IPR-ED8B10B Altera, IPR-ED8B10B Datasheet - Page 20

• Manufacturer Part Number: IPR-ED8B10B
• Description: IP CORE Renewal Of IP-ED8B10B
• Manufacturer: Altera
• Type: MegaCorer

Specifications of IPR-ED8B10B

• Software Application: IP CORE, Interface And Protocols, COMMUNICATION
• Supported Families: Arria GX, Cyclone, HardCopy, Stratix
• Core Architecture: FPGA
• Core Sub-architecture: Arria, Cyclone, Stratix
• Rohs Compliant: NA
• Function: Encoder/Decoder, 8b/10b for Gigabit Ethernet and Fibre Channel
• License: Renewal License
• Lead Free Status / RoHS Status: na
• Lead Free Status / RoHS Status: na

3–2
Generic Framing Procedure
Figure 3–2. 8B10B Encoder/Decoder GFP Typical Application
8B10B Encoder/Decoder MegaCore Function User Guide
(8B/10B Encoded)
Ethernet
f
Stream
Gigabit
The running disparity error output (rderr) is asserted when any of the following
rules apply:
■
■
■
■
For details on running disparity rules, refer to the IEEE 802.3z specification, paragraph
36.2.4.4.
The 8B10B Encoder/Decoder MegaCore function can be used within generic framing
procedure (GFP) applications. See
On ingress to the transport network, if the decoder receives an unrecognized
codeword, such as an illegal codeword or a legal codeword with a running disparity
error, it asserts the kerr or rderr signals respectively. By asserting these error
signals, the decoder indicates to the mapper that an invalid codeword has been
received, the mapper then generates a special control character, the 10B_ERR code. In
addition, the mapper remaps the 8B/10B codewords into 64B/65B codewords before
sending the data to the transport network.
On egress from the transport network, the demapper decodes the 64B/65B codewords
and sends them to the 8B/10B encoder. When the encoder receives the 10B_ERR code,
it sends out one of the two 10-bit illegal codewords with neutral disparity: 001111
0001(RD-) or 110000 1110(RD+), depending on the running disparity.
The current running disparity is positive and the 6-bit group has more ones than
zeros or is 111000.
The current running disparity is negative and the 6-bit group has more zeros than
ones or is 000111.
The running disparity after 6-bit group is positive and the 4-bit group has more
ones than zeros or is 1100.
The running disparity after 6-bit group is negative and the 4-bit group has more
zeros than ones or is 0011.
1
Decoder
8B/10B
Ingress
rderr is asserted for some invalid 10-bit codes and not for others, strictly
based on the rules stated above. The computation of rderr is completely
independent of that of the special control character error (kerr) signal.
A 10-bit code that corresponds to a valid encoding but that has the wrong
disparity—though technically an invalid code—does not cause the kerr
signal to be asserted. Only rderr is asserted.
Mapper
GFP
Transport Network
(64B/65B Encoded)
GFP Data Stream
Preliminary
Figure 3–2 on page 3–2
Demapper
GFP
Egress
Encoder
8B/10B
© November 2009 Altera Corporation
for an example.
(8B/10B Encoded)
Chapter 3: Specifications
Ethernet
Gigabit
Stream
Functional Description