Dallas DS2182A T1 line monitor Datasheet

DS2182A
T1 Line Monitor
www.dalsemi.com
The updated DS2182A includes the following
changes from the original DS2182:
§ Ability to count excessive zeros
§ Severely Errored Framing Event indication
§ Updated AIS detection
§ Updated RCL detection
§ AIS and RCL alarm clear indications
FEATURES
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Performs framing and monitoring functions
Supports Superframe and Extended Superframe formats
Four onboard error counters
– 16-bit bipolar violation
– 8-bit CRC
– 8-bit OOF
– 8-bit frame bit error
Indication of the following
– yellow and blue alarms
– incoming B8ZS code words
– 8 and 16 zero strings
– change of frame alignment
– loss of sync
– carrier loss
Simple serial interface used for configuration, control and status monitoring
Burst mode allows quick access to counters
for status updates
Automatic counter reset feature
Single 5V supply; low-power CMOS technology
Available in 28-pin DIP and 28-pin PLCC
The DS2182A is upward-compatible from
the original DS2182
PIN ASSIGNMENT
INT
1
28
VDD
SDI
2
27
RLOS
SDO
3
26
RFER
CS
4
25
RBV
SCLK
5
24
RCL
NC
6
23
RNEG
RYEL
7
22
RPOS
RLINK
8
21
RST
RLCLK
9
20
TEST
RCLK
10
19
RSIGSEL
RCHCLK
11
18
RSIGFR
RSER
12
17
RABCD
NC
13
16
RMSYNC
VSS
14
15
RFSYNC
28-Pin DIP (600-mil)
DESCRIPTION
The DS2182A T1 Line Monitor Chip is a monolithic CMOS device designed to monitor real-time
performance on T1 lines. The DS2182A frames to the data on the line, counts errors, and supplies
detailed information about the status and condition of the line. Large on-board counters allow the
accumulation of errors for extended periods, which permits a single CPU to monitor a number of T1
lines. Output clocks that are synchronized to the incoming data stream are provided for easy extraction of
S-Bits, FDL bits, signaling bits, and channel data. The DS2182A meets the requirements of ANSI
T1.231.
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DS2182A
DS2182A BLOCK DIAGRAM Figure 1
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DS2182A
PIN DESCRIPTION Table 1
PIN
6
SYMBOL
NC
TYPE
-
7
RYEL
O
8
RLINK
O
9
10
11
RLCLK
RCLK
RCHCLK
O
I
O
12
RSER
O
13
NC
-
15
RFSYNC
O
16
RMSYNC
O
17
RABCD
O
18
ESIGFR
O
19
RSIGSEL
O
21
RST
I
22
23
RPOS
RNEG
I
24
RCL
O
25
RBV
O
26
RFER
O
27
RLOS
O
DESCRIPTION
No Connect. No internal connection. This pin can be tied to either
VSS or VDD, or it can be floated.
Receive Yellow Alarm. Transitions high when yellow alarm
detected; goes low when alarm clears.
Receive Link Data. Updated with extracted FDL data one RCLK
before start of odd frames (193E) and held until next update.
Updated with extracted S-bit data one RCLK before start of even
frames (193S) and held until next update.
Receive Link Clock. 4 kHz demand clock for RLINK.
Receive Clock. 1.544 MHz primary clock.
Receive Channel Clock. 192 kHz clock; identifies time slot
(channel) boundaries.
Receive Serial Data. Received NRZ serial data; updated on rising
edges of RCLK.
No Connect. No internal connection. This pin can be tied to either
VSS or VDD, or it can be floated.
Receive Frame Sync. Extracted 8 kHz clock, one RCLK wide; Fbit position in each frame.
Receive Multiframe Sync. Extracted multiframe sync; positivegoing edge indicates start of multiframe; 50% duty cycle.
Receive ABCD Signaling. Extracted signaling data output; valid
for each channel in signaling frames. In non-signaling frames,
RABCD outputs the LSB of each channel word.
Receive Signaling Frame. High during signaling frames; low
during non-signaling frames (and during resync).
Receive Signaling Select. In 193E framing, a .667 kHz clock that
identifies signaling frames A and C; a 1.33 kHz clock in 193S.
Reset. A high-low transition clears all internal registers and resets
counters. A high-low-high transition initiates a resync.
Receive Bipolar Data Inputs. Sampled on falling of RCLK. Tie
together to receive NRZ data and disable bipolar violation
monitoring circuitry.
Receive Carrier Loss. High if 192 consecutive 0s appear at RPOS
and RNEG; goes low upon seeing 12.5% one’s density.
Receive Bipolar Violation. High during accused bit time at RSER.
If bipolar violation detected, low otherwise.
Receive Frame Error. High during F-bit time when FT or FS
errors occur (193S), or when FPS or CRC errors occur (193E). Low
during resync.
Receive Loss of Sync. Indicates sync status; high when internal
resync is in progress, low otherwise.
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DS2182A
PIN DESCRIPTION Table 2
PIN
SYMBOL
TYPE
1
INT
O
2
3
SDI
SDO
I
O
4
CS
SCLK
I
Receive Alarm Interrupt. Flags host controller during alarm conditions.
Active low; open drain output.
Serial Data In. Data for onboard registers. Sampled on rising edge of SCLK.
Serial Data Out. Control and status information from onboard registers.
Updated on falling edge of SCLK; tri-stated during serial port write or
when CS is high.
Chip Select. Must be low to read or write the serial port.
I
Serial Data Clock. Used to read or write the serial port registers.
5
DESCRIPTION
POWER AND TEST PIN DESCRIPTION Table 3
PIN
SYMBOL
TYPE
14
20
28
VSS
TEST
VDD
I
-
DESCRIPTION
Signal Ground. 0.0 volts.
Test Mode. Tie to VSS for normal operation.
Positive Supply. 5.0 volts.
REGISTER SUMMARY Table 4
REGISTER
ADDRESS
DESCRIPTION/FUNCTION
BVCR2
0000
BVCR1
0001
CRCCR
0010
OOFCR
0011
FECR
0100
RSR1
RIMR1
0101
0110
RSR2
RIMR2
0111
1000
RCR1
RCR2
1001
1010
Bipolar Violation Count Register 2. LSW of a 16-bit presettable counter that
records individual bipolar violations.
Bipolar Violation Count Register 1. MSW of a 16-bit presettable counter that
records individual bipolar violations.
CRC Error Count Register. 8-bit presettable counter that records CRC6 errored
words in the 193E frame mode.
OOF Count Register. 8-bit presettable counter that records OOF events. OOF
events are defined by RCR1.5 and RCR1.6.
Frame Error Count Register. 8-bit presettable counter that records individual
bit errors in the framing pattern.
Receive Status Register 1. Reports alarm conditions.
Receive Interrupt Mask Register 1. Allows masking of individual alarmgenerated interrupts from RSR1.
Receive Status Register 2. Reports alarm conditions.
Receive Interrupt Mask Register 2. Allows masking of individual alarmgenerated interrupts from RSR2.
Receive Control Register 1. Programs device operating characteristics.
Receive Control Register 2. Programs device operating characteristics.
SERIAL PORT INTERFACE
The port pins of the DS2182A serve as a microprocessor/ microcontroller-compatible serial port. Eleven
on-board registers allow the user to update operational characteristics and monitor device status via a host
controller, minimizing hardware interfaces. The port on the DS2182A can be read from or written to at
any time. Serial port reads and writes are independent of T1 line timing signals RCLK, RPOS, and
RNEG. However, RCLK is needed in order to clear RSR1 and RSR2 after reads.
ADDRESS/COMMAND
Reading or writing the control, configuration or status registers requires writing one address/command
byte prior to transferring register data. The first bit written (LSB) of the address/command word specifies
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DS2182A
register read or write. The following 4 bits identify the register address. The next 2 bits are reserved and
must be set to 0 for proper operation. The last bit of the address/ command word enables burst mode
when set; the burst mode causes all registers to be consecutively read or written to. Data is read and
written to the DS2182A LSB first.
CHIP SELECT AND CLOCK CONTROL
All data transfers are initiated by driving the CS input low. Input data is latched on the rising edge of
SCLK and must be valid during the previous low period of SCLK to prevent momentary corruption of
register data during writes. Data is output on the falling edge of SCLK and held to the next falling edge.
All data transfers are terminated if the CS input transitions high. Port control logic is disabled and SDO is
tri-stated when CS is high.
DATA I/O
Following the eight SCLK cycles that input an address/command byte to write, a data byte is strobed into
the addressed register on the rising edge of the next eight SCLK cycles. Following an address/command
word to read, contents of the selected register are output on the falling edges of the next eight SCLK
cycles. The SDO pin is tri-stated during device write and can be tied to SDI in applications where the host
processor has a bi-directional I/O pin.
BURST MODE
The burst mode allows all onboard registers to be consecutively written to or read by the host processor.
A burst read is used to poll all registers; RSR1 and RSR2 contents will be unaffected. This feature
minimizes device initialization time on system power-up or reset. Burst mode is initiated when ACB.7 is
set and the address is 0000. A burst is terminated by a low-high transition on CS .
ACB: ADDRESS COMMAND BYTE Figure 2
MSB
LSB
BM
-
-
ADD3
ADD2
ADD1
ADD0
R/ W
SYMBOL
POSITION
BM
ACB.7
NAME AND DESCRIPTION
Burst Mode. If set (and register address is 0000) burst read or
write is enabled.
-
ACB.6
Reserved, must be 0 for operation.
-
ACB.5
Reserved, must be 0 for operation.
ADD3
ACB.4
MSB of register address.
ADD0
ACB.1
LSB of register address.
R/W
ACB.0
Read/Write Select.
0 = write addressed register
1 = read addressed register
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DS2182A
SERIAL PORT READ/WRITE Figure 3
NOTES:
1. SDI is sampled on rising edge of SCLK.
2. SDO is updated on falling edge of SCLK.
OPERATION OF THE COUNTERS
All four of the counters in the DS2182A can be preset by the user to establish an event count interrupt
threshold. The counters count up from the preset value until they reach saturation. At saturation, each
additional event occurrence sets the appropriate bit in RSR2 and generates an interrupt if enabled by
RIMR2.
The DS2182A contains an auto counter reset feature in the burst read mode. If RCR1.4 is set, then the
user can burst read the four counters (five registers), and all four counters will be automatically reset to 0
after the read takes place. Since the burst mode can be terminated at any time by taking CS high, the user
has the option of reading all of the registers or only the counters. If RCR1.4 is set, then any read of the
registers, burst mode or not, will clear the count in all four counters. If the user wishes to read the port
and not clear the counters, then RCR1.4 must be cleared first.
The counter registers can be read or written to at any time with the serial port, which operates totally
asynchronously with the monitoring of the T1 line. Reading a register will not affect the count as long as
RCR1.4 is cleared. The dual buffer architecture of the DS2182A insures that no error events will be
missed while the serial port is being accessed for reads.
BVCR1: BIPOLAR VIOLATION COUNT REGISTER 1;
BVCR2: BIPOLAR VIOLATION COUNTER REGISTER 2 Figure 4
MSB
BV7
LSB
BV6
BV5
BV4
BV3
SYMBOL
POSITION
BV7
BVCR.7
MSB of bipolar violation count
BV0
BVCR.0
LSB of bipolar violation count
BV2
BV1
BV0
NAME AND DESCRIPTION
Bipolar Violation Count Register 1 (BVCR1) is the most significant word and BVCR2 is the least
significant word of a presettable 16-bit counter that records individual bipolar violations. If the B8ZS
mode is enabled (RCR2.2 = 1), then B8ZS code words are not counted. The BVCR can also be
programmed to count excessive zeros by setting the RCR2.5 bit. In this mode, the BVCR will count
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DS2182A
occurrences of 8 consecutive zeros when B8ZS is enabled or 16 consecutive zeros when B8Z5 is
disabled. This counter increments at all times and is not disabled by a loss of sync condition (RLOS = 1).
The counter saturates at 65,535 and generates an interrupt for each occurrence after saturation if RIMR2.0
is set.
NOTE:
1. In order to properly preset the Bipolar Violation Count Register, BVCR2 must be written to before
BVCR1 is written to.
CRCCR: CRC COUNT REGISTER 2 Figure 5
MSB
CRC7
LSB
CRC6
CRC5
CRC4
CRC3
CRC2
SYMBOL
POSITION
CRC7
CRCCR.7
MSB of CRC6 word error count
CRC0
CRCCR.0
LSB of CRC6 word error count
CRC1
CRC0
NAME AND DESCRIPTION
The CRC Count Register (CRCCR) is an 8-bit presettable counter that records word errors in the Cyclic
Redundancy Check (CRC). This 8-bit binary counter saturates at 255 and generates an interrupt for each
occurrence after saturation if RIMR2.1 is set. The count in this register is only valid in the 193E framing
mode (RCR2.4 = 1) and is reset and disabled in the 193S framing mode (RCR2.4 = 0). The count is
disabled during a loss of sync condition (RLOS = 1).
OOFCR: OOF COUNT REGISTER Figure 6
MSB
OOF7
LSB
OOF6
OOF5
OOF4
OOF3
SYMBOL
POSITION
OOF7
OOFCR.7
MSB of OOF event count
OFF0
OOFCR.0
LSB of OOF of event count
OOF2
OOF1
OOF0
NAME AND DESCRIPTION
The OOF Count Register (OOFCR) is an 8-bit presettable counter that records Out Of Frame (OOF)
events. OOF events are defined by RCR1.5 and RCR1.6. This 8-bit counter saturates at 255 and
generates an interrupt for each occurrence after saturation if RIMR2.2 is set. The count is disabled during
a loss of sync condition (RLOS = 1).
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DS2182A
FECR: FRAME ERROR COUNT REGISTER Figure 7
MSB
FE7
LSB
FE6
FE5
FE4
FE3
SYMBOL
POSITION
FE7
FECR.7
MSB of frame error count
FFE0
FECR.0
LSB of frame error count
FE2
FE1
FE0
NAME AND DESCRIPTION
The Frame Error Count Register (FECR) is an 8-bit pre-settable counter that records individual frame bit
errors. In the 193E mode (RCR2.4 = 1), the FECR records bit errors in the FPS framing pattern
(001011). In the 193S mode (RCR2.4 = 0), the FECR records bit errors in both the FT (101010) and FS
(001110) framing patterns if RCR1.3 is set. If RCR1.3 is cleared, then the FECR only records bit errors in
the FT pattern. This 8-bit counter saturates at 255 and generates an interrupt for each occurrence after
saturation if RIMR2.3 is set. The count is disabled during a loss of sync condition (RLOS = 1).
RSR1: RECEIVE STATUS REGISTER 1 Figure 8
MSB
8ZD
LSB
16ZD
RCL
RYEL
RLOS
B8ZSD
RBL
COFA
SYMBOL
POSITION
8ZD
RSR1.7
NAME AND DESCRIPTION
8 Zero Detect. Set when a string of eight consecutive 0s has
been received at RPOS and RNEG.
16ZD
RSR1.6
16 Zero Detect. Set when a string of 16 consecutive 0s has
been received at RPOS and RNEG.
RCL
RSR1.5
Receive Carrier Loss. Set when a string of 192 consecutive 0s has
been received at RPOS and RNEG. Cleared when 14 or more ones
out of 112 possible bit positions are received.
RYEL
RSR1.4
Receive Yellow Alarm. Set when yellow alarm is detected. The
format of yellow alarm is determined by RCR2.3 and RCR2.4.
RLOS
RSR1.3
Receive Loss of Sync. Set when resync is in progress.
B8ZSD
RSR1.2
B8ZS Code Word Detect. Set when a B8ZS code word is
received at RPOS and RNEG independent of whether the B8ZS
mode is enabled or not (RCR2.2).
RBL
RSR1.1
Receive Blue Alarm. Set when over a 3 ms window, 5 or less
zeros are received. Cleared when over a 3 ms window, 6 or more
zeros are received.
COFA
RSR1.0
Change of Frame Alignment. Set when the last resync resulted in
a change of frame or multiframe alignment.
NOTE:
1. Alarm 8ZD and 16ZD are cleared on the next occurrence of a 1 at RPOS and RNEG.
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DS2182A
RECEIVE STATUS REGISTERS
The receive status registers (RSR1 and RSR2) can be used in either a polled or an interrupt configuration.
In a polled configuration, the user reads the RSR at regular intervals to check for alarms. In an interrupt
configuration, the user monitors the INT pin. When the INT pin goes low, an alarm condition has
occurred and has been reported in one of the RSRs. The processor can then read the RSRs to find which
bits have been set. All of the bits in the RSRs operate in a latched fashion. That is, once set, they remain
set until read. The bits in the RSR are cleared when read unless the read was performed in the burst mode
or the alarm condition still exists.
YELLOW ALARM
193S BIT 2. If RCR2.4 = 0 and RCR2.3 = 0, then the DS2182A examines bit 2 of all incoming channels
for the presence of a yellow alarm. If bit 2 is set to 0 in 256 consecutive channels, then the reception of a
yellow alarm is declared. The alarm is considered cleared when the first channel with bit 2 set to a 1 is
received.
193S S-BIT. If RCR2.4 = 0 and RCR2.3 = 1, then the DS2182A examines the S-bit position of frame 12
for the presence of a yellow alarm. The DS2182A declares the presence of a yellow alarm on the first
occurrence of the S-bit in frame 12 being set to 1. The alarm is considered cleared when this S-bit returns
to 0.
193E FDL. If RCR2.4 = 1, then the DS2182A examines the FDL for a repeating 00FF pattern. If this
pattern is received in the FDL 16 consecutive times without error, then a yellow alarm is declared. The
alarm is considered cleared as soon as any pattern other than 00FF is received.
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DS2182A
RIMR1: RECEIVE INTERRUPT MASK REGISTER 1 Figure 9
MSB
8ZD
LSB
16ZD
RCL
RYEL
RLOS
B8ZSD
SYMBOL
POSITION
8ZD
RIMR1.7
NAME AND DESCRIPTION
8 Zero Detect Mask.
1 = interrupt enabled.
0 = interrupt masked.
16ZD
RIMR1.6
16 Zero Detect Mask.
1 = interrupt enabled.
0 = interrupt masked.
RCL
RIMR1.5
Receive Carrier Loss Mask.
1 = interrupt enabled.
0 = interrupt masked.
RYEL
RIMR1.4
Receive Yellow Alarm Mask.
1 = interrupt enabled.
0 = interrupt masked.
RLOS
RIMR1.3
Receive Loss of Sync Mask.
1 = interrupt enabled.
0 = interrupt masked.
B8ZSD
RIMR1.2
B8ZS Code Word Detect Mask.
1 = interrupt enabled.
0 = interrupt masked.
RBL
RIMR1.1
Receive Blue Alarm Mask.
1 = interrupt enabled.
0 = interrupt masked.
COFA
RIMR1.0
Change of Frame Alignment Mask.
1 = interrupt enabled.
0 = interrupt masked.
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RBL
COFA
DS2182A
RSR2: RECEIVE STATUS REGISTER 2 Figure 10
MSB
SEFE
LSB
RCLC
RBLC
FERR
FECS
OOFS
CRCCS
BPVCS
SYMBOL
POSITION
NAME AND DESCRIPTION
SEFE
RSR2.7
Severely Errored Framing Event. Set when 2 out of 6 framing
bits (Ft or FPS) are received in error.
RCLC
RSR2.6
Receive Carrier Loss Clear. Set when the carrier signal is
restored; will remain set until read.
RBLC
RSR2.5
Receive Blue Alarm Clear. Set when the Blue Alarm (AIS) is no
longer detected; will remain set until read.
FERR
RSR2.4
Frame Bit Error. Set when FT (193S) or FPS (193E) bit errors
occur.
FECS
RSR2.3
Frame Error Count Saturation. Set on the next frame error event
after the 8-bit Frame Error Count Register (FECR) saturates at 255.
OOFCS
RSR2.2
Out Of Frame Count Saturation. Set on the next OOF event
after the 8-bit OOF Count Register (OOFCR) saturates at 255.
CRCCS
RSR2.1
CRC Count Saturation. Set on the next CRC error event after the
8-bit CRC Count Register (CRCCR) saturates at 255.
BPVCS
RSR2.0
Bipolar Violation Count Saturation. Set on the next BPV error
event after the 16-bit Bipolar Violation Count Register (BVCR)
saturates at 65,535.
RIMR2: RECEIVE INTERRUPT MASK REGISTER 2 Figure 11
MSB
SEFE
LSB
RCLC
RBLC
FERR
FECS
OOFS
SYMBOL
POSITION
SEFE
RIMR2.7
NAME AND DESCRIPTION
Severely Errored Framing Event Mask.
0 = interrupt masked
1 = interrupt enabled
RCLC
RIMR2.6
Receive Carrier Loss Clear Mask.
0 = interrupt masked
1 = interrupt enabled
RBLC
RIMR2.5
Receive Blue Alarm Clear Mask.
0 = interrupt masked
1 = interrupt enabled
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CRCCS
BPVCS
DS2182A
SYMBOL
POSITION
FERR
RIMR2.4
NAME AND DESCRIPTION
Frame Bit Error Mask.
1 = interrupt enabled
0 = interrupt masked
FECS
RIMR2.3
Frame Error Count Saturation Mask.
1 = interrupt enabled
0 = interrupt masked
OOFCS
RIMR2.2
Out Of Frame Count Saturation Mask.
1 = interrupt enabled
0 = interrupt masked
CRCCS
RIMR2.1
CRC Count Saturation Mask.
1 = interrupt enabled
0 = interrupt masked
BPVCS
RIMR2.0
Bipolar Violation Count Saturation Mask.
1 = interrupt enabled
0 = interrupt masked
RCR1: RECEIVE CONTROL REGISTER 1 Figure 12
MSB
ARC
LSB
OOF1
OOF2
ACR
SYNCC
SYNCT
SYNCE
RESYNC
SYMBOL
POSITION
NAME AND DESCRIPTION
ARC
RCR1.7
Auto Resync Criteria.
1 = resync on OOF event only
0 = resync on OOF event or Receive Carrier Loss (RCL)
OOF1
RCR1.6
Out Of Frame 1. OOF event description. Valid when RCR1.5 is
cleared
1 = 2 out of 5 frame bits (FT or FPS) in error
0 = 2 out of 4 frame bits (FT or FPS) in error
OOF2
RCR1.5
Out Of Frame 2. OOF event description.
1 = 2 out of 6 frame bits (FT or FPS) in error
0 = follow OOF event described in RCR1.6
ACR
RCR1.4
Auto Counter Reset. When set, all four of the counters will be reset
to 0 when read.
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DS2182A
SYMBOL
POSITION
SYNCC
RCR1.3
NAME AND DESCRIPTION
Sync Criteria. Determines the type of algorithm utilized by the
receive synchronizer; differs for each frame mode.
193S Framing (RCR2.4 = 0)
0 = synchronize to frame boundaries using FT pattern, then search
for multiframe by using FS.
1 = cross couple FT and FS patterns in sync algorithm.
193E Framing (RCR2.4 = 1)
0 = normal sync (utilizes FPS only).
1 = validate new alignment with CRC before declaring sync.
SYNCT
RCR1.2
Sync Time.
1 = validate 24 consecutive F-bits before declaring sync.
0 = validate 10 consecutive F-bits before declaring sync.
SYNCE
RCR1.1
Sync Enable. If clear, the DS2182A automatically begins a resync
if the conditions described in RCR1.7 are met. If set, no auto
resync occurs.
RESYNC
RCR1.0
Resync. When toggled low to high, the DS2182A initiates a resync
immediately.
The bit must be cleared and set again for subsequent resyncs.
SYNCHRONIZER
The heart of the monitor is the receive synchronizer. This circuit serves two purposes: 1) monitors the
incoming data stream for loss of frame or multiframe alignment, and 2) searches for new frame alignment
pattern when sync loss is detected. When sync loss is detected, the synchronizer begins an off-line search
for the new alignment; all output timing signals remain at the old alignment with the exception of
RSIGFR, which is forced low during resync. When one and only one candidate is qualified, the output
timing moves to the new alignment at the beginning of the next multiframe. One frame later, RLOS will
transition low, indicating valid sync and the resumption of the normal sync monitoring mode. Several bits
in the RCR1 allow tailoring of the resync algorithm by the user. These bits are described below.
SYNC CRITERIA (RCR1.3)
193E. Bit RCR1.3 determines which sync algorithm is utilized when resync is in progress (RLOS = 1).
In 193E framing, when RCR1.3 = 0, the synchronizer will lock only to the FPS pattern and will move to
the new frame and multiframe alignment after the framing candidate is qualified. RLOS will go low one
frame after the move to the new alignment. When RCR1.3 = 1, the new alignment is further tested by a
CRC6 code match. RLOS will transition low after a CRC6 match occurs. If no CRC6 match occurs in
three attempts (three multiframes), the algorithm resets and a new search for the FPS pattern begins. It
takes 9 ms for the synchronizer to check the first CRC6 code after the new FPS alignment has been
loaded. Each additional CRC6 test takes 3 ms. Regardless of the state of RCR1.3, if more than one
candidate exists after 24 ms, the synchronizer begins eliminating emulators by testing their CRC6 codes
in order to find the true framing candidate.
193S. In 193S framing, when RCR1.3 = 1, the synchronizer cross-checks the FT pattern with the FS
pattern to help eliminate false framing candidates such as digital milliwatts. The FS patterns are
compared to the repeating pattern ...00111000111000...(00111x0 if RCR2.3 = 1). In this mode, FT and
FS must be correctly identified by the synchronizer before sync is declared. Clearing RCR1.3 causes the
synchronizer to search for the FT pattern (101010...) without cross-coupling the FS pattern. Frame sync
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DS2182A
is established using the FT information, while multiframe sync is established only if valid FS information
is present. If no valid FS pattern is identified, the synchronizer moves to the FT alignment, RLOS goes
low, and a false multiframe position may be indicated by RMSYNC. RFER indicates when the received
S-bit pattern does not match the assumed internal multiframe alignment. This mode will be used in
applications where non-standard S-bit patterns exist. In such applications, multiframe alignment
information can be decoded externally by using the S-bits present at RLINK.
SYNC TIME (RCR1.2)
Bit RCR1.2 determines the number of consecutive framing pattern bits to be qualified before SYNC is
declared. If RCR1.2 =1, the algorithm validates 24 bits; if RCR1.2 = 0, 10 bits are validated. Validating
24 bits results in superior false framing protection while 10-bit testing minimizes reframe time. In either
case, the synchronizer only establishes resync when one and only one candidate is found (see Table 5).
AVERAGE REFRAME TIME Table 5
FRAME
MODE
193S
193E
MIN
3.0ms
6.0ms
RCR1.2=0
AVG.
3.75ms
7.5ms
MAX.
4.5ms
9.0ms
MIN.
6.5ms
13.0ms
RCR1.2=1
AVG.
7.25ms
14.5ms
MAX
8.0ms
16.0ms
NOTE:
1. Average reframe time is defined here as the average time it takes from the start of resync (rising edge
of RLOS) to the actual loading of the new alignment (on a multiframe edge) into the output receive
timing.
SYNC ENABLE (RCR1.1)
When RCR1.1 is cleared, the receiver initiates automatic resync if an OOF event occurs or if carrier loss
(192 consecutive 0s) occurs (depends on RCR1.7). When RCR1.1 is set, the automatic resync circuitry is
disabled. In this case, resync can only be initiated by setting RCR1.0 to 1 or externally transitioning RST
from low to high. Note that using RST to initiate a resync resets the output timing while RST is low; use
of RCR1.1 will not affect the output timing until the new alignment is located.
RESYNC (RCR1.0)
A 0-to-1 transition of RCR1.0 causes the synchronizer to search for the framing pattern sequence
immediately, regardless of the internal sync status. In order to initiate another resync command, this bit
must be cleared and then set again.
14 of 25
DS2182A
RCR2: RECEIVE CONTROL REGISTER 2 Figure 13
MSB
LSB
-
-
BVCRF
FM
SFYEL
B8ZS
-
SYMBOL
POSITION
-
RCR2.7
Reserved; must be 0 for proper operation.
-
RCR2.6
Reserved; must be 0 for proper operation.
BVCRF
RCR2.5
Bipolar Violation Count Register Function Select.
0 = do not count excessive 0s
1 = count excessive 0s
FM
RCR2.4
Frame Mode.
1 = Extended Superframe (193E, 24 frames per Superframe).
0 = Superframe (193S or D4, 12 frames per Superframe).
SFYEL
RCR2.3
SF Yellow Mode Select.
1 = 1 in the S-bit position of frame 12.
0 = 0 in bit 2 of all channels.
B8ZS
RCR2.2
Bipolar Eight Zero Substitution.
1 = B8ZS enabled.
0 = B8ZS disabled.
-
RCR2.1
Reserved; must be 0 for proper operation.
-
RCR2.10
Reserved; must be 0 for proper operation.
-
NAME AND DESCRIPTION
193S RECEIVE MULTIFRAME TIMING Figure 14
NOTES:
1. Signaling data is updated during signaling frames on channel boundaries. Pin RABCD is the LSB of
each channel word in non-signaling frames.
2. RLINK data (S-bit) is updated one bit-time prior to S-bit frames and held for two frames.
15 of 25
DS2182A
193E RECEIVE MULTIFRAME TIMING Figure 15
NOTES:
1. Signaling data is updated during signaling frames on channel boundaries. Pin RABCD is the LSB of
each channel word in non-signaling frames.
2. RLINK data (FDL data) is updated one bit-time prior to odd frames and held for two frames.
RECEIVE MULTIFRAME BOUNDARY TIMING Figure 16
NOTES:
1. RLINK timing is shown for 193E; in 193S, RLINK is updated on even frame boundaries and is held
across multiframe edges.
2. Total delay from RPOS and RNEG to RSER output is 13 RCLK periods.
16 of 25
DS2182A
ALARM OUTPUTS
The transceiver also provides direct alarm outputs for applications when additional decoding and
demuxing are required to supplement the onboard alarm logic.
RLOS OUTPUT
The receive loss of sync output indicates the status of the receiver synchronizer circuitry; when high, an
off-line resynchronization is in progress and a high-low transition indicates that resync is complete. The
RLOS bit (RSR1.3) is a latched version of the RLOS output. If the auto-resync mode is selected (RCR1.1
= 0), RLOS is a real-time indication of a carrier loss or OOF event occurrence.
RYEL OUTPUT
The yellow alarm output transitions high when a yellow alarm is detected. A high-low transition indicates
the alarm condition has been cleared. The RYEL bit (RSR1.4) is a latched version of the RYEL output.
RBV OUTPUT
The bipolar violation output transitions high when the accused bit emerges at RSER. RBV goes low at the
next bit time if no additional violations are detected.
RFER OUTPUT
The receive frame error output transitions high at the F-bit time and is held high for 2 bit periods when a
frame bit error occurs. In 193S, framing FT and FS patterns are tested. The FPS pattern is tested in 193E
framing. Additionally, in 193E framing, RFER reports CRC6 code word errors by a low-high-low
transition (1 bit period-wide) one-half RCLK period before a low-high transition on RMSYNC (see
Figure 17).
RESET
A high-low transition on RST clears all registers and forces an immediate resync when RST returns high.
RST must be held low on system power-up to insure proper initialization of the counters and registers.
Following reset, the host processor should restore all control modes by writing appropriate registers with
control data.
ALARM OUTPUT TIMING Figure 17
17 of 25
DS2182A
NOTES:
1. RFER transitions high during F-bit time if received framing pattern bit is in error. (Frame 12 F-bits in
193S are ignored if RCR2.3 = 1.) Also, in 193E, RFER transitions high 1/2 bit-time before rising
edge of RMSYNC to indicate a CRC6 error for the previous multiframe.
2. RBV indicates received bipolar violation and transitions high when accused bit emerges from RSER.
If B8ZS is enabled, RBV will not report the 0 replacement code.
3. RCL transitions high when 192 consecutive bits are 0; RCL transitions low upon reception of 12.5%
ones density.
4. RLOS transitions high during F-bit time that caused an OOF event if auto-resync is enabled (RCR1.1
= 0). Resync also occurs when loss of carrier is detected (RCL = 1) if RCR1.7 = 0. When RCR1.1 =
1, RLOS remains low until resync occurs, regardless of OOF or carrier loss flags. In this situation,
resync is initiated only when RCR1.0 transitions low-to-high or the RST pin transitions high-lowhigh.
18 of 25
DS2182A
ABSOLUTE MAXIMUM RATINGS*
Voltage on Any Pin Relative to Ground
Operating Temperature
Storage Temperature
Soldering Temperature
-0.1V to +7.0V
0° to 70°C
-55°C to +125°C
260°C for 10 seconds
* This is a stress rating only and functional operation of the device at these or any other conditions above
those indicated in the operation sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods of time may affect reliability.
RECOMMENDED DC OPERATING CONDITIONS
PARAMETER
SYMBOL
MIN
Input Logic 1
VIH
Input Logic 0
Supply
MAX
UNITS
2.0
VCC+0.3
V
VIL
-0.3
+0.8
V
VDD
4.50
5.50
V
DC ELECTRICAL CHARACTERISTICS
PARAMETER
SYMBOL
MIN
TYP
(0°C to 70°C)
NOTES
(0°C to 70°C; VDD = 5V ± 10%)
TYP
MAX
3
UNITS
NOTES
mA
1,2
µA
3
Supply Current
IDD
Input Leakage
IL
-1.0
Output Current (2.4V)
IOH
-1.0
mA
4
Output Current (0.4V)
IOL
+4.0
mA
5
Output Leakage
ILO
-1.0
µA
6
+1.0
+1.0
CAPACITANCE
PARAMETER
(tA=25°C)
SYMBOL
Input Capacitance
Output Capacitance
MIN
MAX
UNITS
CIN
5
pF
COUT
7
pF
NOTES:
1. RCLK = 1.544 MHz.
2. Outputs open.
3. 0V < VIN < VDD.
4. All outputs except INT which is open collector.
5. All outputs.
6. Applies to SDO when tri-stated.
19 of 25
TYP
NOTES
DS2182A
1,2
CHARACTERISTICS
PARAMETER
SERIAL PORT
(0°C to 70°C; VDD = 5V ± 10%)
SYMBOL
MIN
TYP
MAX
SDI to SCLK Setup
tDC
50
ns
SCLK to SDI Hold
tCHD
50
ns
SDI to SCLK Falling Edge
tCD
50
ns
SCLK Low Time
tCL
250
ns
SCLK High Time
tCH
250
ns
SCLK Rise and Fall Times
tR, tF
100
UNITS
ns
to SCLK Setup
tCC
50
ns
SCLK to CS Hold
tCCH
50
ns
Inactive Time
tCWH
2.5
µs
SCLK to SDO Valid
tCDV
200
ns
tCDZ
75
ns
CS
CS
CS
to SDO High Z
NOTES:
1. Measured at VIH = 2.0 or VIL = .8 and 10ns maximum rise and fall time.
2. Output load capacitance = 100 pF.
20 of 25
NOTES
DS2182A
1,2
AC ELECTRICAL CHARACTERISTICS
PARAMETER
SYMBOL
RECEIVE
(0°C to 70°C; VDD = 5.0V ± 10%)
MIN
TYP
MAX
UNITS
Propagation delay RCLK to
RMSYNC, RFSYNC,
RSISEL, RSIGFR, RLCLK,
RCHCLK
tPRS
75
ns
Propagation delay RCLK to
RSER, RABCD, RLINK
tPRD
75
ns
Transition Time All Outputs
tTTR
20
ns
RCLK Period
tP
648
ns
RCLK Pulse Width
tR, tF
324
ns
RCLK Rise and Fall Times
tCCH
20
ns
RPOS, RNEG Setup to RCLK
Falling
tSRD
50
ns
RPOS, RNEG Hold to RCLK
Falling
tHRD
50
ns
Propagation delay RCLK to
RLOS, RYEL, RBV, RCL,
RFER
tPRA
Minimum RST Pulse Width
tRST
75
1
NOTES:
1. Measured at VIH = 2.0 or VIL = .8 and 10ns maximum rise and fall time.
2. Output load capacitance = 100 pF.
21 of 25
ns
µs
NOTES
DS2182A
SERIAL PORT WRITE AC TIMING DIAGRAM Figure 18
NOTES:
1. Data byte bits must be valid across low clock periods to prevent transients in operating modes.
2. Shaded regions indicate “don’t care” states of input.
SERIAL PORT READ1 AC TIMING DIAGRAM Figure 19
NOTES:
1. Serial port write must precede a port read to provide address information.
22 of 25
DS2182A
RECEIVE AC TIMING DIAGRAM Figure 20
23 of 25
DS2182A
DS2182A T1 LINE MONITOR 28-PIN DIP
DIM
A
B
C
D
E
F
G
H
J
K
INCHES
MIN.
MAX.
1.445
0.530
0.140
0.600
0.015
0.120
0.090
0.600
0.008
0.015
1.470
0.550
0.160
0.625
0.040
0.145
0.110
0.680
0.012
0.022
24 of 25
DS2182A
DS2182AQ T1 LINE MONITOR 28-PIN PLCC
DIM
INCHES
MIN.
MAX.
A
A1
A2
B
B1
C
D
D1
D2
E
E1
E2
L1
N
e1
CH1
0.165
0.180
0.090
0.120
0.020
0.026
0.033
0.013
0.021
0.009
0.012
0.485
0.495
0.450
0.456
0.390
0.430
0.485
0.495
0.450
0.456
0.390
0.430
0.060
28
0.050 BSC
0.042
0.048
25 of 25