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REGISTER SET
Copyright 2012
6-8
FibreXtreme HW Reference for FPDP Cards
6.1.6 Receive FIFO Threshold– Offset 0x14
NOTE
: The lower 20 bits of this register, indicating the number of 32-bit
words, is limited to showing a 4 MB value. This count value will decrement
and roll over several times when reading data out of a full 128 MB receive
FIFO. i.e. word count will indicate a decrementing count from 4 MB down
to 0. Then will display 4 MB again until final 4 MB of data is read out of
the FIFO.
Field
Description
Access
Reset
Value
19 to 0
Number of 32-bit words in the Receive FIFO.
R
0
20
Rearm Threshold Interrupt – Write ‘1’ to rearm the
threshold register. Writing ‘0’ has no effect.
W
0
21
Data present – A ‘1’ indicates data is present on the
output. A ‘0’ indicates no data is present.
R
0
29 to 22
Reserved.
None
0
31 to 30
Interrupt Threshold – Selects one of the following levels
of the Receive FIFO to interrupt on:
00 – Interrupt threshold set to Receive FIFO Not Empty
01 – Interrupt threshold set to Receive FIFO ¼ Full
10 – Interrupt threshold set to Receive FIFO ½ Full
11 – Interrupt threshold set to Receive FIFO ¾ Full
R/W
0
6.1.7 Laser Transmitter Control – Offset 0x18
Field
Description
Access
Reset
Value
25 to 0
Reserved.
None
0
26
Manual laser shutdown – Set to ‘1’ to shutdown the
laser. Set to ‘0’ for normal operation.
R/W
0
31 to 27
Reserved.
None
0