RCLXT16706FE Intel, RCLXT16706FE Datasheet - Page 190

• 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
7.2.3
7.2.4
7.2.5
7.2.6
190
Table 23. Byte Stuffing
FCS Generation/Insertion
The Frame Check Sequence (FCS) field is calculated over all bits of the Address, Control,
Protocol, Information, and Padding fields, not including the Flag Sequences nor the FCS field
itself. The FCS field is calculated before Control Escape insertion (before byte stuffing). The FCS
is transmitted least significant octet first, which contains the coefficient of the highest term. Two
different generating polynomials are defined, the CRC-CCITT (CRC-16)
and the CRC-32:
XmtFCSCnf[1:0] (register T_PHCCNF) configures the use of CRC-CCITT, CRC-32, or no-FCS
generation.
The transmit HDLC controller allows insertion of FCS errors by inverting the calculated FCS field
before transmission. This can be done by software control (XmtFCSErrCnf and XmtFCSErr,
register T_PHCCNF)
User Data Scrambling
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. When
XmtTrScrEn = ‘1’ (register T_PHCCNF), user data goes through a self-synchronous scrambler
using the polynomial X
Control Escape Stuffing Insertion (Byte Stuffing)
Before mapping an HDLC frame into the outgoing SONET/SDH SPE, the transmit HDLC
controller escapes all the Flag characters (7EH) and Control Escape characters (7DH) for
transparency. The byte stuffing algorithm analyzes, byte by byte, all the characters between Flags
(the Address, Control, Protocol, Information, Padding, and FCS fields). Every time a Flag or a
Control Escape character is detected, the character is escaped by XORing it with 20H and inserting
a Control Escape character before it.
Transmit Flow Control
The transmit HDLC controller can perform transmission flow control, by inserting a number of
Flag characters between consecutive HDLC frames (interframe filling) by using two different
methods.
Flag
Control Escape
Character
g(X) = 1 + X
g(X) = 1 + X + X
+ X
7E
7D
32
48
+ X
Original
28
5
+ X
+ X
2
12
+ X
27
+ X
+ 1.
4
+ X
7D–5E
7D–5D
16
5
+ X
Escaped
7
+ X
8
+ X
10
+ X
11
+ X
12
+ X
16
+ X
22
+ X
Datasheet
23
+ X
26