R
Figure 8-7
10GBASE-R encoding, 10GBASE-R GearBox, and 64B/66B Scrambler.
TXDATA (2,4,8B)
Virtex-4 RocketIO MGT User Guide
UG076 (v4.1) November 2, 2008
shows the buffered-mode flow through the TX bypassing 8B/10B encoding,
TX_CLOCK_DIVIDER
TXUSRCLK
÷2
÷4
TXUSRCLK2
TXUSRCLK2
TXUSRCLK
TXOUTCLK1/
TXOUTCLK2
8B/10B
Encode
10GBASE-R
TXCHARISK
Encode
(1)
ETC.
PCS
Note: (1) 64B/66B encoding/decoding is not supported.
Figure 8-7: TX Low Latency Buffered Mode: Use Models TX_1D, TX_2D
www.xilinx.com
TXCLK0_FORCE_PMACLK,
TX_CLOCK_DIVIDER
00
10
01
11
010
001
PCS
TXCLK
00
F
10
8x40 bit
Ring
T
Buffer
01
TXENC8B10BUSE,
TX_BUFFER_USE
TXENC64B66BUSE
Transmit Latency and Output Skew
011 000
1XX
PMA TXCLK0
PCS Dividers &
Clock Control
Phase Align
0001
0010
0000
10GBASE-R
Gearbox
(1)
64B/66B
1100
Scrambler
(1)
TXSCRAM64B66BUSE,
TXGEARBOX64B66BUSE,
TXDATA_SEL
TXP
PISO
TXN
PMA
ug076_ch8_07_071907
205