Curtiss-Wright FHK4-FM4MWB04-00, Справочник по аппаратуре, Страница: 53 / 123

REGISTER SET
Copyright 2012 6-3 FibreXtreme HW Reference for FPDP Cards
6.1.3 Link Control (LINK_CTL) – Offset 0x08
Bit Description Access Reset
Value
0
Allow Remote Transmitter – Set to ‘1’ to enable the
remote transmitter to send link data. Set to ‘0’ to
request the remote transmitter to stop sending link
data. This flow control request will be ignored if the
remote end is configured to ignore flow control. This
signal is typically set to a '1' for most applications. It
exists to provide a mechanism to disable the remote
transmitter by forcing the transmitted flow control to a
STOP state.
R/W 0
1
CRC Enable – Set to ‘1’ to enable the CRC
checking/generation of link data. Set to ‘0’ to disable
CRC checking/generation.
NOTE : CRC should be used in almost all applications.
It offers excellent coverage of data errors and has
very little impact on link throughput for maximum
frame sizes. The option of disabling CRC is only
retained for compatibility with older third-part devices.
Both nodes on the link (or all nodes in a loop
configuration) should be set to a common CRC mode
or the resulting mismatch will cause data errors and/or
link errors.
R/W 0
2
Ignore Flow Control – Set to ‘1’ to ignore flow control
from the remote end and continue transmitting when
the link is down. Set to ‘0’ to stop transmission when
the link goes down or the remote end is sending a
STOP ordered set back.
NOTE: In almost every application, flow control should
be enabled. Even if the application must sustain
maximum link throughput, it is better to drop the data
at the sending source should the system experience a
temporary overload condition. Some exotic conditions
could apply where flow control is not desirable, but
they require very careful system planning and should
be confirmed with Curtiss-Wright Controls prior to
architectural finalization. One possible exception is for
applications that cannot utilize a duplex fiber-optic
link, which means status information (link up and state
of flow control) is not available from the remote node.
In this circumstance, flow control should be disabled
to allow the transmitter to function without the receiver
connected normally.
R/W 0
3
Convert SYNC – For all FPDP operations, set to ‘0’.
When ‘1,’ a SYNC without DVALID is appended after
every SYNC with DVALID from the link.
R/W 0
5 to 4 Reserved None 0
6
SYNC as D0 – If ‘1’ then bit 0 of the data stream is
used as /SYNC in the outgoing and incoming data
stream. If ‘0’ then bit 0 is not used as /SYNC.
R/W 0