DP83640TVVX Datasheet, PDF (107/137 Pages) Texas Instruments – DP83640 Precision PHYTER - IEEE 1588 Precision Time Protocol Transceiver

DP83640
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SNOSAY8E – SEPTEMBER 2007 – REVISED APRIL 2013
10.4.4 TDR Window Register (TDR_WIN), Page 2
This register contains sample window control for the Time Domain Reflectometry (TDR) cable diagnostics.
The two values contained in this register specify the beginning and end times for the window to monitor
the response to the transmitted pulse. Time values are in 8 ns increments. This provides a method to
search for multiple responses and also to screen out the initial outgoing pulse.
Table 10-31. TDR Window Register (TDR_WIN), address 0x17
Bit
Bit Name
15:8
TDR_START
7:0
TDR_STOP
Default
0000 0000, RW
0000 0000, RW
Description
TDR Start Window:
Specifies start time for monitoring TDR response.
TDR Stop Window:
Specifies stop time for monitoring TDR response. The Stop Window
should be set to a value greater than or equal to the Start Window.
10.4.5 TDR Peak Register (TDR_PEAK), Page 2
This register contains the results of the TDR Peak Detection. Results are valid if the TDR_CTRL[11] is
clear following sending the TDR pulse.
Bit
15:14
13:8
7:0
Table 10-32. TDR Peak Register (TDR_PEAK), address 0x18
Bit Name
RESERVED
TDR_PEAK
TDR_PEAK_TIME
Default
00, RO
00 0000, RO
0000 0000, RO
Description
RESERVED: Writes ignored, read as 0.
TDR Peak Value:
This register contains the peak value measured during the TDR sample
window. If Min Mode control (TDR_CTRL[7]) is 0, this contains the
maximum detected value. If Min Mode control is 1, this contains the
minimum detected value.
TDR Peak Time:
Specifies the time for the first occurrence of the peak value.
10.4.6 TDR Threshold Register (TDR_THR), Page 2
This register contains the results of the TDR Threshold Detection. Results are valid if the TDR_CTRL[11]
is clear following sending the TDR pulse.
Table 10-33. TDR Threshold Register (TDR_THR), address 0x19
Bit
Bit Name
15:9
RESERVED
8
TDR_THR_MET
7:0
TDR_THR_TIME
Default
0000 000, RO
0, RO
0000 0000, RO
Description
RESERVED: Writes ignored, read as 0.
TDR Threshold Met:
This bit indicates the TDR threshold was met during the sample window. A
value of 0 indicates the threshold was not met.
TDR Threshold Time:
Specifies the time for the first data that met the TDR threshold. This field is
only valid if the threshold was met.
10.4.7 Variance Control Register (VAR_CTRL), Page 2
The Variance Control and Data Registers provide control and status for the Cable Signal Quality
Estimation function. The Cable Signal Quality Estimation allows a simple method of determining an
approximate Signal-to-Noise Ratio for the 100 Mb receiver. This register contains the programmable
controls and status bits for the variance computation, which can be used to make a simple Signal-to-Noise
Ratio estimation.
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