IPR-ED8B10B Altera, IPR-ED8B10B Datasheet - Page 19

• 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

Functional Description
Disparity
© November 2009 Altera Corporation
The MegaCore
(DEC8B10B). See
into a 10-bit transmission code, and the decoder decodes a 10-bit code into one 8-bit
byte of data.
The eight input bits are named A, B, C, D, E, F, G, H. Bit A is the least significant bit
(LSB), and bit H is the most significant bit (MSB). They are split into two groups: the
five-bit group A, B, C, D, E, and the three-bit group F, G, H.
The coded bits are named a, b, c, d, e, i, f, g, h, j (the order is not alphabetical).
These bits are also split into two groups: the six-bit group a, b, c, d, e, i, and the four-
bit group f, g, h, j.
Figure 3–1. 8b10b Conversion
In bit serial transmission, the LSB is usually transmitted first, while the MSB is usually
transmitted last.
Disparity is the difference between the number of 1s and 0s in the encoded word.
■
■
■
The MegaCore function is designed to maintain a neutral average disparity. Average
disparity determines the direct current (DC) component of a serial line. Running
disparity is a record of the cumulative disparity of every encoded word, and is
tracked by the encoder. To guarantee neutral average disparity, a positive running
disparity must be followed by neutral or negative disparity; a negative running
disparity must be followed by neutral or positive disparity.
Neutral disparity indicates the number of 1s and 0s are equal.
Positive disparity indicates more 1s than 0s.
Negative disparity indicates more 0s than 1s.
Figure 3–1
®
function consists of an encoder (ENC8B10B) and a decoder
Figure 3–2 on page
MSB sent last
9
j
H
7
illustrates the bidirectional conversion process.
h
8
G
6
Preliminary
g
7
5
F
8b10b
6
f
3–2. The encoder encodes one 8-bit byte of data
4
E
5
i
D
Conversion
3
e
4
8B10B Encoder/Decoder MegaCore Function User Guide
d
3
C
2
c
2
B
1
b
1
3. Specifications
A
LSB sent first
0
a
0