Teledyne LeCroy Serial Data Debug Solutions - Manual (Page 51)

Operator's Manual
919586 RevA 51
Table 3-3.† For D.x.7, the Primary (D.x.P7) or Alternate (D.x.A7) encoding must be selected in order to avoid a run of five
consecutive 0s or 1s when combined with the preceding 5b/6b code. Sequences of five identical bits are used in comma
codes for synchronization issues. D.x.A7 is only used for x=17, x=18, and x=20 when RD=−1 and for x=11, x=13, and x=14
when RD=+1. With x=23, x=27, x=29, and x=30, the same code forms the control codes K.x.7. Any other x.A7 code can't
be used as it would result in chances for misaligned comma sequences.
‡ The alternate encoding for the K.x.y codes with disparity 0 allow for K.28.1, K.28.5, and K.28.7 to be "comma" codes
that contain a bit sequence that can't be found elsewhere in the data stream.
C ONTROL S YMBOLS
Input RD = -1 RD = +1
HGF EDCBA abcdei fghj abcdei fghj
K.28.0 000 11100 001111 0100 110000 1011
K.28.1 † 001 11100 001111 1001 110000 0110
K.28.2 010 11100 001111 0101 110000 1010
K.28.3 011 11100 001111 0011 110000 1100
K.28.4 100 11100 001111 0010 110000 1101
K.28.5 † 101 11100 001111 1010 110000 0101
K.28.6 110 11100 001111 0110 110000 1001
K.28.7 ‡ 111 11100 001111 1000 110000 0111
K.23.7 111 10111 111010 1000 000101 0111
K.27.7 111 11011 110110 1000 001001 0111
K.29.7 111 11101 101110 1000 010001 0111
K.30.7 111 11110 011110 1000 100001 0111
Table 3-4.† Within the control symbols, K.28.1, K.28.5, and K.28.7 are "comma symbols." Comma symbols are used for
synchronization (finding the alignment of the 8b/10b codes within a bit-stream). If K.28.7 is not used, the unique comma
sequences 0011111 or 1100000 cannot be found at any bit position within any combination of normal codes.
‡ If K.28.7 is allowed in the actual coding, a more complex definition of the synchronization pattern than suggested by †
needs to be used, as a combination of K.28.7 with several other codes forms a false misaligned comma symbol
overlapping the two codes. A sequence of multiple K.28.7 codes is not allowable in any case, as this would result in
undetectable misaligned comma symbols.
K.28.7 is the only comma symbol that cannot be the result of a single bit error in the data stream.
S OURCE
Peter A. Franaszek, Albert X. Widmer, et al. "Byte oriented DC balanced (0,4) 8B/10B partitioned block
transmission code." US Patent 4486739. December 4, 1984.