LAN8740A Datasheet, PDF (75/136 Pages) Microchip Technology – Small Footprint MII/RMII 10/100 Energy Efficient Ethernet Transceiver with HP Auto-MDIX and flexPWR® Technology

LAN8740A/LAN8740Ai
4.2.16 TDR CONTROL/STATUS REGISTER
Index (In Decimal): 25
Size:
16 bits
Bits
15
14
13:11
10:9
8
7:0
Description
TDR Enable
0 = TDR mode disabled
1 = TDR mode enabled
Note: This bit self clears when TDR completes
(TDR Channel Status goes high)
TDR Analog to Digital Filter Enable
0 = TDR analog to digital filter disabled
1 = TDR analog to digital filter enabled (reduces noise spikes during TDR
pulses)
RESERVED
TDR Channel Cable Type
Indicates the cable type determined by the TDR test.
00 = Default
01 = Shorted cable condition
10 = Open cable condition
11 = Match cable condition
TDR Channel Status
When high, this bit indicates that the TDR operation has completed. This bit
will stay high until reset or the TDR operation is restarted (TDR Enable = 1)
TDR Channel Length
This eight bit value indicates the TDR channel length during a short or open
cable condition. Refer to Section 3.8.11.1, "Time Domain Reflectometry (TDR)
Cable Diagnostics" for additional information on the usage of this field.
Note:
This field is not valid during a match cable condition. The Cable
Length Register must be used to determine cable length during a
non-open/short (match) condition. Refer to Section 3.8.11, "Cable
Diagnostics" for additional information.
Type
R/W
NASR
SC
R/W
NASR
RO
R/W
NASR
R/W
NASR
R/W
NASR
Default
0b
0b
-
00b
0b
00h
 2013-2015 Microchip Technology Inc.
DS00001987A-page 75