VGA example for Digilent Nexys A7?

[aeon20]

Is there a simple VGA example suitable for the Digilent Nexys A7 that I could play around with?

I suppose I should start with something simpler, but since the board has a VGA output port on it, it would be nice to just see some splash screen just for fun.

[D@n]

Have you seen this article and the core and video simulator that goes with it?

Dan

[aeon20]

1 minute ago, D@n said:

Have you seen this article and the core and video simulator that goes with it?

Dan

Thanks. Is that a link from your local disk? The URL starts with "localhost". Do you have the real link?

[D@n]

Doh!  Yes, that was a local link from a staging area that I use for drafting articles.

How about this link?

Dan

[aeon20]

2 minutes ago, D@n said:

Doh!  Yes, that was a local link from a staging area that I use for drafting articles.

How about this link?

Dan

Nice! Thanks Dan.

I will try to work through that.

In general I was hoping to find an example repository of sorts for simple examples I could run and play around with. Vivado .xpr projects that I can just load up and program onto the device. That should be possible right? Or am I too naive?

Still, thanks very much for the article.

[D@n]

@aeon20,

I do have a rather hardware generic tutorial of fairly simple exercises that will walk you through the design process using your serial port, any buttons, and your LEDs.  By design process, I mean it will walk you through the Verilog, simulating your design, and formally verifying your design--leaving you to then try your design on your board and see if it does (or doesn't) work.

You can find that Verilog beginners tutorial here.

No, it doesn't go through all of the hardware on your board.  Sorry.  I tried to make it very hardware agnostic so that it might apply to more people.  Well, that and to keep me from writing tutorial upon tutorial for every new board.  On the other hand, if you look through my blog, you'll find countless examples of how to deal with other peripherals, as well as discussions regarding how to connect peripherals together into a design.  My github acount should abound with examples, though many of them are board specific and the ones that aren't are rarely complete designs.  Even better, the blog contains several discussions about how to interact with and debug your design while it is on the board.  Feel free to take a look and browse through it.  You are welcome to post any questions you have either here or on reddit if you would like.  Even better, if you like it, feel free to sponsor my blogging work via Patreon.

Dan

[jpeyron]

Hi @aeon20,

For a detailed explanation of how to work with the  VGA port refer to the reference manual for the Nexys A7 here in section 8. VGA Port.

I would also suggest looking at the resource center for the Nexys A7 here.

Digilent learn, FPGA4FUN.com and asic-world.com should have some basic VGA examples. The Nexys 4 has a slightly more complicated example here. 

cheers,

Jon

[kwilber]

I just retargeted the Arty PmodVGA demo to the Nexys A7. It took changing the project part on the project summary to point to the Nexys A7 and a few pin renamings in the constraint file.

If you are interested, let me know.

[jpeyron]

Hi @kwilber,

I really like this VGA demo originally made by a previous co-worked for the zybo. It does a few different tasks like a move box in the lower left of the screen.  The horizontal/vertical black and white(largest change in color) lines also helped determine resolutions usable by the Pmod VGA without having issues. 

thank you,

Jon

[john_joe]

On 2/22/2019 at 5:22 PM, jpeyron said:

Hi @kwilber,

I really like this VGA demo originally made by a previous co-worked for the zybo. It does a few different tasks like a move box in the lower left of the screen.  The horizontal/vertical black and white(largest change in color) lines also helped determine resolutions usable by the Pmod VGA without having issues. 

thank you,

Jon

Hi @jpeyron,

Can I use this Pmod VGA to output VGA video stream from a video source (for instance media player) and output the video to the RGB2DVI IP-Core?

Thank you

[jpeyron]

Hi @john_joe,

Could you please elaborate more on your project.

The Pmod VGA (resource center) facilitates a VGA connector from two pmod ports.  There are a couple of Pmod VGA HDL projects linked on the bottom of the resource center. Here is a non-digilent product that might be helpful.

best regards,

Jon

[john_joe]

Hi @jpeyron,

actually I was a little bit confused as VGA is output only, right?

What I need to do is  something close to this: input video source -> adjust resolution -> RGB2DVI, where input video source has VGA (640x480) resolution and RGB2DVI has 1920x1080 resolution.

Thank you

[jpeyron]

Hi @john_joe,

It is possible to get a VGA input but the hardware needs to be configured for that. The DIR pin is tied to VDD so in this case the Pmod VGA is set to output as shown on the schematic here and here on the IC data sheet. I believe you would need to alter the DIR connection on the Pmod VGA to ground to have it usable for input. So you are aware this would void the Pmod VGA's warranty.   Here and here are a few threads that discuss VGA input as well.

best regards,

Jon

[john_joe]

Hi @jpeyron,

thank you very much for that information. This needs a careful examination.

Thank you.