DP83822I: DP83822I

Hi Vijay,

What kind of cable are you using and which connector on the EVM are you connecting it to? How is the cable terminated? Is anything connected at the end?

Do you think you could provide me the register values you are getting using the 10m cable and 30m cable?

Best regards,

Melissa

Thanks for your response,

Cable i am using CAT6 cable with DP83822EVM Evalution board, on the Other end of cable cat6 lan conector mounted, cable other end is open.

I just try to read cable fault location lenth with DP83822EVM using USBtoMDIO sofware to read and write resisters address to get data,

I am following these steps-

1. TDR Auto-run from bit [8] in register 0x0009

2. get result on the Read registers 0x0180 to 0x0184 to get TX and RX peak locations. 

Now please help us what I am missing.

Hi Vijay,

Are you also writing to registers 0x0171, 0x173, and 0x177 and checking to see that the TDR run was successful in register 0x001E?

After you've completed all these steps, what are the hexadecimal results from registers 0x0180 to 0x018A?

Best regards,

Melissa

Hi Melissa,

    Please find attached Results and its screen shot, Hope you find out any issue in my pattern 

TDR_AutoRUN.txt file is open...
Register 001f is: 8000 bit[15] Software Reset (Write)
Register 0009 is: 0100 bit[8] TDR Auto-Run (write)
Register 0170 is: 0E52 CDSCR (Read)
Register 0171 is: C85C CDSCR2 (Read)
Register 0173 is: FF1E bit [15:8] Cable Length Configuration (Read)
Register 0177 is: 189B bit [8:12] Short Cables Threshold (Read)
Register 001E is: 0102 bit[0]Cable Diagnostic has not failed,[1] Indication that cable measurement process is complete
Register 0180 is: 0000
Register 0181 is: 0000
Register 0182 is: 0000
Register 0183 is: 0000
Register 0184 is: 0000
Register 0185 is: 0000
Register 0186 is: 0000
Register 0187 is: 0000
Register 0188 is: 0000
Register 0189 is: 0000
Register 018A is: 0000
End of file.

Hi Vijay,

Note that TDR works only when there is a link-down and there is no disturbance from far end. 

Please give me until Monday to look into this.

Best regards,

Melissa

Hi Vijay,

Please follow one of these two procedures.

TDR Auto-Run:

1. Make sure link is established. This is a prerequisite to run TDR-autorun. 

2. Write to the following registers:

0x0171 = C85C

0x0173 = FF1E

0x0177 = FF1E 189B

0x0009 = 0100

3. Introduce a cable fault (you could unplug your cable at the far end for instance).

4. Read registers 180-18A to calculate TDR

Manual TDR:

1. Write to the following registers:

0x0171 = C85C

0x0173 = FF1E

0x0177 =  FF1E 189B

0x001E= 8102

2. Read registers 180-18A to calculate TDR

Here is an example of a setup I ran using TDR auto-run to confirm it works:

Best regards,

Melissa

Dear Melissa,

       I have tried Both cases manual and auto mode as per your instructions:

After Link establised for cable fault detaction i have unpluged other end of socket.

1- Auto Mode:

Register 0171 is: C85C
Register 0173 is: FF1E
Register 0177 is: FF1E
Register 0009 is: 0100

Read registers 180-18A but no result are come.

TDR_AutoRUN.txt file is open...
Register 0170 is: 0E52

Register 0171 is: C85C

Register 0173 is: FF1E

Register 0177 is: FF1E

Register 0009 is: 0100

Register 0180 is: 0000

Register 0181 is: 0000

Register 0182 is: 0000

Register 0183 is: 0000

Register 0184 is: 0000

Register 0185 is: 0000

Register 0186 is: 0000

Register 0187 is: 0000

Register 0188 is: 0000

Register 0189 is: 0000

Register 018A is: 0000

End of file.

2- Manual Mode:

Register 0171 is: C85C
Register 0173 is: FF1E
Register 0177 is: FF1E
Register 001E is: 8102

Read registers 180-18A but no result are come.

TDR_AutoRUN.txt file is open...
Register 0170 is: 0E52

Register 0171 is: C85C

Register 0173 is: FF1E

Register 0177 is: FF1E

Register 001E is: 8102

Register 0180 is: 0000

Register 0181 is: 0000

Register 0182 is: 0000

Register 0183 is: 0000

Register 0184 is: 0000

Register 0185 is: 0000

Register 0186 is: 0000

Register 0187 is: 0000

Register 0188 is: 0000

Register 0189 is: 0000

Register 018A is: 0002

End of file.

I have tried with 3M, 10M, and 30M cables but all are same results.

Hi Meissa,

       I want to infrom you that TDR Resister still not giving any data. you can check on following result. can you help online screen sharing or something other type, because this project for me very importent and I can not expend more time, also be need to resolve this problem as ASAP.

     TDR_AutoRUN.txt file is open...
Register 0170 is: 0E52
Register 0171 is: C85C
Register 0173 is: FF1E
Register 0177 is: 189B
Register 0009 is: 0100
Register 0180 is: 0000
Register 0181 is: 0000
Register 0182 is: 0000
Register 0183 is: 0000
Register 0184 is: 0000
Register 0185 is: 0000
Register 0186 is: 0000
Register 0187 is: 0000
Register 0188 is: 0000
Register 0189 is: 0000
Register 018A is: 0000
End of file.

Dear Melissa,

As per your instructions I have following up -

1. Link establiesd

2. write the resisters 0170, 0171, 0173, 0177, 0009, i have checked also check 001E resister bit 0 Cable Diagnostic Test Fail is 1.

3. unpluged cable

4. read the resisters 0180-018A 

here i have found 001E resister bit 0 Cable Diagnostic Test Fail is 0(Zero). can you please check why this hapened.

Hi Vijay,

Can you provide a register dump of your PHY after step 2 where you perform the register writes to 0x170,171,173,177 and 009?

Could you also try the manual TDR with the separated steps if you have not already?

Manual TDR:

1. Make sure cable is unplugged at far end

2. Write to the following registers only:

0x0171 = C85C

0x0173 = FF1E

0x0177 =  FF1E 189B

0x001E= 8102

3. Check TDR has completed.

4.  Read registers 180-18A to calculate TDR

Best regards,

Melissa

Dear Melissa,

I have tried TDR manual mode now its working but the results are not perfet for me. I was attached first 3M cable its display 3.02M. now i was change 4M cable,after read the cable lenth the result are same. and also i have tried with 30M cable the result are 29.4, after chage cable lenth with 26M after the result are same as 30M cables.  Can you please check.

I used this calculation given bellow:

• Convert peak 1 location from hexadecimal to decimal. 0x33(hex) -> 51(dec)
• IL = (51 x 0.8621) - 8 = 35.97
• FL = 35.97 + ((70 - 35.97) x 0.01) = 36.31m

Hi Vijay,

Our TDR for the 822 is accurate within approximately +-1m on average. If you take many trials, you should see this accuracy take into effect. 

Best regards,

Melissa

Dear Melissa,

                     I can understand that 822 have limitations for accurate but 822 will not work for our project.

Actually i was looking for tdr which is used for soil moisture. If you can suggest any other TDR based soil testing  module or EVM Board, then I will be grateful to you.