Xilinx RocketIO User Manual

RocketIO™ Transceiver User Guide www.xilinx.com 65
UG024 (v3.0) February 22, 2007
8B/10B Encoding/Decoding
R
The RocketIO core receives this data, but for cases where TXCHARDISPVAL is set High
during data transmission, the disp_err bit in CHAN_BOND_SEQ must also be set High.
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.
10-bit literal value
| disp_err
| | char_is_k
| | | 8-bit_byte_value
| | | |
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
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. Figure 2-13 illustrates the TX data map during
8B/10B bypass.
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 illustrates the RX data map during
8B/10B bypass.
Figure 2-13: 10-Bit TX Data Map with 8B/10B Bypassed
Figure 2-14: 10-Bit RX Data Map with 8B/10B Bypassed
UG024_10a_051602
7896543201
First transmitted Last transmitted
TXCHARDISPMODE[0]
TXCHARDISPVAL[0]
TXDATA[7] . . . . . . TXDATA[0]
ghjfiedcab
UG024_10b_051602
7896543201
First received Last received
RXCHARISK[0]
RXRUNDISP[0]
RXDATA[7] . . . . . . RXDATA[0]
ghjfiedcab
Product Not Recommended for New Designs

Xilinx RocketIO Specifications

General

Brand	Xilinx
Model	RocketIO
Category	Transceiver
Language	English