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DS3171/DS3172/DS3173/DS3174
99
DS3/E3
Transmit
LIU
IEEE P1149.1
JTAG Test
Access Port
Microprocessor
Interface
HDLC
FEAC
LLB
DLB
DS3 / E3
Transmit
Formatter
DS3 / E3
Receive
Framer
Trail
Trace
Buffer
DS3/E3
Receive
LIU
TAIS
TUA1
Clock Rate
Adapter
TX BERT
RX BERT
PLB
ALB
UA1
GEN
B3ZS/
HDB3
Encoder
B3ZS/
HDB3
Decoder
The Receive FIFO accepts data from the Receive Packet Processor until full. If a packet start is received while full,
the data is discarded and a FIFO overflow condition is declared. If any other packet data is received while full, the
current packet being transferred is marked with an abort indication, and a FIFO overflow condition is declared.
Once a FIFO overflow condition is declared, the Receive FIFO will discard incoming data until a packet start is
received while the Receive FIFO has sixteen or more bytes available for storage. If the Receive FIFO is read while
the FIFO is empty, the read is ignored, and an invalid data indication given.
10.8 Trail Trace Controller
10.8.1 General Description
Each port has a dedicated Trail Trace Buffer for E3-G.832 link management
The Trail Trace Controller performs extraction and storage of the incoming G.832 trail access point identifier in a
16-byte receive register.
The Trail Trace Controller extracts/inserts E3-G.832 trail access point identifiers using a 16-byte register(one for
transmit, one for receive).
The Trail Trace Controller demaps a 16-byte trail trace identifier from the E3-G.832 TR Byte of the overhead in the
receive direction and maps a trace identifier into the E3-G.832 datastream in the transmit direction.
The receive direction inputs the trace ID data stream, performs trace ID processing, and stores the trace identifier
data in the data storage using line timing. It removes trace identifier data from the data storage and outputs the
trace identifier data to the microprocessor via the microprocessor interface using register timing. The data is forced
to all ones during LOS, LOF and AIS detection to eliminate false messages
The transmit direction inputs the trace identifier data from the microprocessor via the microprocessor interface and
stores the trace identifier data in the data storage using register timing. It removes the trace identifier data from the
data storage, performs trace ID processing, and outputs the trace ID data stream. Refer to
location of the Trail Trace Controller with the DS317x devices.
Figure 10-21. Trail Trace Controller Block Diagram
10.8.2 Features
•
Programmable trail trace ID
– The trail trace ID controller can be programmed to handle a 16-byte trail trace
identifier (trail trace mode).
•
Programmable transmit trace ID
– All sixteen bytes of the transmit trail trace identifier are programmable.
•
Programmable receive expected trace ID
– A 16-byte expected trail trace identifier can be programmed.
Both a mismatch and unstable indication are provided.