Color composite video out, is it possible?

neutron7

Well-known member
I am working on a Teensy 4.1 module that is actually a sound synthesizer, but generates a visualization on ILI9341 with the excellent TGX library.

It's using the synthesizer parameters to control some of the graphics parameters, then does some primitive "video effects" (that can look pretty cool with manipulation of alpha blending and "blanking" with a semi opaque box) and uses the state of pixels of the frame buffer as feedback to the synthesizer control. I posted a video on facebook and right away people were asking for a composite video out for analog video synthesis.

If I do it, It should have the same resolution as the ILI9341 (320x240) I don't think its really worth the bother if it is less than that.

I have mostly worked with audio, and dont know much about composite video, except you can apparently get very low resolution monochrome from an arduino with just 2 resistors (!)

Is it even possible? It seems the frequencies needed, even for 320x240 color are too high for any DAC driven by the teensy, I am guessing it needs to copy the frame buffer to external RAM with SPI then ???? to get composite video out.

Another potential problem is that I am already using most of the pins, including SPI0 for the ILI9341 and SPI1 for the audio DAC.
 
Back
Top