09-18-2014 07:50 PM
I have some issues when I use the GTP of the Spartan 6 .
Here is the setup:
In my design , I used the RX Margin Analysis In the horizontal eye margin scan mode of the receiving end .
Now I need to shut the data sampler PLL of the CDR down ,but I don't know how to shut it down ,
there are two singals that I don't understand,they are PMA_CDR_SCAN and PMA_RX_CFG,I don't know how to set them to shut down the PLL of the CDR.
Wait for your help
Thanks in advance
09-19-2014 03:10 AM
09-19-2014 11:27 AM
09-19-2014 09:31 PM
Er,What I want to shut the data sampler of the CDR down mean that I want to keep a fixed delay from starting to receive data to the CDR out , In other words ,i want to know the phase relationship between the local clock and the CDR ,and i had setted the PAM_RX_CFG as the user guide .I had tested and verified much,but,ican't have a expectant consequence.
Are there any other mechanism for the phase of the CDR? I have no ideas!
09-22-2014 11:43 PM
PMA_RX_CFG[10:0] should be tied to all zeros during eye scan.
sweep PMA_CDR_SCAN[6:0] from 0x00 to 0x7F to vary the CDR phase to find out the link margin.
09-23-2014 12:34 AM