Saturday, February 2, 2013

I got the ADC/DAC working!!!

It works!!!

First of all, I rigged up two separate 3.3V power supplies (using a common 5V supply which uses a common 9V supply).  I don't know if this is a good idea or not but it's what I decided to do.  If anyone sees this as a debacle, let me know :)

Then after some experimenting, I finally got the DAC outputting something similar to the analog source.

Just a black screen:

And here it is with video playing:

The next step is to figure out how to stream this out to dual SD cards at 30 megabytes per second! :)


  1. Hey Matt, this is MAME developer MooglyGuy, who did the HLSL shader system in MAME. Would you be willing to share a few seconds' worth of ADC output with me? I've been curious about writing a set of shaders that will decode an NTSC signal from a raw signal capture, but the raw signal capture has been a *bit* hard to find, to say the least!

  2. Hi MooglyGuy,

    What a coincidence. I've been wanting to learn more about making an LCD screen look like an old CRT recently so it looks like we can help each other :)

    Send me an email at and let's talk over email.