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Spartan-6 FPGA GTP Transceiver Wizard v1.8
UG546 (v1.8) December 14, 2010
Chapter 3:
Running the Wizard
shows the optional ports available on this page.
Table 3-10:
Comma Detection
Option
Description
Use Comma Detection
Enables receive comma detection. Used to identify special protocol comma and
framing characters in the data stream.
Decode Valid Comma Only
When receive comma detection is enabled, limits the detection to specific defined
comma characters.
Comma Value
Select one of several standard comma patterns or User Defined to enter a custom
pattern.
The PCI EXPRESS example is K28.5.
Plus Comma
10-bit binary pattern representing the positive-disparity comma character to
match. The right-most bit of the pattern is the first bit to arrive serially.
The PCI EXPRESS example uses
0101111100
.
Minus Comma
10-bit binary pattern representing the negative-disparity comma character to
match. The right-most bit of the pattern is the first bit to arrive serially.
The PCI EXPRESS example uses
1010000011
.
Comma Mask
10-bit binary pattern representing the mask for the comma match patterns. A 1
bit indicates the corresponding bit in the comma patterns is to be matched. A 0
bit indicates don’t care for the corresponding bit in the comma patterns.
The PCI EXPRESS example matches all ten bits (
1111111111
).
Align to...
Any Byte Boundary
When a comma is detected, the data stream is aligned using the comma pattern
to the nearest byte boundary.
Even Byte Boundaries
When a comma is detected, the data stream is aligned using the comma pattern
to the nearest even byte boundary. This option is available only for 16 and 20 bit
RX data interfaces.
Table 3-11:
Optional Ports
Option
Description
ENPCOMMAALIGN
Active-High signal which enables the byte boundary alignment process when Plus Comma
pattern is detected.
ENMCOMMAALIGN
Active-High signal which enables the byte boundary alignment process when Minus Comma
pattern is detected.
RXSLIDE
Active-High signal that causes the byte alignment to be adjusted by one bit with each assertion.
Takes precedence over normal comma alignment.
RXBYTEISALIGNED
Active-High signal indicating that the parallel data stream is aligned to byte boundaries.
RXBYTEREALIGN
Active-High signal indicating that byte alignment has changed with a recent comma detection.
Note that data errors can occur with this condition.
RXCOMMADET
Active-High signal indicating the comma alignment logic has detected a comma pattern in the
data stream.