AC CHARACTERISTICS -
MULTIPLEXED PARALLEL (0°C to 70°C; VDD=5V ± 5% for DS2152L;
PORT (MUX=1) -40°C to +85°C; VDD=5V ± 5% for DS2152LN)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Cycle Time tCYC 200 ns
Pulse Width, DS Low or
RD
High PWEL 100 ns
Pulse Width, DS High or
RD
Low PWEH 100 ns
Input Rise/Fall Times tR, tF20 ns
R/W Hold Time tRWH 10 ns
R/W Setup Time Before DS High tRWS 50 ns
CS Setup Time Before DS, WR or
RD
active tCS 20 ns
CS Hold Time tCH 0ns
Read Data Hold Time tDHR 10 50 ns
Write Data Hold Time tDHW 0ns
Muxed Address Valid to AS or ALE Fall tASL 15 ns
Muxed Address Hold Time tAHL 10 ns
Delay Time, DS, WR or
RD
to AS or ALE
Rise tASD 20 ns
Pulse Width AS or ALE High PWASH 30 ns
Delay Time, AS or ALE to DS, WR or
RD
tASED 10 ns
Output Data Delay Time from DS or
RD
tDDR 20 80 ns
Data Setup Time tDSW 50 ns
(see Figures 16-1 to 16-3 for details)
DS2152
84 of 93
AC CHARACTERISTICS - (0°C to 70°C; VDD=5V ± 5% for DS2152L;
RECEIVE SIDE (-40°C to +85°C; VDD=5V ± 5% for DS2152LN)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
RCLKO Period tLP 648 ns
RCLKO Pulse Width tLH
tLL
250
250 324
324 ns
ns 1
1
RCLKO Pulse Width tLH
tCL
200
200 324
324 ns
ns 2
2
RCLKI Period tCP 648 ns
RCLKI Pulse Width tCH
tCL
75
75 ns
ns
RSYSCLK Period tSP
tSP
122
122 648
488 ns
ns 3
4
RSYSCLK Pulse Width tSH
tSL
50
50 ns
ns
RSYNC Set Up to RSYSCLK Falling tSU 20 tSH-5 ns
RSYNC Pulse Width tPW 50 ns
RPOSI/RNEGI Set UP to RCLKI Falling tSU 20 ns
RPOSI/RNEGI Hold From RCLKI Falling tHD 20 ns
RSYSCLK/RCLKI Rise and Fall Times tR, tF25 ns
Delay RCLKO to RPOSO, RNEGO Valid tDD 50 ns
Delay RCLK to RSER, RDATA, RSIG,
RLINK Valid tD1 50 ns
Delay RCLK to RCHCLK, RSYNC,
RCHBLK, RFSYNC, RLCLK tD2 50 ns
Delay RSYSCLK to RSER, RSIG Valid tD3 50 ns
Delay RSYSCLK to RCHCLK, RCHBLK,
RMSYNC, RSYNC tD4 50 ns
See Figures 16-4 to 16-6 for details.
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
DS2152
85 of 93
AC CHARACTERISTICS - (0°C to 70°C; VDD=5V ± 5% for DS2152L;
TRANSMIT SIDE -40°C to +85°C; VDD=5V ± 5% for DS2152LN)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
TCLK Period tCP 648 ns
TCLK Pulse Width tCH
tCL
75
75 ns
ns
TCLKI Period tLP 648 ns
TCLKI Pulse Width tLH
tLL
75
75 ns
TSYSCLK Period tSP
tSP
122
122 648
448 ns
ns 1
2
TSYSCLK Pulse Width tSH
tSL
50
50 ns
ns
TSYNC or TSSYNC Set Up to TCLK or
TSYSCLK Falling tSU 20 tCH-5 or
tSH-5 ns
TSYNC or TSSYNC Pulse Width tPW 50 ns
TSER, TSIG, TDATA, TLINK, TPOSI,
TNEGI Set Up to TCLK, TSYSCLK,
TCLKI Falling
tSU 20 ns
TSER, TSIG, TDATA, TLINK, TPOSI,
TNEGI Hold from TCLK, TSYSCLK,
TCLKI Falling
tHD 20 ns
TCLK, TCLKI, or TSYSCLK Rise and
Fall Times tR, tF25 ns
Delay TCLKO to TPOSO, TNEGO Valid tDD 50 ns
Delay TCLK to TESO Valid tD1 50 ns
Delay TCLK to TCHBLK, TCHBLK,
TSYNC, TLCLK tD2 50 ns
Delay TSYSCLK to TCHCLK, TCHBLK tD3 75 ns
See Figures 16-7 to 16-9 for details.
NOTES:
1. TSYSCLK=1.544 MHz.
2. TSYSCLK=2.048 MHz.
DS2152
86 of 93
AC CHARACTERISTICS -
NON-MULTIPLEXED PARALLEL (0°C to 70°C; VDD=5V ± 5% for DS2152L;
PORT (MUX=0) -40°C to +85°C; VDD=5V ± 5% for DS2152LN)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Set Up Time for A0 to A7 Valid to CS
Active t1 0ns
Set Up Time for CS Active to either
RD
, WR , or DS Active
t2 0ns
Delay Time from either
RD
or DS
Active to Data Valid t3 75 ns
Hold Time from either
RD
, WR , or DS
Inactive to CS Inactive
t4 0ns
Hold Time from CS Inactive to Data
Bus 3-state t5 5 20 ns
Wait Time from either WR or DS
Active to Latch Data t6 75 ns
Data Set Up Time to either WR or DS
Inactive t7 10 ns
Data Hold Time to either WR or DS
Inactive t8 0ns
Address Hold from either WR or DS
Inactive t910 ns
See Figures 16-10 to 16-13 for details.
INTEL BUS READ AC TIMING (BTS=0/MUX=1) Figure 16-1
DS2152
87 of 93
INTEL BUS WRITE AC TIMING (BTS=0/MUX=1) Figure 16-2
MOTOROLA BUS AC TIMING (BTS=1/MUX=1) Figure 16-3
DS2152
88 of 93
RECEIVE SIDE AC TIMING Figure 16-4
NOTES:
1. RSYNC is in the output mode (RCR2.3=0).
2. Shown is RLINK/RLCLK in the ESF framing mode.
3. No relationship between RCHCLK and RCHBLK and the other signals is implied.
DS2152
89 of 93
RECEIVE SYSTEM SIDE AC TIMING Figure 16-5
NOTES:
1. RSYNC is in the output mode (RCR2.3=0).
2. RSYNC is in the input mode (RCR2.3=1).
RECEIVE LINE INTERFACE AC TIMING Figure 16-6
DS2152
90 of 93
TRANSMIT SIDE AC TIMING Figure 16-7
NOTES:
1. TSYNC is in the output mode (TCR2.2=1).
2. TSYNC is in the input mode (TCR2.2=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 F-bit locations.
6. No relationship between TCHCLK and TCHBLK and the other signals is implied.
DS2152
91 of 93
TRANSMIT SYSTEM SIDE AC TIMING Figure 16-8
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 16-9
DS2152
92 of 93
INTEL BUS READ AC TIMING (BTS=0/MUX=0) Figure 16-10
INTEL BUS WRITE AC TIMING (BTS=0/MUX=0) Figure 16-11
DS2152
93 of 93
MOTOROLA BUS READ AC TIMING (BTS=1/MUX=0) Figure 16-12
MOTOROLA BUS WRITE AC TIMING (BTS=1/MUX=0) Figure 16-13
DS2152
94 of 93
DS2152 100-PIN LQFP
PKG 100-PIN
DIM MIN MAX
A-1.60
A1 0.05 -
A2 1.35 1.45
b0.17 0.27
C0.09 0.20
D15.80 16.20
D1 14.00 BSC
E15.80 16.20
E1 14.00 BSC
e0.50 BSC
L0.45 0.75
