Figure 2-5: 10-Bit Tx Data Map With 8B/10B Bypassed; Table 2-6: 8B/10B Bypassed Signal Significance - Xilinx RocketIO X User Manual

Block Level Functions

Table 2-6: 8B/10B Bypassed Signal Significance

Signal
(1)
TXBYPASS8B10B
TXCHARDISPMODE,
TXCHARDISPVAL
TXCHARISK
Notes:
1. If 8B/10B is bypassed, this port can be defined if 64B/66B encoding is used.
During transmit, while 8B/10B encoding is enabled, the disparity of the serial
transmission can be controlled with the TXCHARDISPVAL and TXCHARDISPMODE
ports. When 8B/10B encoding is bypassed, these bits become Bits "b" and "a,"
respectively, of the 10-bit encoded data that the transceiver must transmit to the receiving
terminal.
TXCHARISK
TXCHARISK is a byte-mapped control port that is only used when the 8B/10B encoder is
implemented. This port indicates whether the byte of TXDATA is to be encoded as a
control (K) character when asserted and data character when de-asserted. When 8B/10B
encoding is bypassed this port is undefined.
TXRUNDISP
TXRUNDISP is a status port that is byte-mapped to the TXDATA. This port indicates the
running disparity after this byte of TXDATA is encoded. When asserted, the disparity is
positive. When de-asserted, the disparity is negative.
RocketIO™ X Transceiver User Guide
UG035 (v1.5) November 22, 2004
0 8B/10B encoding is enabled (not bypassed)
1 8B/10B encoding bypassed (disabled)
Function, 8B/10B Enabled
00 Maintain running disparity normally
01 Invert the normally generated running
disparity before encoding this byte.
10 Set negative running disparity before
encoding this byte.
11 Set positive running disparity before
encoding this byte.
Received byte is a K-character
Figure 2-5 illustrates the TX data map during 8B/10B bypass.
TXCHARDISPMODE[0]
TXCHARDISPVAL[0]
j
0
Last transmitted

Figure 2-5: 10-Bit TX Data Map with 8B/10B Bypassed

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Function
Part of 10-bit encoded byte
(see
TXCHARDISPMODE[0],
TXCHARDISPVAL[0],
TXDATA[7:0]
[39:32]/[47:40]/[55:48]/[63:56})
Unused
TXDATA[7] . . .
h g f i e
1 2 3 4 5
Function, 8B/10B Bypassed
Figure 2-5):
(or: [1] / [2] / [3] /[4]/[5]/[6]/[7])
(or: [1] / [2] / [3] /[4]/[5]/[6]/[7])
(or: [15:8] / [23:16] / [31:24]/
. . . TXDATA[0]
d c b a
6 7 8 9
First transmitted
UG024_10a_080404
R
49