02-11-2020 12:26 AM
I want to use the IP IBERT on a ZYNQ xc7z045ffg900 to be able to determine the parameters of the transceiver [TXDIFFCTRL, PRECURSOR, POSTCURSOR]
I have connected a SSD on the board. The RX_PLL and TX_PLL are locked, but I have NO LINK status in the Vivado.
What could be wrong ?
Other point :
The IBERT sends a PRBS to the SSD. How can the IBERT understand the answer of the SSD ?
Thanks for any help ...
02-11-2020 07:50 AM
IBERT isn't helpful in this scenario. The SSD would have to be able to send raw PRBS to you. If you use a US or US+ chip you could use in-system IBERT. I'm afraid you would have to use the margin analysis tools to develop your own test for this situation.
02-11-2020 08:14 AM
Thanks for the answer.
One question : if I want to find the correct value for the txdiffctrl pre and post cursor....is it possible to use the ibert and to see the eye on the rx SSD with a scope... with the ibert it is easy to change these values...
02-11-2020 08:34 AM
Hi @sellek ,
you could use xapp1295 to control the TX driver ports in your application directly. You can also do eye scan on the RX side of the FPGA this way.
Of course you can improve the eye on the scope with changing the TX driver settings, but be aware that you do not see how the eye is on the inside of the SSD. It can be quite different. You will measure someplace in the middle of the channel.
02-14-2020 02:55 AM
Thanks for your reply.
One more question :
Is there a rule for the values of the TXPRECURSOR and TXPOSTCURSOR ?
Is it possible for example to have the 2 values equal to 0 dB ?
02-14-2020 03:41 AM
Hi @sellek ,
that would really depend on your channel. You can start with leaving them to '0' and then increase gradually, see what influence they have on their own.