DP83867E: Bit Error Rate Test

Hi,

Can you describe what you mean by "it is not working". Did the PHYs link up? Let me know the register writes which you used to enable PRBS on PHY A and reverse loopback on PHY B.

Thanks,

David

We cannot detect any PRBS packet. We tried to write to 0x0016 register the data:

0xD000

0x5000

0x5004

0xD002

May I ask what should be the sequence of writes to enable the PRBS packet?

Hi,

Section 8.4.5 of the datasheet describes how to operate the PRBS. First, link must be up and reverse loopback must be enabled on PHY B. Is link up and reverse loopback enabled on PHY B?

Thanks,

David 

How do you establish a link?

I tried writing:

0x1140 to register 0x00 then I checked that there is still link up

then

I write 0x20 to register 0x16 then the link is lost

Hello,

Link should be established automatically when the ethernet cable is plugged in. You can check this in register 0x1 bit[2]. 

Reverse loopback should be enabled on PHY B, not PHY A. Then PRBS data should be generated and checked on PHY A.

Thanks,

David

Hi,

Link is established between PHY B and PHY A.

When I enabled reverse loopback on PHY B, the link was gone. Also, if I enabled first the PRBS on PHY A, the link was also gone.

Hi,

Please send me a register dump of both PHYs after you have enabled reverse loopback. 

Thanks,

David