Pmod VGA on Nexys Video

[fp99]

Hi. I am planning to include VGA connectivity to Nexys Video project. In that way, I am considering Pmod VGA and, although on web page says "Pmod VGA provides a VGA port to any board with Pmod connectivity ", I have some doubts with that in a context for Nexys Video project. Pmod VGA need two ports near each one, so JC and JB are the only options. The problem with those ports is that each one is labeled for differential pair signals (Nexys Video reference manual) and I think Pmod VGA work only with single ended signals. 
So my question is, it is posibble to use Pmod VGA with Nexys Video using JC and JB Pmod port?

Thanks in advance.

[JColvin]

Hi @fp99,

You can use the Pmod VGA on JB and JC on the Nexys Video; although the signals on the board are differential they can still be used in a single ended fashion.

Let me know if you have any questions about this.

Thanks,
JColvin

[fp99]

Thanks a lot @JColvin. That really sounds good. Could you please help me? I mean, do I need to set up something differently on constraints file? 
I had a VGA project on Nexys 4 and I planning to use the same files on Nexys Video.

Thanks.

[JColvin]

Hi @fp99,

You don't need to do anything particularly different.

We have a demo for the Pmod VGA on the Zybo Z7 that uses two differential Pmod ports on the Zybo Z7 (https://reference.digilentinc.com/learn/programmable-logic/tutorials/zybo-z7-pmod-vga-demo/start) and looking at the .xdc for the project (https://github.com/Digilent/Zybo-Z7-20-Pmod-VGA/blob/master/src/constraints/Zybo-Z7-Master.xdc) there is not anything fancy done for those differential ports, just the normal naming of the pins to match the name of the signal used in the design.

Thanks,
JColvin

[fp99]

Hi. 
Cool, I didn't notice that demo for other boards, I will definitely check. 
And my last question, as those Pmod ports (JB and JC) are labeled as differential, could be any problem about their routing in the PCB if I use it as single ended? I ask it because I did a little reasearch on internet and I found wire routing could be diferrent for single ended or differential signals. 

Thanks!

[JColvin]

Hi @fp99,

Not particularly for this application. Differential signals tend to be routed such that the pairs are together and of very similar lengths, but if your design does not specifically take advantage of this, it will not matter.

Let me know if you have any questions about this.

Thanks,
JColvin

[fp99]

Great! I understand. That really help me.

Thanks!

[engi]

Did you manage to get that working?