PM5364 pmc-sierra, PM5364 Datasheet - Page 83

• Manufacturer Part Number: PM5364
• Description: Tupp 2488 Assp Telecom Standard
• Manufacturer: pmc-sierra

10.2.2
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2011334, Issue 7
The descrambler block descrambles data according to the SONET/SDH specifications with the
exception of control characters output from 8B/10B decoder (K is high), which are not
descrambled. The descrambler does not modify the K signal output from the 8B/10B decoder.
The descrambler passes output data from the 8B/10B decoder without modification when
DESCREN is asserted low.
The BIP8 block calculates the BIP8 parity on a block basis over a received frame of scrambled
data and compares the result to the expected value in the B1 byte position of the next
descrambled frame. The BIP8 block errors are counted when 8B/10B decoding is disabled. A
maskable interrupt is generated when a BIP8 violation is detected. The BIP8 calculation is
intended for monitoring SNRZ coded line data and is not valid when the 8B/10B decoder is
enabled. The BIP8 interrupt should be masked and LCVs monitored for 8B/10B encoded data or
for 8B/10B encoded SNRZ data.
Pointer Interpreter and PRBS Monitor (PIPM)
A total of 24 PIPM blocks are instantiated in the TUPP 2488 device. There are eight PIPM
blocks on the line side of TUPP 2488 for the four working and four protect Line Ingress Serial
RASIO™ CML links. There are 16 PIPM blocks on the system side of TUPP 2488 for the eight
working and eight protect System Egress Serial RASIO™ CML links.
The PIPM provides line rate PRBS monitoring for SONET/SDH applications, and for raw bit-
streams.
The PIPM receives 8-bit or 10-bit data words depending on the operating mode. In the
SONET/SDH modes, 8-bit bytes are used, which can be data or control bytes. The control bytes
correspond to Serial TelecomBus (STCB) control characters. A frame pulse is also required to
identify the J0 byte. In the Raw mode, the PIPM can be configured for 8-bit or 10-bit data
words as required.
For SONET/SDH, the PIPM supports PRBS monitoring of the STS-Nc payload
capacity/C-4-Xc at the line rate: STS-12c/C-4-4c and STS-48c/C-4-16c. The STS-Nc
SPE/VC-4-Xc payload is floating inside the transport frame, so the PIPM must identify the J1
position in order to locate the STS-Nc payload capacity/C-4-Xc. This can be done in two
different ways depending on the type of input data: using a pointer interpreter, or using the
control bytes in the data stream.
The PIPM contains a simplified pointer interpreter that identifies the J1 position in the
concatenated payload and follows pointer justification events. The pointer interpreter does not
implement the full specification for SONET/SDH pointer processing. Particularly, error
conditions (AIS, LOP) are ignored, since it assumes that the frames containing PRBS will be
correctly formatted. The fundamental operations (new pointer value during normal operation,
new data flag, increment, and decrement) are fully implemented according to
ANSI T1.105-1995.
TUPP™ 2488 ASSP Telecom Standard Product Data Sheet
Released
83