REHOSTABLE CMC FPDP INTERFACE
Copyright 2012
11-6
FibreXtreme HW Reference for FPDP Cards
Signal Name
Signal
Direction
Signal Description
CLK_CFG0
CLK_CFG1
Input
FPDP-TM Clock Configuration
. Controls the FPDP
transmitter clock frequency. The FPDP transmitter clock is
the reference clock (53.125 MHz or 125 MHz) divided by 2,
3, 4, or 6. The clock divisions available for standard cards
are:
CLK_CFG0
CLK_CFG1
SL100
(53.125 MHz)
SL240
(125 MHz)
0
0
26.5625 MHz 62.5 MHz
0
1
13.2813 MHz 31.25 MHz
1
0
17.7083 MHz 41.6667 MHz
1
1
8.8542 MHz 20.8333 MHz
CONVERT_SYNC
Input
Convert Sync
. If /MCU_PRESENT is asserted, this value is
ignored and the internal register value is used. Set to ‘0’ for
all FPDP operations. When set to ‘1,’ a SYNC without
DVALID is appended after every SYNC with DVALID from
the link.
CRC_EN
Input
CRC Enable
. If /MCU_PRESENT is asserted, this value is
ignored and the internal register value is used. Set to ‘1’ to
enable 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.
IGNORE_FC
Input
Ignore Flow Control
. If /MCU_PRESENT is asserted, this
value is ignored and the internal register value is used. 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 when 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.
/INT
Output
Interrupt
. A ‘0’ indicates an interrupt occurred. A ‘1’
