What's Stopping You Building Your Next Project with an FPGA? (Please, Don't Blame the Cost!)

I just noticed FPGAs can be used for HDMI output, which would be a very interesting use case: fpga4fun.com - HDMI

But the assembly-like language used on that example website makes me run for the hills.

My hope is something like this: Basic Arduino to output video and sound (https://playground.arduino.cc/Main/TVout ), with the outputs connected to an FPGA that converts it to HDMI.

The ultimate goal is to show images and play mp3s from an SD card on a TV using an HDMI connection.

Would this be possible? (question is to the FPGA experts re the HDMI part - I can handle the Arduino to TV-out and Audio-out part)

-Nico

Have you tried the Arduino TVout? By the looks of that page, it can only be one bit per pixel and big, chunky pixels at that.

The FPGA could do the HDMI part at 25MHz quite easily. You'd need to look at the signalling levels on the HDMI - I'm not familiar with it hardware-wise, but you could probably work with one of the many differential standards that FPGAs provide. It would need a proper PCB.

A better architecture (than having the Arduino struggling to produce the video timing) would be to have a frame store in the FPGA (or a memory attached to the FPGA if there wasn't enough internal RAM going spare) that got scanned and output. The Arduino would then write to it once (setting or resetting pixels) and the FPGA would then deal with refreshing the display. It would be similar to an old CGA graphics card in a PC, except you'd be designing the graphics chip. The interface between the Arduino and the FPGA could be whatever you wanted, but SPI might work well.

Another fun idea, taking a further step back in history, would be to do a vector display. The Arduino could write a sequence of line end-point pairs to the FPGA and the FPGA could draw the vectors on-screen (you might decide to get the Arduino to sort them into a favourable order first). You could then do Asteroids in it's original form.

I'm not sure you've got time to 'decompress' if you're trying to keep up with a pixel rate that's not too far off the clock rate of the processor.

"FPGA rendering a vector image is a challenge - You'll have to use Bresenham's Line and Circle Algorithms or similar."

No, no. Nico will have to implement the DDAs - I was very generously gifting the challenge to him. It's a natural for an FPGA and with your mentoring he'll do it in no time; I'm just providing a little initial creative input.

For myself, I was wondering about getting the A2 version of the FPGA board that Workshopshed shows above and using it for bitcoin mining. Make my fortune in the new digital gold rush. Can't be too difficult, can it? The hash thing looks like it's just simple boolean stuff with a little arithmetic and a look-up or two thrown in.

Hehe, for the FPGA, I think I'll stick with brake light logic for now   Any HDMI project I'll do on the Raspberry Pi!

You do recall the Digisark bootloader can be changed to start instantly ...?

Adding an FPGA to your trailer is just skitting (edit ...the word is SKITE, not sure of the plural).

>Adding an FPGA to your trailer is just skitting

(I had to google that )

Hahaha yeah, but the little bit of logic required is a good introduction to FPGAs. Not sure if HDMI is going to be biting off too much at once.

And yes, I recall the quickstart Digispark. That's also on my list of things to try. Also a heck of a lot cheaper and easier than an FPGA

ps, I did get the trailer logic working somewhat using 4000 series logic chips. It seems to now be down to a timing issue - it works when I power up the chips first and then apply the 2 inputs.

I also looked into replacing the logic chips with transistors. That's a lot more wiring but it appears to be quite doable.

And if that doesn't work, I'll just buy a MacPro to handle it

-Nico

ntewinkel

>Adding an FPGA to your trailer is just skitting

(I had to google that )

Actually I meant "skite"

noun: skite; plural noun: skites

1.  

   1.

   Australian/NZ a boaster.

    

   •  

     boasting; boastfulness.

      

And if that doesn't work, I'll just buy a MacPro to handle it

HAHA ... that's until Apple decide to slow it down ..

Besides some clever person sent you the code, so all you need to do is arrange some diodes to power it.

Mark

Both words make sense LOL. Hilariously boastful

(re DigiSpark)

>Besides some clever person sent you the code, so all you need to do is arrange some diodes to power it.

True, and no timing issue - it won't read the inputs until after it has powered up.

And I guess I'd have to use a couple of DC-DC voltage reducers, but they are tiny. And I think I have a couple of those already.

And I guess I'd have to use a couple of DC-DC voltage reducers

Digispark has an decent sized 7805 regulator, should handle 12v okay.

I have been known to run the power through a 7808 (8v) regulator first.

True, and no timing issue - it won't read the inputs until after it has powered up.

The worst case scenario is the Indicator only ... there will be a small delay before the output contol is activated.

I'd also look at using LED tailights (replace the lamps, or the whole fitting) and you have more options to drive them.

There are some excellent LED lamps I found here. What went wrong

Mark

We did!

One could try to use a suitable RLL scheme.

>I'd also look at using LED tailights

They are LED, which makes them respond much faster, so a small logic delay probably wouldn't even be noticeable in real life.

I'll look into the regulators. Sounds like a simpler approach, thanks

-Nico

>I'd also look at using LED tailights

They are LED, which makes them respond much faster, so a small logic delay probably wouldn't even be noticeable in real life.

I'll look into the regulators. Sounds like a simpler approach, thanks

-Nico