Figure 3-16: Sonet Alignment Sequence (2-Byte External Data Interface Width) - Xilinx Virtex-4 RocketIO User Manual

Chapter 3: PCS Digital Design Considerations
Figure 3-16
The ports and attributes in
SONET. The MCOMMA attributes are used by the byte aligner only while the PCOMMA
attributes are used by both the byte aligner and the SONET aligner.
The A1 symbol defined by the SONET protocol is 0xF6, and the A2 symbol is 0x28.
Transmission order is MSb to LSb. The Virtex-4 MGT reception order is LSb to MSb, so the
A1 symbol setting must be bit-swapped to 0x6F, and the A2 symbol must be bit-swapped
to 0x14.
Table 3-11: SONET Port Configuration
120
shows the same process, but for a 16-bit external data interface width.
RXUSRCLK
RXUSRCLK2
rxdata_unaligned[31:0]
Unaligned A1A1A1A1A2A2A2A2 pattern =
rxdata_byte_aligned[31:0]
RXDATA[15:0]

Figure 3-16: SONET Alignment Sequence (2-Byte External Data Interface Width)

Fabric Port
SONET aligner:
Byte Aligner:
ENMCOMMAALIGN
SONET aligner:
ENPCOMMAALIGN
Byte Aligner:
www.xilinx.com
0x 0x 0x
80000000 BCBDBDBD 50505050
0x6F6F6F6F14141414,
0x
6F000000
Byte-aligned A1A1A1A1A2A2A2A2 pattern =
Table 3-11 and Table 3-12
Definition
Not used.
= realign byte alignment mux when the A1 symbol is found
1
on a non-byte aligned boundary.
= hold alignment mux position.
0
1 = realign data to the A1A1A2A2 transition so that the A2
stream becomes 32-bit word aligned.
0 = hold SONET alignment mux position.
1 = realign byte alignment mux when the A1 symbol is found
on a non-byte aligned boundary.
0 = hold alignment mux position.
0x
00000000
offset by 2 bits
0x 0x
146F6F6F 00141414 00000000
0x6F6F6F6F14141414
0x 0x 0x
......
6F6F 6F6F 1414
Word-aligned A1A1A2A2 boundary
ug076_ch3_36a_073107
define the proper configuration for
Virtex-4 RocketIO MGT User Guide
UG076 (v4.1) November 2, 2008
R
0x
0x 0x
1414 0000