07-24-2018 12:39 AM
Hello,
I am designing a board using XC7K325T. I will cascade the DCI of the three HP banks, and I intend to use the two memory controllers to connect the DDR3. Here, I want to put the sys_clk needed for MIG into LVDS to DCI master bank. The Vcco voltage of the bank is 1.5V. I would like to know if there are any restrictions to allow LVDS signals to be input from a DCI cascaded bank for DDR3.
Thanks.
07-24-2018 05:26 AM
You can do like what is in figure 1-70
However, if your signal input common mode and singled ended swing add up such that you will violated the VIN recommendation then you need to AC couple like the figure 1-95.
if you have a 1.5V bank you could make use of LVCMOS15 inputs or outputs.
The best thing to do is put this proposed pinout into a vivado pin planning project and then run a DRC to check it is valid.
07-24-2018 01:24 AM
You can put an LVDS input in this bank because there is no requirement on VCCO.
The only thing is you can't use the on chip DIFF_TERM you will need to terminate it on the board.
Please see this AR
https://www.xilinx.com/support/answers/43989.html
Keith
07-24-2018 05:13 AM - edited 07-24-2018 05:15 AM
Thank you for your quick response.
Do you mean that I can connect like this?
Also, UG586 page 211 states that it is also possible to connect such as figure below.
Is it both possible?
Additional questions.
What are the I/O standards that can be used in a bank using DCI (VCCO=1.5V) ?
Is it possible to use all I/O standards that drive at 1.5V voltage without termination?
Thanks.
07-24-2018 05:26 AM
You can do like what is in figure 1-70
However, if your signal input common mode and singled ended swing add up such that you will violated the VIN recommendation then you need to AC couple like the figure 1-95.
if you have a 1.5V bank you could make use of LVCMOS15 inputs or outputs.
The best thing to do is put this proposed pinout into a vivado pin planning project and then run a DRC to check it is valid.
07-24-2018 05:42 AM