Functional Description
Table 3–1 lists the special K codes used by the MegaCore function.
Table 3–1. Character Codes
10-Bit Special K Codes
Equivalent 8-Bit Codes
K28.0
K28.1
8'b000_11100
8'b001_11100
8'b010_11100
8'b011_11100
8'b100_11100
8'b101_11100
8'b110_11100
8'b111_11100
8'b111_10111
8'b111_11011
8'b111_11101
8'b111_11110
8'b111_11111
K28.2
K28.3
K28.4
K28.5 (1)
K28.6
K28.7
K23.7
K27.7
K29.7
K30.7
10B_ERR
Note to Table 3–1:
(1) K28.5 is a comma character used for alignment purposes, and to represent the
IDLE code.
Encoder
To encode an 8-bit word, the 8-bit value must be applied to the datain
inputs and the enainput must be asserted (active high).
When one of the thirteen special 10-bit codes is to be inserted, the
equivalent 8-bit code is placed on the datainlines and the kininput is
asserted. The MegaCore function performs error checking to ensure the
out-of-band 8-bit code is valid. If not, the kerroutput is asserted. See
Table 3–1 for a list of the valid K codes.
1
Although the 10B_ERR code is considered to be an invalid
special character, it does not cause the kerrsignal to be
asserted.
Idle (K28.5) characters can be automatically inserted when enais not
asserted by asserting the idle_insinput.
The encoder encodes invalid characters in the same way it encodes Idle
(K28.5) codes. The decoder treats invalid characters as Idle codes.
3–4
MegaCore Version 7.2
Altera Corporation
October 2007
8B10B Encoder/Decoder MegaCore Function User Guide
ALTERA [ ALTERA CORPORATION ]
