Receiving Vitesse Channel Bonding Sequence; 8B/10B Bypass Serial Output - Xilinx RocketIO User Manual

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Receiving Vitesse Channel Bonding Sequence

On the RX side, the definition of the channel bonding sequence uses the disp_err bit to specify
the flipped disparity.

8B/10B Bypass Serial Output

When 8B/10B encoding is bypassed, the TXCHARDISPVAL and TXCHARDISPMODE bits
become bits "b" and "a", respectively, of the 10-bit encoded data that the transceiver must transmit
to the receiving terminal.
During receive when 8B/10B decoding is enabled, the running disparity of the serial transmission
can be read by the transceiver from the RXRUNDISP port, while the RXCHARISK port indicates
presence of a K-character. When 8B/10B decoding is bypassed, these bits remain as Bits "b" and
"a", respectively, of the 10-bit encoded data that the transceiver passes on to the user logic.
Figure 2-14
66
CHAN_BOND_SEQ_1_1 = 0 0 1 10111100 matches K28.5+ (or K28.5-)
CHAN_BOND_SEQ_1_2 = 0 1 1 10111100 matches K28.5+ (or K28.5-)
CHAN_BOND_SEQ_1_3 = 0 0 1 10111100 matches K28.5- (or K28.5+)
CHAN_BOND_SEQ_1_4 = 0 1 1 10111100 matches K28.5- (or K28.5+)
CHAN_BOND_SEQ_LEN = 4
CHAN_BOND_SEQ_2_USE = FALSE
Figure 2-13 illustrates the TX data map during 8B/10B bypass.
TXCHARDISPMODE[0]
TXCHARDISPVAL[0]
TXDATA[7] . . .
a b c
0 1 2
First transmitted
Figure 2-13: 10-Bit TX Data Map with 8B/10B Bypassed
illustrates the RX data map during 8B/10B bypass.
RXCHARISK[0]
RXRUNDISP[0]
RXDATA[7] . . .
a b c
0 1 2
First received
Figure 2-14: 10-Bit RX Data Map with 8B/10B Bypassed
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Chapter 2: Digital Design Considerations
10-bit literal value
| disp_err
| | char_is_k
| | | 8-bit_byte_value
| | | |
. . . TXDATA[0]
d e i f g
3 4 5 6 7
Last transmitted
UG024_10a_051602
. . . RXDATA[0]
d e i f g
3 4 5 6 7
Last received
UG024_10b_051602
RocketIO™ Transceiver User Guide
h j
8 9
h j
8 9
UG024 (v2.3.2) June 24, 2004