VSC7216-02
Data Sheet
8B/10B Encoder
Each channel contains an 8B/10B encoder that translates the 8-bit input data on Tn[7:0] into a 10-bit encoded data
character. C/Dn inputs are also provided in each channel which, along with KCHAR, allow the transmission of
special Fibre Channel Kxx.x characters (see Table 3). Note that KCHAR is a static input, and does NOT have the
same input timing as Tn[7:0], C/Dn and WSENn. Normally C/Dn is LOW in order to transmit data. If C/Dn is HIGH
and KCHAR is LOW, then a Fibre Channel defined IDLE Character (K28.5 = 0011111010 or 1100000101 depending
on disparity) is transmitted and Tn[7:0] is ignored. If C/Dn is HIGH and KCHAR is HIGH, a Kxx.x character is
transmitted as determined by the data pattern on Tn[7:0] (see Table 4). Data patterns other than those defined in Table
4 produce undefined 10B encodings.
Table 3. Transmit Data Controls
WSENn
C/Dn
KCHAR
Encoded 10-Bit Output
Data Character
0
0
0
1
0
1
1
X
X
0
1
X
IDLE Character (K28.5)
Special Kxx.x Character
16-Character Word Sync Sequence
Table 4. Special Characters (selected when C/Dn and KCHAR are HIGH)
Code
K28.0
K28.1
K28.2
K28.3
K28.4
K28.5
K28.5+
Tn[7:0]
Comment
User Defined
User Defined
User Defined
User Defined
User Defined
IDLE
Code
K28.5-
K28.6
K28.7
K23.7
K27.7
K29.7
K30.7
Tn[7:0]
Comment
User Defined
User Defined
Test Only
000 11100
001 11100
010 11100
011 11100
100 11100
101 11100
101 01100
101 01101
110 11100
111 11100
111 10111
111 11011
111 11101
111 11110
User Defined
User Defined
User Defined
User Defined
User Defined
Encoder Bypass Mode
When ENDEC is LOW the 8B/10B encoders are bypassed and a 10-bit input character Tn[7:0] is serialized directly
in each channel, bit Tn0 is transmitted first. The C/Dn input becomes Tn8, and WSENn becomes Tn9. The KCHAR
input becomes ENCDET, which is not used in the transmitter, but when HIGH, enables “Comma” detection in all
four receivers. For a description of this mode of operation in the receiver, see “Decoder Bypass Mode” on page 16.
The latency through the transmitter is reduced by one character time when ENDEC is LOW. This mode of operation
is similar to a 10-bit interface commonly found in serializer/deserializers for Fibre Channel and Gigabit Ethernet
markets.
Word Sync Generation
The VSC7216-02 can perform channel alignment (also referred to as “word alignment” or “word sync”), meaning
that the four receive data output streams are aligned such that the same 4-byte word presented to the four transmit
channel inputs for serialization will be transferred on the receive channel parallel outputs. The Word Sync Sequence
6 of 40
G52367 Revision 4.2
December 2006
VITESSE [ VITESSE SEMICONDUCTOR CORPORATION ]
