
PM5317 SPECTRA-9953 Telecom Standard Product Data Sheet
Release
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2000741, Issue 5
495
Figure 27 64-Byte Trail Trace Message, sync on CR/LF
1st BYTE
2nd BYTE
ALGO = 01/10 , LENGTH16 = 0 , SYNC_CRLF = 1
40H, 80H, C0H
41H, 81H, C1H
...
CR
LF
7EH, BEH, FEH
7FH, BFH, FFH
63th BYTE
64th BYTE
...
To avoid declaring an unstable/mismatch defect when the transmitter updates the trail trace
message, the RTTP considers an all zeros message to be matched. An all-zeros captured
message in algorithm 1 and an all-zeros accepted message in algorithm 2 are not validated
against the expected message but are considered match. That is, a match is declared when the
captured or accepted message is all zeros regardless of the expected message. This feature can
be turned off by setting the ZEROEN register bit to logic one.
Note: The transmitter is required to force an all zeros trail trace message when the trail trace
message is updated.
17.9 Using the Transmit Trail trace Processor
The TTTP generates a one-byte, 16-byte, or 64-byte trail trace message. To generate a one-byte
message, the BYTEEN register bit must be set to logic one. The trail trace byte is placed at
address 40H. To generate a 16-byte message, the BYTEEN register bit must be set to logic zero
and the LENGTH16 register bit must be set to logic one. The trail trace message is placed
between the 40H and 4FH addresses. To generate a 64-byte message, both the BYTEEN and
the LENGTH16 register bits must be set to logic zero. The trail trace message is placed
between the 40H and 7FH addresses.
The trail trace message must include synchronization because the TTTP does not add
synchronization to the message. The synchronization mechanism is different for a 16-byte
message and for a 64-byte message. When the message is 16 bytes, the synchronization is
based on the MSB of the trail trace byte. Only one of the 16 bytes has is MSB set high. The
byte with its MSB set high is the first byte of the message. When the message is 64 bytes, the
synchronization is based on the CR/LF (CR = 0Dh, LF = 0Ah) characters of the trail trace
message. The byte following the CR/LF bytes is the first byte of the message.
Figure 28 64-Byte Trail Trace Message, sync on CR/LF
1st BYTE
BYTEEN=1
40H