xrt94l33 Exar Corporation, xrt94l33 Datasheet - Page 257

• Manufacturer Part Number: xrt94l33
• Description: Multi-channel, Multi-function Device Aggregates 3 Ds3/e3/sts-1 Into Oc3/stm-1
• Manufacturer: Exar Corporation

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3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
2.2.8.1
The Transmit SONET POH Processor block receives ATM cell data from the Transmit ATM Cell Processor
block; and maps this data into an STS-1 SPE.
As the Transmit SONET POH Processor block receives this ATM Cell data from the Transmit ATM Cell
Processor block, it will perform the following functions.
• It will map these ATM cells into the payload bytes, within the STS-1 SPE.
• Compute and insert the B3 byte
• Source (per user configuration) the J1, C2, G1, F2, H4, Z3, Z4 and Z5 bytes
•
indicator
• To (automatically or upon software command) transmit the REI-P (Path – Remote Error Indicator) indicator
• To (upon software command) transmit the AIS-P (Path – Alarm Indication Signal) indicator
• To (upon software command) force pointer-adjustment or NDF (New Data Flag) events into the outbound
STS-1 data-stream.
Each of these functions is described in detail below.
2.2.8.2
The Transmit SONET POH Processor block creates STS-1 SPE data and computes a BIP-8 value over this
STS-1 SPE. The results of this calculation are inserted into the B3 byte-position within the very next STS-1
SPE.
checking/detection on the incoming STS-1 SPE data that it receives.
TRANSMISSION OF ERRED B3 BYTES IN THE OUTBOUND STS-1 DATA-STREAM
The Transmit SONET POH Processor block permits the user to insert errors into the “B3 Bytes”, within the
outbound STS-1 SPE data-stream.
The user can accomplish this by writing a non-zero value into the “Transmit SONET Path – Transmitter B3
Byte Error Mask” Register. The “Transmit SONET POH Processor block will perform an XOR operation with
the contents of the “outbound” B3 byte, and the contents of this register. The results of this calculation are
written back into the B3 byte position, within the outbound STS-1 SPE data-stream.
The bit-format of the “Transmit SONET Path – Transmit B3 Byte Error Mask” register is presented below.
Transmit SONET Path – Transmitter B3 Byte Error Mask Register (Address = 0xN997)
Note:
To (automatically or upon software command) transmit the RDI-P (Path – Remote Defect Indicator)
B
R/W
IT
0
7
The Remote PTE (Path Terminating Equipment) will use this byte, in order to perform error-
For normal (e.g., un-erred) operation, the user should ensure that this register is set to “0x00” (the default value).
RECEIVING ATM CELL DATA FROM THE TRANSMIT ATM CELL PROCESSOR BLOCK
COMPUTATION AND INSERTION OF THE PATH BIP-8 (B3) BYTE
B
R/W
IT
0
6
B
R/W
IT
0
5
Transmit_B3_Byte_Mask[7:0]
B
R/W
IT
0
4
257
B
R/W
IT
0
3
B
R/W
IT
0
2
B
R/W
IT
0
1
XRT94L33
Rev.1.2.0.
B
R/W
IT
0
0