RCLXT16706FE Intel, RCLXT16706FE Datasheet - Page 186

• Manufacturer Part Number: RCLXT16706FE
• Manufacturer: Intel

Specifications of RCLXT16706FE

• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 2.97V
• Operating Supply Voltage (max): 3.63V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Lead Free Status / Rohs Status: Not Compliant

Intel IXF6048 — 51/155/622/2488 Mbit/s SONET/SDH Cell/Packet Interface
7.1.1
7.1.2
7.1.3
7.1.4
7.1.5
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Table 22. Byte Destuffing
SPE Descrambling
Intel IXF6048 performs self-synchronous descrambling of the incoming HDLC frames (the
incoming SPE bytes) using the polynomial X
HDLC frames are processed (frame delineation, byte destuffing, etc.). The self-synchronous
descrambling can be disabled by setting RcvDescrEn = '0' (register R_PHCCNF).
HDLC Frame Delineation
After SPE descrambling, the receive HDLC controller finds the HDLC frame boundaries by
searching the Flag character (7EH). As minimum, one Flag character must be used to separate two
consecutive frames. Flags are also used for interframe spacing (two or more consecutive Flag
characters). All the Flag characters are eliminated (not written into the receive FIFO).
Frame Intrafilling Removal
Instead of aborting frames when the FIFO underflows in the transmit POS processor, pairs of
Control Escape characters (7DH) can be used to fill the gap between valid user data. These Control
Escape Characters are added to the frame, after byte stuffing. Frame intrafilling can also be used
for flow control purposes.
When the frame intrafilling is enabled (RcvFifEn = '1' in the register R_PHCCNF), the receiver
POS processor removes all the Control Escape character pairs found in the middle of a frame
before performing byte destuffing. Control Escape pairs are not allowed at the beginning or end of
a frame.
Control Escape Stuffing Removal (Byte Destuffing)
The byte destuffing block searches for the Control Escape character (7DH). The Control Escape
characters are added for transparency in transmission and must be removed by the receiver to
restore the user data. The byte destuffing block eliminates all the Control Escape characters and
then XORs the next character with 20H, unless it is the Flag character (which aborts a frame). The
byte stuffing/destuffing algorithm is performed over the Address, Control, Protocol, Information,
Padding, and FCS fields (between Flags).
User Data Descrambling
In order to avoid frame extension by malicious users and allow data-transparent behavior, the POS
frame can be scrambled in the POS transmit processor before going through byte stuffing. The POS
receiver processor can optionally descramble received frames, after byte destuffing, recovering the
original user data. The descrambling process is self-synchronous and uses the polynomial X
X
This descrambler can be disabled by setting RcvTrDescEn = '0' (register R_PHCCNF).
Flag
Control Escape
28
+ X
Character
27
+ 1.
7D–5E
7D–5D
Received
7E
7D
43
Destuffed
+ 1. The descrambling is performed before the
Datasheet
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