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APPENDIX D
10-7
FibreXtreme User Guide Copyright 2017
FIXED SIZE REPEATING FRAME DATA
· Synchronization must occur prior to data to which it applies.
· Synchronization occurs at the same time the last data word in the block before is
transferred.
· /SYNC must be asserted at the end of the data block while /DVALID is still asserted.
·
Because synchronization occurs at the end of the data block, the first data block will
not be synchronized.
· Synchronization occurs frequently.
· All data frames are the same size.
When fixed or dynamic size repeating frame data is transmitted onto the FPDP bus,
the FPDP-TM must assert a /SYNC pulse while /DVALID is already asserted. The /
SYNC pulse must be asserted at the same time as the last data item of every frame.
The FPDP-RM and FPDP-R devices must recognize that the current data is the last
data item in current frame when both /SYNC and /DVALID are asserted. Since /
SYNC is asserted at the end of a frame, the first data frame transmitted will not be
synchronized. As a result, the system designer may wish to discard this first
unsynchronized data frame. All data frames are the same size when fixed size repeating
frame data is transmitted.
DYNAMIC SIZE REPEATING FRAME DATA
· Synchronization must occur prior to data to which it applies.
·
Synchronization occurs at the same time the last data word in the block before is
transferred.
· /SYNC must be asserted at the end of the data block while /DVALID is still asserted.
· Because synchronization occurs at the end of the data block, the first data block will
not be synchronized.
· Synchronization occurs frequently.
· Data frames may vary in size.
For dynamic size repeating frame data, the behavior of the /SYNC pulse is the same as for fixed
size repeating frame data, with the exception of varying sized frames.
10.4 Serial FPDP Theory of Operation
The protocol and framing for Serial FPDP are listed in Appendix C. Serial FPDP operates similar
to parallel FPDP with respect to maintaining data framing with the SYNC signal, but the SYNC
signal does not correlate with data frames on the fiber. Any form of data framing listed in section
8.3.2 can be mapped to Serial FPDP, since the data stream and SYNCs are maintained.
However, the timing may not be exactly the same as the parallel FPDP version due to link
framing overhead and the fact that the link operates asynchronously to the parallel FPDP
frequencies.