XRT94L33_06 Datasheet, PDF (424/465 Pages) Exar Corporation – 3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET

XRT94L33
Rev.1.2.0.
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3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
Header Bytes (4 Bytes)
HEC Byte (1 Byte)
User Defined Field (3 Bytes)
Cell Payload Bytes (48 Bytes)
As a consequence, the user must read out a total of 14 “32-bit” words from the “Receive Cell Extraction”
buffer for each ATM cell that is read out of the Receive Cell Extraction Buffer.
Procedure for Reading a Cell from the “Receive Cell Extraction Buffer”
The user can read an ATM cell from the “Transmit Cell Extraction Buffer” within the Transmit ATM Cell
Processor block, by executing the following steps.
STEP 1 – Flush the contents of the “Receive Cell Extraction Buffer”
This is accomplished by executing a “Transmit Cell Extraction Buffer” RESET. The user can perform this
“Cell Extraction Buffer” RESET by doing the following.
STEP 1a – Write a “0” into Bit 4 (Extraction Memory RESET*) within the “Transmit ATM Cell – Memory
Control” Register; as depicted below.
Receive ATM Cell – Memory Control Register (Address = 0xN713)
BIT 7
R/O
0
BIT 6
Unused
R/O
0
BIT 5
R/O
0
BIT 4
Extraction
Memory
RESET*
R/W
1->0
BIT 3
Extraction
Memory
CLAV
R/W
0
BIT 2
Insertion
Memory
RESET*
R/W
1
BIT 1
Insertion
Memory
ROOM
R/W
1
BIT 0
Insertion
Memory
Write SoC
R/W
0
STEP 1b – Write a “1” into Bit 4 (Extraction Memory RESET*), within the “Receive ATM Cell – Memory
Control” Register; as depicted below.
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