21
Table 16. Register 20 (Extended Control 2)
Bit Name Description
Hardware
Reset
Software
Reset Details
20.15
RO
Link down on no idles 1 = Link lock lost
0 = Link lock intact
0 0 If idle patterns are not seen
within 1 ms, link lock is lost and
link is brought down.
20.14:4
R/W
N/A to SFP Module 00011000110 0001100110 When writing to register 20, be
sure to preserve the values of
these bits. Changes to these
values can interrupt the normal
operation of the SFP module.
20.3 Reserved N/A to SFP
module
This bit must be read and left
R/W unchanged when per-
forming a write.
20.2:0R/W N/A to SFP Module 000 000 When writing to register 20, be
sure to preserve the values of
these bits. Changes to these
values can interrupt the normal
operation of the SFP module.
Table 17. Register 21 (Receive Error Counter)
Bit Name Description
Hardware
Reset
Software
Reset Details
21.15:0
RO/SC
Receive errors Counts errors received
on the 1000BASE-T side
0 0 These bits do not
roll over when they are all
ones.
Table 18. Register 22 (Cable Diagnostic 1)
Bit Name Description
Hardware
Reset
Software
Reset Details
22.15:2
RO
N/A to SFP Module
22.1:0
R/W
MDI Pair Select 00 = Pins 1 & 2 (Channel A)
01 = Pins 3 & 6 (Channel B)
10 = Pins 4 & 5 (Channel C)
11 = Pins 7 & 8 (Channel D)
For VCT results, choose the
twisted pair on which regis-
ter 28 will dsiplay.
